Motor vehicle electrical system with multiple generators

A motor vehicle charging system comprises a first alternator including a first power output and a discrete alternator enabling input, a second alternator including a second power output and an electronic controller having a switchable output. The switchable output is coupled to the alternator enabling input. A method for controlling a motor vehicle charging system having a first alternator, a second alternator and a source of switched system voltage having an ON state and an OFF state comprises providing continual enabling power to the first alternator whenever the source of system voltage is in the ON state. The method also includes providing switchable enabling power to the second alternator whenever the source of system voltage is in the ON state. Alternatively, the method for controlling a motor vehicle charging system comprises providing continual enabling power to the first alternator whenever the vehicle's engine is running and providing switchable enabling power to the second alternator, also whenever the vehicle's engine is running.