Several weeks ago I was doing a breakjob on my car wifes car. I left the door open for about 45 minutes while I did all four brakes. When I was finished, the car wouldn't start. So I charged the battery and then it started. I check and battery and saw that it was in need of replacing. So I changed the battery.

The car ran great for several weeks, and then I started getting an intermediate electrical problems. Ie lots of lights flashing on the dash, abs failure, low battery etc. If you kept driving it to your destination, and then turned it off it would start like a charm and seemed to have forgotten about its prior issues. It happened again today, so as soon as the problem manifest itself, I pulled over to the side of the road and turned the car off. It didn't have enough cranking amps to restart. I waited 15 minutes while I tried to get someone with jumper cables, and then mariculaously the battery had charged up enough to turn over and start. I took it to an Advanced Auto Parts and a totally clueless guy tested the Alternator (using jumper position in the front) and he said the reading was telling him bad diode ie bad alternator. I went up the street to Auto zone and they tested it much more thoroughly and they said I had a good battery and alternator. So I went to a second Advanced Auto Parts and they also told me the same thing about having a good battery and alternator. The car was running fine for the rest of othe day with no problems. The car shut down under similar circumstances several months ago on my wife at a gas pump. I came and jumped her and it never had a problem again. Because of the battery drain while driving it would seem to be the alternator, but in my experience Alternator brushes etc. wear out with time and slowly die all togethery. They don't cut in and out suddenly. I thinking it could be a bad ground connection on the alternator or something simlilar. Any thoughts would be appreciated.

And yes it is out of warranty.
Thanks,
Adam

Hey,
I see you're in Charlotte. There's an independent factory trained mechanic in Mooresville on Hwy 150 (exit 36 off of 77) at McCarty Motors. Might be cheaper than a dealer if you can't get your problem sorted out.
Good luck!
Brandy

I would think with your problems that it would have shown a trouble code when Auto Zone hooked it up to the OBD reader. or did they just check by hooking to the battery cables?

Last week I drove from Seattle to Spokane (300 miles), parked the car for two days, then when I tried to start it the battery was too weak. A Jump start got me back to Seattle. Two days later, after a 100 mile drive, I parked the car and listened to the radio for about 20 minutes with the engine off....the battery light came on and I had to jump start the car again to get going. The dealer told me that I must have left the parking lights on, or I bumbed the turn signal stalk and the turn signal lights stayed on...that's what the error codes showed. I'm sure I did neither. I was also told that you shouldn't run the entertainment system without the engine running. Now I'm worried that it will happen again. This is a real problem....you need to be able to depend on your car to start...particularly if you paid $60,000 for it.

My 04 545i put on a light show one day as you describe. First to go out was iDrive screen, but then all kinds of lights, and then engine started to run erratically. Fortunately, I was close to the dealer. They replaced the alternator. My car was just a few thousand miles out of warranty, but they did it for free. They said they have seen alternator failures before. The light show is due to voltage dropping below the threshold required for the computer, etc.

Good luck.