The alternator is the component that charges the battery in your car. When you use electrical components in your car (stereo, lights, etc.), the battery loses power. The alternator recharges the battery, replenishing the lost battery power. The alternator is located in the engine compartment. If the alternator is not working properly, your car will only stay running for as long as the battery has power stored. Once the battery loses power, your car will not start. Normally, a malfunctioning alternator will turn on the battery warning light or will have a low volt gauge reading.
Symptoms of faulty alternator: