discussion F30 320d Volatge irregular

[Danielb1]

Hi everyone,

I recently replaced my car battery, but after a few weeks, I noticed that the Stop/Start function stopped working. I called Atlas Battery to check the battery, and they found that it wasn't being charged, so they replaced it without any issues.

Later that week, I took the vehicle to a local auto electrician to check the alternator. They removed the alternator and serviced it. When measured with a multimeter, we were getting about 14V. I was advised to use the car to allow the battery to pick up a charge.

Today, I plugged in my OBD diagnostic tool and drove to work while measuring the voltage. I noticed that the voltage was very irregular, ranging from a minimum of 12.3V to a maximum of 13.6V.

I believe this irregular voltage is the reason why the Stop/Start function isn't working.

Is my alternator still faulty, or is it a battery issue? I would really appreciate your assistance. I’m located in Durban and my number is 081 574 1164

Thanks!

 

[Solo Man]

Normally the alternator should charge at least about 14.2v but i have seen as high as 14.7v. I recently saw a post about how modern BMW's batteries are regulated so that when the car decelerates the battery gets extra charge. Browse this forum. I think your alternator is at fault here. Also, let it idle for a few minutes while you check the charge rate. Found on a previous 1 series i had that the charge would go down to below 12v for a split second then go back up to 14.2v. Regulator was kaput.

 

[Clint@MMS AUTO]

Did you register/code the new Battery to the car once it was fitted?

 

[Mytfine]

How may k's is your daily drive ?

 

[calem_chetty]

Today, I plugged in my OBD diagnostic tool and drove to work while measuring the voltage. I noticed that the voltage was very irregular, ranging from a minimum of 12.3V to a maximum of 13.6V.

Based on this I presume it is an alternator issue, more specifically the voltage regulator within the alternator. It's a really cheap and easy fix, so if it turns out that it wasn't the issue then it's not the end of the world that you had it replaced.

Caelex in Pretoria are great suppliers of voltage regulators, among many other electrical things. You can try call them and provide your car's vin/alternator/voltage regulator part number to purchase a new voltage regulator and have it shipped to you (if they offer such a service).