An integrated starter generator provides idle-stop capability and uses a high voltage battery with increased energy capacity over typical automotive batteries. This higher voltage allows many of the engine-driven belts to be removed reducing the load on the engine, thereby improving efficiency. Using a higher voltage battery also allows the engine to be shut off when the vehicle is stopped in traffic. The engine will then restart when the throttle is depressed. This saves fuel because the engine is not running when a car would normally be in idle mode.