UK solar doldrums - Page 1
Forum section: electronics / general

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 11, 2018, 09:32:20 am
content: We seem to be surrounded in clag, the utilities must be rubbing there hands with glee!!My daily output here in Norfolk has been zero for several days and down to 0.2Kw/h average per Kw installed this week, anybody doing any better ?

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: January 11, 2018, 11:20:38 am
content: It's sunny clear blue sky here in Bristol..

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 11, 2018, 04:17:04 pm
content: Quote from: DenzilPenberthy on January 11, 2018, 11:20:38 amDang just have to move house then

author: tggzzz
author_rank: Super Contributor
timestamp: January 11, 2018, 04:22:00 pm
content: According tohttp://www.gridwatch.templar.co.uk/UK solar output peaked at ~2GW today. vs 4GW last Sunday.

author: stj
author_rank: Super Contributor
timestamp: January 11, 2018, 05:14:44 pm
content: i dont think the suppliers are too happy actually.there is a gas shortage right now because a transfer center in Europe went up in flames over the new year.the u.k. is now breaking it's own sanctions buying emergency gas shipments from Russia - and i bet they are not selling it cheap!!

author: metrologist
author_rank: Super Contributor
timestamp: January 11, 2018, 05:39:47 pm
content: why not? supply is tight so double the margins. end consumers will pay for it...

author: tggzzz
author_rank: Super Contributor
timestamp: January 11, 2018, 06:42:28 pm
content: Quote from: metrologist on January 11, 2018, 05:39:47 pmMany individuals are on fixed price contracts, and they change supplier regularly.I would expect that businesses have similar arrangements.

author: stj
author_rank: Super Contributor
timestamp: January 11, 2018, 06:49:48 pm
content: blame the government.they are to blame for alienating the region's biggest fuel suppliers.we could have cheap russian gas and cheap iranian oil,but oh-no - that would upset the stateless shadow-scumbags working with government to carry out petty revenge against country's that are still independent from central banking!

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 11, 2018, 06:57:03 pm
content: Quote from: tggzzz on January 11, 2018, 04:22:00 pmIt's a long time since I looked there and I don't think they used to have solar seperated out, anyway I note with interest whilst solar has dipped badly in the winter Bio is takeing off and I spent a few days this week making compost from all the annual hedge cuttings etc, now theres an ideaprinciple must be similar to brewing beer/wine right ?

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 11, 2018, 07:01:59 pm
content: I didnt think we had a gas pipeline connection to europe BUT we have shutdown one of the feeds from the north sea due to a fracture that will take a good while to repair. Interesting that story about the russian LPG ship unloading at the thames estury, it was claimed to be a transfer shipment only and anyway I thought our bulk LPG import was tother side of country (all locations left vague deliberatly).

author: Simon
author_rank: Unknown
timestamp: January 11, 2018, 07:37:26 pm
content: Quote from: stj on January 11, 2018, 06:49:48 pmLet's keep the politics out please.

author: metrologist
author_rank: Super Contributor
timestamp: January 11, 2018, 07:59:26 pm
content: Quote from: tggzzz on January 11, 2018, 06:42:28 pmI'm not familiar with those kinds of contracts.

author: Simon
author_rank: Unknown
timestamp: January 11, 2018, 08:31:15 pm
content: in the UK you sign up for an energy supply contract that lasts for a certain time. The price is fixed for the durationso if there is a massive hike in price you don't pay it until you need to renew. On the one hand you get a better deal, on the other you are locked to a supplier for at least 1 year. suppliers often offer a discount on your first year to get you hooked and hope you don't move on after the first contract is up.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 11, 2018, 08:51:36 pm
content: I am suprised that nobody so far has added there own figures so I added a survey (wow that was easy) as a teaser, maybe I am verging on being an ECO nut hahaha please join in the fun

author: Simon
author_rank: Unknown
timestamp: January 11, 2018, 09:41:50 pm
content: I'm kicking out about 200W each day but my panels are a bit shaded at the moment being in the garden and with part of a tree in front of them on the ground. The panels are 1.5KW maximum output is usually 1.1KW in the height of summer.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 11, 2018, 09:53:50 pm
content: Quote from: Simon on January 11, 2018, 09:41:50 pmYou must be somewhere sunny like BristolI am getting only 30W peak and like 9W average atm from a 1.1Kw array but hey it's really awfull weather here atm. BTW my energy logger is a bit primative (as it was written by me) and has a threshold of 100W/h before it logs anything, hence reporting zero the last few days!Is that 200W instantanios or watt/hours or watt (pun) ?

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 08:00:41 am
content: that's 200 watts for the day I think I have seen it peak at 150W instant. Oh you have a threshold of 100W? you didn't design the powervault did you ?

author: tggzzz
author_rank: Super Contributor
timestamp: January 12, 2018, 09:45:23 am
content: Quote from: Simon on January 12, 2018, 08:00:41 amWhat do you mean "200W for the day"? If it is for a day then the units should be kWh or Joules (i.e. energy not power).

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 09:52:37 am
content: What do you think ? what would my inverter say? how would I value it and how do the rest of us value it? we are talking standard energy delivery not physics, what unit does the world use to measure generation and consumption of power?

author: tggzzz
author_rank: Super Contributor
timestamp: January 12, 2018, 10:12:33 am
content: Quote from: Simon on January 12, 2018, 09:52:37 amThis is O-level physics; look at any electricity meter: kWh.Watts areby definitionJoules per second, i.e. energy/time. Hence kWh is energy/time*time => energy.In the context of power systems, energy/kWh indicates howmuchuseful work you can do whereas power/kW indicates howfastyou can do it.If you like analogies, in the context of cars kW indicates howfastyou can go, kWh indicates howfaryou can go.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 10:16:22 am
content: Of course it is KWh, in this context it should be unmistakably KWh!

author: tggzzz
author_rank: Super Contributor
timestamp: January 12, 2018, 10:21:26 am
content: Quote from: Simon on January 12, 2018, 10:16:22 amGreenwashers and publicity machines frequently get this wrong through ignorance and/or deceit. It becomes impossible to determine what their statements mean.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 10:23:47 am
content: Yes I'm sure they do but we are talking about a standardised thing using standard off the shelf kit, I'd be very surprised if anyone inverter stated anything different for "KW" than KWh, most people don't even understand the concept of instantaneous energy at which point you end up talking joules and coulombs just for it to make sense in your head.

author: metrologist
author_rank: Super Contributor
timestamp: January 12, 2018, 03:52:11 pm
content: So, you meant 200 kWh / day from your 1.5 kW panel array?I got 70Wh out of my 100W panel yesterday, but there is no load other than an old FLA...

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 12, 2018, 04:03:31 pm
content: Quote from: Simon on January 12, 2018, 09:52:37 amI don't understand your statement?Power=watts or kWEnergy=joules or kW*hr or MW*hr ....

author: tggzzz
author_rank: Super Contributor
timestamp: January 12, 2018, 04:47:41 pm
content: Quote from: Simon on January 12, 2018, 10:23:47 amAny inverter that has a spec in kWh is simply and grossly wrong."Instantaneous energy" has a simpler name: energy.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 04:58:14 pm
content: well no inverters tend to tell you how much KWh the power they are delivering is equivalent to. Obviously this figure fluctuates, no inverter tells you in Ws or any other arbitrary unit. Watts by its very definition is a time related definition so we do standardize on KWh or the amount of KWh the current level of power is equivalent to if sustained for an hour. If you want to talk instantaneous power you either still have to narrow it down to a time frame however small and ridiculous or move to a unit that describes a quantity of energy in joules. The same goes for amps, what is an amp? it's 1 coulomb per second or 3600 coulombs per hour, you can't refer to amps without inferring a time frame.

author: metrologist
author_rank: Super Contributor
timestamp: January 12, 2018, 05:13:31 pm
content: I installed a DC meter that displays volts, amps, W, and Whr. I think I can change it to display Ah as well. Since my panel is 100W, I like the W reading also indicates the % output from the panel.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 05:18:42 pm
content: but your Wh presumably is simply an accumulation of instantaneous measurements that if maintained for an hour will give you the same in W as in Wh, as I have just explained watts is a time based definition so when you say "instant watts" what you really mean is a level of power that if maintained for an hour will give this W as Wh. as a solar panel output varies you can't measure the power delivered now in equivalent Wh and assume it will last for an hour. so multiple instantaneous levels are given that are integrated to give your actual Wh.

author: metrologist
author_rank: Super Contributor
timestamp: January 12, 2018, 05:41:33 pm
content: It did not seem the math was that complex. The W display is the instantaneous output. The Wh accumulates over time, and I suspect the algorithm is probably very linear. I'm sure it just takes a sample of VxA at periods and adds the normalized value.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 05:45:31 pm
content: Yes you are measuring the volts and amps now and assume they remain the same until the next sample, divide the results by the amount of samples per hour and add them together. For example if you take a sample every second you calculate the current watts (Wh) and divide the result by 3600 and then keep doing that every second and add the results together. After 1 hour you will have the average Wh delivered.

author: stj
author_rank: Super Contributor
timestamp: January 12, 2018, 06:04:08 pm
content: i would be very suspicious of meters that show Ah or Wh,they probably take one sample and do some math on it.using the assumption that supply/usage is stable.highly unlikely that most meters actually use bulk sampling unless they activly advertise a logging or graphing function.

author: tggzzz
author_rank: Super Contributor
timestamp: January 12, 2018, 06:46:58 pm
content: Quote from: Simon on January 12, 2018, 04:58:14 pmOf course they don't! That would be as non-sensical as equating "miles" with "miles per hour".It would be entirely reasonable for them to state "you are currently generating x kW, and over the last day you have delivered y kWh", or "you are currently going at x mph and over the past day you have travelled y miles".

author: tggzzz
author_rank: Super Contributor
timestamp: January 12, 2018, 06:55:58 pm
content: Quote from: Simon on January 12, 2018, 04:58:14 pmPower is not a "time related" conceptper se.QuoteEr no. That's what calculus is all about.Energy is the integral of power over time.QuoteEr no. I have a current of 5 amps flowing. There is no need for any timeframe.If, OTOH, you want to discuss how many coulombs have passed when a 5 amp current is flowing, then you have to state a time interval - since charge is the integral of current over time.

author: Avacee
author_rank: Unknown
timestamp: January 12, 2018, 07:36:59 pm
content: As an example of how overcast its been here in North-West England; pretty much all the solar-powered road signs weren't working when I was driving this lunchtime/afternoon.E.g. the happy/sad faces you get as speed reminders ..Does anyone know how much battery capacity those types of signs typically have?

author: metrologist
author_rank: Super Contributor
timestamp: January 12, 2018, 08:02:37 pm
content: Quote from: stj on January 12, 2018, 06:04:08 pmprobably. it's on the order of one of those USB power monitor things, which I have a couple. They show me volts, amps, amp hours, and watt hours. looks like they update about once per second, so that is probably a reasonable enough calculation.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 12, 2018, 08:06:49 pm
content: Quote from: Simon on January 12, 2018, 08:00:41 amUmm no I didnt design the powervault does it have a threshold ?Well the reason I have one is I am in it for the long term so every hour write the accumalated watt/hours to an EEPROM but being mean squash it into one byte, so thats one place a comprimise is made and then the other is the display, I only use a 2x40 char LCD with lots of stuff on it so various energy readings get displayed as 10ths of Kwh. Primative I admit but then I dont want a PC running 24/7 and economics preclude something like a raspi for me anywayI should explain I personally don't rely upon a GTI display as the GTI only get's fired up when the water tank is >64degC and that is where most of the power is used, water heatingActually saves a significent amount of Oil especially in summerI loved the to and fro here about instantanious power vs energy over time, can be confusing at times (inadvertant pun alert)!Hey I got 700Wh (0.7Kwh) today, the clag is lifting a little, maybe I dont have to move to Bristol

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 12, 2018, 08:14:56 pm
content: Quote from: tggzzz on January 12, 2018, 06:55:58 pmThats naughty introducing yet another confusing measureOhh I apologise I see Simon started it

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 08:22:12 pm
content: Quote from: tggzzz on January 12, 2018, 06:46:58 pmerm yes it is exactly like that, miles per hour describes the distance you travel in an hour, again time related, just because you are doing 60mph now does not mean that you will travel 60 miles in one hour unless you keep at that speed, your speed may vary, if you look once at your speedo and it says 60 and you never look at it again and assume you will travel 60 miles in one hour you will find yourself quite wrong.you cannot say that you will produce 200Wh just because your power meter says that you are making the equivalent of 200Wh in that instant no more than you can say that you will travel 60 miles just because now you are traveling at a speed that will take you 60 miles in one hour. if your power output varies and say for 1/2 hour you produce nothing and for 1/2 hour you produce 200W you will produce 100Wh over the hour but not the 200Wh that was shown as the instant equivalent when you happened to look at the meter.even if they say you are generating x KW it is still a figure of equivalence to x KWh if you sustain that KWh over the period of one hour. I'll check what mine says tomorrow.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 08:25:29 pm
content: Quote from: fourtytwo42 on January 12, 2018, 08:14:56 pmW = J*s,A = C*sThere is always a reference to time, if you want to take time out of it you will talk in units of C not A and units of J not W, any measurement of W or A is an assumption over time and can be only taken as an equivalent or verified after 1 hour if it is to be Ah or Wh, we could equally use minutes or seconds but for general transmission, storage and generation we use the hour as the unit of time

author: metrologist
author_rank: Super Contributor
timestamp: January 12, 2018, 08:33:43 pm
content: Well, yeah, but I am using a 60 watt light bulb, and it was drawing 5 amps.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 08:37:43 pm
content: yes and if you run your 60 "watt" lightbulb for 1 hour it will use 60Wh, you could say it uses 1Wm (W') or 1/60W"

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 12, 2018, 08:43:11 pm
content: Quote from: Simon on January 12, 2018, 08:25:29 pmI think the word equivalent is important and it need not be verified, for example if 300W is measured for 30 minutes it is correct to quantify it as 600Wh because that is the equivalent hourly energy production. I have some Kwh displays that update every minute (for example how much energy have I consumed today), its just a ratiometric progression.BTW I see we have added miles into the mix now

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 12, 2018, 08:45:03 pm
content: Quote from: metrologist on January 12, 2018, 08:33:43 pmThen it's a 12V bulb right and every hour it will use 60Wh of energy

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: January 12, 2018, 08:53:01 pm
content: Quote from: fourtytwo42 on January 12, 2018, 08:43:11 pm300W * 1/2h = 150 Wh

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: January 12, 2018, 09:08:59 pm
content: Quote from: Simon on January 12, 2018, 08:37:43 pmWatt the... ?? No.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 09:14:01 pm
content: Quote from: GeorgeOfTheJungle on January 12, 2018, 09:08:59 pmWhy ? when we say 60W we are implying 60 watts over 1 hour period or 60Wh or 216'00 Joules in one hour.Where people can be justified for being pedantic is in defining battery storage where Wh is really a good precisation to make, but in ongoing energy use/generation/flow watts is generally meant in one hour period unless otherwise specified.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 12, 2018, 09:34:54 pm
content: Quote from: Simon on January 12, 2018, 08:25:29 pmwatts are joules per second not times seconds. SoW=Joule/secondAmps are coulombs per secondA=coul/second.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: January 12, 2018, 09:36:21 pm
content: Quote from: Simon on January 12, 2018, 09:14:01 pmNo, "watts is generally meant in one hour period" is wrong. Look, the analogy is as tggzzz has told you before, above, this:power (Watts) = speed (kilometers/hour)energy (joules) = distance (kilometers)So if you travel at a speed of 100 km/h for half an hour you have moved 100 km/h * 1/2 h = 50kmIn the same vein if you consume energy at a "speed" (power) of 100W for half an hour you have consumed 100 watts * 1/2 h = 50 WhWhy would you say that 100 km/h "is generally meant in one hour period"? It makes no sense.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 09:37:03 pm
content: erm yes sorryW = J/sA = C/s

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 12, 2018, 09:38:44 pm
content: Quote from: fourtytwo42 on January 12, 2018, 08:43:11 pm300 watts for 30 minutes is 300 watt* .5 hours =150 watt-hr.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 09:39:58 pm
content: both speed and watts are time related, you have to set a standard unit. 1W = 1J/s but we never intend a watt as the energy (Joules) used in a second but in one hour and probably hence the more accurate but not always used Wh, we would equally say 3600 J/h

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: January 12, 2018, 09:48:37 pm
content: Quote from: Simon on January 12, 2018, 09:39:58 pmBecause Wh is not the same as W/h, 1Wh is not 3600 J/h, it is 3600 J, or, if you prefer, 1Wh = 1W * 1h = 1J/s * 3600s = 3600J.But you're trolling me, no?

