Abstract: After disconnection from the power supply system, a discharge characteristic of the no-load voltage is recorded automatically by means of a control unit across a discharge resistance during a stage-by-stage discharge cycle from a charged battery which is being operated for the first time on the power supply system. This stage-by-stage discharge cycle is repeated at times which can be defined, in order to record an instantaneous discharge characteristic of the no-load voltage, and an alarm no-load voltage is determined from the instantaneous discharge characteristic of the no-load voltage from a previously defined reserve time and from the final discharge voltage as determined in the first measurement, which alarm no-load voltage represents a measure of the energy which in each case still remains in the battery, and on reaching which during operation on the load, an alarm is produced for the operator of the power supply system.

Abstract: At least two parallel battery paths are provided which functionally have equal authority and each of whose capacities is sufficient to supply a load on its own for a specific time period. By arranging a switch in each battery path, both at the current generator end and at the load end, respectively, by means of which switches the respective battery path can be disconnected from the power supply system by a control unit for investigations on the battery, while the other battery paths continue to supply the load.

Abstract: After disconnection from the power supply system, a discharge characteristic of the no-load voltage is recorded automatically by means of a control unit across a discharge resistance during a stage-by-stage discharge cycle from a charged battery which is being operated for the first time on the power supply system. This stage-by-stage discharge cycle is repeated at times which can be defined, in order to record an instantaneous discharge characteristic of the no-load voltage, and an alarm no-load voltage is determined from the instantaneous discharge characteristic of the no-load voltage from a previously defined reserve time and from the final discharge voltage as determined in the first measurement, which alarm no-load voltage represents a measure of the energy which in each case still remains in the battery, and on reaching which during operation on the load, an alarm is produced for the operator of the power supply system.