Why does my BMW 2 Series battery die overnight even after a recent replacement?

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Why does my BMW 2 Series battery die overnight even after a recent replacement?

I replaced the battery in my BMW 220i just two months ago, but it keeps dying overnight. I don’t leave any lights o r accessories on. Could there be a hidden electrical drain o r something BMW-specific causing this issue?

Gari Specialist asked on 13 Jun 2025 13:02:22 pm

1 Answer

8 views |

Gari Master - on 13 Jun 2025 13:04:40 pm

If your battery dies overnight despite being new, the issue likely isnt the battery itself. Possible causes include:

Parasitic drain: A module o r component like the infotainment system, door lock module, o r internal light might be drawing power when the car is off.

Faulty IBS Intelligent Battery Sensor: If malfunctioning, it may incorrectly measure o r manage battery charging.

Aftermarket accessories: Alarm systems, dash cams, o r GPS trackers wired incorrectly can slowly drain the battery.

📌 What to do:
Get a parasitic draw test from a mechanic familiar with BMWs. You can also check the car’s mode status BMWs should enter mode ~30 minutes after being locked. If the battery draw continues past that, something is staying active when it shouldn’t.