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 09:56:03 pm
content: Quote from: GeorgeOfTheJungle on January 12, 2018, 09:48:37 pmErm why would I be trollin you?1W = 1J/s, there are 3600s in 1h, so if you are using 1W for 1h you need to use 3600W as in 3600 J/s, but we usually refer to watts as over an hour period so what might technically be referred to as 1W is actually 1Whif 1W = 1J/s then 1Wh = 3600W = 3600 J/s.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 09:57:28 pm
content: what is the difference between Wh and W/h then ?

author: coppice
author_rank: Super Contributor
timestamp: January 12, 2018, 10:41:47 pm
content: Quote from: Simon on January 12, 2018, 09:57:28 pmWh is a measure of energy - i.e. the first integral of power over time.W/h is a rate of change of power - i.e. the first differential of power with respect to time. E.g. if a load is increasing by 10W every hour it would be increasing at a rate of 10W/h.

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 10:49:14 pm
content: but I was previously corrected and told that 1W = 1J/s which is intended as joules per second not changing by a rate of 1J every second.

author: coppice
author_rank: Super Contributor
timestamp: January 12, 2018, 10:55:13 pm
content: Quote from: Simon on January 12, 2018, 10:49:14 pmA steady sustained load power of 1W means the consumed energy is increasing by 1 Joule every secondConversely a steady sustained generated power of 1W means the produced energy is increasing by 1 Joule every second

author: Simon
author_rank: Unknown
timestamp: January 12, 2018, 10:58:26 pm
content: but no one has talked about changing power levels simply constant power use to use x amount per second is usually referred to as W/s same as m/s is speed not changing speed.

author: coppice
author_rank: Super Contributor
timestamp: January 12, 2018, 11:04:38 pm
content: Quote from: Simon on January 12, 2018, 10:58:26 pmm/s is a rate of change of position = distance/time = speed.W/s is a rate of change of power.You were the one to introduce rates of change of power, by using the wrong units.

author: tggzzz
author_rank: Super Contributor
timestamp: January 12, 2018, 11:12:05 pm
content: It might help Simon to look athttps://cleantechnica.com/2015/02/02/power-vs-energy-explanation/

author: tggzzz
author_rank: Super Contributor
timestamp: January 12, 2018, 11:31:10 pm
content: Quote from: Simon on January 12, 2018, 09:39:58 pmWhy are you concentrating on "standard" time units? Power is not the energy transferred in unit time; power is therateof transfer of energy.Consider that if you have a resistor that is perfectly thermally insulated, then any of the following will increase its temperature by the same amount:1W for 1ms0.25W for 4ms1mW for 1s1MW for 1ns1/pi mW for 1 nanocentury (OK, only a reasonable approximation!)In all cases the same energy is dumped into the resistor.

author: lewis
author_rank: Frequent Contributor
timestamp: January 12, 2018, 11:52:13 pm
content: Quote from: Simon on January 12, 2018, 09:56:03 pmNO! One watt is one watt whether you're using it for an hour or a century. Power is not a time-dependent quantity.One watt for one hour (1Wh) is 3600 joules. Not 3600 J/s.Quote from: Simon on January 12, 2018, 09:56:03 pmNO NO NO! We do NOT refer to watts as over an hour period. A 60W lightbulb uses 60 watts even if I switch it on for half a second.1W is NOT 1Wh. They are completely different units. Watt = power. Wh = energy.1Wh does NOT equal 3600W. 1Wh = 3600J.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 13, 2018, 02:31:54 am
content: Quote from: lewis on January 12, 2018, 11:52:13 pmI suggest looking at a Physics book.

author: Simon
author_rank: Unknown
timestamp: January 13, 2018, 09:06:51 am
content: Quote from: lewis on January 12, 2018, 11:52:13 pmYes I know that 1Wh is not 3600W I was just trying to emphasis the confusion that can arise. but if 1W = 1J used in one second then the definition of a watt is tied to seconds. So yes 1Wh is 3600 joules because to use 1W for one hour you are burning 1J every second and there are 3600 seconds in one hour so you need a joule for each of them to sustain 1W for 1h and as we measure everything in hours you get 1Wh. If you were to say that this thing uses 1W anyone would assume you are saying it is a 1Wh device and yes in an instant, or second it will have 1W going into it.We would do just as well to rate storage systems in joules and state how many joules can be put out in a second, minute or hour. If in seconds then it ties directly with the definition of a W so you just say I am using xW as 1 second is small enough to consider instantaneous but as we meter everything in hours we end up saying Wh

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: January 13, 2018, 12:29:01 pm
content: Good grief, I thought this was supposed to be a technical forumNext time I get pulled over, I will claim to be driving at "22 meters"

author: tggzzz
author_rank: Super Contributor
timestamp: January 13, 2018, 01:52:23 pm
content: Quote from: donotdespisethesnake on January 13, 2018, 12:29:01 pmAlternatively, when somebody asks "how far away is London", you could answer 66mph.

author: tggzzz
author_rank: Super Contributor
timestamp: January 13, 2018, 01:57:02 pm
content: Quote from: Simon on January 13, 2018, 09:06:51 amLet's consider a different phenomenon - heartbeats.What is your heartrate, expressed in beats per minute, bpm? You can add any caveats you feel helpful or appropriate; the answer cannot be exact.I'll give youmyanswer later, but I'm curious aboutyouranswer or answers.

author: lewis
author_rank: Frequent Contributor
timestamp: January 13, 2018, 04:23:08 pm
content: Quote from: ahbushnell on January 13, 2018, 02:31:54 amNot sure what you mean, did I get something wrong?

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 13, 2018, 04:38:39 pm
content: Quote from: lewis on January 13, 2018, 04:23:08 pmYes

author: lewis
author_rank: Frequent Contributor
timestamp: January 13, 2018, 04:45:53 pm
content: Quote from: ahbushnell on January 13, 2018, 04:38:39 pmCare to elaborate?

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 13, 2018, 04:46:22 pm
content: Quote from: lewis on January 13, 2018, 04:45:53 pmLook at what I wrote above.

author: lewis
author_rank: Frequent Contributor
timestamp: January 13, 2018, 04:49:26 pm
content: Quote from: ahbushnell on January 13, 2018, 04:46:22 pmPerhaps you can help me out a bit more than that! Which part of my post was wrong?I suggest reading it again.

author: lewis
author_rank: Frequent Contributor
timestamp: January 13, 2018, 05:03:51 pm
content: Quote from: Simon on January 13, 2018, 09:06:51 amYou said:QuoteI think you're confusing yourself!Quote from: Simon on January 13, 2018, 09:06:51 amNo. A 1W thing is not a 1Wh device:A 1W thing, if left on for 1 minute, uses 0.0167Wh of energyA 1W thing, if left on for 30 minutes, uses 0.5Wh of energyA 1W thing, if left on for 1 hour, uses 1Wh of energyA 1W thing, if left on for 10 hours, uses 10Wh of energyA 1W thing, if left on for 1 year, uses 8760Wh of energyQuote from: Simon on January 13, 2018, 09:06:51 amA 1W load has 1W going into it for 1 secondA 1W load also has 1W going into it for 1/2 secondA 1W load also has 1W going into it for 1 nanosecondA 1W load still has 1W going into it even for 1 picosecondA 1W load also has 1W going into it for 1000 yearsThe power (watts) of a constant load does not change depending on time.The energy (joules or watt-hours) DOES change depending on time.

author: coppice
author_rank: Super Contributor
timestamp: January 13, 2018, 05:26:09 pm
content: Quote from: Simon on January 12, 2018, 09:56:03 pmOne of the very first things they would have taught you in high school science is that units must match across an equals sign, so what you wrote there is bogus. 1Wh = 3600W is the most blatant garbage any 11 year old with an IQ around average should know is wrong, even if they struggle to figure out what is right.Try something that keeps the units in good shape, like:1Wh = 3600Ws = 3600J

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 13, 2018, 05:32:09 pm
content: Quote from: coppice on January 13, 2018, 05:26:09 pmIt's good to know someone is learned in physics class.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 13, 2018, 06:36:20 pm
content: Shame really what I started as I light hearted thread about the poor weather for PVers seems to have become a spat about units by people (going by the survey) who have nothing to do with PV anyway!Maybe this site has a lot of bored people who like nothing better than hijacking threads for a good argument

author: Simon
author_rank: Unknown
timestamp: January 13, 2018, 07:57:56 pm
content: Sorry, seems some do like to pick up and pick holes in things that in the context were pretty self explanatory.

author: tggzzz
author_rank: Super Contributor
timestamp: January 13, 2018, 09:08:22 pm
content: Quote from: Simon on January 13, 2018, 07:57:56 pmPossibly to the writer, but not to me (and maybe other readers).I find statements like "London is 63mph away" or "speed when travelling to London is 150miles" to be confusing.I would have thought a simple (i.e. easily correctable) mistake had been made; I'm surprised there has been all this discussion.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 13, 2018, 09:49:21 pm
content: TGGZZZ I would say to those of who are involved in renewable energy and have a genuine interest it was perfectly obvious.To those who seem to enjoy picking holes in things being said on threads they have nothing to do with and obsfucating the thread for no other purpose than some inane self satisfaction I wish to hell you would firstly desist and secondly bugger off somewhere else!!

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 13, 2018, 09:57:00 pm
content: Quote from: fourtytwo42 on January 13, 2018, 09:49:21 pmSo you don't think people should use watts and joules correctly? It's a very basic concept.

author: tggzzz
author_rank: Super Contributor
timestamp: January 13, 2018, 10:07:12 pm
content: Quote from: fourtytwo42 on January 13, 2018, 09:49:21 pmIf it was obvious then a simple explanation would have avoided all this long discussion. The long discussion indicates that it wasnotobvious to many participants.I am interested in renewable energy, both personally and because it is of vital importance to our children -- I want to see it succeed. To that end I have frequently been toprofessionalmeetings about the subject; the next one is on the 18th January. However Ill have to re-check whether it has been pre-empted by some recent developments.I want to see hard numbers and well-reasoned arguments; like others I am frustrated by the "hot air" and "obfuscation" that often accompanies the subject.I have no idea what a "non-genuine" interest might be.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 15, 2018, 05:51:55 pm
content: I wish to unreservedly apologise for my earlier comments, although they may have been called for the language was intemperate to say the least.

author: tggzzz
author_rank: Super Contributor
timestamp: January 15, 2018, 06:27:48 pm
content: Quote from: fourtytwo42 on January 15, 2018, 05:51:55 pmApology accepted. We all make mistakes, and the test is what happens thereafterNever did manage to convince my daughter I was perfectBesides, sometimes a strongly expressed difference of opinion is entirely appropriate, and we shouldn't betoohung up about slightly offending people. I'm sure we have all met people for whomhttp://dilbert.com/strip/2018-01-08is warranted.

author: stj
author_rank: Super Contributor
timestamp: January 15, 2018, 11:02:06 pm
content: here is an interesting thought.*if* you could gather evidence showing who was behind chemtrail spraying in a specific country,could you drag them into court for a class-action on bahalf of solar users??

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 16, 2018, 05:35:24 am
content: Where's the "my solar setup doesn't have an inverter" option?I only do occasional checks with a clamp meter just to make sure there's no problems with the system. The exact amount of power coming out of the panel is not that important. What is tracked more often are the altcoins coming out of the miners (powered by the solar setup), since that's what my best friend and I really care about.

author: nfmax
author_rank: Super Contributor
timestamp: January 16, 2018, 12:29:51 pm
content: I have a grid-tied inverter on a nominal 1.7kW system. For the last 6 years, I have been logging the generation meter pulses (1 pulse per Wh). While this has not been without hiccups, I have enough data to be able to generate the mean annual generation plot shown. This gives, for each day of the year and each 15 minute interval, the mean power generated by the array and delivered to the grid (i.e. subtracting the inverter losses). The colour scale shown is in kW. Overlaid on this plot is the position of the sun at every moment, in the form of a double contour plot. The green contour lines are elevation, the purple lines azimuth.This shows up the shading which limits the afternoon/evening performance of the array, and the surprising* variability of the weather, even in the summer. Also, how dire the winter performance is at this latitude!From the sun contour plots, you should be able to work out roughly where this array is located...*Only really surprising to people who don't live in the UK.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 16, 2018, 04:23:06 pm
content: Quote from: nfmax on January 16, 2018, 12:29:51 pmVery cool plat.

author: BradC
author_rank: Super Contributor
timestamp: January 16, 2018, 05:03:24 pm
content: Quote from: nfmax on January 16, 2018, 12:29:51 pmI don't live in the UK, but I've spent enough time there to grok it.I will say that is (in the language of my 3 year old) "10 times awesome". It's rare to see such a large amount of data presented in a format that makes the intended view so obvious. It really is 10 times awesome.

author: nfmax
author_rank: Super Contributor
timestamp: January 16, 2018, 06:38:48 pm
content: Quote from: BradC on January 16, 2018, 05:03:24 pmAww, thanks! This kind of data presentation, and wrangling the raw outputs from sensors into something presentable, is more or less what I do for a living these days. I used to be an electronics engineer...

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 16, 2018, 06:57:56 pm
content: Quote from: nfmax on January 16, 2018, 12:29:51 pmWoww that is an astonishing data presentation, so many axis intelegbly displayed, I guess it helps that mother earth has related them all in a nice orderAs for the performance at this lattitude I think we are at the limit's of financial viablity (without subsidy) for DIY systems (IMOP). Am I being stupid or are you about 10 degrees further north than me (I am 52deg) ?

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 16, 2018, 07:04:20 pm
content: Quote from: NiHaoMike on January 16, 2018, 05:35:24 amI do apologize it ran out of options after five and I already put in the easy onesFirst time I tried a poll.Yours is an interesting use of solar energy, I am not sure where it fit's on the saving the planet scale as it's like doing something we don't need to live but them some would argue that keeping me alive is also a waste of energy!

author: nfmax
author_rank: Super Contributor
timestamp: January 16, 2018, 07:08:46 pm
content: Quote from: fourtytwo42 on January 16, 2018, 06:57:56 pmAbout 50.94 degrees N

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 16, 2018, 07:11:45 pm
content: The clag lifted a little today and I got 1.4 EUEU'ts, average for the last week prior to today 0.1 EUEU'ts.Please note an EUEU is an Ebonian Universal Energy Unit apparantly invented to avoid disputes or misunderstandings with there neighbors

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 16, 2018, 07:17:05 pm
content: Quote from: nfmax on January 16, 2018, 07:08:46 pmIsnt that in the English channel or Irish sea(Guess I can't work out the azmuth) ?

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 17, 2018, 02:21:41 am
content: Quote from: fourtytwo42 on January 16, 2018, 07:04:20 pmI do proudly say that the positive impact of just that one solar panel was felt around the world. It is also important to note that because my mining setup is very efficient, it doesn't even use the full output of the panel. What's left over runs my other IT equipment.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 17, 2018, 05:30:57 am
content: Quote from: NiHaoMike on January 17, 2018, 02:21:41 amHow long will it take to pay for it with bit coins?

