Abstract: A storage battery is first substantially fully discharged before it is charged. A load impedance is first connected across the battery to receive current from the battery and develop a signal representative of the state of charge of the battery. Sensing this signal provides an indication of when the battery becomes substantially fully discharged. The load impedance is then disconnected, and the battery then receives charging current. A full-wave rectifier couples the battery to an LED that may be coupled to the battery to provide the indication of when the battery becomes substantially fully discharged. This indication may be used to operate relays to disconnect the load impedance from across the battery and charge the battery.