How to diagnose a faulty alternator in an Audi 80?

My Audi 80's battery keeps dying even after replacing it multiple times. How can I determine if the alternator is the source of the issue?

First, start by checking the voltage of your battery with a multimeter. If it's below 12.6 volts, it could be a sign of a faulty alternator. Next, turn on the engine and check the voltage again. If it's not significantly higher (around 14 volts), then your alternator is likely not charging the battery properly.

Another way to test the alternator is by starting the car and turning on all of the electrical components, such as the headlights, radio, and A/C. If the car's performance is struggling or the lights are dim, it could be a sign of a faulty alternator.

If you have access to a voltmeter, you can also do a load test on the alternator by connecting the positive lead to the positive terminal on the alternator and the negative lead to a ground. Running the engine at 2000 RPM should result in a voltage reading of at least 13.8 volts. Anything lower could indicate a faulty alternator.