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 17, 2018, 07:06:44 am
content: Quote from: ahbushnell on January 17, 2018, 05:30:57 amAltcoins are not the same as Bitcoin. That setup (4 smartphones, 2 tablets, and a small ASIC) was actually making a very good profit of nearly $150/month until the difficulty went up. Now it's doing about $45/month.The real gain for me, though, is that all my friends were really impressed with what I do with technology. And that I'm helping to make the world a better place.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 17, 2018, 11:30:49 am
content: Quote from: NiHaoMike on January 17, 2018, 07:06:44 amThats an amazing system and much better than burning fossil fuels to do it as I have heard some are doing on an industrial scale! I found out it's easy to add a 6th option to the vote for non-GTI systems as was mine till recentlyOf course the variations on a PV system are endless I was trying to keep it not too techy

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: January 18, 2018, 03:03:28 pm
content: I do have a couple of panels I use for battery charging, but in a UK January forget it. Only a tenth of summer output.

author: metrologist
author_rank: Super Contributor
timestamp: January 18, 2018, 03:59:54 pm
content: only 78Wh yesterday.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 19, 2018, 12:17:26 am
content: Quote from: metrologist on January 18, 2018, 03:59:54 pmWhat fraction of the year do you get "usable" power?

author: metrologist
author_rank: Super Contributor
timestamp: January 19, 2018, 04:55:17 am
content: don't know, just tossed it out on the patio table a few months ago. I've not been keeping records either, just casual glances at the watt meter - 158Whr today. Solar insolation here is generally 4.5.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 19, 2018, 06:51:24 am
content: Well don't despair entirely in January I have done better the last few day's allowing the weekly rolling average to lift to a dizzying 0.6Units per day so far this weekLong may it continue!

author: metrologist
author_rank: Super Contributor
timestamp: January 19, 2018, 03:29:20 pm
content: I just have it connected to a tired old FLA. I'm not sure if my SCC does the right charge cycles so I may consider monitoring that somehow. I set the terminate voltage to 13.5 and it looks like the SCC just goes to a trickle charge at that voltage. It does let me select one of three difference LA battery types, so it must be doing something different for each one.

author: splin
author_rank: Frequent Contributor
timestamp: January 21, 2018, 06:52:29 pm
content: The OP's sunshine shortage is not an isolated incident.QuoteIt's not just the UK.QuoteFromhttps://www.theguardian.com/world/2018It does highlight the problem with large scale PV in these northern climes; lots of power in midsummer when demand is lowest and b*gger all in winter when it's needed most. And it doesn't help that inter-seasonal storage is hellishly expensive - perhaps the only viable option being synthesised liquid fuels, or possibly gas for which long term storage costs aren't totally out of reach. Unfortunately, I understand the cost and efficiency of the synthesis processes are very poor.The interesting question (to me) is should PV play any worthwhile role in these low insolation regions if renewables are to reach close to 100% of total generation? In winter the only viable source is wind. But if you have enough turbines to cover winter, alongst with short term storage (and FF backup for the occasional one or two week doldrums that can cover much of Europe) then you likely have more than enough wind generation in summer as well - average wind speeds may be lower than winter but demand is also much lower.So why bother with PV? It obviously would be useful supplying power when there is no wind but the economics would be terrible - the viability of PV in the UK at present is predicated on being able to sell all the annual generation at reasonable prices which would not be available for large parts of the year when the wind is blowing. Fixed typos.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 21, 2018, 10:07:56 pm
content: Quote from: splin on January 21, 2018, 06:52:29 pmMy intention was to keep the post to personal or small scale systems as a whole new dimension of issues apply at a national level that I think have been discussed elsewhere. As for wind or water power I am not gifted in location and in any case small scale wind is sadly outlawed by planning requirements for those with a normal sized garden.

author: metrologist
author_rank: Super Contributor
timestamp: January 22, 2018, 08:25:50 pm
content: I also wanted to install a small wind generator. We get a stiff breeze many afternoons, but I'll have to check the regulations on it.My panel is in a poor spot, blocked in the AM by clouds/fog and noon hours by building and tree. I get full sun on it starting about 1pm. I moved it and set it up more perpendicular to the sun and managed a 250Wh day.There is this new global darkening I hear now?

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 23, 2018, 06:55:20 am
content: Quote from: metrologist on January 22, 2018, 08:25:50 pmIf your in the uk the rule is base must be at least as far from any boundary as the tower height plus blade length, that pretty well knackers you from getting up enough to avoid ground turbulance and building/tree shadow in most domestic gardensThats a pretty good result for solar, I got 1.1U yesterday and the monthly average finaly lifted from 0.3U/day to 0.4!!I guess your talking about atmospheric pollution rather than the sun going out

author: paulca
author_rank: Super Contributor
timestamp: January 23, 2018, 07:58:47 am
content: Tehe.I averaged about 120mW power yesterday with the odd spike to 300mW.It's an indoor 50W system though. Saturday was different. I got quite a long period of 15-25W.

author: grifftech
author_rank: Frequent Contributor
timestamp: January 23, 2018, 05:49:08 pm
content: I have solar, but it is a 6vdc system

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 23, 2018, 06:46:30 pm
content: Quote from: paulca on January 23, 2018, 07:58:47 amPerhaps you forgot to draw the curtains yesterday! Good today thoughSome days with my 1Kw outdoor system you would think it's covered in curtains too, maybe 15W if lucky so 1.5%! Don't you count as a no GTI but keep records man in the survey ?

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 23, 2018, 06:48:23 pm
content: Quote from: grifftech on January 23, 2018, 05:49:08 pmIt all counts, mine pushes DC (sometimes a bit chopped) into the hot water tank heater and only converts to AC to use any surpless from that.

author: paulca
author_rank: Super Contributor
timestamp: January 23, 2018, 06:50:47 pm
content: Quote from: fourtytwo42 on January 23, 2018, 06:46:30 pmIt's in my vampire cave, but it's on the daylight side of the curtains.Haven't looked at today's graph, no point. The sun did come out briefly at one point, but the battery voltage moved from 12.1 to 12.2.And my last downstream lithium just low voltage alarmed.

author: paulca
author_rank: Super Contributor
timestamp: January 23, 2018, 06:59:07 pm
content: I know this is UK, but I'm up at 54.5* North. It's only just got to being barely daylight when I leave for work at 8:20am and there was a tiny hint of light in the sky at 5:00 when I left for home.I hate this time of year.Of course in June it's the other way.

author: paulca
author_rank: Super Contributor
timestamp: January 23, 2018, 07:10:40 pm
content: Hmmm. The graph suggests it did okay.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 23, 2018, 07:22:28 pm
content: Hey cool paul, is that a PI ?I collect mine with a PIC in an EEPROM for dynamic display on an LCD and only periodically dump the data to produce a graph on the PC, my last looked like this to the beginning of December and I know from the LCD it got down to 0.3U/day late Dec / early Jan. Horizontal axis is hours, vertical is unit's per day and its rolling averaged over 7 days.Going by the LCD display things are at last picking up again so guess I will do another dump and new graph beginning of Feb.Of course cannot wait for summer, hoping to drive my big outdoor woodsaw from it this year

author: paulca
author_rank: Super Contributor
timestamp: January 23, 2018, 07:59:10 pm
content: Quote from: fourtytwo42 on January 23, 2018, 07:22:28 pmKinda. It's a PI and an ESP8266. This more or less:https://www.eevblog.com/forum/projects/nodemcu-esp8266-rs485-epever-solar-monitor-diy/https://www.eevblog.com/forum/beginners/finally-got-my-first-project-actually-complete/It's moved on a bit. I now have the RRDs automated, 1 once per minute for all data. Graphs are done byrrdgraph.It's a bit "how you doing" at the moment. It all works, but it's kinda like breadboard. I have to log in and run commands to generate graphs. I hope to make it generate them daily and create web pages for each group of data.Graphs could be prettier too. The RRA databases contain data for 10 years and can produce daily, weekly, monthly, yearly graphs or any time window or parameters you want. Multiple data sources can be overlayed, stacked etc. There are web UIs for it, I might resort to one for convenience.

author: Blocco
author_rank: Regular Contributor
timestamp: January 24, 2018, 08:45:31 am
content: Quote from: fourtytwo42 on January 23, 2018, 06:55:20 amI wonder whether the same regulations apply to mobile structures i.e. a mast mounted on a trailer or vehicle.

author: paulca
author_rank: Super Contributor
timestamp: January 24, 2018, 01:07:23 pm
content: Today looks like a cracker over here in Northern Ireland. It's been 5-10% cloud all day so far.https://www.windy.com/?clouds,54.615,-5.713,10,m:fcfafZGDoes anyone know where you can get "sun" power levels on a weather forecast?

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 25, 2018, 07:57:20 am
content: Quote from: Blocco on January 24, 2018, 08:45:31 amI assume you mean pseudo mobile as in stuck in your garden then yes and frankly the guy's would have to be at a greater radius than a road vehicle. If you mean a 20ft mast on a road going vehicle I think your chances of getting down your road before being pulled up by the police are nill.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 25, 2018, 08:01:35 am
content: Quote from: paulca on January 24, 2018, 01:07:23 pmNot seen it, I just go by the cloud cover given inhttps://www.netweather.tv/weather-forecasts/uk/today/2520~((%20Belfast%20))#forecastfor example and your place doesnt look to good today while mine is coolThanks so much for the links to the software, makes my efforts using GnuPlot look primative!

author: paulca
author_rank: Super Contributor
timestamp: January 25, 2018, 08:11:57 am
content: Quote from: fourtytwo42 on January 25, 2018, 08:01:35 amNo problem. The easier solution is to install a linux distro's version of "Cacti" and hack in a datasource for whatever you want. Usually just a script based one. Cacti takes care of the rest, although it can be a bit fiddly at first understanding the different names for things.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 31, 2018, 03:48:13 pm
content: Things are slowly picking up here in the new yearI just dumped this primative chart in units/day averaged over a week, bottom scale is hours.

author: paulca
author_rank: Super Contributor
timestamp: January 31, 2018, 05:04:44 pm
content: Quote from: fourtytwo42 on January 31, 2018, 03:48:13 pmI'm going to try and produce some graphs to work out if my system is consuming more internally than it's actually producing on grey daysYes it's that bad here. Monday was a cracker though. Tuesday and today, rubbish. Days are getting longer though.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 31, 2018, 07:51:37 pm
content: Quote from: paulca on January 31, 2018, 05:04:44 pmI have two things powered by the grid in the solar system (running 24/7), one is the data logger and the other is the grid import/export power measurer and together they consume 1100mW.I am guilty of using lots of cheap USB power supplies around the house for powering gadgets and most of them consume >500mW each with no loadOne day I might install a low power low voltage buss (say 12) just for the gadgets! I used to have some guided missile wire (almost invisable) that would have been ideal but it vanished completely in various house moves

author: nfmax
author_rank: Super Contributor
timestamp: February 07, 2018, 08:42:58 pm
content: 3.842 kWh today! The sun is coming back!

author: paulca
author_rank: Super Contributor
timestamp: February 07, 2018, 09:15:35 pm
content: Nothing today. Anything I did get got used by the charge controllerDoesn't look like we will get sun until Friday and even then it's a few hours. My panel only produces a decent amount between 10am and 1pm. The joys of having a panel in a window.Still, it's meeting demands for charging USB devices, running my bench supply and running my headphone amp. Basically anything I can run off 12V battery on my desk. I can even run a 3W LED lightbulb or two when I feel like it.I call it NanoGen.

author: nfmax
author_rank: Super Contributor
timestamp: February 16, 2018, 08:31:26 pm
content: 3.898 kWh today

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 17, 2018, 07:09:30 am
content: Quote from: nfmax on February 16, 2018, 08:31:26 pmYeyy the sun is coming back, my average weekly finally hit 1Kwh/day after a winter low of 0.3Kwh/day from a 1Kwe array. How many Kwe is yours, 4 ?

author: paulca
author_rank: Super Contributor
timestamp: February 17, 2018, 09:27:03 am
content: I also got a load this week. All my batteries are topped up. Each evening I end up running the battery down to 12.1 or 12.2 and come home to it up at 12.6 or 12.7. I might let it fully charge some day, but I expect in summer that will easy.So far I've hit a peak, from a 50W panel, of 28W. For a panel behind a window this has to be good.

author: nfmax
author_rank: Super Contributor
timestamp: February 17, 2018, 01:50:55 pm
content: Quote from: fourtytwo42 on February 17, 2018, 07:09:30 am1.71 kWp, according to the installation certificate.

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 17, 2018, 04:26:25 pm
content: Wowww thats a really good result. Mine is 1060We/p but at this time of year I am not able to use all of a good day as the boiler is still heating the water a bit due to central heating and I don't use enough electricity! Tried today by shredding loads of compost and using the hedge trimmer

author: paulca
author_rank: Super Contributor
timestamp: February 17, 2018, 04:48:33 pm
content: Solar energy storage is the future. I wonder if micro-hydro works if you don't like batteries. Probably not

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 17, 2018, 04:55:11 pm
content: Quote from: paulca on February 17, 2018, 04:48:33 pmHey cool idea, I actually have a stream with almost zero fall/head, I could build a pond further up the garden but I think the frost will be a problem as well as a dual purpose pump/turbine! Never mind I continue to use the grid as my battery! To me it's all about contribution, like that retailer slogan "every little helps"

author: nfmax
author_rank: Super Contributor
timestamp: February 23, 2018, 05:31:11 pm
content: And a whopping 5.264 kWh today! Cold, sunny & cloudless

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 23, 2018, 08:19:18 pm
content: Wowww well done, weather not so good here so just 0.8Kwh todaybut over 2Kwh couple of days ago

author: nfmax
author_rank: Super Contributor
timestamp: February 24, 2018, 05:49:13 pm
content: Today we got 5.396 kWh. One more sunny day forecast, then cloud & possible snow

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 24, 2018, 06:21:37 pm
content: 1.9Kwh today on a 1Kw array, still held back by terrible Fronious software, drops out all the time and has 5 minute restart delay but hey it will be in the bin soon I hopeso most of my load is water heating atm. Your figures really are very good sure your really in the UK hahaha

author: paulca
author_rank: Super Contributor
timestamp: February 24, 2018, 09:11:49 pm
content: I need to move house and get better panels.Today I started with 12.0V on the battery and ended with 11.9V. Took more to run the charge controller and 485 Wifi monitor than I actually got from the sun. It was a pretty dark and miserably day though.

author: John Heath
author_rank: Frequent Contributor
timestamp: February 25, 2018, 08:22:32 am
content: I have a solar power system. It is home brew with a 2 by 2 inch solar cell and a nicad power storage capacity of 200 ma at 1.2 volts. This power is automatically used at night to light a single white IR type white LED , 1 volt 20 ma. The reason was to back light an outside temperature gauge so it can be seen at night. All went well for the winter with 3 to 4 hours of a solar powered back lighting. However in the summer the LED attracted small flies. This did not escape the attention of the local spiders who soon set up camp on my solar power system. Not sure what they did but the white LED no longer shines at night. Easier to build another as all the part are in a 4 dollar back yard garden light sold in most stores. I guess my point is even micro solar power systems have their problems. The best laid plans...

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 25, 2018, 09:25:43 am
content: Quote from: paulca on February 24, 2018, 09:11:49 pmJust start by getting it outside and faceing southSimple wooden frame on the ground and use the battery to weight it down ?

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 25, 2018, 09:29:47 am
content: Quote from: John Heath on February 25, 2018, 08:22:32 amThat's so funny I have thousands of spiders BUT they refuse to make home in the solar converters, maybe being chopped up by fans, roasted on heatsinks, burnt on 500V terminals and deafened by shreiking 25Khz ferrites doesnt suit them

author: paulca
author_rank: Super Contributor
timestamp: February 25, 2018, 09:43:45 am
content: Quote from: fourtytwo42 on February 25, 2018, 09:25:43 am1st (and 2nd) floor apartment. If I carted it up stairs I could hang it out the skylight onto the roof, but with no way to fix it in place without consulting the landlord it would be "under supervision" on calm days only. I might do this the next blue sky day to see if I can get the full 50W.In it's south facing window the most it has produced so far is around 28W.The charge controller hasn't even clocked to 2kWh and it's been running for over a month now.

