Why is my BMW 2 Series battery draining quickly — could it be alternator failure?

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Why is my BMW 2 Series battery draining quickly — could it be alternator failure?

My BMW 220i’s battery dies frequently, even after replacing it. A mechanic in Lahore suggested the alternator might not be charging the battery properly. How can I confirm if the alternator is failing and not just a battery issue?

Gari Specialist asked on 13 Jun 2025 12:36:09 pm

1 Answer

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Gari Master - on 13 Jun 2025 12:38:24 pm

Yes, a failing alternator is a common cause of a battery that keeps draining, especially if your battery is new. The alternator is responsible for charging the battery while driving. If it’s faulty:

The battery icon may appear on the dashboard.

You may experience dimming lights, weak starts, o r stalled electronics.
To confirm:

Have a mechanic do a voltage test with the engine running. It should read between 13.8V and 14.5V.

If the voltage is lower o r fluctuating, the alternator o r its voltage regulator may be bad.
It’s a common issue in older BMWs in Pakistan due to dust, heat, o r wear from poor roads.