Overheated alternator from HKB voltage booster
 

In my very low miles 2003 4R, 5 serpentine belts shredded in year and a half w/o apparent causes. OEM and Bando. Last one also went behind damper and damaged crank seal.
Several times took out all pulleys, cleaned meticulously, greased, all OEM, bought new OEM ones but did not use them cause originals where perfect in all senses. Could not understand what was the problem.

In all ocassions damage to the belt occured soon after new belt installed, at the edge close to engine , not the radiator.

Called my attention after a while that the alternator pulley gradually lost its black brilliant color paint and alternator that was always clean, start staining small amount grease in the front. Alternator voltage was fine ( have amazon voltmeter/USB charger installed).

Review my notes and everything started 1 month after installing a HKB voltage to properly charged my AGM batt. I was running higher voltage 14.2-14.5v while in the road and higher than 12.2 when engine off that made me very happy.

Decided to remove booster and put original alternator fuse. End of problem. Several months now serpentine like new. Back to lower voltages

Will service alternator and buy new Denso one to have as spare for my long trips cause I may have shorten life of the original.

Any similar experience with voltage boosters?

been running the same booster for a few months now, not sure what your setup is, but i have a mechman high output 240 amp alternator, big 3 wire upgrade with 1 gauge wires, heavyduty green belt from gates and new belt tensioners and idle pulleys. didnt seen any downside of my setup since its putting out 14.6v to my dual battery setup.
the booster just tricks the alternator to give it more charge. did you verify that you at getting 14.5 or 14.6 while running? if not, then its backwards.

If you saw grease oozing out of the alternator, it has a failed bearing. That would account for all the shredded belts.

I believe it consequence not cause. It was not oozing initially and it is not oozing now, same alternator and zero belt problem. I do believe damage was done to bearing, new denso alternator ordered and will service the original.

As mentioned initial post, was running higher voltage similar 14.5-.6 and I was very happy for my AGM Batt. Don't have a mechan alt (I wish). It is the original Denso that came with the 4R. I do think that alternator overheated when tricked to get higher volts during long trips.