A method for managing a vehicle's electrical power bus and charging system. A current sensor is utilized to measure a current produced by an alternator. The alternator current is controlled in a feedback system such that the current is equal to the amount required for the vehicle loads or, if the battery is being charged, the amount required for the vehicle loads plus the optimum charging current. Alternatively, the method may measure and control the amount of current delivered to and from the battery such that, in a fuel efficiency mode, no current is delivered to the battery.