Looking at getting a home Solar system - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: October 14, 2012, 07:25:52 am
content: As the title says.Anyone in Sydney got any pointers for the best deal/company/parts et.al?I got this spam in the mailbox:http://spnsw2012.loginwindow.com/customPages/solar-power?subSiteId=1$1500 for a 1.5KW system ($2000 with 3KW inverter for expansion)Preferably want an inverter than comms/data logging capable. e.g. ethernet/usb etc.Would be cool if I could feed the data live to my web site or something.An Oz made inverter would be nice.Dave.

author: poptones
author_rank: Frequent Contributor
timestamp: October 14, 2012, 07:51:22 am
content: Cheap Chinese solar just about killed a few American companies.Wouldn't anything be ethernet ready with one of those $5 arm development kits? 12 bit analog i/o, ethernet, usb...

author: EEVblog
author_rank: Unknown
timestamp: October 14, 2012, 08:02:04 am
content: Quote from: poptones on October 14, 2012, 07:51:22 amOnly if the inverter supports data transfer to begin with.Would be nice if I didn't have to dick around and could just plug it in and it generates a usage graph for the web.Dave.

author: EEVblog
author_rank: Unknown
timestamp: October 14, 2012, 08:03:48 am
content: According to this calculator:http://www.solarchoice.net.au/blog/wp-content/uploads/Sydney-Solar-Power-System-Return-on-Investment-Calculator-Spreadsheet.xlsPayback would be about 3 years for a 1.5KW system.We get jack-all feed-in tariff now.Dave.

author: poptones
author_rank: Frequent Contributor
timestamp: October 14, 2012, 08:28:41 am
content: Have you seen this?http://youtu.be/m5rM7QDi_5ELots of simple and meaningful ideas. He raises several good points relative to the issue of "cost."

author: EEVblog
author_rank: Unknown
timestamp: October 14, 2012, 10:09:06 am
content: Quote from: wilfred on October 14, 2012, 09:53:31 amWe are both home during the day now (unless I'm at the lab), so power usage during the day would get offset.Wasn't the case when we both worked 9-5, so makes sense to get a system now.Dave.

author: GeoffS
author_rank: Unknown
timestamp: October 14, 2012, 10:10:33 am
content: OpenEnergyMonitorhas a cheap DIY setup for monitoring power usage including solar.If it wasn't for the hassle of getting the current transformers installed in the meter box, I'd have one of these running now.

author: poodyp
author_rank: Regular Contributor
timestamp: October 14, 2012, 12:06:26 pm
content: It's way too late here and I've been chasing a space shuttle but for a minute I thought you meant a "solar system" model of some sort, and was confused about why a little foam model of the solar system would need 1.5kw...I should go...BTW have you watchedmjlorton'ssolar videos?

author: tom66
author_rank: Super Contributor
timestamp: October 14, 2012, 12:26:50 pm
content: Is it bad that when I saw home solar system I thought of a model of the eight planets in the home?

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 14, 2012, 01:26:50 pm
content: An open hardware grid tie inverter would be a good idea. I have a design for something similar (but it's for a stationary bicycle) but it was designed to work on 120V and would require a lot of modifications to work on unbalanced 240V. (And there were quite a few design shortcomings, like a lot of beginner unfriendly high voltage electronics and a topology that is optimized for low cost and doesn't scale well.)Maybe it could be possible to design one that used a mains transformer so the amount of circuitry directly connected to the mains is minimized? That could also be a way to work around the "no mains DIY" laws in some areas. Make a box connected to the mains that just has some large mains transformers, a contactor, a low loss mains sense ("standby") transformer, overcurrent protection, and maybe a fan, then call it and certify it as a "power supply". (Or if possible, find an existing power supply that would be usable for this purpose and is already certified.) The actual inverter would be in a separate box connected to the first with a short cable, and would work with only low voltages in order to be exempt from certification.

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: October 14, 2012, 02:26:00 pm
content: Dave ,I'm a little surprised that your not more familiar with solar stuff , one of the better companies for making inverters etc. is spouse to be from your country I thought , Outback Inverters ,http://www.outbackpower.com/products/sinewave_inverter/.As for the chineeze , I happy that they are selling low enough to turn the screws on American companies , they have been ripping us off for far too long , with artificial high prices .Trying to keep the use of alternative energy .A number of new manufacturing process's & companies have been bringing down prices for yrs. but those prices never make it to the street .Nano solar ,http://www.nanosolar.com/index.html, is one them , was spouse to be available for .99 per watt several yrs. ago .Home Power magazine is one of the best sources of info here ,https://homepower.com/.Another low cost internet site ,http://www.sunelec.com/From what I have worked with almost any of the quality systems have the abilities your looking for for at least 10-15 yrs. , just have to avoid the cheap stuffI would be happy so supply any other info .John

author: GeoffS
author_rank: Unknown
timestamp: October 14, 2012, 02:31:30 pm
content: Despite the name, Outback Power are a US company.

