Starting, lighting, and ignition (SLI) batteries are a type of lead-acid battery designed primarily for starting internal combustion engines. They provide a quick burst of energy to start the engine and power electrical systems like lights and radios when the engine is off. SLI batteries are typically found in vehicles such as cars, trucks, and motorcycles. They are built to deliver high current for short periods, making them ideal for starting engines. Once the engine is running, the vehicle's alternator recharges the battery, ensuring it remains ready for the next start.