The alternator converts mechanical energy from the engine into electrical energy to charge the battery and power the vehicle's electrical systems while running. A failing alternator leads to a flat battery, dim lights, and eventually a vehicle that won't start. Modern alternators are compact, efficient, and typically last 100,000-150,000 miles. We stock alternators from Bosch, Valeo, Denso, and other leading brands.
Alternator problems often mimic battery issues. A simple voltage test while the engine is running distinguishes the two: 13.5-14.5V indicates a healthy alternator; below 13V suggests failure.
Alternator output (measured in amps) must meet your vehicle's electrical demand. Vehicles with start-stop, heated windscreens, or powerful audio systems require higher-output units.