Originally Posted by tclaridge
I have an IR question on battery capacity size. I measured two big 6S5000mah batteries that are 45C Nanotech. They came to about 1.9mohm. But the little 3S2200mah 45C Nanotechs measure 4.7mohm. Is it just because a smaller cell capacity has more resistance?
If one good 2500 25C cell has a 5 milli ohm internal resistance, then two in parallel would have a resistance of 2.5 milli ohms. The combination would be a 5000 mah cell. ESR is really a measure of how much the volts drop for a given pulse of current. It is a figure derived from measuring volts and current. Two identical batteries in parallel provide twice as much current as one and hence 'measure' half the internal resistance.