An apparatus that estimates the ohmic resistances of N batteries includes voltage and current measurement modules that respectively measure the voltage and current of each of the N batteries. An ohmic resistance estimating module over N+1 time periods receives the voltage and current measurements of each of the N batteries and receives consecutive voltage and current measurements for one of the N batteries. N is a positive integer and the ohmic resistance estimating module estimates the ohmic resistance of the battery that is associated with the consecutive voltage and current measurements.