Audi A3 and A4: Why is My Battery Dead?
A dead battery could mean more than just forgetting to turn off the dome light on in your Audi A3 or A4. Read on to learn how to diagnose it.
This article applies to the Audi A3 and A4 (2002-2008).
A dead battery could happen when you forget to shut off certain electrical components running in the Audi A3 or A4. However, there are a few other reasons why your battery is dying. The battery works to give current to your components; when the car is on, your engine turns, and it turns the serpentine belt with it. The serpentine belt is connected to your alternator, which works hard to re-charge your battery. So, unlike your energizer AA battery, your car battery is supposed to re-charge each time you drive your car. If your car battery isn't holding a charge, read on to learn how to diagnose this issue.
Materials Needed
- Voltmeter
- Baking soda and water
- Wrench
Step 1 – Inspect the battery terminals
They could be corroded.
The most common reason your battery stops charging or providing current is corroded terminals. The more corroded your battery terminals are, the less current goes through. Therefore, your battery uses all of its voltage, but it doesn't get recharged because the current isn't going through. You can visually tell when the terminals are corroded. If it has white powder-like material on it, remove the terminal with your wrench, then use baking soda and water to clean it.
If the terminals are clean, proceed to Step 2.
Step 2 – Check the alternator
It could be faulty.
The alternator, as mentioned above, works to charge your battery. If the alternator fails, the battery will fail shortly after. The best way to detect a bad alternator is to start the car, then remove the negative battery terminal with the engine on. If the car stalls, then your alternator isn't working, and your battery is taking its place. You can also detect a bad alternator by a high pitched whistling sound, a burning smell, or if you step on the gas pedal and the headlights dim. This means your battery is working for the alternator.
If the alternator is working properly, proceed to Step 3.
Step 3 – Check the battery voltage
It could be faulty.
A faulty battery won't hold a charge. If you keep jumping your battery, and you know your alternator is working properly and your battery terminals are clean, you could be faced with a bad battery. A voltmeter could come in handy here. Charge the battery overnight at an auto shop; most won't charge you for this service. Put your positive voltmeter probe on your positive battery terminal, and the negative probe on the negative terminal, then watch the reading. A healthy battery will read 12.6 or above. If your battery is reading less than that after you've charged it fully, then the battery is faulty.
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