hybridfree/eevblog-posts huggingface dataset:
Fresnel lens based CPV experimental bits and pieces available (Australia) - Page 1
Forum section: electronics / general

author: salbayeng
author_rank: Frequent Contributor
timestamp: August 30, 2018, 09:47:26 am
content: Hi Cleaning out the shed.I have some Concentrating PhotoVoltaic experimental bits and pieces.some bits are for a smaller test unit 600mm square lens (see photo below)other bits are for much larger test units with a 1200mm diameter fresnel lens with ~ 1m focal length.They focus about a kW of sunlight down to about a 20mm spot, so quite easy to set fire to the test equipment, your lawn, shoes, socks, cables, - whatever gets in the beam.When tracking properly with the right PV cells, you can get about 160W at 10v, although the heatsink requires water cooling.These would suit a serious mad-scientist experimenter.Located north of Newcastle (Australia)
some updated lyrics - SpaceX Oddity - Page 1
Forum section: electronics / general

author: besauk
author_rank: Contributor
timestamp: August 23, 2018, 01:16:39 am
content: Bond Holders to Elon MuskBond Holders to Elon MuskTake your sleeping pills and put your helmet onBond Holders to Elon Musk (ten, nine, eight, seven, six)Commencing write-down, collections on (five, four, three)Check covenants and may God's love be with you (two, one, charge-off!)This is Wall Street to Elon MuskYou've really made it graveAnd the papers want to know which drugs you takeNow it's time to leave the factory if you dare"This is Elon Musk to Bond HoldersI'm stepping through the doorAnd I'm floating in a most peculiar wayAnd the stars look very different todayFor hereAm I sitting on a small cotFar below quotaPlanet Earth’s not greenAnd there's nothing I can doThough I'm past three hundred thousand carsI'm feeling very illAnd I think my auto knows which way to goTell my longs I love them very much they knowBond Holders to Elon MuskYour bonds are junk, there's something wrongCan you pay us, Elon Musk?Can you pay us, Elon Musk?Can you pay us, Elon Musk?Can you "Here am I floating 'round my small cotFar below quotaPlanet Earth’s not greenAnd there's nothing I can do"hope this provided a laugh or two...
Looking for a source for powered (warm-white?) LED panels - Page 1
Forum section: electronics / general

author: cdev
author_rank: Super Contributor
timestamp: August 17, 2018, 01:57:23 pm
content: I want to set up some low voltage lighting around my house and power it off of a central 12 and 5 volt PC power supply with battery backup. So basically I would like to get a bunch of small, bright flat, mountable LED panels and drivers or integrated with drivers. Whats the best way to proceed? I'm not in any big hurry, I want to do it right and learn something as I go along without spending too much.

author: nctnico
author_rank: Super Contributor
timestamp: August 22, 2018, 11:20:39 pm
content: Quote from: cdev on August 17, 2018, 01:57:23 pmLook on Aliexpress. I've bought a bunch of led panels for my bath room. I'm working on building the driver electronics myself though. There are several boost converter chips available for this purpose.
High power SSR wanted - Page 1
Forum section: electronics / general

author: danjenkins
author_rank: Contributor
timestamp: August 02, 2018, 05:38:22 pm
content: Hi,Does anyone know an SSR that can switch an 11kW at 3ph 380V with a control voltage of 220VAC. and which is not larger than an ordinary relay?I found one that could work from ABBhttps://files.clrwtr.com/userfiles/ct/documents/abb-low-voltage/abb-solid-state-relays.pdfbut the dimensions won't work for my application. I probably won't find them, due to the physical dimensions and the required cooling.Thank you
Electronic load testing - Nickel Metal Hydride batteries - Energy storage  - Page 1
Forum section: electronics / general

author: Transformedmaggot
author_rank: Newbie
timestamp: July 04, 2018, 12:09:34 am
content: Hey everyone,I recently found a way to recondition used cylindrical NiMH batteries pretty well (typically those used in the Honda Insight series). However, I want to know whether the batteries will hold practically in the real world outside the laboratory. My aim is to utilize these batteries as back-up storage for a house or maybe even put them back into the car. These batteries have a nominal voltage of 7.2 Volts and a rated capacity of 6.5 Ah (Though the reconditioned pack is obviously lesser than this value). To succeed in this, I'm aware that I need to test these batteries and mimic real world situations.I purchased the Agilant N3301A/N3304 electronic load tester to help me do just that. The device can do a lot with various settings - CC discharge, CV discharge, constant resistance discharge, pulsed discharge, transient discharge etc etc. I'm completely new to this so my question is:What tests should I typically run to mimic that of the battery being deployed in a hybrid vehicle? In addition to that, what tests should I perform to know whether these batteries can sustain being used as a back-up storage center for residential purposes? In other words, what are the key things to look out for during these tests.All inputs on different tests to perform are hugely appreciated! I'm still an amateur at this, but I'm keen to learn and continue developing. Thanks for the time guys!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 04, 2018, 02:22:41 am
content: Cat fall asleep?Anyway...My understanding is you want to discharge them very slowly at first, to prevent reversing any low cells in the "stick". As you cycle charge in and out, they will gradually equalize, and you can do so at higher and higher currents until it's back to a normal condition.Do not discharge below one flat cell's worth below nominal voltage, because you're probably reversing cells at that point. On the V(t) curve, zoomed out, you'll see the voltage drop suddenly, as each cell poops out.I designed a couple tools for a Honda hybrid battery service company, a few years back; I'd have suggested talking to them, except you've already bought a pricey bit of test gear so I guess you won't be needing that right now.Tim
New Distant Wireless Power Technology ? - Page 1
Forum section: electronics / general

author: zborac
author_rank: Newbie
timestamp: June 14, 2018, 07:59:38 pm
content: Any comment abouthttp://getcorp.com/technology?

