FIELD: electrical engineering. SUBSTANCE: battery capacity is determined by measuring potential difference across battery loaded with regulated current pulse; in case it is other than value specified for particular type of battery, cells are checked for condition one after another in response to signal coming from control unit and charged if required. Standard curve is compared with RMS value by comparison unit whose signal goes to control unit. Output signals of control unit arrive at switching unit and battery charger. Cell found discharged is charged in response to signal coming from control unit. Upon end of charge, control unit yields signal for checking battery capacity. EFFECT: provision for holding storage battery ready for use under any conditions of off-line power supply system. 1 dwg
