Abstract: A generator adapted to be driven by rotational forces applied to the wheel of an automotive vehicle or the like comprising a stator coupled to the vehicle frame and a rotor which includes wheel mounting structure so that the rotor is adapted to be effectively driveably coupled to the wheel. The rotor includes a cup-shaped body telescopically received over the stator coaxially with the axis of rotation, with a plurality of axially spaced circumferential arrays of magnets being mounted internally of the cup-shaped rotor body. A plurality of core assemblies are mounted on the stator in axially spaced positions corresponding to the circumferential magnet arrays. A disc brake flange projects from the rotor body and is adapted to cooperate with disc brake calipers carried by the vehicle frame for applying braking forces to the wheel.In a charging system for the energy storage batteries of an electrically powered vehicle or the like, the batteries comprise individual low voltage batteries connected in series.