author: f4eru
author_rank: Super Contributor
timestamp: June 14, 2018, 10:05:03 pm
content: One comment :Don't approach it if you have any metal inside you, or if you want to keep your mobile phone, car keys, RFID credit cards, passports working.Yeah, they reinvented the multiturn loop antenna with a cable. Yay. And put lots of power into it. Cool looking transmitter. We cam make HAM transmissions with that. just avoid to operate it near people.QuoteTranslated: We'll cook you from the inside out. Or not if our frequency is low enough, which it seems to be.Cooooome and visit our demo area ! Get cancer for free, perhaps.
Do someone still use big NiCd at home/work for solar storage? - Page 1
Forum section: electronics / general

author: Miyuki
author_rank: Frequent Contributor
timestamp: April 19, 2018, 10:33:22 am
content: Hi,I have a possibility to buy big NiCd battery (120Ah cells) for almost no price should be at 75-80% capacityI want to ask if someone have experience with it ?

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 19, 2018, 02:33:15 pm
content: Do you have a way to test it first? NiCd is a very forgiving chemistry, even more so than lead acid. What I'm not sure about is disposing of it when it finally does fail, since it's hazardous waste just like lead acid, but I don't think auto parts stores would accept large used NiCd.

author: Miyuki
author_rank: Frequent Contributor
timestamp: April 19, 2018, 02:44:06 pm
content: Disposing is not a problem here as here is still manufacturer and buy them back for a few cents per kiloWhat is best way to test them at first ?I can buy 89 of 120Ah cells so it will be lot of cells to inspect

author: james_s
author_rank: Super Contributor
timestamp: June 04, 2018, 03:40:06 am
content: If it's really cheap just grab it, if nothing else it should be fun to play with. I use a deep cycle lead acid battery to power an inverter during power outages, a big NiCD battery would offer higher energy density.

author: David Hess
author_rank: Super Contributor
timestamp: June 04, 2018, 09:33:01 am
content: If these are flooded cells then you should be able to check the electrolyte (potassium hydroxide) level and top it off with distilled water and they are practically indestructible; only flooded nickel-iron cells are tougher. They would be fabulous for off-grid solar storage if you can find a suitable charge controller.

author: james_s
author_rank: Super Contributor
timestamp: June 04, 2018, 06:28:54 pm
content: Flooded NiCD? I don't think I've ever encountered such a beast, what are they used for? Aircraft batteries?

author: David Hess
author_rank: Super Contributor
timestamp: June 04, 2018, 07:17:46 pm
content: Quote from: james_s on June 04, 2018, 06:28:54 pmAircraft and military applications were common because they have a wider operating temperature range, are more rugged, and perform better than lead acid batteries. Flooded cell NiCd were also used in traction and backup applications. Lead acid batteries are cheaper but do not last as long.They still make them for demanding applications:http://www.sbsbattery.com/products-services/by-product/batteries/nickel-cadmium-batteries-1.htmlhttp://www.advancedbattery.ca/content/alcad-flooded-ni-cd

author: james_s
author_rank: Super Contributor
timestamp: June 04, 2018, 08:55:01 pm
content: Those are neat, they look very expensive though.

author: David Hess
author_rank: Super Contributor
timestamp: June 04, 2018, 10:54:30 pm
content: They were more expensive than lead-acid for a given energy storage but less expensive once service life was taken into account because they last so much longer.
dodgy solar panels? - Page 1
Forum section: electronics / general

author: Simon
author_rank: Unknown
timestamp: July 06, 2018, 01:11:49 pm
content: I bought 6 of these panels here:https://www.ebay.co.uk/itm/142829791758Yes they have clearly been hanging around but I am a bit concerned about the markings inside the panels that looks like moisture to me corroding the collector wires.Should i exert the powers of PayPal and my credit card company on this seller ?

author: ahbushnell
author_rank: Frequent Contributor
timestamp: July 06, 2018, 08:30:04 pm
content: Quote from: Simon on July 06, 2018, 01:11:49 pmGood luck!

author: Simon
author_rank: Unknown
timestamp: July 06, 2018, 09:07:01 pm
content: Are the panels any good ?

author: Simon
author_rank: Unknown
timestamp: July 07, 2018, 09:14:29 am
content: Well I messaged him and got a very fast response saying that he does indeed have a pile of rejects and a pile of good ones (2 of 6 are indeed good) and the person he left in charge of shipping picked the wrong ones and he will send replacements. So hopefully all will be well and i may even end up with 4 spares a couple of which are not so bad but I'd not trust to put them in a string of 14 and have one panel fail the lot.

