Patent ID: 8278872

Claim:
A charging device, comprising: a rotating unit; an axle unit assembled to the rotating unit and engaging the rotating unit to coaxially hold the rotating unit on a middle portion of the axle unit; and two charging units, each charging unit coaxially assembled to one of the two opposite ends of the axle unit, each charging unit including a magnet retainer assembled to the axle unit and engaging the axle unit, a plurality of magnets received in the magnet retainer, and a case rotatably assembled to the axle unit and including a plurality of windings; wherein rotation of the rotating unit drives the axle unit and the magnet retainers to rotate, the rotating magnet retainers and magnets further rotate relative to the cases due to the inertia of the cases, and the magnets move relative to the windings and generate induction currents in the windings, for charging a battery; and wherein a diameter of any portion of the rotating unit is less than a diameter of the magnet retainer of each of the two charging units.