If your battery in the car is no longer charging properly, you can check whether the alternator is defective. You don’t even have to go to the workshop. In this article, we will tell you how you can carry out the test yourself.
Each car has a generator that is responsible for generating electricity – the alternator. The term comes from a time when an alternator was solely responsible for the light on the vehicle. A modern alternator supplies the numerous electricity consumers in the car with the necessary energy. Although alternators are not wear parts, defects are not uncommon. However, the alternator itself is not always the cause.
How to check an alternator
- Set the multimeter to DC voltage (DCV / V- / VDC).
- Connect the measuring cables to the battery.
- The voltage now displayed should be at least 12.3 volts.
- If the value is lower, charge the battery first.
- Start the engine and read the voltage. This should quickly rise to 13.8 to 14.6 V.
- If the voltage does not rise or only increases slightly, take a second measurement.
- Connect the black measuring cable to the housing and the red measuring cable to the thick cable of the alternator. The voltage should also be 13.8 to 14.6 V here.
- If you do not reach these values, your alternator is probably defective.