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: July 07, 2018, 10:14:58 pm
content: If they were described as New then this is unacceptable. All depends on the description.

author: Seekonk
author_rank: Super Contributor
timestamp: July 07, 2018, 10:33:07 pm
content: I had two bad panels where a section in each got week. Test the voltage across the bypass diodes. Each panel still has a good section and I used the two good sections in series to make the equivalent of one good 12V panel. Alas, two years later those other sections had failed too.

author: Simon
author_rank: Unknown
timestamp: July 08, 2018, 08:25:41 am
content: Well that is under the epoxy and the wires appear corroded. I don't know if it is unmixed compound that is acidic unless mixed.

author: station240
author_rank: Unknown
timestamp: July 08, 2018, 08:14:24 pm
content: The solar installers online have been calling these "snail trails".Believed to be caused by microcracks in the cells during install, eg from people walking on the panels.

author: Simon
author_rank: Unknown
timestamp: July 08, 2018, 08:24:33 pm
content: So why the colour and apparent corrosion? it does not look cracked, just like there is something wrong with the potting.
Can dave buy POWR tokens with his solarroofways? - Page 1
Forum section: electronics / general

author: Beamin
author_rank: Super Contributor
timestamp: May 26, 2018, 01:38:55 pm
content: Would that make sense? It would be great to get 1st hand knowledge of the one alt coin that serves a greater purpose. Also I missed out on taking full advantage of the powr ICO buy a few days. DOH! Could have turned 400$ into $5000 but instead I kept the tokens so it may be good in the long run. I think they are available in his city? Don't tell but I invested before reading the white paper which according to youtube is all you have to do to make huge GAINZZZZ on alts. Read bitconnects white paper don't try to understand it and TO THE MOON ALICE... one day …I'm sure there are restrictions but still would be a great step away from fossil fuel economy.
Where to buy quality PV panels in the US? - Page 1
Forum section: electronics / general

author: DougSpindler
author_rank: Super Contributor
timestamp: April 26, 2018, 05:43:15 pm
content: In one the posts I made about PV solar someone posted a link of where to buy good quality solar panels at very affordable prices in the US? Can'f find the link, anyone have any recommendations?Thanks

author: ez24
author_rank: Super Contributor
timestamp: April 26, 2018, 06:40:47 pm
content: Is this it:https://www.solar-electric.com/residential/solar-panels.html

author: DougSpindler
author_rank: Super Contributor
timestamp: April 26, 2018, 06:48:51 pm
content: Quote from: ez24 on April 26, 2018, 06:40:47 pmThanks but no. And it's not Wholesale Solar either. The web site say the company is located in Florida and they offer panels by the container, pallet or panel. The panels are located in Florida and California.

author: bicycleguy
author_rank: Frequent Contributor
timestamp: April 29, 2018, 12:15:59 am
content: That was before trump tariff. Ever since he mentioned tariffs the prices have been rising.

author: DougSpindler
author_rank: Super Contributor
timestamp: April 29, 2018, 03:59:24 pm
content: Someone posted a link a couple of weeks ago to one of the other messages posted in this forum. Stupid me, I didn’t flag it or comply the link. I’ve now spent a couple of hours trying to find it without success.I’m wondering if it might have been removed?I hope the person who posted will re-post a link.

author: mtdoc
author_rank: Super Contributor
timestamp: April 29, 2018, 04:52:46 pm
content: Sun ElectronicsFor small volumesSolar Blvdis good too.

author: DougSpindler
author_rank: Super Contributor
timestamp: April 29, 2018, 05:04:19 pm
content: Quote from: mtdoc on April 29, 2018, 04:52:46 pmlThanks. the first one, Sun Electrocnics is the one I’ was looking for.Have you punched anything from them? I need about 20 panels and they have panels about an hour’s drive from me.

author: mtdoc
author_rank: Super Contributor
timestamp: April 29, 2018, 05:19:35 pm
content: I've purchased 2 different pallets of panels from them. I also purchased an inverter from them. 3 separate transactions over a few years. Phone sales staff sometimes a bit "unprofessional" in their interactions but they've always been responsive to call backs or emails and I've had no problems with the sales and delivery (via freight). I know several others who have also had good experience with them.

author: DougSpindler
author_rank: Super Contributor
timestamp: April 30, 2018, 05:46:53 pm
content: Quote from: mtdoc on April 29, 2018, 05:19:35 pmThanks

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: May 03, 2018, 01:58:21 pm
content: I can not verify there info , it is the only one I have that gives who made what where ,https://www.solar-facts.com/panels/panel-manufacturers.php
Inverter power range and battery mismatch correction - Page 1
Forum section: electronics / general

author: HumbleBumble
author_rank: Newbie
timestamp: June 02, 2018, 01:28:02 am
content: Hello!So im here to find out (what my gut tells me) why this idea wont work. I am currently running an inverter with a battery range of 41v to 63v. However the usable battery range is 38 to 49. Obviously I am only able to get the top end of the battery. If I were to connect a boost converter from the battery to the battery to boost the voltage for the inverter, would it work? Battery resistance is about 400mohms. Boost converter is Chinese special claiming 1000w, goes for about 25 dollars.

author: f4eru
author_rank: Super Contributor
timestamp: June 02, 2018, 07:49:44 am
content: Test it !Often, a guaranteed 41V still works at 40 or 39.But you'll have to keep the cabling short and thick to avoid losses at full power.
PCB-4S7A-01 Lithium Ion protection board won't start - Page 1
Forum section: electronics / general

author: AlienRelics
author_rank: Unknown
timestamp: April 17, 2018, 03:23:21 pm
content: Is there something I need to do to start these boards?I've installed two new boards, PCB-4S7A-01 4S on four cells. The cells are at about 4V each, within a few hundredths of a volt each. But the output from the PCB is zero volts.I can't link to where I bought the boards, but these appear to be a slightly higher current version of the same thing.https://www.alibaba.com/product-detail/led-panel-pcb-printed-circuit-boards_60395421986.htmlIs there something special I need to do to get these to work? Or a specific order I need to solder the cells to the boards? Because of the way they are laid out in the pack (I'm replacing a bad board), the simplest way is to solder B+, B-, then B3, B2, and B1 last.

