Vehicle battery charger and heater

A system and method are disclosed for efficient management of energy within a vehicle wherein the vehicle includes a battery and a motor. The method comprises generating electrical energy through the use of the motor and determining the battery temperature and the battery's state of charge. The method further includes applying electrical energy from the motor to the battery to simultaneously charge and heat the battery when the battery's state of charge is less than a predetermined battery charge limit and the battery temperature is greater than a lower charge efficiency temperature, at which both charging and heating may occur, but lower than an upper charge efficiency temperature, beyond which heating is not required. The system is suitable for a motor vehicle with a regenerative braking system.