I'm creating a weather station and want the station to be completely power independent. I'm using the Arduino Fio (https://www.arduino.cc/en/pmwiki.php?n=Main/ArduinoBoardFio) and have estimated the power requirements of the station to be an average of 273 mAh / day with a max load of .06A. I'm pretty sure I'll use the 850 mAh battery (https://www.sparkfun.com/products/13854) but need to know if a solar panel will work to charge the battery. Based on my current home location, I have about 3 hours of good sun per day during the winter.

The Arduino Fio has a Mini USB that seems like its sole purpose is to charge the battery but will a solar panel work or is the Fio designed to have that be a more regulated power supply? If so, will this 2W Panel (https://www.voltaicsystems.com/2-watt-panel) be compatible with the Fio to charge the battery and suite my needs.

Thanks for the help

  • The open circuit voltage of that panel (7.7V) is above the absolute maximum rating of the MCP73831. So when the battery is full, the voltage coming from the panel will be too high. – Gerben Jun 5 at 10:50
  • Note that Arduinos typically use linear voltage regulators (After a quick search I couldn't tell if the MCP73831 does or not. Linear regulators waste power by converting excess voltage to heat. You could both increase the efficiency of your setup and solve the over-voltage problem mentioned by Gerben by using a switching 3.3V supply and feeding the 3.3V pin on your MCP73831 directly. – Duncan C Jun 5 at 12:12
  • Also note that Lithium Polymer cells require special charging circuits. You can't just trickle-charge them like you can lead-acid cells. Quoting the docs for the battery you linked: "These batteries require special charging. Do not attempt to charge these with anything but a specialized LiPo charger." – Duncan C Jun 5 at 12:15

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