author: AlienRelics
author_rank: Unknown
timestamp: April 17, 2018, 03:36:49 pm
content: I answered my own question....I connected the power terminals P+ and P- to a generic power supply set at 14.8V@100mA, and the PCB has started working.
Ausnet runs suburban street in off grid mode for almost 24 hours - Page 1
Forum section: electronics / general

author: station240
author_rank: Unknown
timestamp: March 19, 2018, 06:27:22 am
content: http://reneweconomy.com.au/ausnet-takes-suburban-street-off-grid-almost-24-hours-91549/https://www.ausnetservices.com.au/en/Misc-Pages/Groundbreaking-trial-uncovers-new-possibilitiesnote: Ausgrid is a Victorian electricity company, not a national one as the name implies.QuoteA big improvement on the 9 hours in an earlier test.QuoteYup Australian summer does that, still they got very close to their planned 24 hours.

author: ludzinc
author_rank: Unknown
timestamp: March 19, 2018, 06:32:06 am
content: Quote from: station240 on March 19, 2018, 06:27:22 amAnd this is a good thing?

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: March 27, 2018, 03:37:25 pm
content: The cost of electricity in Victoria might have had something to do with it.
Genset rotor Diode question - Page 1
Forum section: electronics / general

author: Trailboss
author_rank: Contributor
timestamp: March 09, 2018, 04:38:41 am
content: I didn't want to double post, but I posted a question in the repair section on the Genset rotor diode issue, figuring maybe there might be some power folks in this forum knowledgeable on generator windings etc, thanks.
DC to AC converter - Page 1
Forum section: electronics / general

author: WilliamBarati
author_rank: Newbie
timestamp: February 22, 2018, 09:20:51 am
content: HiAs I know about the pure sine wave inverter they consist of two main stage, first is isolated DC-DC converter to bring the voltage up then is H-Bridge and low pass filter, am I right?I know about isolated DC-DC converter but I have no idea about the low pass filter and how the schematic will look like.Anyone can help me?

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 23, 2018, 02:09:20 am
content: The LPF is going to be a simple LC filter.
Anyone using homemade biogas? - Page 1
Forum section: electronics / general

author: niladherbert
author_rank: Contributor
timestamp: October 03, 2018, 10:14:23 am
content: It's something I have looked at every once in a while (Really for if the oil runs out). Is anyone running a biogas system of any kind? Either for heat, electricity or transport.

author: RoGeorge
author_rank: Super Contributor
timestamp: October 03, 2018, 10:33:49 am
content: http://www.biteco-energy.com/biogas-calculator/From 1000 Kg of pig manure and litter, you get the equivalent of only 8 KWh in biogas.

author: f4eru
author_rank: Super Contributor
timestamp: October 03, 2018, 10:48:17 am
content: Quote from: niladherbert on October 03, 2018, 10:14:23 amit's not a matter of "if" but "when"Quote from: niladherbert on October 03, 2018, 10:14:23 amYes, it's in use
2-3kW PV setup advice / ideas. - Page 1
Forum section: electronics / general

author: shakalnokturn
author_rank: Super Contributor
timestamp: February 19, 2018, 04:11:08 pm
content: I have some equipment as it is but I'm seeking ideas from wiser people here as I do not know of half the equipment that exists.I'd like a setup that can:MPPT at all times.Grid-tie only to not waste any excessive PV production.Run disconnected from the grid if needed.If possible switch automatically from grid-tied to standalone without blowing-up.Charge batteries. (48V)Run off batteries if needed.Things I have:(Sorry some datasheets are French but the specs should be clear enough.)3kW non-isolated grid-tie inverter.http://ecosun.fastsite.fr/images/ecosun/upload/fiche_technique_Ainel_K_v2.pdfTen 280W polycrystalline PV panels.http://recom-sillia.com/downloads/datasheets_en/RECOM-SILLIA-60P_265-285_(Plus)_EN.pdfThree (only) second hand Marathon L12V80 12V 80Ah batteries.https://www.blueboxbatteries.co.uk/dyn/filemanager/exide-marathon-l12v80-by-blue-box.pdf

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 19, 2018, 06:23:48 pm
content: Well first of all if you want a battery based system you do NOT want a transformerless GTI or else your battery bank will be at grid potential, highly dangerious!It seems your best bet is a charge controller to connect your panels to your batteries though I have not seen one that powerful and then a low voltage input ISOLATED grid tie (that also has an inverter mode and a transfer switch) to connect your batteries to the grid.You mention a 48V battery bank and then seem to say you have 3 X 12V batteries ?