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 25, 2018, 04:33:14 pm
content: Quote from: paulca on February 25, 2018, 09:43:45 amAhh ok, well I hate to suggest polishing the window both sides as maybe you have already done that but I did see someone using baco-foil reflectors with a small panel to improve output!

author: jc101
author_rank: Frequent Contributor
timestamp: February 25, 2018, 06:31:31 pm
content: Best day of the year today, managed to get 9.99kWh from our 2.57kW array.Strategic use of dishwasher, washing machine, and drier has meant that only ~20% was exported today.

author: paulca
author_rank: Super Contributor
timestamp: February 25, 2018, 06:38:27 pm
content: I had an interesting experience today. It might be hard to explain... or you will understand straight away and berate me for not knowing....When the sun is directly in front of the panel around noon (through a window), leaning it back slightly to "look up at the sun" and get a more direct perpendicular angle, produces a little more current. This seem intuitive and obvious. We are talking about producing 23W and leaning to back 10 degrees produces 25W.However at 2pm when the sun is off to the side a little (not much) the output fall dramatically. From around 25W to around 6W.I found this annoying, so I played with the position and found that pointing the panel directly at the sun produced very little output - 5-7W.Pushing the panel tight against the window and completely off axis with the sun produced the highest output. 20W.I conclude that the insulation through a window is HIGHLY dependant on the angle of incidence between thepaneland thewindowand less on the angle of the sun and the panel.EDIT: I think the relationship is the intuitive; "on axis" to the sun is better. However, loss through the window at an angle is huge, so an off axis panel produces more output than an on axis panel with an angular offset trough glass. Outdoors the window is removed and an on-axis panel alignment will always win.

author: John Heath
author_rank: Frequent Contributor
timestamp: February 25, 2018, 06:49:01 pm
content: Quote from: fourtytwo42 on February 25, 2018, 09:29:47 amElectrocution or the nasty indifference of a spinning fan is a little much. We all have to get by in life and I have nothing against spiders. I just want them away from the micro solar power plant. I am liking the sounds of the shrieking 25 KHz ferrite , pun intended. Bats hunt insects so I imagine most insects would find the ultrasonic chirps of a bat alarming. A low powered PIC programmed to make the ultrasonic sound of a chirping hungry bat every 60 seconds. This should keep then too nervous to call this home for a good 12 inches around the solar power system. Somewhat like hocks near an airport to keep the birds away. Micro solar power plant 2 should have bat simulated sounds. This would be a chance to home some skills in PIC low power applications. With the addition of smart PIC the micro solar power plant could reach out into other energy sources , a tiny 2 inch fan for those windy days.

author: paulca
author_rank: Super Contributor
timestamp: February 25, 2018, 06:57:52 pm
content: Quote from: jc101 on February 25, 2018, 06:31:31 pmWhile I understand that batteries for that kind of through put are difficult. Does it not make you think that some sort of storage solution would be beneficial? I know that I, like many people, are out during the day 5 days a week. Power requirements for half the year (at these latitudes) are minimal when you are out at work (The whole "solar power day").For Northern Ireland at 54* North solar without storage would be next to pointless. Of course the investment companies don't see it that way. They see the advantage. They charge you a meer deposit of a few thousand pounds and put 3kw of panels on your roof. You get to use whatever you want and the rest gets exported to the grid. But the market is young professionals who are out all day. They think they are doing their bit for the environment, but really they are doing their bit for the investment banks who fund their panels.The panels might produce 10kwh that they don't use at a rate of 3p. But you get none of that on these schemes. It apparently works out that it's a money maker for the investment banks who have sold decades of energy futures based on it... then dumped the products to the next investor.On such schemes you are forbidden to install a storage solution as it will directly impact the investors profit...... or I am exaggerating and the reality is less severe....

author: ahbushnell
author_rank: Frequent Contributor
timestamp: February 26, 2018, 02:13:41 am
content: Quote from: paulca on February 25, 2018, 06:38:27 pmAs the sun get's lower in the sky the atmosphere blocks more solar radiation.

author: paulca
author_rank: Super Contributor
timestamp: February 26, 2018, 08:02:32 am
content: Quote from: ahbushnell on February 26, 2018, 02:13:41 amYes, that accounts for the drop from 25W to 20W, but not the drop to 6W which happens pretty quickly over the space of 30 minutes.

author: capt bullshot
author_rank: Super Contributor
timestamp: February 26, 2018, 08:23:22 am
content: I've seen this thread only now - I'm keeping track of my solar power by some homebrew data logging stuff.The public interface is here:http://wc.wunderkis.de/webcam1.php(sorry, it's German labeled), the last chart is the kWh / installed kW of my solar panels.So got a few really nice and sunny days after very dark December and January.For my purposes (not available to the public), I've got more charts, like these telling me the amount of produced solar power and the ratio to power used by the household (daily for the last 30 days and over one year):

author: paulca
author_rank: Super Contributor
timestamp: February 26, 2018, 08:33:57 am
content: Yah! Another RRD Graph user

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 26, 2018, 07:49:41 pm
content: Quote from: paulca on February 26, 2018, 08:02:32 amI am wondering if this has something to do with diffraction through the glass or special glasses often used in double glazing (high iron content) is that possible ?

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 26, 2018, 07:53:18 pm
content: Quote from: capt bullshot on February 26, 2018, 08:23:22 amOK I can see my primative graphs with GNU look entirely out of date wrt you guy's so when we hit the end of the month and I suck some fresh data from the logger I will have to try RRD too

author: ahbushnell
author_rank: Frequent Contributor
timestamp: February 26, 2018, 10:55:31 pm
content: Quote from: paulca on February 26, 2018, 08:02:32 amThe reflection coefficient on glass (or anything) changes with the angle of incidence by Fresnel's Law.https://www.brown.edu/research/labs/mittleman/sites/brown.edu.research.labs.mittleman/files/uploads/lecture13_0.pdfI added a plot for glass of index 1.5. Transmission starts to drop off around 50 degrees from normal. Not sure the window reflection accounts for what you see. Low angle sun going through thick air and more water vapor?This is interesting.http://www.ecgllp.com/files/3514/0200/1304/2-Solar-Radiation.pdfAndy

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 01, 2018, 04:50:53 pm
content: Things are definetly improving as the days get longer again, here is my weekly average output to date in Kwh/day, horizontal axis is elapsed hours (500hrs = 21Days) still in GNUplot

author: paulca
author_rank: Super Contributor
timestamp: March 01, 2018, 07:08:38 pm
content: Quote from: ahbushnell on February 26, 2018, 10:55:31 pmIt could have been. What surprised me was how sharp it fell. I had the little query monitor open in a terminal on my desktop. I could see the bright sunshine coming through the window (well a gap in the curtains), but the Panel Amps was really low. So I went to investigate as it had been sitting happily around 1.8-2.0 amps from 10am through to 2pm. Yet at 3pm it had fallen to like 0.5A. Pushed the panel back up to the window and it went back up to 1.5A.I've left it against the window, I might lose 10% or so in the morning when the sun is bang on, but it should keep the watts higher further into the afternoon.

author: nfmax
author_rank: Super Contributor
timestamp: March 02, 2018, 05:26:23 pm
content: And today we had - nothing at all! Not an electronic sausageClearly I need to add some snowlar panels

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 02, 2018, 06:05:12 pm
content: Quote from: nfmax on March 02, 2018, 05:26:23 pmTo right but suprisingly mine have been hauling in up to 250W through 4 inches of white stuff!! (25% peak power).Actually I seem to remember reading long ago that the poly panels I have are better at diffuse light than amorphous even though the latter have a bit more efficiency in full sun.

author: paulca
author_rank: Super Contributor
timestamp: March 02, 2018, 06:16:23 pm
content: I lost energy today. Another day costing more electrons running the charge controller than the panel produced.

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 02, 2018, 06:22:57 pm
content: Maybe pay some attention to the thirst of this charge controller, I spent a lot of time when I first started reducing the power needed to run converters to the barest minimium so my pickup light level was as low as possible. Not sure how much I really gained from it apart from the design excercise and being able to see my converters hang on in the evening right down to a measly 1 watt

author: paulca
author_rank: Super Contributor
timestamp: March 02, 2018, 07:58:01 pm
content: I measured it. 50mA with pulses of 75mA when the ESP8266 fires the data out on the Wifi every 5 seconds. <-- Should drop that back to once a minute.Doesn't sound like much but when you multiply it (avg. 60mA) out to 24 hours, it's 1.4Ah.I switch the whole system off at night, so at the moment it's probably only about a third of that.

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 03, 2018, 09:27:22 am
content: One idea, are you using a switching or linear regulator to get from your battery voltage (13.8V?) to your mpu (3V3?) a switcher could save you a lot of power if it's reasonably efficient and I expect Ebay is loaded with the things ready built

author: paulca
author_rank: Super Contributor
timestamp: March 03, 2018, 09:58:33 am
content: Switching MPPT DC/DC. 50mA/75mA isn't an awful lot to run a charge controller, it's LCD (no backlight) a RS485 to Serial adapter and an ESP8266 and a wifi client.According to the controller it's efficiency is suspiciously near perfect. If its showing panel power of 6.1W the battery charge watts show as 6.1W.Still have to shorten the panel cable, or replace with some mains flex.

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 03, 2018, 03:51:40 pm
content: You just told me that was the consumption you measured sorry if I was wrong but the mpu supply doesnt need to have anything to do with MPPT surely it can just run off the battery I thought.Maybe the reselution of measurement is such that it's internal consumption just doesnt show.So your cables are still acting as room heaters ?

author: paulca
author_rank: Super Contributor
timestamp: March 03, 2018, 08:58:28 pm
content: YesI was in homebase and lifted a 5 meter bundle of 15A mains wire, but set it down again when I read the price. £12.99. Ouch.I'll order some on ebay, I have run out of "kettle leads" to salvage. When you are looking for other cables there are fecking dozens of them, but when you are looking for power leads, you can't find any for USB leads and wall wartsThe way it goes.I mentioned the MPPT, DC/DC bit in case you thought it was a PWM duffer or linear regulator.Yes the controller and monitor runs off the battery, but it doesn't seem to show internal load. It registers watts and amps to 2 decimal places though, so it should. However it does other weird things too.Over RS485 if you have 1Amp of solar, and 0.5Amp of load it will show:Panel current: 1ABattery current: 1ALoad current: 0.5AThere is a separate register for "Charge Current" which would read 0.5A. It seems the battery sense is before the load gets split off. On the panel LCD it does the sums though and subtracts the load from the battery current to be fairer. Over RS485 you have to remember to do it yourself.

author: Zero999
author_rank: Super Contributor
timestamp: March 03, 2018, 11:31:27 pm
content: I believe solar panels are more efficient, at lower temperatures, because the voltage drop of the diode junction increases.It's been cold in the UK recently, so has anyone noticed an increase in output, above what would be expected for the increase in day length? I suppose it's been cloudy recently so may be not. The MPPT also changes with temperature, so the inverter would need to monitor the temperature, in order to increase the efficiency of the panels, when they get cold.

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 04, 2018, 09:14:53 am
content: Quote from: paulca on March 03, 2018, 08:58:28 pmAhh sorry of course it's all one lumped in unit with the charge controller, I had an idea you had a seperate MPU that you were powering. Seems like you are slowly learning this things quirksI agree on the cables I was looking for a straight Ethernet the other day and all I could find were crossovers that are normally like rocking horse poo!!

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 04, 2018, 09:28:57 am
content: Quote from: Hero999 on March 03, 2018, 11:31:27 pmOther way around a silicon junction voltage reduces at -2mV/degC.Quote from: Hero999 on March 03, 2018, 11:31:27 pmThe whole point of MPPT is Tracking, so it adapts to changes in the maximium power point all by itself, this is the advantage of MPPT compared to some who claim constant voltage is adiquite!Interestingly the plot thickens, when I checked the spec of the panels I use (enclosed) although Voc indeed has a negative coeficient Isc has a small posotive one but the overall Pmpp has a negative one!

author: paulca
author_rank: Super Contributor
timestamp: March 09, 2018, 10:10:28 pm
content: How quickly things turn around.I had resorted to mains power for charging my devices for a week. Ran the solar battery down to 12.0V and watched it drop running just the charge controller to 11.8V over a week of snow and heavy cloud.Wednesday this week the sun peeked out once of twice and it rose back to 11.9VThursday the sun graced us for a few hours through broken cloud and it rose to 12.3VToday it was sunny blue sky from 7am till 4pm and I came home to 12.8V, damn near full charged.

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 10, 2018, 09:53:19 am
content: Quote from: paulca on March 09, 2018, 10:10:28 pmMaybe we can go into business selling the met office historical data to improve there forecastsNot to bad over here in the east but cloud cover at least every other day so averageing 1Kwh/day (from 1Kwe) ATM

author: poida_pie
author_rank: Regular Contributor
timestamp: March 13, 2018, 01:31:50 am
content: Here is my system's data from 1/1/2016 to date. I supply the house with some of it's energy needs from a 3kW solar array. I have a 18kWhr battery, and only cycle it about 6 kWh a day. Sometimes I can run large loads on solar AND charge the battery which explains the 15kWhr peaks in inverter energy.Early Sept '17 the inverter died, hence zero energy during that period. Location is Melbourne, AUS.You can see the seasonal dips and peaks.

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 18, 2018, 11:12:52 am
content: Hi Poida thats a great systemSure wish I was in Melbourne except maybe the hurricane! Do you have a make & model for the inverter or is it a DIY ?I woke to ZERO POWER today, seems the panels are part snowbound and although the inverter happily reports zero watts it doesnt want to start and guess what, in minus4C I dont want to go out there with the laptop and pic debugger to ask it why hahahaMost likely there is just enough voltage for the mpu to run but the 12V isnt solid enough (it checks that to ensure there is enough to turn the mosfets hard on).

author: paulca
author_rank: Super Contributor
timestamp: March 18, 2018, 12:56:35 pm
content: Hot water hose?

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 18, 2018, 01:17:07 pm
content: hahaha now if I lived on a ship I might just have one of those to handmaybe this is where keeping your panels indoors in the warm is a winnerEDIT interestingly just used summer washer (sponge on long stick) to wipe snow off lower 3rd of panels and output immediatly lept up to a respectable 100W or so. Lesson is oriantation of shadow is important to whether the shading diodes work or not!!

author: Zero999
author_rank: Super Contributor
timestamp: March 19, 2018, 10:33:34 am
content: Quote from: fourtytwo42 on March 04, 2018, 09:28:57 amExactly, as the temperature rises, the voltage drops, so lower temperatures should yield higher a efficiency.As long as the solar panels aren't covered in snow, the colder it is, the more power you'll get, for the same amount of sun.What's it like today? Where, I live most of the snow has now melted, although it's still near freezing.

author: woody
author_rank: Frequent Contributor
timestamp: March 19, 2018, 12:07:01 pm
content: Over here (Netherlands) today it's completely cloudless with an outside temperature of 3 deg. C. The maximum power I saw today from our 30 panels (one of which is broken) is around 6300W, average inverter temperature is 35 deg C, average panel temperature is 25 deg. C. A total of 7200Wp is installed with (not so efficient) microinverters.In my experience clear days in spring (March/April/May) always have higher yields than clear days in summer. Monthly yields are higher in summer due to more fair weather and longer days, but record days are always in the spring.I think this is not only due to lower panel temperatures but also because the air contains much less water on fair cold days. What also helps is the fact that my panels are at angles that work better in spring (45+55 degrees).

author: woody
author_rank: Frequent Contributor
timestamp: March 19, 2018, 04:45:15 pm
content: And indeed, today's total generation is at an all -time-high of 38.1 kWh. Now I wish I had replaced the one broken microinverter earlier....

