tons of sudden issues, alternator?

[Clavurion]

Originally Posted by andrewwynn

Coreect not until e70. I've programmed new batteries on other BMW and it's very interesting to read the histogram off of the (other) IBS. It will show how many hours at each state of charge broken down by 20% groups. 0-20,20-40,40-60 etc. It instantly confirmed my clients battery was shot when over the past six months or something the state of charge was mostly under 60 and almost entirely under 80.

And on the versions with CO2 package (brake energy regeneration) the charge doesn't even go above 80% with alternator. A devastating feature in cold climate countries. And that's why it's sane to code it out.

[StephenVA]

Yes, newer heavy loaded electronic vehicles are going to chew through batteries at a high clip. Oh, the new world of engineering excellence to recycle everything.

Follow up on the steady of voltage readings during alternator charging, you are right on target. Most good alternators display only a fluctuate of a few .01~.02 Volts throughout RPM changes. Now dying ones are all over the place or only kick in at idle due to the carbon build up/worn out tension springs/worn brushes, etc. Had one where it shows ZERO charging at idle and put out 14.2V erratically at 2,000, but ZERO again at anything higher. No brushes left at all internally with metal everywhere from bearing wear.

Back in the 60-80's local alternator/generator shops could pop in new bearing, brushes, clean the slip ring and shafts all for $35. Off you go for another 50-100K. Those days are gone.

andrewwynn thanks again for posting the instructions on how to replace the brushes and regulators. Unfortunately most of the new posters are looking for a cheap as possible rebuilt unit that requires no DIY skills other than R&R and install the belt.

[Clavurion]

Originally Posted by StephenVA

Back in the 60-80's local alternator/generator shops could pop in new bearing, brushes, clean the slip ring and shafts all for $35. Off you go for another 50-100K. Those days are gone.

Nowadays you have to do everything by yourself including alternator refurbishment. I've even seen some factory refurbished alternators which had less slip ring surface (slip ring not renewed) than the original which it should replace.

[andrewwynn]

It’s actually literally easier to swap brushes than to pull out an air cooled alternator which is why I made the DIY repair pages. People with a fair skill level will have no problem copying me especially with the brush only repair.