DUAL VOLTAGE MOTOR VEHICLE ELECTRICAL SYSTEM

摘要

A dual voltage motor vehicle electrical system comprising series connected cranking and accessory batteries that are used to energize an electric vehicle engine cranking motor. The accessory battery is charged by a vehicle engine driven generator and the cranking battery is charged by a battery charging circuit having an input connected to the accessory battery and an output connected to the cranking battery. The battery charging circuit is maintained in operation for a period of time after shut down of the engine to charge the cranking battery from the accessory battery. The battery charging circuit includes an inductance coil for transferring energy between the accessory and cranking batteries which may take the form of an actuating coil of a magnetic switch the contacts of which disconnect the accessory battery from an electrical load when the actuating coil is deenergized.