If a battery of open-circuit voltage EB has a loaded voltage VL when supplying load current IL, the battery internal resistance RB is:
RB = (EB - VL) / IL The load voltage VL and load current IL for a load resistance RL are:
VL = ILRL = EB - ILRB = EBRL / (RB + RL)
IL = VL / RL = (EB - VL) / RB = EB / (RB + RL) The battery short-circuit current Isc is:
Isc = EB / RB = EBIL / (EB - VL) |