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 19, 2018, 06:17:13 pm
content: Wowww thats amazing around 7.2Kwh per Kw installed!!I made 2.8Kwh per Kw installed today a record for this year so farMine is lower partly because I dont export so everything is used in the house.Peak power today was 0.9Kw per Kw, this depends on the load offered at the best time of day, it sometimes hits 1.05Kw.I agree on spring sunshine, again my panels are about 52degrees that also happens to be my LattitudeClearer air, no high haze this time of year and no airborn dust from the feilds, as for pollution the surrounding pig farms dont seem to affect solar as much as my nose hahahaAbout the same conditions here Heroand yes the Axitec panels Pmpp increases 0.45% every degree C lower.

author: woody
author_rank: Frequent Contributor
timestamp: March 20, 2018, 08:14:39 am
content: I'm not sure how you arrive at 7.2kWh/kW installed. PVOutput tells me 5.3kWh/kW which seems more accurate. Still amazing to me; our yearly average hovers around 2kWh/kW

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 20, 2018, 09:47:50 am
content: Quote from: woody on March 20, 2018, 08:14:39 amNeither am I and I cannot now figure out how I arrived at such a number, many thanks for the correctionMy annual average is just about 1.1Kwh/Kw but that includes downtime for tinkering, holidays when it's switched off and as explained earlier the fact that I don't export. Your figures show me what is possible, may I ask your lattitude and oriantation ? Mine is 52,35N and SSW(235deg) almost on the meridian, roof angle 51deg.

author: woody
author_rank: Frequent Contributor
timestamp: March 20, 2018, 03:13:59 pm
content: Our position is 52.44N 4.40E, give or take a couple of miles. Orientation is 190 deg. 16 panels under 55 deg and 14 panels under 45 deg. We have lots of part-time shading, hence the micro inverters. The system is net connected and always on. Except the one inverter that broke down last March and still is not fixed by me

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 20, 2018, 04:28:01 pm
content: Were almost identical, very interesting to exchange information, fortunatly I dont have any serious shading. I have wondered about a steerable array to pick up the rising sun but from what I could estimate the power gain would not justify it. Interesting issue with micro inverters having to scamper up the roof to replace them but as you say good for heavy shading.

author: woody
author_rank: Frequent Contributor
timestamp: March 20, 2018, 05:16:48 pm
content: Are you east or west in the UK?Microinverters are a bit of a tradeoff imo. Using them means (apart from a number of other advantages) that if one stops, the rest of the system keeps working. When your central inverter fails, nothing works. The downside is indeed that for every failing inverter you have to go on the roof, remove the panel, replace the inverter underneath and reinstall the panel. Which is a b*tch. So it gets postponed as long as possible.I use Enecsys inverters.These inverters were sold with an operating life expectancy of greater than 25 years and came with a 25 year warranty. They were designed to be more or less unbreakable due to not using electrolytic caps inside. I got them in early 2013 and then Enecsys became insolvent in early 2015. So much for the warranty. Out of the 30 inverters on my roof I have 2 broken so far. I'm kinda hoping that these 2 are the early failures on the left side of the bathtub curve

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 21, 2018, 09:23:53 am
content: East 0,48E in East Anglia so quite close to the NetherlandsAs for microverters IMOP the cost is very hard to justify dramatically increasing the payback time of the system but for many that is not a concern. Also for me I wanted to build my own converters for water heating so microverters were not an option. I have see many blown single inverters on Ebay and many lurid stories about failures so I guess the commercial units are built for a price. I had a few mosfet failures in the early day's caused by turning on the immersion heater switch with inadiquate gate voltage but since then no more problems.Shame about Enecsys they had a good idea but I guess the real world performance was not up to the marketing hype hence the companies failure.Beutiful sunny day here today so out potato planting

author: woody
author_rank: Frequent Contributor
timestamp: March 21, 2018, 10:36:10 am
content: We indeed are at comparable latitudes. Nice for comparison.I'm still not decided about those micro inverters. They do solve the 'bad panel in a string', mppt-per-panel and shading problem. The latter is important on my roof. Single point of failure vs multi point of failure is also better with micro inverters. But IF something goes wrong there is way more work than with a single inverter. I start to see that as a disadvantage. Then there is the better monitoring, you can pinpoint malfunctioning solar panels. But solar panels themselves hardly ever fail so that advantage is minimal. A last advantage is that you don't have high DC voltages on the roof. Only 230VAC. Disadvantages are slightly higher costs and slightly lower efficiency.If I had to do this again I probably would use 4 smaller, 2 kW central inverters, strategically distributed over the panels.

author: coppice
author_rank: Super Contributor
timestamp: March 21, 2018, 11:32:01 am
content: Quote from: woody on March 20, 2018, 05:16:48 pmIf a small company offers you a 25 year warranty, you can be sure they aren't expecting to be around for long, and probably don't care too much about the product's durability. Even if its a big company, they may have partitioned the activity into a subsidiary which they can let go to the wall, without pulling down the main enterprise.Micro-inverters seem to be very popular in the US. They nicely avoid things like shade issues, but the cost is a problem.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: March 21, 2018, 02:18:33 pm
content: Quote from: woody on March 21, 2018, 10:36:10 amIsn't the reduced efficiency offset by fixing the shading problem?

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 21, 2018, 04:11:19 pm
content: Quote from: woody on March 21, 2018, 10:36:10 amI have seen central inverters with 2 seperate mppt channels supporting 2 strings and hence reducing the voltage and helping with shading. I would not be suprised if a little hunting might turn up one with even more though that doesnt help your single point of failure issue. Another thing that concerns me with many recent inverters is they are so called "transformerless" for a gain of a few percent efficiency (read reduced manufacturing cost) and IMOP dramatically reduced safety by connecting your rooftop panels directly to the grid!

author: capt bullshot
author_rank: Super Contributor
timestamp: March 22, 2018, 06:28:15 am
content: Quote from: fourtytwo42 on March 21, 2018, 04:11:19 pmThe rather high DC voltage with these (typically 300V under full load, but allowed to 450V for smaller ones, and 900V for large installations) is way more dangerous than the direct mains connection. In case of a broken wire within the panels or the wiring, you'll get a nice arc setting your roof on fire (yes, the panel's plastic rear side can burn like hell). And there's another issue with the non-symmetric DC volatage in relation to earth with some panel, causing early degradation by some weird kind of internal material migration.Anyway, mine (a dual string transformerless one) does just fine, and I haven't seen any dead pigeon dropping from my roof yet

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 22, 2018, 02:07:42 pm
content: Quote from: capt bullshot on March 22, 2018, 06:28:15 amNot that I wish to provoke an argument on our thread devoted to output but the operating conditions of the panel string is identical irrespective of whether there is a transformer in the inverter or not, the only differance being whether or not they are galvanically isolated from the grid, so all of your worries concerning arcs etc apply equally to a transformerless inverter regardless of what you may have been told by your installer.

author: Monkeh
author_rank: Super Contributor
timestamp: March 22, 2018, 02:13:29 pm
content: Quote from: fourtytwo42 on March 21, 2018, 04:11:19 pmForget to turn off the DC isolator and you can get a pretty nasty surprise - it's not directly connected but I've had a ~600V leakage belt out of mine, that woke me up in a hurry. The big isolators and labels aren't for show!

author: woody
author_rank: Frequent Contributor
timestamp: March 22, 2018, 03:51:50 pm
content: Quote from: ahbushnell on March 21, 2018, 02:18:33 pmOn my roof I'm pretty sure that that's the case. The reduced efficiency is only a couple of percent anyway and I am not really complaining. Only noting that on bright days in summer when shading is less of an issue some electricity is wasted by micro inverters when compared to central inverters.To be honest, I think it is really difficult to prove one system is better than the next. Way too many variables are at play.

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 22, 2018, 06:24:03 pm
content: Quote from: woody on March 22, 2018, 03:51:50 pmExactlya few percent here or there can easely be lost in measurement accuracy, I think the choice is personal maybe even depending on availability of something for a good deal at the time. Most people will stand by what they have selected and thats only naturalSadly the clouds from the Atlantic arrived this afternoon, westerlies bad for solar, easterlies bad for potatoes what a choice

author: woody
author_rank: Frequent Contributor
timestamp: March 23, 2018, 07:40:27 am
content: And not only measurement accuracy. Bird shit. Leaves. Lichen. Temperature. Snow. Clouding. Humidity. Con trails. Fired ground fault interrupters that only get noticed after a week. There are a myriad of reasons why a solar array does not deliver its designed output. The choice of inverter technology is only one of them and in my experience, a small one at that.Hope the potatoes work out or else it's going to be a lot of Fish and Chips in the fall

author: Bassman59
author_rank: Super Contributor
timestamp: March 24, 2018, 12:18:00 am
content: I live in sunny Tucson, Arizona. There are 18 panels on my roof, with a maximum generation capability of 6.1 kW. The energy production is about 40 kWh a day, and right now most of that is going back to the grid. We don't turn the air conditioning on until the monsoon season (July) when the humidity makes swamp cooling ineffective. Even with the A/C on in the summer, I expect to have electric utility bills that are just the connection fees and the taxes, around $22/month.We expect mid-summer daytime temperatures to be above 100ºF starting in May, and it'll remain like that until the end of September. If this year is like last year, we'll have a month of 110ºF + days in the middle. Wheeeee!

author: paulca
author_rank: Super Contributor
timestamp: March 25, 2018, 07:04:46 pm
content: Well my nano setup hit boost voltage on the battery for the first time. Panel voltage shot up, amps fell, battery pinned at 14.40V, so rapidly found things to charge off it. I now have a pile of charged LiPos. No point wasting sunlight. I expect I'll be needing it next few days look rubbish and it can be cloudy for weeks at a time here, so having an energy stock pile helps.

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 26, 2018, 09:40:09 am
content: Quote from: Bassman59 on March 24, 2018, 12:18:00 amA solar power paradise, payback very fast I should imagine where here in northern europe it's a real struggle to make it economic. Many years ago the subsidies were very much higher but I dont see many new installations going in now, ok for those already on high subsidies as I seem to remember they were fixed for 25 years..........

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 26, 2018, 09:42:34 am
content: Quote from: paulca on March 25, 2018, 07:04:46 pmSounds like your ready for anything the atlantic has coming to you, forecast for later this week not to good over here in the east either. So hopefully this will encourage you now we are past the spring equinox the worst part of the year is done with and it's make hay while the sun shines

author: coppice
author_rank: Super Contributor
timestamp: March 26, 2018, 10:04:35 am
content: Quote from: fourtytwo42 on March 26, 2018, 09:40:09 amYeah, but you use a lot of that power just running the air cons.

author: paulca
author_rank: Super Contributor
timestamp: March 26, 2018, 10:19:35 am
content: Quote from: fourtytwo42 on March 26, 2018, 09:42:34 amIf only lead acids weren't so expensive. I would consider doubling up on the 26Ah. Instead I can charge all my RC LiPos and use them until the sun returnsDownside is, they don't like being fully charged, so they need to be used up first.

author: woody
author_rank: Frequent Contributor
timestamp: March 27, 2018, 07:12:17 am
content: Quote from: fourtytwo42 on March 26, 2018, 09:40:09 amYes, but many years ago solar panels were much more expensive and much lower in power.I'm not too pessimistic about this. I think that you can run solar on your rooftop without subsidy and at least break even.The biggest problem IMO (at least here in Holland) is that solar was and is sold to people as a moneymaker. The installation cowboys promise a 7-10% ROI on your system. So much more than your bank gets you on your savings account. Only, that kind of ROI is all coming from subsidies.The honest story should be that solar is a means to make all the electrical power you need in the cleanest way possible. Somewhere in the near future you will be paying a decent fee to solve the problems you create because you make way too much in summer and make way too little in winter (so somewhere somehow some storage or alternative generation has always to be on stand-by for you). You will be paying your energy tax like everybody else. But still you will break even in the time your installation runs (20 years). So the ROI moneywise (if there at all) is low but the ROI for the environment is high.Subsidies should be used to get new technology out of the lab and into the field. But when new technology can hold its own they should vanish pronto. We have a gigantic problem on our hands that will cost us many many billions to solve. There are better ways to spend that money than subsidizing already proven technology.

author: fourtytwo42
author_rank: Super Contributor
timestamp: April 12, 2018, 08:16:57 am
content: Third sucsesive day of fog here and that was preceded by several days of rain so the daily output has been at winter levels for a week now, only saving grace is the extended hours of very low output! Apparently the scientists say the gulf stream is weekened by ice melt (global warning) hence our stuck claggy weather systems so maybe the clock is ticking against solar in northern europe. Maybe that retirement cottage/tent in the Sahara beckons

author: paulca
author_rank: Super Contributor
timestamp: April 12, 2018, 08:22:46 am
content: Yea, looks like the whole of April is set to be cool, wet and breezy. Nothing unusual over here though. Fingers crossed for May.

author: woody
author_rank: Frequent Contributor
timestamp: April 12, 2018, 09:10:27 am
content: Today is grey. Yesterday was good. The whole of April so far looks nothing like last year; I need to make 500kWh in the 18 days left to equal it. And looking at the forecasts that's not gonna happen. Good thing is it will help me explain to my wife why I decided to cut down on the vacuuming :-)

author: fourtytwo42
author_rank: Super Contributor
timestamp: April 12, 2018, 10:10:26 am
content: Quote from: woody on April 12, 2018, 09:10:27 amCarefull she might suggest you buy a vintage hand powered one!Actually in our house the oil boiler and heating pump combined use about a unit a day in cold weather and thats from 25-30% of our entire consumption! Roasting a joint uses about 3 units but hell I just love roast dinner

author: woody
author_rank: Frequent Contributor
timestamp: April 16, 2018, 05:15:30 pm
content: Today was a good day: 38.1 kWh. Forecasts promise lots of sunshine up until Saturday .That boiler uses little energy then. Our (natural gas) CV from 2011 uses at least 2 kWh per day in cold weather. On a yearly basis this turns out to be one of the most energy consuming devices in our house. The oven with the occasional steak and Guinness stew does not come close, that's for sure.But, as I make more power in a year than I need, I don't complain.

author: metrologist
author_rank: Super Contributor
timestamp: April 17, 2018, 01:46:04 pm
content: Jeebs my average household energy use barely cracks 10kWHr

author: paulca
author_rank: Super Contributor
timestamp: April 17, 2018, 02:00:28 pm
content: Quote from: metrologist on April 17, 2018, 01:46:04 pmPer?

author: metrologist
author_rank: Super Contributor
timestamp: April 17, 2018, 02:50:05 pm
content: daily use

author: paulca
author_rank: Super Contributor
timestamp: April 17, 2018, 02:55:15 pm
content: Yea, mines about the same. 10-15kWh/day. Circa £1.50-£2 per day. £50 of leccy lasts me about a month. Less in summer as less lights, less heating running (gas boiler still and pump uses about 300W).Changed all my bulbs to LED and a few CFLs, so the main consumers now would be:1) The PC/Monitor, 150W idle, 450W gaming.2) Cooker/microwave3) The incandescent 300W up-lighter (though usually dimmer to about 25%) to light the main living space, although I intend to see how well an LED replacement does.When I move house the plan is to install enough solar and batteries to run the PC from solar.

author: metrologist
author_rank: Super Contributor
timestamp: April 17, 2018, 04:04:59 pm
content: I always blame the fridge. My "gaming" PC is about 5 years old and draws 100W surfing (I've lost my lust for games). I should just get a netbook or something more economical for that. We use mostly gas for cooking, and I don't usually run the heat or AC. Gas is actually costing a good portion of the bill now - that is just hot water and the stove. ~$70USD/mo total and we are billed in two tiers, $0.20 and $0.28/kWh.I have a couple of white gas camping stoves that I should try using for a month to see, and soon I'll turn down the water heater. I miss the $40 bills.

author: fourtytwo42
author_rank: Super Contributor
timestamp: April 17, 2018, 04:54:45 pm
content: Quote from: woody on April 16, 2018, 05:15:30 pmI supliment the boiler with a woodstove in the lounge afternoons and evenings in winter so the boiler is only used in the mornings, usually an hour, sometimes two if its extremely cold. Like you said before it's all about insulation, all the windows are argon filled, the walls are filled with foam and the roof with up to 500mm of fiberglass.I am shocked by other peoples daily electric consumption here, ours is 3.5Kwh/day on average and that includes an electric cooker BUT if we use the oven (an exception) it's a 6Kwh day! We also rarely watch television (boring) a DVD is probably half a unitWe do lots of small things to save energy for example using a big thermos to store boiled water to save boiling the kettle to make tea all the time, using simple laptops and having all non-essentials not on standby but unplugged. We have a small modern chest freezer that is only on for 6 months (summer harvest surpluss) and a well insulated modern fridge freezer. All lighting is CFL and I try to only run irrigation pumps when the sun is out and of course in summer a lot of our cooking is outdoorsOur background power is about 45W but I am always working to reduce it, thats where I keep thinking of installing a DC-bus, so many gadgets many with small mains transformers with 1W magnetisation current, but they get swamped by the fridge etc anywayho hum!

author: woody
author_rank: Frequent Contributor
timestamp: April 17, 2018, 08:41:06 pm
content: @fourtytwo42I admire your efforts!We use approx. 5300kWh / year, or a bit less than 15 kWh / day. We run a house, an office with a couple of computers and a server and my workshop on it. So all in all not too bad taking into account that all the living and the making of money is done here and no office buildings elsewhere need to be kept warm and lighted for us. My other excuse is that the solar panels on the roof generate 5400+ kWh / year so in principle all electricity we use is home-made, green and already paid-for and we do not have to be frugal with it.But (and this is a big but) this only works because of the so-called 'salderingsregeling' in my country, which means that generated (and grid-delivered) kWh's cancel out kWh's we take from the grid 1:1. Which is quite unreasonable as in the summer during the day we generate a lot of energy that maybe nobody uses, while at night and in the winter a big, probably coal fired power station somewhere is making the energy we use then. For that luxury we do not pay a cent.Good thing that this salderingsregeling will be moderated in a couple of years. This will be an incentive to save power. I only hope they'll invest the money I then give them in storage. Although more tarmac is more likely@metrologistEarly 2016 I replaced the desktop (120W) with an Intel NUC. As long as you do not try to render Avatar on it it works perfectly. It runs webbrowsers, LibreOffice, Lightroom, Kicad, Eagle, Gimp etc. with 'twee vingers in z'n neus', as we say. And that while using <15W. Also replacing the 10 year old CCFL based monitor with an LED unit saved nearly 50 watts.And I would trade you our gas bill anytime. We use approx. 2500m3/year, at €0.57/m3. For heating the house, the office and the workshop (85%) and hot water for showers etc (15%).

author: paulca
author_rank: Super Contributor
timestamp: April 18, 2018, 11:08:52 am
content: Quote from: metrologist on April 17, 2018, 04:04:59 pm5 years you might be okay, but around that time the PC hardware folks came under serious scrutiny about power usage of devices.I was spec'ing a gaming system back then that needed a 650W power supply. The next system, 3 years ago I was worried I'd be looking at 1000W PSU, but... as it turns out the new one consumed less.It's the video card that churns through the power when running flat out. I believe mine consumes something like 200W at full tilt, the CPU up to 220W.

author: fourtytwo42
author_rank: Super Contributor
timestamp: April 18, 2018, 07:05:52 pm
content: 1st BBQ of the year and a record production for 2018 so far of 3.4Kwh/KW of our quirky PV installation. The oil boiler has not been on for several days and we have more hot water than we know what to do with (we don't wash much). Of course if we were exporting to the grid like most I know our production would be much higher but this is an entirely subsidy free systemIn connection with the other day and consumption figures we do use extra power in winter as we run a de-humidifier, this contributes some heat as well as enabling us to keep the windows tight shut in all the nasty cold weather. I found the humidistat in modern de-humidifiers totally useless, the old one that was near on 30 years old before the coolent circuit was perforated beyond repair ran a hair humidistat and worked perfectly. The new de-humidifier is overridden by yet another of my gadgets enabling the energy consumption to be sensibly controlled.@woodyThats a good combination of premises use and of course also avoids commuting! There is just two of us and I am retired although still run some consultancy also home based. I reckon the amount of hardware/software I get involved in now has hardly diminished as now I don't have to waste valuable time politicing and stuck in endeless meetingsOn top of that we grow our own fruit & veg and I am an avid home brewer hick!!