author: mtdoc
author_rank: Super Contributor
timestamp: February 19, 2018, 06:49:26 pm
content: To do what you want you will need a "grid interactive" inverter.For example these Outback Power invertersOutback used to sell inverters compatible with the European market - not sure if that is still the case.German company SMA makes the Sunny Island inverterI think Victron (Dutch company?) also makes some grid interactive models.For an MPPT charge controller - I can highly recommend the Midnite Solar Classic 150 inverter for your application.
Adhoc Grid Tie Inverter in the UK - Page 1
Forum section: electronics / general

author: paulca
author_rank: Super Contributor
timestamp: February 02, 2018, 11:49:30 am
content: So, I was looking up on how GTIs work. I also seen several videos of people running basic 1000W GTIs in the UK, but without a RoC or renewables contract with the energy provider and special meter.If I understand correctly due to voltage drop the power will go to running the closest load, ie. your house, your ring main, you lights. However if your load drops below the output of the GTI then the slightly elevated voltage will cause power to leak back out onto the grid.This is fine. However what is not fine is if it runs you meter backwards. In fact in the UK that is a criminal offence. it would/could be considered tampering with your meter to get free electricity. You could also be considered rogue micro-gen and fined.It would be a while before I would be able to produce enough power to leak out onto the grid, but it is possible when I move house and beef up my panel(s) it could happen.Would it be safe enough to test the meter does not run backwards (a lot will not) and just stop. If the meter does run backwards then are there anyways to sense and limit the GTI to the current load in your house? Maybe a clamp meter on the meter box input live and allow the GTI to ramp up until that hits 0 and back off if it hits -0.01 Amps.

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 02, 2018, 03:50:04 pm
content: Where the current goes strictly follows ohms law so if multiple loads are present it will be apportioned according to impedance, e.g. lowest gets the most!Insofar as meters you had best check the details of your meter online to find out what it's reaction will be, I would be suprised if you had an electro-mechanical one, most are electronic these days but many are not bi-directional and may indeed flag up fraud if there is any reverse current flow.If you are considering a GTI you should speak to your DNO (Distribution Network Operator) (not who you pay bills too) who you report power cuts too. They will advise you if your contemplated GTI is acceptable or not.Finally you cannot obtain credits for the power in the UK unless the whole installation and installer person meets the renewable certification requirements (MCS).As for knowing when you are exporting some meters change there LED color so you could potentially detect that or it's a current clamp and voltage tap (for that I use an AC wallwart) and some software to determine the phase relationship between voltage and current, ignoring power factor this swaps 180degrees between import and export.Have fun and play safe
Do PVs with a load run cooler than without it? - Page 1
Forum section: electronics / general

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: January 28, 2018, 07:10:16 pm
content: Imagine a one square meter totally black matte PV with 100% efficiency receiving 1kW/m2 radiation from the sun. If it has no load connected all that energy (1000 joules/s) turns into heat and raises its temperature. Now you connect a 1kW load 10 meters away and instead of heat you'd be pumping all that energy to the load and... the PV won't heat up.Does that sound about right?In the real world the efficiency is ~20% max, but if the same principles apply it should be cooler if fully loaded than if not?

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: January 28, 2018, 07:59:23 pm
content: Quote from: blueskull on January 28, 2018, 07:15:46 pmOk, good... that's what I was saying yesterday in this threadhttps://www.eevblog.com/forum/chat/crazy-claims-made-by-electronicselectrical-salesmen/msg1411459/#msg1411459when you told me "Are you on some good stuff?"

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: January 28, 2018, 09:22:07 pm
content: Modulo the hyperboles, as in "save that PV energy into batteries, a zillion powerwalls, climate change solved", the principle of "capture the sun's energy (somehow) don't let it turn into heat" is sound, isn't it?We are burning enormous amounts of fuel to turn 20..40% of its energy into useful work and in the process we release 60..80% as waste, useless heat, if we instead got all that work from the sun: 1) we would be removing that heat from the surface of the earth and turning it into useful work instead and 2) we would not be releasing that 60..80% of waste, useless heat.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 28, 2018, 10:09:49 pm
content: Quote from: blueskull on January 28, 2018, 08:09:38 pm1kWh of lithium batteries go for around $200 nowadays and $200 worth of electricity at commercial rates is only about 5000kWh. In reality, the raw materials are the majority of the cost so the actual factor would be much less than that.The point that there are cheaper ways to manage energy for a lot of applications still stands.
Artificial Photosynthesis as a Frontier Technology for Energy Sustainability - Page 1
Forum section: electronics / general

author: cdev
author_rank: Super Contributor
timestamp: January 22, 2018, 03:52:55 am
content: Artificial Photosynthesis as a Frontier Technology for Energy SustainabilityEnergy Environ. Sci., The Royal Society of Chemistry 2013, DOI: 10.1039/c3ee40534fAbstractHumanity is on the threshold of a technological revolution that will allow all human structures across the earth to undertake photosynthesis more efficiently than plants; making zero carbon fuels by using solar energy to split water (as a cheap and abundant source of hydrogen) or other products from reduced atmospheric carbon dioxide. The development and global deployment of such artificial photosynthesis (AP) technology addresses three of humanity’s most urgent public policy challenges: to reduce anthropogenic carbon dioxide (CO2) emissions, to increase fuel security and to provide a sustainable global economy and ecosystem. Yet, despite the considerable research being undertaken in this field and the incipient thrust to commercialization, AP remains largely unknown in energy and climate change public policy debates. Here we explore mechanisms for enhancing the policy and governance profile of this frontier technology for energy sustainability, even in the absence of a global project on artificial photosynthesis.Keywords: artificial photosynthesis, solar fuels, solar energy, renewable energy, sustainability, nanotechnologyDownload athttps://ssrn.com/abstract=2235961

