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Q & A: solar powered lights and heaters

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Most recent answer: 11/21/2016
I have 21 dogs I rescued in large runner kennels on my proprty. To far to run electricity. What size solar panel would I need to power 60 watt bulb for 12 hours a day. I would like to install tin can bulb heaters in all dog homes. Thank you very much.
- jeanna davis (age 52)

If you can put up with just light, you'd do much better with a 10W LED rather than a 60 W incandescent. You can get LED's that work directly with the 12V from a standard lead-acid car battery, which could be charged by the solar cell using a standard commercial circuit.

On a sunny day, you can get roughly 100W per square meter from a commercial solar cell. So allowing for cloudy days, and some energy loss storing and recovering from a lead-acid battery, 1 m2 should be enough for the LED bulb, or maybe even for several.

Getting enough power for heaters is more of a problem. 60W would take 6 times the area needed by the 10W LED bulb. You could use heat pumps (backward air-conditioners) that are about 5 times as efficient as bulb heaters, but those are really pricey compared to a few bulbs and even a few solar panels.

Mike W.

(published on 11/21/2016)

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