Battery Pack for Android Fio

I have a two part problem.

  1. I've looked online for a 3.3v Li-Po battery pack to power the Arduino Fio but the closest match that I've been able to find is a 3.7v pack. Does anyone know where I can find a 3.3v battery pack? Or could I use the 3.7v pack to power the Fio without damaging it? If not, is there some sort of resistive adapter that I could attach to the pack to lower the voltage or perhaps some other device that I could use?

  2. Could I connect a 40mm x 40mm 12v Peltier cooler to the Fio using a boost converter to increase the voltage out put of 3.3v to 12 volts and use PWM to regulate the temperature? In addition, would it be possible to change the polarity of the current flow so that I could control which side of the Peltier is cold and which is hot? Any comments or suggestions would be greatly appreciated.


LiFePO4 batteries are 3.2V nominal. For instance:

1500mAh 18650 cell

Or even 10Ah monster: Headway screw terminal 10Ah

Lithium polymer are all 3.7V, lithium iron-phosphate is different chemistry and a whole lot safer too.