author: Kleinstein
author_rank: Super Contributor
timestamp: January 22, 2018, 04:55:07 pm
content: There is already the option to use PV and electric production of H2. So the artificial Photosynthesis would only be good if really cheap. With the likely needed tubing this is not very likely. In addition PV could be used to electricity too - so separating the energy collecting cells and H2 conversion has additional benefits.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: January 22, 2018, 11:10:52 pm
content: From what I can remember from studying natural photosynthesis years ago it's not very efficient, on the order of 1 - 2 % incoming radiant energy to chemical bonds. So beating it not necessarily impressive or useful. As Kleinstein says it also has to beat the incumbent solar panels which are at industrial scale pricing now. The devil is in the details of how it can scale outside the lab and does it require ultra-expensive and delicate catalysts.
Infratech's Energy on Demand System - Page 1
Forum section: electronics / general

author: fusionwaste
author_rank: Newbie
timestamp: January 19, 2018, 03:05:43 am
content: Hi, do anybody know technical details or scientific analysis performed on this system?Just heard about it but was unveiled April 2017 and was/is backed apparently by the University of Newcastle and received a CSIRO grant.They are vague about the actual chemical process and claim is patented but received a lot of media hype.Some technical claims they make look thermodynamically dubious at the least.Thanks.

author: Someone
author_rank: Super Contributor
timestamp: January 19, 2018, 03:54:35 am
content: Being a "patented" process all that information is by definition public, you can see the implementation details in US patents 9314740 and 9346013. The bigger questions are what are the actual efficiencies of this process compared to existing co-generation turbines and batteries.
DIY hydrogen fuel cell? - Page 1
Forum section: electronics / general

author: adjustttt
author_rank: Contributor
timestamp: December 19, 2017, 07:14:36 pm
content: Is it possible to build a hydrogen fuel cell that is capable of producing 2 watts with the same kind of technique youtube user Cody'sLab used in this video? But have it produce 2 watts.I read in the comments that he didn't have the electrodes close enough together and that that could decrease the efficiency.Or this is completely impossible since I calculate that it would need to be 2778 times more efficient than his.I know that even this is possible it is extremely inefficient and other bad things but I am after the unlimited charge/discharge cycles this could or so I think. thanks

author: Belrmar
author_rank: Regular Contributor
timestamp: December 28, 2017, 08:03:42 pm
content: welll..... for the amount of platinum that it would need , its not worthit to wonder around that, pretty wastefull of a precious metal and it wouldnt efficient at all

author: amorphous
author_rank: Newbie
timestamp: December 29, 2017, 03:22:24 pm
content: Yes, it's possible using this method. This is similar to how the first fuel cell was made in 1839. You would need a lot of platinum to do it this way. Modern fuel cells use platinum nanoparticles on carbon micro-particles for very high surface area fuel cells. If you do it the modern way, you can get very high power densities. For example, the Toyota Mirai fuel cell car uses a fuel cell stack that has a power density of 3kW per liter. So, if you wanted 100kW peak power, you would need a fuel cell of this type that is 33L in volume.This is a nice little demonstration and everything he says in the video is true. It is important to note that most fuel cells (including the one in the Toyota Mirai) only combine hydrogen and oxygen to make water and electricity. Splitting water to make hydrogen and oxygen in large amounts and for a long time requires a different setup than a "regular" fuel cell.I worked on fuel cells for over 10 years. They are a lot of fun and can do some amazing things, and are very energy efficient, especially compared to internal combustion engines.
Lithium iron phosphate flat cells - Page 1
Forum section: electronics / general

author: cRash1001
author_rank: Contributor
timestamp: December 04, 2017, 05:50:41 am
content: I am looking for LiFePO4 3000-4000 mAh Flat Battery Cells. All I could find was cylindrical batteries and flat batteries which are too large about 170mm in length for my project, i want a flat battery of dimensions of that of a Lithium Ion battery used in mobile phones like 80mm in length, 60mm in Width and about 5-10mm in height. Plz suggest some LiFePO4 batteries of any dimensions less than 100mm in length, 80 mm in width, 5-15 mm height.

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 21, 2017, 08:28:10 pm
content: I think there is no big market for that yet, hence they are hard to find. For the dimensions you suggest though, you won't find LiFePO4 batteries in that capacity range. They will be significantly bigger (see theproduct list on the web site below).What you call "flat" is actually what is called the prismatic form factor.You can actually find some here:http://www.pdbattery.com/prismatic-lifepo4-battery.htmlI've worked with this chinese company a few years back, and as you may guess, you won't be able to buy less than hundreds or thousands of batteries per order. You can always contact them though, last I did they were very friendly.But that's still interesting to know that these batteries do actually exist. LiFePO4 is so much safer than LiPo or Li-ion and supports many more cycles.
Thermoacoustic engine from trash  - Page 1
Forum section: electronics / general

author: Free_WiFi
author_rank: Regular Contributor
timestamp: December 07, 2017, 01:45:37 pm
content: This man is just a genius

author: cdev
author_rank: Super Contributor
timestamp: December 07, 2017, 02:45:22 pm
content: I recognized Helmholtz resonance! I don't speak Russian, unfortunately.So, what exactly is going on, I suppose I should just look up thermoacoustic engine.. okay..https://en.wikipedia.org/wiki/Thermoacoustic_heat_engine>>https://en.wikipedia.org/wiki/Rijke_tubeHe has what appears to be a large neodymium magnet, the tubes appear to be sealed (?) except for where the magnet is?This is a fairly efficient generator that is easier to build than an electromagnetic one.

author: Free_WiFi
author_rank: Regular Contributor
timestamp: December 07, 2017, 04:57:33 pm
content: The tube is completely sealed,the magnet is glued on the top of the rubber of tube.

