It is a device that converts chemical energy into electrical energy. It belongs to a DC power supply and its functions are:
(1) When starting the engine, provide a strong starting current (about 10A) to the starter.
(2) When the generator is overloaded, it can assist the generator to supply power to the electrical equipment.
(3) When the engine is idling, power is supplied to the electrical equipment.
(4) The battery is also a large-capacity capacitor, which can protect the electrical appliances of the car.
(5) When the voltage at the generator terminal is higher than the electromotive force of the lead storage battery, a part of the electrical energy is converted into chemical energy for storage, that is, charging.