The battery light on my dash came on a few months ago and my mechanic says that can only mean the alternator is not charging properly. First a little background...I only drive the car a few hundred miles a year at most. Since last spring I think I've only driven it to test the alternator. It reads 12.5V with the car off and the maintainer disconnected. After 15 min of idle, the voltage only drops to ~12.0V after shutting the car off. With the car running, the voltage does not rise to the ~14V (??) expected. I assume this is still consistent with a bad alternator even though I would not expect a battery to drain that slowly with no alternator charging. New info from today: I took the car out and the battery light went off after a little while and stayed off (mostly). It would occasionally dimly reappear and would go on/off with the bumps in the road. So this might be a connector. However, the voltage upon return did not charge higher...same ~12V at stop. So it still appears not to be charging.

Aside from a potential connector issue, does this sound like a bad alternator? I had planned on repairing it myself. Assuming I get the alternator out to decipher which one I need, Rockauto versions are priced waaaayyyy cheaper than the Audi-certified version that my mechanic can get ($600 vs ~$200). FWIW, he is trust-worthy. Sounds like "Audi-certified" is what costs the extra money. Is this a scam, or is there really value-add for buying the "certified" version?

I started to dig in and remove the alternator and immediately ran into an issue with one of the screws that holds the sound absorber in place. The one just below the dip stick. I stripped the phillips head. Should I just drill it our or is there enough meat to that screw to try an extractor?

Thanks,
Mike