The start stop car batteries work by automatically turning off the engine when the vehicle is suspended to save fuel, for example, when the vehicle stops at a red traffic light. Ordinary car batteries only provide current to the starter to make it display, while modern start stop car batteries can discharge and charge many times. This means that even if the engine is stopped and the battery is idle, the start stop car batteries still supplies power to the auxiliary systems (lights, air conditioning and music). There is also a braking regeneration system, which stores energy during braking so that it can be used repeatedly in the future.