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 19, 2018, 01:32:04 am
content: Quote from: paulca on April 18, 2018, 11:08:52 amSandy Bridge was the last time the performance per watt jumped by a large amount. After that, the improvements were more or less incremental. I have an old HP Z600 (Westmere - just one generation older than Sandy Bridge) that I rarely use because it is not particularly efficient. (And running it as a miner really heats up the room - handy on very cold days but not profitable otherwise.)GPUs use a lot of power, but the performance per watt is still improving a lot with every generation at this point.

author: paulca
author_rank: Super Contributor
timestamp: April 19, 2018, 06:44:22 am
content: Monitors and TVs have become much more efficient too. I have two monitors here. Both Acer. A 24" 16:9 and a 34" 21:9 1440p. Guess which consumes more power? The smaller one as it's about 4 years older. When it's been on for a while it's about 50*C at the top vent. The larger, newer monitor even runs off a DC brick and is barely more than ambient at it's exhaust vent.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 19, 2018, 07:13:16 am
content: Quote from: paulca on April 19, 2018, 06:44:22 amMy Seiki 50" 4K only uses about 40W. Of course, it really is more of a monitor than a TV with very limited ability to play media by itself. Basic upscaling can use surprisingly little power, however - a Tegra X1 can upscale 1080p to 4K on just 6W. A desktop GPU will easily outdo it in upscaling quality, though. (I have to admit that I have no idea how much power my 970 uses just doing 1080p to 4K upscaling since I started mining Curecoin/Foldingcoin well before I found content that really does call for good upscaling.)

author: fourtytwo42
author_rank: Super Contributor
timestamp: April 19, 2018, 07:40:09 pm
content: Quote from: NiHaoMike on April 19, 2018, 07:13:16 amHey guy's thanks for the info I didnt realise LED display's saved so much compared with CCFL's, of course all my displays are the latter. I kinda know how much computing efficiency has moved on from the bad old P4 daysI run a smallish T2300 laptop on about 75W and just put up with the extra time simulations and compilations take (time for more tea) I am always looking for way's to save energy as well as generate it, one of my biggest standing consumers is the DSL modem, 15W 24/7turn it off and the exchange software marks you down, it doesnt understand your just trying to save energy!P.S. Another cracking 3.3Kwh/Kw production today but there are clouds on the horizon!

author: coppice
author_rank: Super Contributor
timestamp: April 19, 2018, 07:45:06 pm
content: Quote from: fourtytwo42 on April 19, 2018, 07:40:09 pmLED backlighting does save quite a lot of power in a modern LCD monitor, but you shouldn't discount how much the power draw of every other component has dropped. The use of finer geometries and higher integration levels has transformed the chip sets from rather hot to barely warm.

author: paulca
author_rank: Super Contributor
timestamp: April 20, 2018, 07:16:43 am
content: That and voltage. The CPU/GPU race has been about running on lower and lower core voltages to save power. Higher voltage usually means more heat. Overclockers will generally up the voltage as it allows for faster clock speeds without lock ups, with caveats about burning it out, though they are fairly well protected.Today things like the i7 and (I believe) Ryzen have variable voltage, so when idle the drop their voltage to a minimum and consume less power, produce less heat, but when you kick off a compilation or a game the voltage ramps up, along with the clock frequency/divider.I believe they are as low as 1.1v in some cases, maybe lower. My CPU is power hungry and runs at 1.45V

author: woody
author_rank: Frequent Contributor
timestamp: April 20, 2018, 05:48:12 pm
content: As a panel owner you got to love the spring: another 38.8 kWh (5.3 kWh / kW) dayI just GOT to replace that inverter to get this to 40k...

author: fourtytwo42
author_rank: Super Contributor
timestamp: April 20, 2018, 06:58:09 pm
content: Quote from: woody on April 20, 2018, 05:48:12 pmGood weather for being on the roof too, no nasty slippy slidy wet moss!! SWMBO is really keen on this this year, she checks if the grid tie is running before doing the ironing

author: woody
author_rank: Frequent Contributor
timestamp: May 01, 2018, 09:55:45 am
content: Spring 2018 in NL. Yesterday I made 0.879 kWh. In a day. With 7kWP on the roof. The day before that 1.05 kWh. The entire month of April was 86kWh behind April 2017.On the up side, the rain just stopped, the sun shines a bit and forecasts for the next week are not bad. And the boat floats again after spending the winter on the shore

author: fourtytwo42
author_rank: Super Contributor
timestamp: May 01, 2018, 04:53:15 pm
content: Just plotted mine till the end of April, spring came, the plums and damsons all flowered and immediatly we were hit by a cold washout! 1C last nightApples are just starting now so I hope the weather improves for the bees in time!Y axis is weekly average Kwh/day, X axis is hours.House was in danger of floating away a while ago, who needs a boat

author: G7PSK
author_rank: Super Contributor
timestamp: May 02, 2018, 08:27:35 am
content: I am looking at getting solar, but I think wind might be better here in Norfolk so am looking at that as well. I built a wind system for my father twenty years ago and although he no longer is there last time I went past the turbine was still up.

author: fourtytwo42
author_rank: Super Contributor
timestamp: May 02, 2018, 11:05:15 am
content: Quote from: G7PSK on May 02, 2018, 08:27:35 amI live in Norfolk tooI have also tried wind but if you only have a small plot it's very very fussy and the planning regs get in the way hence I gave that up and moved to solar. There are still problems with the planning regs (not enough room to fit tracking gear on a roof) but I am getting a lot more output than I ever managed from wind. Depends entirely upon your circumstances and I guess you already know about the problems with turbulent flow and obstacles to close!

author: woody
author_rank: Frequent Contributor
timestamp: May 03, 2018, 05:34:58 pm
content: Quote from: woody on April 20, 2018, 05:48:12 pmScratch that. Today, not too hot and very very sunny, we made 40.920 kWh / 5683kWh/kW. That is an all time high for this installation.

author: paulca
author_rank: Super Contributor
timestamp: May 04, 2018, 07:29:25 am
content: My mini 50W system has been running with full battery now for a week. With a few blue sky days I got all my batteries charged and the broken sunshine since is just enough to keep up with demand of my phone, electronics PSU and USB devices.I bought a 22400mAh power bank to try and capture some more of the energy for when it becomes miserable and dark again. So that came at 70% charge so didn't really dent the solar battery that much charging it. 13.1V down to 12.6V. Today will probably put that back to 13VIf only it was this easy in winter.

author: woody
author_rank: Frequent Contributor
timestamp: May 24, 2018, 06:49:22 am
content: Got the yearly settlement from my power company yesterday. Used 3753 kWh from the grid and put back in 4193 kWh. That leaves me with 440 kWh * €0,11 * 1.21 (VAT) = €58,56 in cash.Total electricity use over the last year (including the energy generated by the panels and directly used) was 5367 kWh. Up 1.9% from the year before. Which fuels my pet peeve that LED lamps do not save energyOh, and May 2018 is looking to be a very good month for solar over here

author: fourtytwo42
author_rank: Super Contributor
timestamp: May 24, 2018, 05:19:04 pm
content: Woww Woody good figures indeedSo adding your saved electric bill to your rebate have you worked out how many years the system will take to break even on present performance ?Last week was great here averaging over 3Kwh/day/Kw but as usual I lost quite a bit through not having completely converted the household to not using electricity unless the sun is shining and the water is hot alreadyIMOP the CCFL's are/were far more efficient till someone discovered they had a drop of mercury in them and outlawed them, I wonder what poison they will decide exists in LEDs meaning the get the same treatment in years to come!!

author: metrologist
author_rank: Super Contributor
timestamp: May 24, 2018, 05:38:48 pm
content: I've been very happy with all my LED lights, and the W numbers printed in them are much lower than the CCFL's they replaced.In two rooms, however, there are remote 4-pin CCFL supplies where I used compatible LED bulbs - so I am sure some efficiency is lost.My lowly panel just keeps my battery topped up. It would be much better if I set up my aquariums to run off solar, and just during sun time too. That's only 12W.

author: woody
author_rank: Frequent Contributor
timestamp: May 25, 2018, 07:52:56 am
content: Quote from: fourtytwo42 on May 24, 2018, 05:19:04 pmI find that a very difficult discussion. If you look at it from the sunny side break even is maybe 7 years. But I could argue for 15 years as well. It is the same with my car; I never managed to work out the break-even for that.My take is that since 2013 we produced 25,8MWh of clean energy and thereby avoided between 5 and 12 tons of CO2 (depending on the fuel mix used in the power plant). That at a cost that is cheaper than getting it out of the grid. How much cheaper? I don't know. Time will tell. But cheaper, that is for sure.And when I take into account the foot-between-the-door effect that decentralized solar systems like mine have on how the grid is run by those big power companies, for me break even is already reached

author: fourtytwo42
author_rank: Super Contributor
timestamp: May 25, 2018, 02:32:37 pm
content: Since asking the question I have tried to calculate mine, given its upgrading, early failures and weather changes from year to year it's hard to grab the figures as most of the output is converted into oil fuel savings. My initial small 500W system would have had an estimated payback of 6 years but that was before the oil price shot up recently. The extended 1kw system with a gti but no subsidy has a calculated payback of 4 years, this is in part due to the rising oil price but also because the incremental cost of extending a system is not as high as the initial. My costs are much reduced as a lot of the electronics came from my junkbox (recycling at it's best), the only things directly purchased were the panels themselves and there mounting hardware.I am also concerned for the environment and this is one way I can contribute, in my case directly by burning less oil for heatingThe contribution via the gti to reduced grid consumption is minimal as unless it's a hot day in summer water heating takes most if not all of the available energy.I will continue to monitor the results to see if a further extension is worthwile but presently it is large enough to provide all the summer hot water so a larger system would simply spend more time idle! Of course the real nut to crack is energy in the winter, already tried wind and that was no good, I have a small stream but no fall (3 inches on my land at most) and hydro has it's own problems in winter (freezing) leaving heat pumps. I was fortunate enough to experience air source HP's at someone else's expense and they were completely hopeless in freezing weather (spent all there time going into reverse to de-ice the external unit). My trusty woodburner helps out but they are now under threat from PC! I still say the best solution is for mankind to copy the sensible part of the animal kingdom and hibernate for the duration

author: fourtytwo42
author_rank: Super Contributor
timestamp: May 31, 2018, 03:48:54 pm
content: End of this month weekly averages, definetly getting out of the doldrumsVertical scale is Kwh/day horizontal is hours so the droop in the middle is Dec/Jan/Feb

author: woody
author_rank: Frequent Contributor
timestamp: June 01, 2018, 01:07:08 pm
content: Nice figures!For our panels it turns out that May 2018 was the best ever; May always is the top month of the year. The previous record was May 2015 with 761 kWh. May 2018 broke that easily: 905 kWh. +19%, with one inverter still broken.Now what am I going to do with all that power

author: ahbushnell
author_rank: Frequent Contributor
timestamp: June 23, 2018, 12:30:57 pm
content: Updates on energy generation?

author: paulca
author_rank: Super Contributor
timestamp: July 08, 2018, 09:53:38 am
content: Quote from: ahbushnell on June 23, 2018, 12:30:57 pmIt's been unseasonally sunny here in Northern Ireland. We are into our third or forth week of actual summer weather. 25*C+ blue skies all day.My 50W panel, in a window has been generating much more than my original demands, so I have taken to charging large LiPos and using them via a laptop car charger to run my laptop in the evenings.I expect those with large systems will be doing rather well in the UK this last month.

author: Bassman59
author_rank: Super Contributor
timestamp: July 16, 2018, 03:26:41 am
content: Quote from: coppice on March 26, 2018, 10:04:35 amLike I said, we were running the swamp cooler through May. (OK, I realize that the whole concept of an evaporative cooler makes no sense in the UK.) We turned it on in late May because, well, why not, it was hot.We were sending back to the grid between 400 and 500 kWh for the months up to May. For the May bill we sent back 216 kWh. The bill ending June 25 we used 422 kWh in excess of what we generated; that is, that month was the first month since the panels were installed (started up beginning of last September) that our use exceeded our generation. We used about the same amount of power this June as last June, about 1600 kWh, which cost almost $250 last year.Even though May and June are hotter than July (June has many days over 110 degrees F), July is typically the month with the most energy usage here. That's because the humidity becomes unbearably high, as our monsoon season starts. We don't get monsoons in the tropical sense; the native word for the storms is "chubasca," but basically every day starts out hot and dry and as the day progresses, moisture in the air builds up and in the late afternoon we get thunderstorms and a lot of rain, and an hour later both the temperature and the humidity drop significantly. But during the day, before the storms, it's hot and sticky so we run the A/C, and that's our energy use.Monsoon "season" lasts from July to the middle of September, and its start is defined as when the dew point exceeds 54 degrees F for three consecutive days.Of course, today it was rainy and the temperature never got above 80 degrees and we opened the windows.ANYWAY, we have nearly 1300 kWh in credit (what we've generated in excess of what we've used) and my guess is that even with another month of high-ish humidity and temperature, we will end up not paying anything to the utility for our electricity usage.I really think that in the desert southwest, not having solar panel installations for both residences and businesses is a mistake. The problem is that the incumbent utilities are wholly against residential solar power and probably don't want businesses to have solar power, either. But rather than invest in solar farms and even installing the panels for customers, they'd rather continue to push the natural-gas-fired turbines as the only source for electricity.

author: fourtytwo42
author_rank: Super Contributor
timestamp: October 03, 2018, 06:48:11 pm
content: I sooo wish I lived in a hot country and needed aircon, it would be so simple to solar power it per the last post. Interestingly I have spent time near the equator in several countries where aircon is an expensive luxury but PV is almost unheard of. Anyway back to the UK and the doldrums are beginning to return, this is my last 15 months data (rolling averaged over a week) vertical axis in Kwh/day and horizontal in hours so you can see Autumn beginning to have its effect in shorter days and more cloud. The glitch around 9600 hours coincides with downtime caused by equipment experimentation. Ohh I should mention this system is controlled to prevent export so sometimes energy production is limited by what can be consumed locally by water heating or electricity use.

author: Kibi
author_rank: Unknown
timestamp: October 09, 2018, 07:49:18 pm
content: Alas, the doldrums are returning rapidly. However, after a recent upgrade of 1.1KW of additional PV atop my garage, my system reached a record of 10.03KWh today here in sunny Norfolk2.78KWh went into the battery, 0.35KWh was used directly. 6.89KWh left the shed and went towards the house, of which 3.4KWh went into my hot water cylinder.Quite a good day.

