2015 320i XDrive Charging Issues

[Tyler.Ramirez]

Hey there!
Today on my drive home in my 2015 320i XDrive I got a battery not charging error on my dash. About two hours later as I was getting home another error popped up that said drive train malfunction which now I am convinced is related to an electrical issue. Because I was only a block away from my house at this point I just finished the drive. I have been driving the car for about three years and have not had any issues like this before. I grabbed my multimeter and tested the battery and it read 12.6v, I then started the car and watched it go up to around 14v. I turned on some lights and my radio, A/C, and seat heaters and watched the voltage adjust properly to the load. I accessed the voltage readout on the hidden menu and took my car for a test drive, within ten minutes I had the battery not charging issue appear on my display and then disappear twice. It came on both times as I was decelerating and I saw my battery voltage drop below 12.2v. Both times after about 1-2 minutes the voltage would climb again to about 14v and the error would go away. Any ideas as to why I am seeing this issue? Thank you!

[pshovest]

How many miles?
Failing voltage regulator or worn voltage regulator brushes causing poor/intermittent contact with slip rings. Either will cause reduced alternator output.

[Tyler.Ramirez]

Thanks for the response! I have about 140k miles on it.
Also another note, I had assumed that the battery was the original but the date code says its from 2018, either way its getting older.
Hoping to not have to take a bath and replace both...

[Tyler.Ramirez]

you were 100% correct. About six months ago I did an oil change and accidently out the filter cap gasket on wrong which caused an oil leak directly on to the alternator. I fixed the gasket and hosed it down but now am running into this issue. Today I took the alternator out and started taking it apart and tons of dirt and grease came out and was built up in the brush housing.