Charging issue

[bstephens157]

I have a 1997 bmw 540i. The car died after the charging warning light came on fir a few days. We jump started it and it died again. The battery was a 6v. I put a battery from my truck in it and it started but it showed it was not charging on my tester. I pulled the alternator out and it tested good. I know the battery was good because it's been in my truck for several days with no issue. Any ideas?

[MauiM3Mania]

Moved from General BMW Discussion sub-forum.

[edjack]

A battery at 6V is a goner.

How did you check the alt?

[geargrinder]

I have a 1997 bmw 540i. The car died after the charging warning light came on fir a few days.....Any ideas?

1. Definitely a great idea to just keep driving the car with the charging warning light on. Cuz you know, most of the time cars just fix themselves and get better with time. Best thing to do is remove the instrument cluster and snip out all those lights anyway because they only cause confusion and trouble.

2. 99.99% it is either your alternator, or a bad cable/ground someplace.

[Ed CT]

I have a 1997 bmw 540i. The car died after the charging warning light came on fir a few days. We jump started it and it died again. The battery was a 6v. I put a battery from my truck in it and it started but it showed it was not charging on my tester. I pulled the alternator out and it tested good. I know the battery was good because it's been in my truck for several days with no issue. Any ideas?

OP Did you really put a 6 volt battery in your Bimmer???!??? Or did you, as Edjack refers, measure the battery charge at 6 volts?

1. Definitely a great idea to just keep driving the car with the charging warning light on. Cuz you know, most of the time cars just fix themselves and get better with time. Best thing to do is remove the instrument cluster and snip out all those lights anyway because they only cause confusion and trouble.

LOL A good Sunday morning chuckle.

[JimLev]

LOL, with all the lights snipped out the battery will last 10 seconds longer, you just might be able to make it home.
Sounds like your alternator and battery are toast unless it's a bad connection like GG mentioned.

[StephenVA]

Gee another charging system battery post. I think this make #25 this year.
search for battery issues charging system issues, if you can not do that break out your volt meter and on the battery post in the trunk, measure voltage with the key in your pocket, over 12.5V?
start car
measure at the same point battery posts, over 13.5v?
post results and we will move to step B

if this is too complicated move back up three posts and start snipping...