Device for monitoring the state of cells of a battery

The circuit samples the voltage on the accumulator terminals at intervals, and also monitors re-charging to follow battery status. The monitoring device includes a circuit (5) for periodically sampling the voltage on the terminals of each accumulator (2), and a further circuit (5A) for comparing this with a reference value. The system also includes a circuit (6) for electrically connecting a failing accumulator to an equalization charger (7) which includes a control of charging the accumulator at constant current. This continues until the voltage is equal to the equalization voltage. A circuit (8) operates just before the end of the charging period to sample the residual charging current from the charger. A comparator (9) compares this residual charging current value with a threshold value which is a function of the nature of the accumulator.