1991 525i system voltage check?

[takemehigher]

hey, so i want to check the system voltage on my e34 using the OBC in my car. Can anyone tell me what the correct voltage should be or range of it while the car is running? And obviously if its too low, i got to buy a new battery right? Let me know. thanks

[David325e]

If its too low that would mean an alternator or voltage regulator needs to be replaced. If you expect the battery to be bad use the OBC or a multimeter to check current across the terminals of the battery with the car off. If you think its the alternator then voltage either of those same ways should be 13-14.X