Most new cars have some type of battery saver feature, but the specifics vary by make and model. Typically, when you turn off the car, the system will automatically disconnect the battery to prevent it from draining. Some cars also have a timer that will automatically turn off the battery after a certain period of time if the car isn't used. Battery saver features are designed to prolong the life of your car's battery and prevent you from having to replace it prematurely.