Abstract: A system used to charge a battery of an electric or gas/electric vehicle is disclosed. The system comprises an axle having a rear suspension, at least one voltage generating device and a voltage regulator. The axle is attached to a wheel of a vehicle. The voltage generating device is fitted in line with and driven by the axle. The voltage regulating device is configured to operate by modulating the small field of current of the voltage generating device to produce a constant voltage at the battery terminals. In one embodiment, a gear box may be used with the system. In another embodiment, a shield may be used to protect the voltage generating devices. A method used to charge a battery of an electric or gas/electric vehicle is also disclosed.