Alternator or power regulator change at e64 2005

Hello, did someone already changed the alternator or regulator? When I lay under the car it looks very tide. My Voltage always change from 12V to 13.7V very seldom stable. Sometimes I start and drive I read for a while 12V, it is not charging at all. Then suddenly it goes to 13.8 or 14V as like nothing been before.
So I guess the regulator need to change, its the cheaper part, so first try.
In the net I don't find something about the change.
Thanks

If you have access to an oscilloscope you can test the alternator first.

Looks like there are two different alternators.

Instructions for alternator 1.
Instructions for alternator 2.

Also google for 550i alternator DIYs. They are almost identical.

Hello,

it look like I have alternator 1. So far easy, but the guy wont come out, I could tilt it to the right side but no movement out, something is still holding it. I do it carefully not to break something. For me would be enough to reach the Voltage regulator so I didn´t remove the fan cowl with electric fan. To tilt it later forward to remove the regulator would be enough.