An automotive battery is a type of rechargeable battery that supplies electric energy to an automobile. An automotive SLI battery (starting, lighting, ignition) powers the starter motor, the lights, and the ignition system of a vehicle’s engine.
Automotive SLI batteries are usually lead-acid type, and are made of six galvanic cells in series to provide a 12-volt system. Each cell provides 2.1 volts for a total of 12.6 volts at full charge. Heavy vehicles, such as highway trucks or tractors, often equipped with diesel engines, may have two batteries in series for a 24-volt system or may have parallel strings of batteries.