Kevin Sullivan, all rights reserved. www.autoshop101.com Understanding the Alternator The charging system has three major components. The Battery, Alternator, and the Regulator. This alternator works together with the battery to supply power when the vehicle is running. The output of an alternator is direct current, however AC voltage is actually created and then converted to DC as voltage leaves the alternator on its way to the battery and the electrical loads. The Charging System