A system for determining an operating limit of at least one battery according to some embodiments of the present invention comprises a voltage module that measures a voltage V across at least one battery during first and second periods. A current sensor that measures current I supplied by the at least one battery during the first and second periods. A limit module estimates an ohmic resistance R.sub.0 based on at least one of a temperature of the at least one battery and a time difference between the first and second periods, and that estimates a sum of a polarization voltage V.sub.P and an open circuit voltage V.sub.0 of the at least one battery at the second period based on the voltage V and current I of the at least one battery at the first period and an ohmic resistance R.sub.0 of the at least one battery.