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# Solar Panels and Arduino

## Solar Panels and Arduino

(OP)
Hey everyone,
First off I would like to say that I am a computer scientist not an engineer so this question might seem I little foolish but I recently started programming an Arduino I wanted to use solar power to power it. I bought two .5W 6V solar panels from radioshack. However when I tired to power the arduino it would not turn on. I measured the voltage using a multimeter and got 4.33V, I connected them to a 10ohms resistor to measure current and got .83mA, but according to Ohm's law shouldn't I be getting about 433mA. What is wrong are the panels not working correctly or am I doing something wrong. The measurements were taken with the solar panels connected in parallel, but I have also tried with the panels connected in series and still nothing(very little current).

Thanks for the help

### RE: Solar Panels and Arduino

> Your math is a bit wonky. 0.5W/6V=0.083A
> A 10 ohm resistor would pull 0.6A, which is way more than your panel's capacity
> Your solar panels are too wimpy; the Arduino, whichever one it is, since you haven't said, is allowed to draw up to 0.5A.

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### RE: Solar Panels and Arduino

That peak power is also likely somewhere over 8V. Welcome to the world of solar where published powernis not obtainable in real life situations. If you are doing anything real, expect no more than 1/3 to 1/2 rated power.

### RE: Solar Panels and Arduino

Luckily, there are plenty of relative inexpensive "6 watt" panels available for $30-$40 price class. Unfortunately, 12 volts panels are by far the most common, so they'd provide only 400-500mA ("6 watt"). This could be solved with a rechargeable 12v lead acid battery and a cheap DC-DC converter (12VDC in, 5VDC out - with higher current) available on the 'net for a few dollars. You might also need a charge controller (so you don't charge the battery to 18v on sunny days).

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