Alternator rebuild issues
 

Posting in case anyone has a similar situation.
The alternator in my 2002 4.4 went out late this summer. I occassonally use either of the X5's, so I was in no rush to get it back on road. I removed the alternator and sent it to a local shop that I have my starters, alternators, and other items rebuilt at. When I picked it up they told me that the positive diodes where all bad and that they replaced all of the other ones also as well as a complete rebuild. It was bench tested and checked out good. I installed it and only put a couple hundred miles on it until three weeks ago when I wanted to go on a road trip. The battery light came on again before I made it out of the driveway. I ended up having to take the E46 and parking the X5. Turns out the positive diodes were shot again. The battery is shorting straight to ground through the alternator diodes. With the positive cable disconnected from the alternator there is no short, it is isolated to the alternator.
This is the second rebuild, as a precaution I am installing a new battery to prevent the alternator from over charging. Since I don't drive it very often I have to throw a battery charger on it every now and then, so the true health of my battery is in question. Fingers crossed that this will take care of the issue. Keep you updated.

**update**

It's been a couple of months now and I have put about 1,000 miles on since the repairs. I am confident that the issue is resolved now.
I installed a new battery along with the alternator that had the positive diodes replaced again. I think that the battery was the source of all my problems placing a high demand on the alternator until it failed. The battery had been tested and held a full charge, so I didn't think of going back to it as the issue.

why didn't you just get a new or rebuilt one?

A new or rebuilt alternator?
I did have my alternator rebuilt. It had been completely rebuilt twice, I was pointing out the failed component as the positive diodes. After pricing a "new" one from the dealer and seeing that even those are rebuilt for $600+, I decided to have mine rebuilt.