author: fourtytwo42
author_rank: Super Contributor
timestamp: October 10, 2018, 06:03:58 pm
content: Hi Kibi, I knew there was a Norfolk also in the USA but not one in ZimbabweSo perhaps you have a home in both countriesYour results are very good, what is the installed power of your solar panels, mine is 4*265W poly ?BTW according to the weather forecast today was the hottest in October since 2011 BUT tomorrow the rain comes (some say at last!!).

author: Kibi
author_rank: Unknown
timestamp: October 10, 2018, 08:47:46 pm
content: Yes, I'm from Zimbabwe, patriotism sometimes gets the better of me when selecting the location settings. No solar doldrums in Zimbabwe, winter time is the best because it is not the rainy season and it's often fine weather for days on end. Alas I don't live there or even visit anymore.I have a mixture of PV. The modules you buy at any one time are never available the next time you have more pocket money.Several years ago, I started out with 4x 250W Renesola poly modules followed later on by two Trina Honey 265W poly modules. The latest addition is a set of 4x JA Solar 275W mono modules. A total of 2.63KV nominal. Like a conventional grid tied system, this assortment of PV arrays operates at the maximum power available all day. My system is rather unconventional though. Its mainly Victron components tied together in an ESS system.1KW Renesola array is DC coupled via a Victron 35A MPPT charge controller. Same for the JA Solar array via its own Victron 35A MPPT controller. These are on a 24V DC system which means they are charging at just about 1KW each at the top end of the charge.The two Trina modules are in parallel feeding a Enphase Energy M215 micro GTI. This array is over powered for the GTI, but it's fine and only really a waste on sunny days when I have excess anyway. I get about 229 Watts out of the Enphase at full chat. I might get another GTI one day and get more out of those two modules.The Enphase GTI is connected to the AC-OUT of my Victron MultiPlus Inverter / Charger which enables that energy to charge the battery and also to work off grid if necessary. If the grid fails, the MultiPlus will frequency-shift to control the output of the Enphase GTI when the battery is full.I have configured my MultiPlus with the G83-2 grid code so that it can back feed via its AC-IN when the battery is full and the power has nowhere else to go. Therefore both the DC coupled and AC coupled arrays will go full blast all day without rest. This excess energy then goes back into the house. This is what helps bolster my output figures. I have a Solar iBoost immersion heater controller which ensures that any energy not consumed by house loads goes into the hot water cylinder.My batttery bank is an old worn out LiFePO4 set that spent the first 8 years of it's life in a motorcycle, where it got hammered, often. The battery bank has a nameplate capacity of about 7KWh, but I'm lucky if I get 4KWh out of it. This is usually enough energy for the electronics lab, workshop and observatory.The battery's BMS is an OpenReVolt design (from the EV community) but with 4springs firmware instead. This is quite basic and simply signals the MultiPlus with two signals, 1) charging allowed, 2)discharging allowed.The ESS system is designed to run on Victron's (expensive) CCGX unit which ties the charge controllers, MultiPlus, battery monitors, fuel tanks, GPS (for mobile applications) etc. all together. It performs the data gathering and publishes the data to their (free to use) portal. They have opened up the code (Venus) for the CCGX, so people are running it on RaspberryPi and other machines. I am running Venus on a BeagleBone Black. The portal is still free to use even if you use a RaspberryPi.It's taken me several years to cobble this lot together, but it's ever so rewarding.

author: fourtytwo42
author_rank: Super Contributor
timestamp: October 11, 2018, 08:03:14 am
content: Good morning Kibi thank you very much for your excellent system description! The problem of mismatched panels can be severe indeed, I was lucky when upgrading from ~500W to ~1Kw to get two more panels of the same make and type. I am sticking at 1Kw for the time being as that is enough to serve the primary purpose of water heating. Unlike just about everybody else as my system was designed from scratch primarily as a water heater it uses a combined buck/boost converter to drive the 3Kw/240Vrms element directly from the panels. The GTI was added later merely to soak up the excess but is controlled to prevent export. If/when I eventually move house the whole system is up for re-design as I would like to add wind to the mix to provide more winter energy. Your system has the advantage of being able to store excess energy though at 1Kw I really have very little and not enough to amortize the cost of the equipment.

author: Kibi
author_rank: Unknown
timestamp: October 11, 2018, 12:51:02 pm
content: Quote from: fourtytwo42 on October 11, 2018, 08:03:14 amThis is another feature that the ESS system supports. Certain MODBUS energy meters can be included in the system. If one of these energy meters were to be placed directly after your main switch, then any loads downstream of the meter will be supplied by back-fed energy from the MultiPlus. The MultiPlus will do everything it can to ensure that the energy meter reads 0 Watts (or whatever offset you choose). If a 3KVA MultiPlus is runnung at full capacity because a 10KW shower is on, then the remaining 7KW will simply come from the grid.Of course in the event of a grid failure, the MultiPlus disconnects it's AC-IN, so no loads on that side are supplied.My dream is to have such an energy meter connected in the Consumer Unit beyond the shower and cooker circuits so that these are never supplied by the system. "Luxury" circuits (ringmains, welders, EV charging) can then sit between the energy meter and MultiPlus' AC-IN to be supplied by Grid Tied renewable energy. Then "critical" circuits like lights, fridge, boiler and security systems can be fed by MultiPlus' AC-OUT and always be supplied by renewable energy until the battery runs down.I just need to talk to an electrician who understands my needs and is willing to try something different.

author: Kibi
author_rank: Unknown
timestamp: October 14, 2018, 05:49:29 pm
content: It's days like today which are really depressing, a start contrast in weather from just a few days ago.Today my 2.6KW of PV harvested just 300Wh.This is one of the worst harvests that I can remember.This is a snapshot of the pwer levels when the weather was at its most miserable:

author: fourtytwo42
author_rank: Super Contributor
timestamp: October 14, 2018, 06:46:01 pm
content: Me too, peak today was just 30W and less then 100Wh for the day, means I have to burn expensive oil fuel to heat the water tomorrow morningHowever I must say the garden was in need of a drink and still very dry, maybe a bit more rain tomorrow too. As you can tell as a gardener I am torn hahaha Altogether I collected around 100Ltrs that will be used for all sorts of things including wine & beer making

author: HB9EVI
author_rank: Frequent Contributor
timestamp: October 14, 2018, 06:56:58 pm
content: seems to be quite a grey weather up in the UK, guysmy small 200Wp system fed 500Wh in the batteries today; so far we're just running the house lighting over the system and got along with the capacities of batteries and panels for our needs, but I guess it'll get tight with different weather and the upcoming shorter days.I'll add soon a 400Wp windmill to back up for the poorer weather days

author: nfmax
author_rank: Super Contributor
timestamp: October 14, 2018, 07:34:48 pm
content: 0.28kWh from my 1.7kW panels today. Rain. Lots of rain. Peak 15-minute average power was 170W, at 11:00 to 11:15 BST

author: woody
author_rank: Frequent Contributor
timestamp: October 16, 2018, 05:20:06 pm
content: 22.5 kWh out of our 7.2 kWp system today. On October 16th. This month so far we made 301 kWh. Last year October we made 296 kWh in the entire month.I know that global warming has little to do with this but whatever the reason 2018 is a GREAT year for solar in NL

author: fourtytwo42
author_rank: Super Contributor
timestamp: October 18, 2018, 06:07:31 pm
content: Quote from: woody on October 16, 2018, 05:20:06 pmGreat to know your still outperforming me at 3.125Kwh/Kwp in October, best I have seen this month was about 2.4Kwh/Kwp so I reckon your orientation and shading is a mite better than mine and of course the Netherlands maybe has better weatherBut as you say even here October weather is proving weird this year, very very dry still!!

author: Kibi
author_rank: Unknown
timestamp: October 20, 2018, 09:45:07 am
content: It's been a bit of a rollercoaster week!Over the last few day at least, the excess energy "has been making a meaningful contribution to the hot water system - which is nice!"

author: fourtytwo42
author_rank: Super Contributor
timestamp: October 21, 2018, 08:14:07 pm
content: Do you get paid for your export Kibi ?

author: Kibi
author_rank: Unknown
timestamp: October 24, 2018, 08:56:13 am
content: Quote from: fourtytwo42 on October 21, 2018, 08:14:07 pmNo, "export" in my current system refers to energy being "exported" beyond my own private meter which is installed in the Consumer Unit for the workshop (an outbuilding). This exported energy ultimately gets consumed within the house. If the house loads are covered, then any excess will be consumed by the immersion heater which is controlled proportionally by a Marlec Solar iBoost.No energy actually leaves the house into the grid.One day when I get a "proper" domestic roof installation, I'll have it tied in to this system and ensure that as little energy is wasted into the grid as possible.

author: fourtytwo42
author_rank: Super Contributor
timestamp: October 30, 2018, 06:43:26 pm
content: Maybe we ought to go for a new competition, worst day recorded (a sort of how low can you go)Today from my 1Kw array I got less than 100Wh (logger resolution) and a peak instantaneous power of just 41Watts but it was raining most of the day!

author: fourtytwo42
author_rank: Super Contributor
timestamp: November 15, 2018, 12:05:09 pm
content: As the sun gets lower and lower the number of hours of meaningful production goes down too and we become more and more aware of whats on the horizon as our panels see it. As can be seen in the attached pics even at 2pm in the afternoon facing SSW I have a tree who's shadow can also be seen on the panels reducing output from ~500W/Kwe to ~150W/Kwe. Finding somewhere to live where there is nothing on the horizon at this angle is probably impossible

author: ahbushnell
author_rank: Frequent Contributor
timestamp: November 15, 2018, 01:55:28 pm
content: Quote from: fourtytwo42 on November 15, 2018, 12:05:09 pmI'm not familiar with the units W/Kwe? W is watts. What is Kwe?Thanks!

author: metrologist
author_rank: Super Contributor
timestamp: November 15, 2018, 02:01:57 pm
content: Quote from: fourtytwo42 on November 15, 2018, 12:05:09 pm

author: fourtytwo42
author_rank: Super Contributor
timestamp: November 15, 2018, 02:24:32 pm
content: Quote from: ahbushnell on November 15, 2018, 01:55:28 pmI am very sorry I meant Kwp meaning the peak power, or power installed. So to level the playing field I like to quote everything in per kilowatt installed.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: November 15, 2018, 03:53:43 pm
content: Thanks!

author: fourtytwo42
author_rank: Super Contributor
timestamp: November 26, 2018, 09:49:31 am
content: Winter in northern Europe is returning! Here are my stats till today.....I have done a little more work with pre-processing the data (Cygwin) and presentation in GnuPlot.The horizontal axis is now week numbers BUT it is not precise as there are holes in the log due to power outages (something we get here in the countryside)The main difference between last year and this year is the contribution of the GTI soaking up some of the excess after water heating.This year there was a few days downtime around wk31 and last year there was lots around weeks 23-26 mostly due to mosfet failures and badly performing software (can't get the staff).The log is a micropower standalone system with a bytewide 32Kbyte EEPROM for storage, two bytes (power & temperature) per hour so no means of time recovery if data is lost due to power failure. It could be more sophisticated but then it would consume more power!

author: paulca
author_rank: Super Contributor
timestamp: January 10, 2019, 08:17:21 pm
content: Well, a week before xmas my solar system shut itself off. I hadn't been able to pull any power from it for weeks. The battery was down to 11V. When it shut off I decided it was time to recondition the battery and a good job I did it promptly as the battery registered only 8.8V on the charger.It's been that bad here through December. Normally you would get a sunny morning or afternoon once a week, but no. It's been dead overcast for a month. When the sun does peek out it's only been for half an hour late in the afternoon through broken clouds.Unfortunately the 8.8V thing may have harmed the batteries as when condition charged to 14.40V for an hour, then floated at 13.6V for 2 hours, when rested over night they register only 12.8V. They should register 13.1V. Still servicable, but I think they took a hit.The only thing they are running is the charge controller itself and the microcontroller wifi which sends the stats.I might start switching it off at night when I get home and on again in the morning before I leave until the days get longer.

author: Zero999
author_rank: Super Contributor
timestamp: January 11, 2019, 01:12:06 pm
content: What do you expect from a solar system north of 50oparallel? It's only reasonable to expect useful output from April to September.Being eastwards of a large expanse of a relatively warm ocean doesn't help either, as the moisture will form clouds, blocking out the sun.Over all 2018 must've been a good year for solar power, as it was the second sunniest on record.https://www.metoffice.gov.uk/news/releases/2018/weather-review-of-2018

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 11, 2019, 02:42:31 pm
content: Quote from: Zero999 on January 11, 2019, 01:12:06 pmThat sounds a bit negative, I get around 10% of my summer output and that is very useful to me defraying my oil bill. We are not all fortunate to live near the equator but I am more than happy with what I get and so I am sure are many othersAs for battery problems I was looking for but could not find a thread I saw somewhere recently about someone trying to recover AGM batteries and the story was not good, I am sorry for your troubles Paulca. I think I decided early on for that reason to avoid batteries in my solar experiments as they seem an expensive and unreliable way to store energy so instead I store mine in my hot water cylinder though that is not a suitable solution for everybody.PS found the threadhttps://www.eevblog.com/forum/repair/attempt-rejuvenating-old-gel-cell-lead-acid-batteries-with-a-bench-supply/?topicseenPPS to illustrate the point about power output here is the latest plot I have to hand and it only drops below 0.5Kw/h/day for a few weeks a year, not months as proposed above!

author: cdev
author_rank: Super Contributor
timestamp: January 11, 2019, 02:52:49 pm
content: How can an entire country be better than average? Is that the thermal anomaly? Global warming?

author: paulca
author_rank: Super Contributor
timestamp: January 11, 2019, 02:53:07 pm
content: fortytwo42... my solar system wouldn't be able to heat a cup of water! 50W panel behind a double glazed window.However it was successfully running a lot of my battery tech gadgets, including (during our brief 2 weeks of summer) my laptop in the evenings for an hour.

author: paulca
author_rank: Super Contributor
timestamp: January 11, 2019, 02:56:21 pm
content: On the battery damage. I hope they have been that badly damaged. It's possible though as I checked it last night and in only one week running on the system it has dropped from 12.8V to 11.7V only running a 60mA load. I haven't done the maths, but that sounds like too much of a drop.I did change my Wifi router, so there is a small chance the microcontroller wifi is pulling more power.... or the batteries are not holding charge anymore

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 11, 2019, 03:07:50 pm
content: Quote from: paulca on January 11, 2019, 02:53:07 pmTry a thermos flask, you might get enough for a cup of tea when you get home from workseriously though had you considered a tracking mount on a tripod behind your window or maybe the window is not big enough to follow the azimuth very much. I can get ~150W+ from a cloudy sky if the azimuth is right so that's 15% so you should be able to get 7.5W from your 50W panel certainly enough to float a 12V battery + a small amount of charge. Sounds like maybe you don't have any monitoring system to let you know the state of charge so you end up taking out much more than the panel is able to put inOf course if you don't have a real mppt charge controller (not chinese fake) then the panel performance may simply be total cr*p ?

author: Zero999
author_rank: Super Contributor
timestamp: January 11, 2019, 03:47:30 pm
content: Quote from: cdev on January 11, 2019, 02:52:49 pmI'm not sure what you're saying.The map I posted shows the percentage of sunshine over 2018, compared to previous years, averaged over 1981 to 2010.The sunshine anomaly last year was due to a prolonged anticyclonic period from April to August. It's not a thermal anomaly because clear skies also increase thermal losses, causing the temperature to drop at night, especially in winter, when more sunshine will often give lower temperatures, both day and night.Temperature-wise, 2018 was another warm year, the 7th on record, across the UK, going back to 1910 and the 4th warmest for central England going back to 1659, despite a cold spell from February to March.https://www.metoffice.gov.uk/climate/uk/summaries/2018/annualhttps://www.metoffice.gov.uk/hadobs/hadcet/ssn_HadCET_mean.txtWeather or climate change? No one knows for sure. In the UK, with the exception of 2018 and 2013, summers since 2007 have become wetter and less sunny, than those in the late 1980s to early 2000s. No one knows why. Some say it's climate change and have linked it to increase ice melt over Greenland, others say it's part of a natural cycle. I tend to side with the latter and think increased ice melt over Greenland is more likely to be an effect of the weather pattern which brings increased summer rainfall to the UK, rather than a cause.

