Battery discharge while stopped?

STEVENMETZ

MEMBER
2011 BMW 750LI
V8
TURBO
2WD
AUTOMATIC
80,000 MILES

After a few days with this warning, I started getting all kinds of errors. The mechanic replaced a blown fuse and disconnected the comfort access on both back door handles (the suspected cause of the battery discharge while stopped). Started getting the same battery discharge warning again, and then while driving all kinds of warnings came on then the car shut down completely. Had it towed to the same shop and now the mechanic is saying I need a new alternator and it's going to cost $3,000.00. I think the problem is with something draining the battery. Why would the alternator need to be replaced to fix a problem with something drawing from the battery?

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
48,380 POSTS

The battery drains while you drive if the alternator is no good is normal. Is the charge warning light on while driving? If so, the mechanic is correct but if you want to confirm the failure this guide will show you how to check the alternator. Also, I have included how to change the alternator out in the images below.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

I don't know why it would be $3,000.00 to fix here is the part cost and labor time.

Alternator, R&R 4.5 @ shop rate.

https://amzn.to/3C2gz7x

For the part between $200 and $600.00.

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem.

Images (Click to make bigger)