Alternator Output Test
Category: automotive
A diagnostic procedure to verify if the alternator is producing enough voltage to keep the battery charged.
The alternator keeps the car running once the engine starts. If it fails, the car runs off the battery until it dies. We test the alternator under load to ensure it hits the 13.5V–14.5V range required to power the vehicle and recharge the battery.
Common Examples
- We performed an alternator test and found it was only outputting 11V, which explained the intermittent "battery light" on the dash.
- An alternator test is the standard follow-up after a battery load test shows a battery that refuses to hold a charge.