Abstract: A battery operated electric power plant for motor driven vehicles powered by rechargeable electric storage batteries and one or more dynamoelectric devices capable of operation both as a motor for driving the vehicle and as a generator for recharging the batteries. Electronic switching circuitry cyclically alternates operation of the dynamoelectric devices in a motor phase and generator phase during each cycle and varies the relative duration of the motor phase and generator phase during each cycle according to the power demand on the electric motor.