What causes an alternator to produce too much voltage?
If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty. Other potential problems are a faulty voltage regulator or a problem in the charging system wiring.
How many volts does a 12 volt alternator put out?
A car alternator needs to be putting out at least 13-14 volts (ideally between 13.8 and 14.2 volts) to effectively charge a 12 volt car battery. If the alternator is putting out too much voltage (15+ volts), it is likely your battery acid will boil over out of the battery.
Is 15 volts too much for an alternator?
Higher than 15 volts indicates a fault in the charging system’s voltage regulator or related circuits. If it’s substantially excessive, this can cause electrical system and/or battery damage.
Is 12 volts bad for an alternator?
– Gauge readings should be between 12.0 and 12.6 volts for this condition. – A reading below 12 volts could indicate insufficient charging, low battery, or corroded, broken, loose or frayed wires/connections. – A reading exceeding 14.4 volts could indicate a bad battery, failed regulator or poor wire connections.
What happens if your alternator is over 14 volts?
Under that and the car installation and battery isn’t getting enough electric power. Over 14.5 volts can cause serious damage to the alternator and car battery. After taking the voltage output reading, remove the tester cables from the battery poles and remove the multimeter. Close the battery casing-holder.
Where is the voltage setting on the alternator?
It’s mostly located in the engine bay, but also in the trunk or under the windshield. Anyway, it’s mostly in a visible place so it should be easy to find. The car battery, installation, and devices all work on 12 volts. There will be no setting for 12 V exactly so set to the next bigger number and that will be 20 volts.
What to do if your alternator is over charging the battery?
Ask an assistant to start the engine and hold engine speed at about 1500 RPM. Measure voltage across the battery with your DMM. You should get 0.5 to 2 volts higher than base voltage. If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty.
When does the alternator light turn on the battery?
On older vehicles, the battery light would turn on the alternator light when the alternator output or battery voltage dropped below a preset value. The battery light on modern vehicles, however, is controlled by data and trouble codes. This is why a scan tool is essential to diagnosing a charging system.