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: October 14, 2012, 02:52:44 pm
content: Ya , that's why I said I thought , because of the name .Normally I would worry about US companies losing sales to chineez , but when they go out of there way to gouge and keep from moving into the future , the hell with them , move on .I look to efficiently spend my money , I would be willing to spend a little extra to keep my money here , but when I can buy panels for $0.90 to about $2.90 per watt , as compared to some of the store fronts here selling the same products , repackaged , renamed for $10 - $14 per watt , I think they should be prosecuted , when there is some disaster flood etc. and someone is selling on the street water for 10 times the price they prosecute the little guy .I've been into alternative energy for about 30 yrs. and have seen this all the time , just get tired of the BS .Enough on that .

author: tom66
author_rank: Super Contributor
timestamp: October 14, 2012, 03:05:15 pm
content: If the 1.5kW system is $1,499, and the 3kW system is $4,990, what's stopping you just buying two 1.5kW systems and tying them together? Is that not possible?In fact, the 1.5kW system is half the price per kW as the 10kW system. What gives?

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: October 14, 2012, 05:51:04 pm
content: My friend Orris is just wrapping up the installion of I believe a 4 kW system. At nearly 49 degrees, I'm sure the challenges here are somewhat different than they will be for you.Solar Farm UpdateOrris did a lot of research with two major conclusions:1. Active aiming of the panels can tremendously boost performance. Interestingly, tracking either rotation or elevation provide about the same boost. Tracking both wouldn't add much improvement.2. At our elevation, reflectors are a much more cost-effective boost than additional panels.Inverters are used to sell back power to the utility. A GPS module and Aurdino are used to control the tracking.

author: PeterG
author_rank: Frequent Contributor
timestamp: October 15, 2012, 06:13:23 am
content: I have only seen solar panels on house roofs. If i get solar installed i would want the panels installed over my carport(i can fit about 4kw of panels on my car port). Anyone know if the panels 'have' to be installed on the house roof?Regards

author: Rerouter
author_rank: Super Contributor
timestamp: October 15, 2012, 06:19:49 am
content: they can be provided the structure can support them and the men fitting them, the main reason they go for the roof over say a carport is because then you need to raise and tilt the panels, enough that they can act as pretty good sails,

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: October 15, 2012, 06:34:34 am
content: Wind loading of free-standing panels is huge. Orris used fence post stations anchored in concrete. There's a lot of steel holding those panels in place.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: October 15, 2012, 06:36:47 am
content: QuoteI am fairly sure what gives is a subsidy (RECs or somesuch) for the first 1500watts. The effect of this obviously tapers away quite fast above 1500w.You may need to qualify to get this discount too, but it doesn't stop the companies advertising that price with an asterisk.I have a neighbour who moved his system onto his garage, to get more sun. He also has added 3 altitude positions Summer , Middle, Winter and a 180 degree carousel.He moves the thing around by ropes, it moves quite easily. But this only works if you are at home a fair bit.If I got such a system I would make sure that they can do a good quality install, and one that looks good too. If you have partial shade then you must get (I think Monocrystalline) because the polys will give little power if so much as 10% of the panel is shaded.Obviously the siting and aspect can be critical, so double check what they plan to do because they don't give a shit about your efficiency they just want to install and go.

author: G7PSK
author_rank: Super Contributor
timestamp: October 15, 2012, 05:31:52 pm
content: Have a look at this site it is all alternative energy.http://www.fieldlines.comThere is a section on solar.

author: gxti
author_rank: Frequent Contributor
timestamp: October 15, 2012, 06:10:21 pm
content: An OSHW inverter would be cool to design and study but there's no way anyone would let you connect it to the grid without lots of expensive certifications. And without any company to take the blame when one burns your house down, the liability would be on you. I've been tinkering with a multi-channel power meter myself and even just the idea of selling something to read off current transformers makes me a little fidgety. Even though it's only connected to the mains through current and voltage transformers, someone is going to do something stupid and I can't stand the thought of taking the blame.

author: nukie
author_rank: Frequent Contributor
timestamp: October 15, 2012, 11:19:07 pm
content: You might want more than 3kW to support a household during winter time. My 1.8kW hardly produce any power during winter time in Melbourne it was a regret for not having a 3kW. Now I have to upgrade my inverter to support more panels. Going for bigger inverter is good idea, the new panel efficiency goes up over time so you don't have to change much when upgrading the panels in the future.I suggest name brand inverters, they have all their efficiency and specs published and long warranty.I have a SMA SunnyBoy inverter, the webserver? and wireless connectivity is optional and its not expensive. With the feed back tarrif going down, I think it will take a little longer to pay for itself. But the ultimate goal for most solar powered home owners is to boast how much they are saving the earth from burning more coal. Regardless how much energy it took to produce the panels and inverters in the first place.Hopefully the cost(energy used) of these panels will drop, then more people can benefit from Sun power. But being in Australia of the greedy business models it might not happen anytime soon.If you are building a new home, may I suggest solar hot water system with gas boosted. It saves a lot of money and slightly more complicated than in tank electric heater. And also gas ducted heaters.

