Batteries
Adafruit on Batteries
PV Education on Batteries
CR2032 Cell from Maxwell
CR type cells, heat resisting, Maxwell
Battery capacity $C$ in $mAh$ or $Ah$.
Examples:
$C = 1000\mathrm{mAh} = 1\mathrm{Ah}$
Nominally: Continuous current of 1A for 1h. But: High discharge currents often lead to a reduced capacity!
Better: 10mA for 100h.