author: jpanhalt
author_rank: Super Contributor
timestamp: December 07, 2017, 06:27:48 pm
content: There is some similarity to the "acoustic laser" built at Pennsylvania State University (aka Penn State) about a decade ago:http://www.acs.psu.edu/thermoacoustics/refrigeration/Demo_Inst5(no_specials).pdfI bought the kit at that time and it is neat. The link still lists it, but I didn't check to see if orders were still being taken.John

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: December 11, 2017, 09:14:35 am
content: Would seem to use the same principle as the free piston Stirling engine, with the sound acting as the displacer piston.Stirling engines are/were used to power electronics in areas with no mains. They are not very efficient but are highly reliable and need little maintenance. They will run off just about any heat source. These days they've mostly been replaced by thermocouple generators or solar PV and batteries.

author: jmelson
author_rank: Super Contributor
timestamp: December 28, 2017, 10:44:02 pm
content: Quote from: IanMacdonald on December 11, 2017, 09:14:35 amYup, it definitely looks like an acoustic Sterling engine (no solid displacer). Does anybody have a drawing for this thing?Looks like one of of the tubes he used is made of glass. Does it have to be? Is the stuff at one end of the glass tube steel wool?That would be the regenerator material. That improves efficiency as it retards heat loss from the hot side to the cold side.This unit seems to be delivering a fair bit of energy, seems you can draw a couple Watts off it without killing the resonance, which is pretty good.There are lots of micropower Sterling designs out there, but this one delivers at least a bit of real power.Jon

author: jpanhalt
author_rank: Super Contributor
timestamp: December 28, 2017, 10:56:36 pm
content: Quote from: jmelson on December 28, 2017, 10:44:02 pmDid you miss something in the PSU link?
Presentaiton given by PG&E on how power companies opperate and solar - Page 1
Forum section: electronics / general

author: DougSpindler
author_rank: Super Contributor
timestamp: November 27, 2017, 02:00:06 am
content: Our local power company, G&E has several presentations on the power industry and solar.The first one goes into a lot of detail about how power companies produce, sell and buy power, and has detailed information about solar including the finances. I found the part about the power industry very interesting. The other two are much shorter.I'm posting links, hope you find them interesting..... I did.https://www.pge.com/includes/docs/pdfs/shared/solar/solareducation/pv_basics.pdfhttps://www.pge.com/includes/docs/pdfs/shared/solar/solareducation/renewable_energy_terms_and_concepts.pdfhttps://www.pge.com/includes/docs/pdfs/shared/solar/solareducation/solar_power_basics.pdf
Brilliant Light Power's SunCell - Sounds fishy - Page 1
Forum section: electronics / general

author: blargg
author_rank: Contributor
timestamp: December 20, 2017, 10:31:07 am
content: I read about BLP's SunCell recently and it sounds suspect. It supposedlyQuoteQuoteIt involves a small area with intense light, and photovoltaic cells to capture the light and output energy, a tabletop model supposedly generating at least enough to power a house (or a whole block of houses??). How could photo cells even be small enough to capture such intense energy? I'd think they have a limit of a few times normal sunlight, not ten thousand as seems to be required. The cells would melt down.QuoteI smell bullshit.
California - PG&E is now chanrging $0.85 kWhr on peak days and paying $0.80 kWhr - Page 1
Forum section: electronics / general

author: DougSpindler
author_rank: Super Contributor
timestamp: November 25, 2017, 08:32:57 pm
content: Anyone tracking what power companies are charging for electricity?In California PG&E starting Nov 1, 2017 started charging as much as $0.85 per kWhr on peak days. (Yes, about $1.00) But this means they will credit solar producers about $0.80 kWhr. For the rate plan I am on PG&E charges $0.45 kWhr during summer months. PG&E had nine rate plans for residential customers.Curious what other people are paying.

author: ez24
author_rank: Super Contributor
timestamp: November 25, 2017, 09:20:16 pm
content: Quote from: DougSpindler on November 25, 2017, 08:32:57 pmA couple months ago this was asked and got several answers. I would try and find them but I need to go and look for my bill and check out this peak billing. I thought it was for commercial users only.
POSSIBLE ELECRIC CAR MOTOR GENERATOR WITH LIGHTS - Page 1
Forum section: electronics / general

author: magnetman12003
author_rank: Contributor
timestamp: November 07, 2017, 04:10:57 pm
content: Click the above and note comments

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: November 10, 2017, 11:52:06 am
content: So, you can light mains LEDs from a gel cell using a rotating transformer? Tell me something I don't know.I could make a more efficient nonrotating one with a ferrite core and transistor driver. Big deal.

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 10, 2017, 11:53:47 am
content: Quote from: IanMacdonald on November 10, 2017, 11:52:06 amYou're forgetting the cardinal rule. There has to be some mystical spinnamathinging.

