Squeaky Alternator Belt

Hey all. I have searched the forums for a solution to this common problem, but noone seems to know how to fix it. However, I think mine is different from others. I have a 90 Eclipse GSX and my alternator belt squeals only when the voltage for the car gets below 12.5. It is normally at 13.5. I got a new 135 amp alternator and a red top optima battery, new belts for PS, AC, and the alternator, but nothing seemed to work. And my alternator belt has been shrinking as I have been trying to keep it at a 1/2" deflection. My alternator is now at the closest it can get to the engine and now if I want to take the belt off, I will need to cut it off. It is really annoying and i want to get rid of it b/c it doesn't fit the car. DSMs should not sound like that! I would appreciate the feedback so I can stop banging my head against the wall :banghead:

hmm im not sure maybe its the bearings on one of your pulleys and it doesnt make noise untill theres a load on it... maybe try spraying some wd40 on the pully bearings?