What component recharges the vehicle's battery and powers electrical systems while the engine runs?

The alternator generates electricity while the engine runs, recharging the battery and powering the vehicle's electrical systems (lights, ignition, accessories). It is driven by a belt from the engine and converts mechanical energy into electrical energy. The battery, by contrast, provides the initial power to start the engine and stores energy; the starter is the motor that cranks the engine to start it. A failing alternator leads to a dead battery and electrical problems even though the battery itself may be fine. Distinguishing the alternator (charges) from the starter (cranks) and battery (stores) is common content.