If the keys are left on position "II", which is the accessory position, the battery will eventually go dead. This is because the accessory position powers various electrical components in the car, such as the radio, lights, and climate control system. Even though the engine is not running, these components will continue to draw power from the battery, and eventually drain it.
Therefore, it is important to make sure that the keys are always turned to the "0" position when the car is not in use. This will help to prevent the battery from going dead.
Also note that leaving the key in the ignition in the "On" position can also cause the alternator to overheat and fail.
