Problem with voltage s65

[JakubK]

I need help with my 2010 m3 e93.
The problem is with voltage. While driving, all errors (from gearbox, traction, abs, brake) popped up several times and the car starts to stall and after stopping it doesn't want to move from a standstill and runs unevenly. When checking in the application it shows 8v and after turning it off and on again the errors disappear and the alternator charges 13.5-14.2 and the car keeps 1000 rpm all the time as if it had a weak battery. The first starts after the error are difficult and then it starts normally and has power. Where to look for the problem?

[Redd]

Check your ground strap.

[JakubK]

Where can I find it?

[Helmsman]

Originally Posted by JakubK

Where can I find it?

Under the car but if you google it you'll get pictures and easy to follow guide lines. Come back after the the strap is checked.

[JakubK]

looks like this. it is from the bottom by the exhaust pipe. the strange thing is that when errors pop up, after restarting everything is ok. I will add that the charging voltage is 13.6-13.8 and then increases

[pjk380]

what is the condition of your battery? A weak battery will cause all kinds of issues. The batttery may not be holding the charge. If the battery is good, have the alternator checked.

[JakubK]

do you think it could be the ibs cable at the battery?