I just had an alternator installed on my 2007 XKR maybe 18-24 months ago. Actually put 2 on… the first went out in a few days and the mechanic told me it was because I supplied a cheap alternator. So next time I went with a Bosch. But yet here I am with “battery not charging” light again. So what is a good brand to get and what amperage rating do I need. I see several different ratings for this. Thanks!

 

Well, Bosch does provide higher and lower quality parts.
Furthermore, battery charging relies on the “generator” (as described in the workshop manual ), the battery, the drive belt, fuse 5 and the ECM.
I would confirm that the generator is or is not operating at spec before replacing it.
And that the battery is in fact able to accept charging. Older batteries lose their capacity over time.

The section titled “charging system” in the workshop manual lays out an efficient path through pinpoint tests to discern what is the root cause of the situation and, the remedy.

 

I replaced the battery when I replaced the alternator. I didn’t know about a “generator”.

 

Ohh I re-read your comment, I think you just mean all of it is “the generator”. Got ya. New battery, I’ll check belt tightness and condition, and I’ll look for where to find fuse 5. When I start the car. It will run for about 5 mins. Then throw the not charging message up. Maybe not the case, but that makes me think it’s not the fuse.