author: apis
author_rank: Super Contributor
timestamp: January 11, 2019, 09:35:07 pm
content: Quote from: Zero999 on January 11, 2019, 03:47:30 pmYou can't know if a single warm year (especially in a local geographical region) is due to random variations (basically noise) or a long term trend. But there is a very clear (i.e. statistically significant) long term pattern of global warming. It is as undeniable as a round earth. And the only theory that fits the data is that it is caused by greenhouse gas emissions, and we know where those come from.You don't have to take my word for it, a summary of all the science is available on the web here:https://www.ipcc.ch/report/ar5/wg1/

author: Zero999
author_rank: Super Contributor
timestamp: January 11, 2019, 11:19:48 pm
content: Quote from: apis on January 11, 2019, 09:35:07 pmYes, I know. Why do you insinuate I was denying that was the case?What's also interesting is that the heatwave covered a larger area this year, than previous hot UK summers. However it wasn't hot everywhere: some places were anomalously cooler than normal, such as Iceland and Greenland, which is typical for a positive phase of the North Atlantic oscillation.

author: apis
author_rank: Super Contributor
timestamp: January 11, 2019, 11:41:02 pm
content: I'm sorry if I misinterpreted you. I though you were saying that it's not possible to know if global warming is just a natural variation or if the earth is actually warming up, but it's very clear it is warming, so I wanted to point that out. In my defence, I've heard all kinds of misconceptions wrt climate change in the past so I jumped to conclusions.

author: paulca
author_rank: Super Contributor
timestamp: January 17, 2019, 11:40:19 am
content: So my solar system is back to normal. I believe I read the wrong value which made me think the battery was not holding charge. I read the "Load schedule" which is always 117, which I read as 11.7V which worried me. The battery was actually at 12.5V which is more like it for running the solar system with overcast sky for nearly a week.The charge controller is indeed an MPPT, although a fairly cheap chinese brand it is not an ebay random product, but an epEver 10A controller that I have verified is MPPT.Anyway we have had a few days now with sunlight at least and the battery was happily floating up to 13.6V for a few hours before began putting load on it again.Hopefully December was just a dull month here and things will be back to normal ... and the days are getting longer again. We only really get about 7 hours daylight in December/January. Out of those hours the sun is only really in the correct alignment for my panel for about half of that time. It's pulling in 1.5A this morning. Not that bad for a sun barely peeking over the house roves in front.Also, I do have monitoring which logs all the parameters once a minute. However I haven't looked at it in a while and it was offline for about a month due to a new Wifi router from my ISP not supporting my 10.x.x.x IP range. It's working again though.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 17, 2019, 09:21:45 pm
content: Hi Paul it's really great to hear that your battery is ok after all, today was a day of surplus for me getting 1.5Kwh from my 1Kw array, I could have got more but I ran out of load, hot water full, de-humidifier on and freezers on but I still could not absorb it all so you see I am thinking BATTERY (one day)!As for confusing technology tell me about it, I blew another IRS2110 half bridge driver today yet not the mosfets I hope all because I suspect a PIC is not terminating the current cycle on overcurrent, very hard to prove without further losses, so although your system and problems are at a very high level I can assure you even at the coalface life remains confusing!I think you are from Ireland, I spent a lot of time there inside steam engine boilers at Whitehead, I hope the RPSI is still going strong and entertaining families with the Portrush flyer

author: paulca
author_rank: Super Contributor
timestamp: January 19, 2019, 11:02:49 am
content: Not sure about the RPSI but they have opened a train museum in Downpatrick where they collect old trains and have about half a mile of line to run them on.I live just across from Whitehead in North Down.

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 02, 2019, 05:22:06 pm
content: Quote from: paulca on January 19, 2019, 11:02:49 amI am sooo jealousmany is the time I have been down there lighting up at 4am! You must be able to see, smell and hear them hahaha but I must admit most of the big trains for tours were stabled overnight in Belfast the night before the off.Anyway an update covering the last three years up till the end of last month from my tiny 1Kw array here in the dull UK! 52deg North. This is predominantly a water heating system but during 2018 a GTI was added (export inhibited) to use some of the surplus in the house, this improved the utilization in summer 2018 compared with 2017. There are several outages due to experimentation and uhum magic smoke emissions

author: paulca
author_rank: Super Contributor
timestamp: April 24, 2020, 04:09:43 pm
content: I have too much solar power. My panel is sitting at 22V producing FA squared.I have charged every battery I can find. I have now:100Ah marine primary fully charged.26Ah old primary AGM charged.12Ah Maplin salvage charged.55Ah old car battery charged.About a dozen LiPos charged.My 22Ah USB powerbank charged.Phone, all eCigs, anything I can find, fully charged.It's painful watching the panel sit open circuit. I need ideas.12V 50W off grid hobby system.EDIT: I could use the laptop as the bedroom TV source again, rather than the media PC and run it off a Lead acid to use up some of the power.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 24, 2020, 05:40:37 pm
content: Quote from: paulca on April 24, 2020, 04:09:43 pmIf you have unlimited Internet, run some old laptops/tablets/phones playing Youtube videos to help out makers who currently have lost their primary source of income (including temporarily) as a result of the current crisis? Not sure if that would make them enough to cover the usual cost of electricity but if it's going to waste otherwise...I have since (back around early 2019) reclaimed most of my crypto mining setup to use for other purposes due to coins either crashing or going up in difficulty to the point where they're no longer worth mining. What's left is a tablet mining Swagbucks, now down to about $5/month. The 100W panel I have is now mostly being used to power my IT setup.My latest project with solar is a system that can power the whole house, with no significant rewiring needed. More or less it makes use of a modified Prius inverter connected to a FPGA in order to source current in step to what the load is drawing, in order to not export any power and avoid the hassles associated with doing so.

author: fourtytwo42
author_rank: Super Contributor
timestamp: April 25, 2020, 10:29:07 am
content: Quote from: paulca on April 24, 2020, 04:09:43 pmHow about water heating, do you have an immersion ? If so a small boost converter with MPPT would be an interesting project maybe. If not that then a desk fan to cool your sweaty brow whilst working from homeOf course the weatherman is about to take the sun away again so nature may also have an answer to your problem

author: paulca
author_rank: Super Contributor
timestamp: April 25, 2020, 03:29:34 pm
content: Quote from: fourtytwo42 on April 25, 2020, 10:29:07 amI have a combi boiler nowI did wonder if I could make beer with solar power, but running a 3kw boiler for nearly 2 hours, 6 Kwh, is a bit beyond a 50W panel and a few lead acids.And yes, looks like it could rain for weeks now. Probably my fault, I ordered a BBQ.

author: Zero999
author_rank: Super Contributor
timestamp: April 26, 2020, 09:08:13 am
content: So far this thread has just confirmed that solar power in northern Europe is only from April to September. For it to be any use, we need more energy storage, cables to get power from more sunny places and other energy sources such as wind.We'll probably have another wet summer, especially has we've had a warm and dry April, which is often a prelude to a soggy summer.

author: fourtytwo42
author_rank: Super Contributor
timestamp: April 26, 2020, 06:22:45 pm
content: Quote from: Zero999 on April 26, 2020, 09:08:13 amI would say it shows solar solutions are perfectly feasible at the DIY level with an economic return on investment without spending large amounts of money on so called turnkey solutions. Wind is not practicable in an ordinary UK household as the land area is not available. Energy storage (as in batteries) at a household level is unlikely to ever pay for itself and cables to carry power from north Africa to the uk beggars the imagination. This thread is about SMALL SCALE DIY PV, nothing else.

author: fourtytwo42
author_rank: Super Contributor
timestamp: April 26, 2020, 06:29:56 pm
content: Quote from: paulca on April 25, 2020, 03:29:34 pmI have often thought the same as I make lots of wine & beer, sometimes I plan it so my small 1Kw array is generating when I do the boil for a brew but as often as not I don't have the patience! I have also thought of increasing PV capacity for such occasions (and cooking) but it would be hard to justify it as on average in my case 1Kw is enough for both water heating and the standing loads (like fridge, freezer & PC etc).Actually with a dry garden I am looking forwards to the rain

author: Zero999
author_rank: Super Contributor
timestamp: April 26, 2020, 08:18:01 pm
content: Quote from: fourtytwo42 on April 26, 2020, 06:22:45 pmYes, that's true. Small, domestic solar panels are practical, whilst wind is not and batteries don't pay off. The problem is, what happens if everyone does it? There will be surplus energy in the daytime, especially during spring and summer. There could be some energy storage, like the hydroelectric one in Wales, but we need much more of it. Otherwise energy will end up being wasted during the day, only for oil and gas generators to start up overnight. I can foresee more wastage in areas where there's already a large power station, such as nuclear, which can't be shutdown.

author: Marco
author_rank: Super Contributor
timestamp: April 27, 2020, 02:22:17 am
content: Quote from: Zero999 on April 26, 2020, 08:18:01 pmGrid connection costs will have to go way up, too much of the grid costs are put into kWh pricing.PV costs are going to keep plummeting though, assuming civilization doesn't collapse, so I doubt they will stop making sense. It might stop making sense as retrofit, but I wouldn't be surprised if things like roofing rubber for flat roofs will start becoming PV ... it's not going to add enough cost relative to the bulk cost of the rubber and labour to matter much. Same with siding.QuoteIf you give it out for free, people are going to use it. Hydrogen generation might be energy inefficient, but if the energy is free who cares?

author: paulca
author_rank: Super Contributor
timestamp: December 11, 2020, 03:07:50 pm
content: I think it's time to shut the micro-solar down for the winter. Either that or put the battery charger on it for a few daysIt can't even power the charge controller with the daylight it's getting.

author: f4eru
author_rank: Super Contributor
timestamp: December 11, 2020, 04:20:35 pm
content: your charge controller probably consume quite a lot. What model i it and how much power does it draw ?

author: coppice
author_rank: Super Contributor
timestamp: December 11, 2020, 06:08:36 pm
content: Quote from: paulca on December 11, 2020, 03:07:50 pmBut surely we just need some battery storage to ride over the lulls in output, and existing renewable solutions are going to be fantastic.

author: fourtytwo42
author_rank: Super Contributor
timestamp: December 11, 2020, 09:43:54 pm
content: Good to see the good ole thread still ticking away! daily average this week down to 0.4Kwh/day from a 1Kwe array but last few days steadily worsening due to rain & cloud/fog/clag!I always find this time of year good for maintenance & testing new generations of equipment etc as there's no serious production going on. I am now on my 3rd generation of pcb's (means a big hardware architecture change) and similar in software for the converter having finally integrated the hot water and GTI functions into a single converter.Most recently been tuning the PD loop to get the best transient performance, I tried so hard to model the thing but as I suspect many have found with servo systems the only real method is empirical on the actual machine. Sitting outside with the laptop with the temperature below freezing is a particular kind of torture especially when the sun wont play ball!For those of you using off the shelf equipment I can only feel sorry that you are missing all the pain/funP.S. I seem to get down to about 2W before the system gives up in the evening and start-up at about 4W in the mornings so I am quite pleased with that.Pictures are always fun so here are some scope shots I hope.....

author: paulca
author_rank: Super Contributor
timestamp: December 12, 2020, 12:11:55 pm
content: Quote from: f4eru on December 11, 2020, 04:20:35 pmIt's an EPever 10A MPPT. Last time I checked it and the monitor it powers consumed something like 60mA. Half of that is the Wifi monitor.It works out something like, the 100Ah battery can run the system for 70 days. Although that's probably 40 days as it's a lead acid. It's just that right now progressively more is going than coming in.It hit 30W this morning, for about an hour. So it might live another day or two without life support.

author: Northy
author_rank: Regular Contributor
timestamp: December 13, 2020, 03:19:58 pm
content: What are you guys doing to monitor what's going in/out?I've got a couple of cheap 20W panels charging some gel cells.It was great through the good weather months, I could charge every battery in sight! Phones, tablets etc.It seems at the moment that I can't get any spare capacity, but I don't monitor what goes in/out.Is it just time to turn it off for the winter?Is there a way to cut connection in the dark so the controller doesn't flatten the battery?Are/can home built charge controllers be more efficient?Would adding more panels give me any spare capacity at this time of year?Thanks,G

author: HB9EVI
author_rank: Frequent Contributor
timestamp: December 13, 2020, 04:47:43 pm
content: the Wifi dongle to the Epever sucks in indeed quite much; I left it out of the setup and read out the rs485 by a python script.if the controller kills the battery you have either too little capacity on the battery side or too little input power by the panels.like already said the EPever Tracert 10/20A sucks about 30mA what seems to me quite acceptable for its features.around this time of the year I get my 120Ah battery about every 4/5th day to float charge. When the battery goes under 12,2V, I activate the charger which is integrated in my inverter; this I need to do about 2-3 times per winter; well I'm not consuming any power from the battery december/january, so it's idling. Solar power I have 200Wp, so it's a small island onlyIf you are a good EE, you can construct your own charger, otherwise you're maybe better off with a commercial product, since they are really cheap in the meantime. Imo it's questionable if you can construct one for the money the Epever costs - with the same set of features.

author: paulca
author_rank: Super Contributor
timestamp: December 13, 2020, 06:09:34 pm
content: To collect EPEver stats I wrote this:https://gitlab.com/paulcam/home_heating/-/blob/master/esp8266/epever_rs485_v3/epever_rs485_v3.inoWhich uses an ESP8266 to publish the RS485 epever controller stats.Hardware required is:ESP8266 devboard.MAX485 breakout board.BiDirectional logic level changer (5V / 3.3V)There is a thread of mine about 2 or 3 years old with more details.I then publish that along with all my other "home" stats. Which ends up producing this:Open in new tab and zoom in a lot. I'm going to be porting most of it to MQTT to open it to others.

author: paulca
author_rank: Super Contributor
timestamp: December 13, 2020, 06:19:34 pm
content: Quote from: Northy on December 13, 2020, 03:19:58 pmEven if you do turn it off for winter, if it's outside and a lead-acid, I would charge it fully first. Most solar systems are protected enough for you to just stick a normal 2A car battery charger across the battery without disconnecting it. That's what I do, when the voltage drops below about 11.8V I put the car battery charger on it overnight. Repeat as needed.The EPEver has a handful of low-cut off and low-restore voltage triggers, however I wouldn't trust them. Mine is set to cut off at 10V, but last year the battery collapsed and the charge controller didn't connect it until it hit 8V.The issue with making disconnect circuits is they have to take the full DC amps available at the battery fuse which leaves you with a large power mosfet or a relay. You have to account for the voltage dropping under load and relaxing back up when you disconnect it. You can also risk the charge controller remaining off due to disconnect but it's a rare bluesky winter day.Home MPPT charge controllers are feasible. It's just a buck converter and scanning algorythm. Jullian Ilett on Youtube did a series where he built one. The EPEvers were cheap and featured enough that I didn't bother. Though I was going to revisit it just for fun.Adding more panels would give you more capacity, but also more loss in summer when you can't quite use it all.You'd be better off making sure the panel is mounted high as you can and angled up nearly straight for the winter sun. Battery capacity is more practical.That said it really comes down to the amount of energy you can get in a solar day, what the weather is like and how long your system will run on it's battery with the limited top ups from the panel in winter.

author: paulca
author_rank: Super Contributor
timestamp: December 13, 2020, 06:40:04 pm
content: Calculating my system drain...60mA (30mA for the charge controller and 30 average for the Wifi monitor).60mA * ~12V = 0.72W0.72W * 24 hours = 17 Wh per day = 121 Wh per week.The 100Ah Marine Lead Acid has a theoretical 1200Wh, but a usable 600Wh - degradation having been flattened once, survived two winters and now being 1.5 years old daily cycled. So probably about 400Wh600Wh / 121Wh/w = 5 weeks.The graph I posted shows it's daily decline, occasionally lifted by an hour or two of 25-35W, over 5 months. I need a minimum of 17Wh per day. In November/December/January/February I just don't average that. Working out what I do average will just take a nicer DB query.The only requirement of this solar system is that it runs my garage lights. So I need it for the laundry weekly for 5 minutes. In summer I charge all my battery powered stuff from it and am adding a large LED strip for a few hours after dust in summer.

author: Northy
author_rank: Regular Contributor
timestamp: December 28, 2020, 02:02:36 pm
content: My Solar controller is just one of the cheap blue generic ones from Ebay, initially it was just an experiment to see if I could get a useful amount of energy. In the Summer it seems I can.I'm tempted to buy a 2nd hand big panel now and stick it on the gable-end of the garage to move things on a bit.Maybe the smaller panels would run some garden lights even in winter?G