Described is a device and process for charging the battery of a self-powered electric transport vehicle, in particular self-powered transport trolleys in workpiece-transfer systems. The device is characterized in that a charge-control unit (15) is fitted in the transport vehicle (11), the charge-control unit including a processor (24) connected to at least one memory unit (23), a device (33) for determining the battery charge status and a device (25) for regulating the charging. In the process disclosed, the charge status is compared by the processor (24) in the transport vehicle (11) with at least one reference level and the result used by the processor (24) to control the charging in such a way that the battery (14) is charged at least to the reference level stored in the memory unit (23), in particular to the minimum level required for the vehicle to reach the next charging station (16) or to a pre-determined maximum level.