What are the main components of an automotive power supply system?

[MacFinn]

An automotive power supply system mainly consists of a battery, alternator, and voltage regulator. The alternator is responsible for charging the battery to maintain it in a fully charged state over time, while both the battery and alternator supply power to all electrical components in the vehicle. The battery is an essential part of the automobile and can be categorized into traditional lead-acid batteries and maintenance-free batteries. Since the battery uses lead-calcium alloy for its grid framework, it produces less water decomposition during charging and has lower water evaporation rates. The alternator serves as the primary power source for the vehicle, functioning to supply electricity to all electrical devices (except the starter) when the engine is running normally (above idle speed), while simultaneously charging the battery. The voltage regulator is necessary because the alternator is driven by the vehicle's engine, and since engine speed is not constant, it would cause instability in the alternator's output voltage. Therefore, an electronic device is required to control the alternator.