[nsjames]

that's normal bulk charge voltage for a colder flooded battery.

agreed that you need to charge the battery and have access to a scan tool.

you can pop the trunk by applying jmper cables to the underhood jump points.
that's where you should attach the charger as well.

[vncung]

Originally Posted by Tschultz31

I checked the voltage before it died completely but after I replaced the alt and it was reading 15.1-15.2 area but it was pretty early and cold plus it was already in limp mode when I tested it. But I thought that was just because I didn't register/code the battery but I guess I was completely wrong. And the codes I posted wer after the alt was replaced too when it died and wouldn't start it still had some power and I had the scan tool from my work with me I read the codes when I was waiting for the tow truck.

Over voltage means bad alternator voltage regulator.
Replace that and you are good to go.
$50 part and easy diy.

I had these codes when my voltage regulator fail

[Tschultz31]

Originally Posted by vncung

Over voltage means bad alternator voltage regulator.
Replace that and you are good to go.
$50 part and easy diy.

I had these codes when my voltage regulator fail

I replaced the battery and alternator and this has continued to happen do you think maybe I just got a part bad out of the box?

[nsjames]

Originally Posted by Tschultz31

I replaced the battery and alternator and this has continued to happen do you think maybe I just got a part bad out of the box?

again.

15.2 is normal for a battery that is cold that has not yet reached saturation.

that's cold flooded lead acid bulk charging voltage.

at 0F you can expect a lead acid battery to want 2.6ish V per cell.

16V is too much.
15.2 is the upper end of proper charging voltage and is not an immediate indicator of a regulator problem.


the system charges hard until the battery reaches saturation, then decreases the voltage to a to peak charge the battery, then decreases the voltage again after the battery is fully charged to float voltage.
that's how you get maximum life out of a battery, and that's the whole purpose of the IBS. to keep it perfectly balanced between sulfating the negative plates and eating the positive ones.
not fully charged=sulfation
overcharged=outgassing and positive plate damage.



stop throwing parts at it until you diagnose it.

[Tschultz31]

Originally Posted by nsjames

again.

15.2 is normal for a battery that is cold that has not yet reached saturation.

that's cold flooded lead acid bulk charging voltage.

at 0F you can expect a lead acid battery to want 2.6ish V per cell.

16V is too much.
15.2 is the upper end of proper charging voltage and is not an immediate indicator of a regulator problem.


the system charges hard until the battery reaches saturation, then decreases the voltage to a to peak charge the battery, then decreases the voltage again after the battery is fully charged to float voltage.
that's how you get maximum life out of a battery, and that's the whole purpose of the IBS. to keep it perfectly balanced between sulfating the negative plates and eating the positive ones.
not fully charged=sulfation
overcharged=outgassing and positive plate damage.



stop throwing parts at it until you diagnose it.

I appreciate you very much that’s exactly where I am I’m not doing anything until I know exactly what’s wrong that’s why I asked the forum to get more information I just need to get it to my work so I can diagnose it properly the only reason I thought it was the battery and alt is because the battery tested so low on cold cranking amps and my buddy had the same thing happen and it was the alt so I thought I just had the same issue but agai thank you and I appreciate your help

[vncung]

Originally Posted by Tschultz31

I replaced the battery and alternator and this has continued to happen do you think maybe I just got a part bad out of the box?

I had this issue before. Here is what happened:
Voltage regulator failed causing high voltage which fried your battery.

Did your new alternator come with new voltage regulator?
If not, You need to replace the voltage regulator. And since your battery is fried. You will need a new battery as well. Good luck

https://www.fcpeuro.com/products/bmw...ch-12317561939

DIY

[nsjames]

Originally Posted by vncung

I had this issue before. Here is what happened:
Voltage regulator failed causing high voltage which fried your battery.

Did your new alternator come with new voltage regulator?
If not, You need to replace the voltage regulator. And since your battery is fried. You will need a new battery as well. Good luck

https://www.fcpeuro.com/products/bmw...ch-12317561939

DIY

of course it came with a new regulator, it's part of the assembly.


and for the last time.
15.2 volts is not over voltage for a cold and discharged battery.

just stop.