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 16, 2012, 01:09:58 am
content: Quote from: gxti on October 15, 2012, 06:10:21 pmThus my suggestion to use transformers in a separate box so the inverter itself only work with low voltages. Preferably, it would be nice if someone could find a box containing the transformers that is already certified. There are AC wall warts, but they tend to be lossy and too low power. We could resort to using a transformer along with an external power switching module and a wall wart (for sensing), but just how hard is it to certify a box that only contains a few transformers, a contactor, a fuse or circuit breaker, and maybe a fan? The electronics that make it work won't need certification because they only work with low voltages.And most (if not all) open hardware (and open software) licenses include disclaimers so the creator would not be liable.

author: EEVblog
author_rank: Unknown
timestamp: October 16, 2012, 07:08:26 am
content: Quote from: nukie on October 15, 2012, 11:19:07 pmI've been paying for wind power for a decade now, no coal for me.The solar is mostly for kicks, and eventually financial payback.Dave.

author: G7PSK
author_rank: Super Contributor
timestamp: October 16, 2012, 07:39:41 am
content: If you pay for wind power electricity how do you know that the electricity being delivered was from a wind generator and not a coal powered unit. We have the option to pay more for wind power here in the UK but as you are already charged extra on all power used in order to subsidize the wind farms I think that it is a complete con to then charge a further extra amount for so called green energy for which I have already paid once. I also live in one of the windiest areas of the world and there are wind turbines all around me, I have also built wind turbines and know from first hand experience that the wind does not blow all the time, in fact it is surprising how often the wind does not blow despite being one of the windiest areas of the world. The best place for the wind turbines would be in the jet stream but what would taking energy out of that do to the worlds weather, the gulf stream would be another great source as would geothermal which to my mind offers the best solution and on a cost par with nuclear power and would go down with increased use, the factor against it that I have seen cited most often is drilling cost, then the nutters turn around and drill for oil and gas in deep water or the arctic, geothermal drilling could be done on dry land.