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: November 10, 2017, 12:07:50 pm
content: Not if you have a flux capacitor.Of course you mustn't wash the board in that case, or it ceases to be over-unity.

author: CJay
author_rank: Super Contributor
timestamp: November 10, 2017, 05:16:49 pm
content: Quote from: IanMacdonald on November 10, 2017, 11:52:06 amAnd they don't necessarily need mains voltage, something I discovered and was verified by Big Clive, so it's possibly even more unimpressive than it seems.
It's in Electronic Design, must be true - Page 1
Forum section: electronics / general

author: Gavin Melville
author_rank: Contributor
timestamp: October 21, 2017, 10:15:53 pm
content: http://www.electronicdesign.com/power/11-myths-about-wireless-powerMyth no. 2 is just awesome.

author: vk6zgo
author_rank: Super Contributor
timestamp: October 21, 2017, 10:43:00 pm
content: Quote from: Gavin Melville on October 21, 2017, 10:15:53 pmThe myth or the bullshit answer?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 22, 2017, 06:26:11 am
content: What do you expect from,1. The founder of a wireless power company,2. Numerous poorly-constructed straw men, appeals to authority, and other dubious arguments, and3. An e-mag that desperately wants more copy to sell ads on top of?Tim

author: Mjolinor
author_rank: Frequent Contributor
timestamp: October 22, 2017, 08:14:08 am
content: Got to love his arithmetic and logic.Charging one phone from a wall wart is 14%,if you use it to charge two phones it halves to 7%.So charging 1000 phones from one wall wart obviously you would be into negative efficiency, is that an over unity machine, I had better email him, he is sure to know.

author: schmitt trigger
author_rank: Super Contributor
timestamp: October 23, 2017, 05:01:13 pm
content: "It will bounce off walls, floors, and ceilings to reach the transmitter."Has he heard about absorption and attenuation of the waves?What about multipath reception, which could result in signal cancellation?

author: ruffy91
author_rank: Regular Contributor
timestamp: October 23, 2017, 08:29:12 pm
content: I really love that he says straight to the reader that 12 is more than double than 10 and that 12 parts of 22 is 14%.And someone like this calls himself a CTO...Also the technology is ready for primetime according to the company of the author since 2013 and can be licensed but no one did it:http://www.ossia.com/cota/

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 24, 2017, 05:19:35 am
content: No. 2 O RLY?There is only one solution...SAFE YOU SAY?!Well that means I can totally strap some magnetrons to the author's face and it will be totally fine right? And if for some odd reason their face burns off Indiana Jones style, well they can't complain becuase they said it was ok.These people are either lame con artists that can't think of an original scam and instead tout the same old garbage we've already heard, or they're some more serious idiots. Some really dark part of me kind of hopes they actually do try high power wireless stuff and get a Darwin award.
Battery voltage drop. - Page 1
Forum section: electronics / general

author: McBryce
author_rank: Super Contributor
timestamp: October 31, 2017, 02:40:06 pm
content: Hi all,I was just messing about with some old batteries, setting up my DC Load for a battery capacity test. I have two old 9V batteries, both read about 7.5V with no load. If I connect either one to my DC Load and try to pull 500mA, the voltage drops to about 3V, but supplies the 500mA. All as expected so far. However, if I connect the two batteries in series (total no load voltage now around 14.8V) and try to pull 500mA the voltage drops to 0.027V and can only manage around 280mA. I wasn't expecting this, but I'm no battery expert.I would have expected somewhere around 6V and the 500mA still being supplied, but obviously I was wrong. Is this due to the two ESRs being added together? The maths don't add up for me. Can anyone explain exactly what's happening here?Thanks,McBryce.

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: October 31, 2017, 02:59:32 pm
content: The internal resistance per battery is (7.5-3)/0.5 or 9 ohms.With two in series the volts drop across the two internal resistances (18 ohms total) with 500mA flowing would be 9v, so the terminal voltage should be (7.5x2)-9 or 6v.I suspect you have some kind of measurement error with the result you get.

author: McBryce
author_rank: Super Contributor
timestamp: October 31, 2017, 03:20:22 pm
content: Thanks for confirming that my maths wasn't wrong.After some experimentation I found the answer: One of the batteries seems to have an issue. It only supplies the 3V / 500mA for about 10 seconds and then drops to 0V. I suspect I didn't wait long enough when checking the batteries individually.McBryce.
steve30's new solar PV installation (South Yorkshire, England) - Page 1
Forum section: electronics / general

author: steve30
author_rank: Frequent Contributor
timestamp: September 27, 2017, 07:12:04 am
content: I'd just thought I'd post a quick overview of my new PV installation.I've got 9 x 300W panels mounted on the roof of our end terrace house. Panels are JA Solar Monocrystalline panels. Total theoretical capacity is 2.7kW.The inverter is a Growatt 2500 with a capacity of 2.5kW and is mounted in the loft.Someone must have notified the sun that I had this installed, as its mostly been dull since. On the dull days, it has been producing between 200-300W totalling 2-3kWh per day. We did have a nice sunny day on Sunday where I clocked it going at 1.9kW, and totalled about 8kWh for the day. Yesterday was moderately sunny and it produced about 5kWh.I'm very pleased with it. I'm expecting it to perform quite well.I've attached some photos.

author: steve30
author_rank: Frequent Contributor
timestamp: October 26, 2017, 02:24:48 am
content: I've had the system for about a month now and I'm pleased to report that it seems to be working nicely.Unfortunately the weather isn't very good for it, but even when its producing 300W on a dull day, its enough to power things like my computers, lights, audio equipment etc.I hooked the inverter up to a computer and ran Growatt's crappy chinese software 'Shinenet' to graph some of the output. The first screenshot shows a dull-ish October day which produced a couple of kWh.The other screenshot shows a very sunny October day which produced over 9kWh by the end of the day. This particular day was very windy - you can see around 12 o'clock where the sun went behind a tree and the wind kept blowing the tree over 2 or 3 panels. Normally when there is no wind, only one panel is slightly shaded here.I think it'll do very well during the summer. I'm looking forward to seeing how it performs through next year.