Q: How much current do I get from a single H04R20?
A: Most CR2032 coin-cell batteries are about 200mAh capacity with a standard discharge current of 0.2mA and voltage of 3V. With two in series, you can get same capacity but double the voltage. The voltage is regulated back down to 3.3V to be compatible with other Hexabitz modules. You can also solder H04R20 modules together, connecting them in parallel, to get more capacity or use the sister module H04R10.