Patent ID: 7489101

Claim:
A battery control system for a hybrid vehicle, comprising: a hybrid powertrain battery; a vehicle accessory battery; a prime mover driven generator adapted to charge the vehicle accessory battery; a detecting arrangement configured to monitor the vehicle accessory battery's state of charge; and a controller configured to: activate the prime mover to drive the generator and recharge the vehicle accessory battery in response to the vehicle accessory battery's state of charge falling below a first predetermined level, and transfer electrical power from the hybrid powertrain battery to the vehicle accessory battery in response to the vehicle accessory battery's state of charge falling below a second predetermined level, wherein the controller is configured to command the prime mover to start and to drive the generator to charge the vehicle accessory battery; wherein the controller is configured to command the prime mover to turn off once the vehicle accessory battery has been charged to a third predetermined level; and further wherein the third predetermined level is greater than the second predetermined level, and the second predetermined level is greater than the first predetermined level.