chasing of e70 battery drain in progress

[Ron07x5]

Originally Posted by Just Looking

Alternator charging the battery and the battery drain are two issues, IMO. There are posts with suggested procedures to seek out the source of the battery drain. Essentially, you take the fuse out of the fuse box, one by one, until you identify the source of the problem. A multi-meter is quite cheap. I just bought one for under $20. With a quick search, you should be able to find posts from people who have already gone through this process. Alternatively, you can ask a dealership to diagnose. It will take a minimum of one hour, likely many more, to do a good job so that will be $$ expensive.

The drain could come from any module but again, the navigation system is a common source. Perhaps you can start from there first.

Good luck.

Yes Likely many hours for dealership to diagnose and then likely they will replace many more expensive parts as they replace the one likely cheap wire that has a short. I will suffer the education and learn to fix type of problem because unfortunately I assume this car will have this type of problem again. If it turns out to be an old wire I will replace all the old wires I can and not wait to have the problem again. Learning the truth will be interesting and will likely help many here in the future. No wonder BMWs out of warranty have such a poor resale value ... the market knows they have way to many costly issues to pay to have fixed. It a great driving machine provide you can deal with the issues!

[Ron07x5]

I went on a trip for 6 days the x5 just sat, came back and the car wasn't significantly discharged.

The next day drove it 3 miles to work and drove home, I could see the alternator charging at 14+ volts and holding battery with 13.8. All looking good!

The following day I drive to work and see it holding with alternator putting out ~13.8. Then I go to lunch and see it showing 11.9 volts so no charging is taking place. why? after work I drive home still no charging with 11.9 volts. I hook up the 10 amp battery charger and see the battery is about 50%? discharged. Over hours I charge the battery up. Then when I use the x5 it is once again charging and holding with 13.8+

I believe there is a drain which takes battery down, seems like when the battery gets lower than 25%? down then voltage regulator refuses to charge the battery?

What do you all think?

I have a valeo regulator and brushes I ordered on ebay, I am now wondering it is time to pull the alternator and try replacing the regulator. I would bet a BMW engineer somewhere would know these symptoms, wish I knew him!

[ninja_zx11]

Originally Posted by Ron07x5

I went on a trip for 6 days the x5 just sat, came back and the car wasn't significantly discharged.

The next day drove it 3 miles to work and drove home, I could see the alternator charging at 14+ volts and holding battery with 13.8. All looking good!

The following day I drive to work and see it holding with alternator putting out ~13.8. Then I go to lunch and see it showing 11.9 volts so no charging is taking place. why? after work I drive home still no charging with 11.9 volts. I hook up the 10 amp battery charger and see the battery is about 50%? discharged. Over hours I charge the battery up. Then when I use the x5 it is once again charging and holding with 13.8+

I believe there is a drain which takes battery down, seems like when the battery gets lower than 25%? down then voltage regulator refuses to charge the battery?

What do you all think?

I have a valeo regulator and brushes I ordered on ebay, I am now wondering it is time to pull the alternator and try replacing the regulator. I would bet a BMW engineer somewhere would know these symptoms, wish I knew him!

In ISTA, there are several test plans for diagnosing power related problems.It will pin point your problem area.There is even test plan for verifying alternator function.When you run that test plan,ISTA automatically turn on headlights,runs radiator fan at full speed and also turns on other electrical accessories. and then measures alternator output.You should try to use ISTA.

[mkurniawansyah]

Originally Posted by ninja_zx11

In ISTA, there are several test plans for diagnosing power related problems.It will pin point your problem area.There is even test plan for verifying alternator function.When you run that test plan,ISTA automatically turn on headlights,runs radiator fan at full speed and also turns on other electrical accessories. and then measures alternator output.You should try to use ISTA.

Could you point the way for this test on ISTA+?
I'm new to ISTA+ and this test might come in handy in the future.

Thanks,

[ninja_zx11]

Originally Posted by mkurniawansyah

Could you point the way for this test on ISTA+?
I'm new to ISTA+ and this test might come in handy in the future.

Thanks,

Sure.

[mkurniawansyah]

Cheers!