author: Lightages
author_rank: Unknown
timestamp: October 16, 2012, 03:15:55 pm
content: First off: Unless you get grid tie payback, and/or tax rebates, then solar is still not cheaper than just using the grid in almost any part of the world.So some some questions need to be answered first about what you want a solar system to do for you.Is the solar system to be an experiment or education or practical offset of less environmentally friendly power or a total replacement for grid or grid tie payback system?If this is a grid tie payback system, or a system to offset less environmentally friendly power, then you optimize the system to dump power back to the grid at peak payback/cost times. If it is to go off grid completely then you maximize power production all day. The two optimizations are not necessarily the same. It might be that peak power consumption is late afternoon so you optimize you panel orientation for that time of day. If you are maximizing power production it is sometimes beneficial to optimize the panel orientation for late morning before the panels start getting too hot and lose efficiency.If you are going grid tie, you might also want to consider having a big enough battery bank to have some autonomy for a period of power outage from the grid.If you are going off line, the biggest consideration in "making" energy is lowering your consumption first. Get rid of parasitic power use, buy a better fridge or freezer, more efficient anything! A watt saved here will lower your off grid system costs by a huge factor. Before you design any off grid system you NEED to measure your actual daily use of power so as to not find yourself in a deficit power condition.Some useful tips:1. DO NOT think that you can have a huge battery bank for long autonomy and then trickle charge them when power production is good. Lead acid batteries (they are by far the most commonly used) require a minimum % of their rated capacity in charge current or they will die an early death from plate sulphation. The minimum charge current is to ensure that the electrolyte gets moved and that not just that in contact with the lead plates is "locally" charged.2. Count on destroying, or at least causing the early demise, your first battery bank. This happens to almost everyone the first time until they get a grasp on batteries and their quirks. They are not simple devices but rather a mixture of electronics and chemistry.3. For the best bang for the buck used forklift batteries can be very useful especially as a first battery bank that might get trashed.4. The most expensive but least problematic batteries are AGM types. They will withstand freezing, lower discharge and lower minimum charge rates. They are also safe for use inside the house without ventilation.5. The most flexible inverter on the market, IMHO, is the Schneider/Xantrex range of grid tie inverters. They can manage a connection to the grid, a generator, and a huge battery bank all at once. If you connect this with their MPPT60-150 solar charger and some software and a cable, you can get full real time data from the system for a webpage and logging too. There is also a generator management controller. All of this connects together on their proprietary buss which is an adaption of CANBUS.6. Solar panels are now so cheap that sun tracking is not worth it. The added expense and maintenance for the tracking system and mounting can gain you around 30% more energy harvest per day. Usually it is cheaper to add more panels to get that extra 30% at less cost and maintenance. Seasonal panel angle changes ARE worth considering.7. If designing for total off grid, consider the number of days you might not have sun at a stretch and design the battery size to meet that length of time, and then the number of panels needed to charge the minimum rate required by the batteries.8. Design for battery depletion of no more than down to 70% capacity for normal daily use, and for occasional 50%. Batteries do not like being discharged to less than 50% and should be recharged above 90% as soon as possible, better within two days always. Take a battery system down to less than 50% and their life will be shortened dramatically. Take them to 0% charge and kiss them goodbye.9. If you plan on piece by piece expansion of a system then it should be noted that you cannot add more batteries into a bank after they have been cycled more than somewhere around 50 times. There will too much of an imbalance in the batteries that they will die quite fast from imbalance of charge/discharge. It is always better to have too much panel instead of too much battery as far as battery life goes. But on the other hand it is better to have the size of battery bank you need for proper autonomy time as it is not easy to add to the bank later.10. For an off grid system, you need a generator. Don't cheap out. Get a good inverter output generator and not one of the cheap Chinese simple generators. Their output waveform is usually atrocious and some inverters will probably reject them as power source or they can be dangerous for fridge motors for example. The good inverter output generators are also usually quieter and more fuel efficient.11. If you do not want to go totally off grid then maybe a good design is to have your solar system take care of specific items you wish to have working during a power outage. A fridge, wireless telephones, cable modem, a couple of lights and a laptop are usual targets for this approach. That way you still have the food safe, and some light consumption conveniences.If this is to be an experimental/play system then there are so many options in the low range it is hard to recommend anything specific. The most important thing is to not bother with anything other than sine wave output inverters as the "modified sine wave" ones are useful for some things but absolutely useless for other equipment. DO NOT use car batteries for energy storage. They are not designed for this and will die within months from this kind of use. Deep cycle marine batteries are still not suitable as they are designed with slightly thicker plates and can take a slight deeper discharge for a slightly longer period of time but they are not designed for long term discharge. A good start for small systems are wheel chair batteries in either AGM or GEL cell types.

author: johnnyfp
author_rank: Frequent Contributor
timestamp: October 17, 2012, 04:03:16 am
content: If money was no object, what about LiFEPO4 cell's? They seem to have better cycling capabilities then Pb.

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 17, 2012, 04:28:11 am
content: If you're looking to make an independent power system (on board a RV, for example), it's much more cost effective to try to use the energy as it's being generated. For example, you could have the refrigerator automatically set itself to a lower setpoint when there is a lot of sunlight, resorting to batteries only if it really needs to. (Add more thermal mass to the fridge in the form of water in order to make it work more effectively. It works really well if the water can freeze, since phase change is a really good way to store energy.)

author: EEVblog
author_rank: Unknown
timestamp: October 17, 2012, 05:28:48 am
content: Quote from: G7PSK on October 16, 2012, 07:39:41 amYou don't know where your actual electrons comes from, it's called the grid for a reason.The whole idea is that you pay extra to buy available capacity on a wind farm, or solar, or gas, or whatever.In Australia it is a government audited program and publicly available info, and there are various levels from 10% to 100%, and 100% "new" which means new infrastructure put in place after a certain date.It is very important who you sign up with and what plan to know exactly what you buying.When we first signed up we did our own auditing of the whole thing, and it was all above board and added up.Dave.

author: Strada916
author_rank: Frequent Contributor
timestamp: October 17, 2012, 05:40:43 am
content: Had a 3kw panel array in stalled. With a sma Sunnyboy 4000tl. Its been runn oi ng for a yesr now. In that year it has made 4500kWh. Thats about 13kwh a day that we are not billed. On average synergy snd WA gov pays us about $25 a month in feedin.Sma have Bluetooth connectivity and you can use sunny explorer so read data remotely within the house.

author: G7PSK
author_rank: Super Contributor
timestamp: October 17, 2012, 12:47:43 pm
content: Quote from: EEVblog on October 17, 2012, 05:28:48 amHere in the UK due to the EU regulation we pay a levy on all the power used if I then went for so calld green power I then get charged extra on top having already paid the levy used to subsidize wind power, and all this government regulated.Also if I buy green power I still get to pay the carbon emmisions tax.