The alternator in your vehicle is the only device that is responsible for sustaining your battery. A car’s battery is not an unlimited energy source; the battery requires a constant charging source to maintain adequate voltage and amperage for the vehicle. Without the alternator, your vehicle will completely exhaust the battery in as little as 20 minutes. If you recognize the signs that your alternator is going bad, you can avoid draining your battery and becoming stranded.
Test your alternator with a voltmeter as your vehicle is idling. If the voltmeter goes to 12.8 volts or less, the alternator is creating strong resistance in the electrical system, suggesting failure.