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Topic: 12 volt Solar Panel and 9 volt battery test (doesn't work) (Read 2711 times) previous topic - next topic

Big Oil

I tried powering an arduino 24/7 using a 12 volt solar panel and a 9 volt battery.
Sleep Mode Power Down doing nothing: On for 2 1/2 days, what you would expect from a 9 volt battery.
It is Ok for running during the daytime, and using the battery to handle brief cloud cover, but it goes out every night.

This is the circuit that was used, from this instructable: http://www.instructables.com/id/Self-Sufficient-Arduino-Board/

The Solar Panel cost around $10 U.S. on ebay:

Maybe a 3.3 volt arduino would last longer, but I don't imagine it lasting too long.  If you want 24/7 coverage you will have to go with more expensive options.


What kind of Arduino board? A standard Uno type boards has some current draw over and above what the processor chip draws even in sleep mode. There is the USB serial convertor chip, the auto voltage selector switch circuit, even a power on led. Also typical recharable small 9vdc batteries have very little current storage capacity.

So measure the whole board's current draw even when 'sleeping'. Find out the mah capacity rating for the battery you are using. Then you will have the basic variables need to calculate your answers, assuming the sun keeps shinning.  ;)

Big Oil

It's a duemilanove.  I'll have to try a smaller board in the future.


Yeah, try running just a bare Atmega328 chip with the minimum of support components (clock crystal and caps), run it at 3.3v if you can, and find a more efficient voltage regulator. 9v batteries aren't all that great for long life, I'd go with 4 D-cell (rechargeable) batteries. And I'd setup the solar panel to charge the batteries, though you may already have it setup for that, I can't really tell.
Oh, and that solar panel looks a bit like a toy.. You might consider getting a more potent one.. Like 10-15 watts would really charge those batteries well.


Perhaps also adding a photo-resistor and a couple of servos, you could always have the panel pointed at the sun. Maximizing your solar harvesting.

Kudos for giving it a whirl though.

- Nicholas

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