An automotive battery is a rechargeable battery that supplies electric energy to an automobile. Traditionally, this is called an SLI, for starting, lighting, ignition, and its main purpose is to start the engine. Once the engine is running, power for the car is supplied by the alternator. Typically, starting discharges less than three per cent of the battery capacity. SLI batteries are designed to release a high burst of current, measured in amperes, and then be quickly recharged. They are not designed for deep discharge, and a full discharge can reduce the battery’s lifespan.
Modern SLI batteries are lead-acid type and provide 12.6 volts of direct current, nominally 12 V. The battery is actually six small batteries, or cells, connected in series.
Battery electric vehicles are powered by a high-voltage electric vehicle battery, both they usually have an automotive battery as well, so that it can be equipped with standard automotive accessories which are designed to run on 12 V.