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40% efficient solar cells

2007-06-02 15:24:14.379255+00 by Dan Lyke 6 comments

[ related topics: Current Events Photovoltaics ]

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#Comment Re: made: 2007-06-02 16:09:08.832657+00 by: meuon [edit history]

Those are pretty pricey cells, and seem to be tuned for enhanced light.. ie: focus a lot of light on them via mirrors or fresnel lenses, or above atmosphere direct light. Still it shows promise and I am sure techniques that will eventually bleed down to the plebian users.

Nancy and I just bought a "cheap" (relative) very used 15' travel trailer. on of the first things it got was two $79 solar cells and a couple of deep cycle batteries. For reference, these cheap good $79 solar panels, put out a max of 1 amp at 12 volts. - Should work very well for our kind of off-grid/off-hookup camping. I've glued/mounted one to the angled roof of the trailer permanently, and have the other one movable/portable to be able to charge the truck battery or other things, as well as adding to the charge of the trailers system.

As LED Lighting becomes mainstream in-house (and I think it will) and the big power users (fridges, washers and dryers) become more energy efficient, the idea of running a real house off of solar becomes very do-able.

A solar house, with a Hydrogen generator/fuel cell powered car.. Well, I can dream, can't I?

#Comment Re: made: 2007-06-02 17:33:11.916842+00 by: Dan Lyke

I think refrigerators and hot water heaters (and heating systems in general) will have to start using thermal masses of some sort, and be smart enough to have some predictive energy load and availability notions, to make full solar realistic.

And given that people work away from the house during the day, what do we do about dryers?

Previous experience with solar panels... You might want to check the static load of these and see if you need to put a diode or other switching capability inline, lest they suck your batteries dry at night.

#Comment Re: made: 2007-06-03 00:13:50.520839+00 by: TheSHAD0W [edit history]

Just FYI, at 40% efficiency solar cells can produce ~300W per square yard. It would mean an array 10 miles on a side in a nice sunny desert could power the entire US.

#Comment Re: made: 2007-06-03 11:09:29.722419+00 by: meuon

re: battery drain: We also installed the charge controller. It has a charge limiter and flow protection and was only $29.00. Has 'Status LED's' - WhooHoo!

My original Solar panels (That I had at the Burn) are currently on Clem's Casita Travel Trailer (Currently in Southern Baja Mexico) Amazing how useful even just a little solar power can be.

On other things: Nancy likes her "Solar Power Clothes Dryer" and it only requires a little rope and pulleys and clothespins.

So, my big amperage normal users are: Fridge, the Electric Dryer, HVAC and hot tub. Our washer is a 'high tech' Fisher&Paykel with a direct drive stepper moter that uses little current. They say less than 25% a typical washer. Of those, the starting current of the Fridge is the biggest amperage killer. Estimating: 10amps for a second? The Hot tub could be converted to direct thermal water heater as could the house water... I really should do that.

Computers.. using laptops mostly: 60 watts / 1amp each max?

On the occasional use side: My drill press, table saw, mill and lathe probably draw 5 amps each.. but my welder.. 10-15? They are short time use devices, a couple of deep cycle batteries in parallel and a BIG inverter would work for my purposes.

My typical electric bill is usually under $50.00 now, it'd take forever to get a return on the investment at current electric rates. But if Shawn's 10 miles per side is correct: TVA could have a 10 mile by 10 mile solar array and take care of this region of the country easily, pumped water and other sources would be backup for cloudy days and nights.

#Comment Re: made: 2007-06-03 11:18:14.762756+00 by: Nancy

Just don't leave the bedsheets out in the sun too long! They deteriorate. Mike likes to think it was from use, but I know better ;-)

I know now that overcast windy days are actually best. That, or keep a close eye out and don't leave anything out longer than necessary.

#Comment Re: made: 2007-06-09 22:09:17.237764+00 by: Larry Burton

I once sold a guy plans for a solar powered clothes dryer. After he saw the plans he demanded his money back.