How many volts should a 12 volt alternator put out?

The voltage should read a minimum of 13 volts. A good alternator should put out between **13.5-14.5 volts. Stress test the alternator – Place a load on the alternator by turning on the headlights, the radio and the air conditioning. The voltage should remain high with these circuits on.

Why does my car battery light stay on after I start the engine?

When you start the engine, your power comes from the alternator, so the battery light is supposed to turn off. If the battery light stayed on after you started the engine, that would be bad. It would mean you have an alternator problem.

What happens to the battery when an alternator fails?

If there is an alternator failure you will be running on the car’s battery which may last about a half hour. As your car’s engine runs, the battery may continue to charge, depending on the failure. Additionally, one of the biggest battery drains is starting your car.

Is it normal for the battery light to come on then turn off?

Yes! It’s perfectly normal for your car’s battery light to come on then turn off after you start it. Thanks! What do I do if my car is saying it has a low battery? You may need to replace the battery or alternator.

What should the charge voltage be on an alternator?

Turn on the high beams for 10 seconds and then turn them off. Measure battery voltage across the battery posts with your DMM. You should get between 12.4 and 12.6V. This means your battery is fully charged. If you get a reading below 12.4V, charge the battery before continuing. 5b. Measure the Charging System’s No-Load Voltage

What does it mean when an alternator light comes on?

If the light illuminates only intermittently, it usually indicates a loose or worn drive belt or serpentine belt, worn-out or bad carbon brushes in the alternator. But remember that the light doesn’t always mean there is a bad part; the light may be triggered by a sensor giving a wrong message or there’s something wrong with the circuit itself.

Why does my battery light not come on when I start the car?

Excessive corrosion at the battery terminals can cause a low voltage condition which makes the starter turn slowly when trying to turn on your vehicle, but it will not illuminate the battery light if the alternator is charging properly once the car is started. Step 4: Secure the clamps on to the battery terminals.

When does a battery charger light come on?

This light illuminates whenever the charging system does not charge the battery with a voltage above approximately 13.5 volts. As this warning may be triggered by a number of things, it is important to take steps to ensure that you know what the actual issue is before replacing any parts.