I just replaced my alternator, and before I tightened everything (service position regarding) and put the bumper and all, I tried to start it,
It started and showed 14V, I revved it slowly up to 3, fine, then tried higher and voltage dropped to 12.
Stayed there, I suspected the alternator so I disconnected the battery and it died

I checked the two connections to the alternator and they're fine, what else could be causing this,


(It's a 2001 a6 Quattro 2.7 sedan )

 

if everything is well connected - the alt. must be defective - while engine is running try placing a screw drive in front of alt pulley and see if you feel a magnetic pull if so alt is ok