VT Alternator issues

[BOGANV8]

Hey all hope someone might be able to help..
Put a new alternator in a mates vt V6 the other day as his other one had died and was bringing the battery light on.. Checked the charge rate and no charge out of it so replaced it.

Was fine for 4 days then on Friday the battery died so he got it replaced.. Drove 100klms today (i showed him the digi volt thing on the hidden menu) he watched it all day and it was only at 11v but no battery light on. when he turned the A/C on the guages (speed,tacho, temp,fuel) would drop to nothing.

Now the car started to run badly turned the A/C off and would come good again. Got to where he was going and the car wouldnt idle. So i guessing the battery voltage getting low and not enough to run the car ECU.BCM.

I went round had a look and defintly no charge coming out of the Alt so i pull it off have a quick look at it. seemed all good not noisy. Put it back on started the car check charge rate with multimeter at idle 12.75v bring the revs up 13.8v turn the lights on still 13.8 at 2000rpm. Even get 13.8v out of the back of the alternator

I would be saying dodgy alt but before i take it back to the supplier i thought i would just ask here bout it sounds funny that its not charging at idle like it should be. One other thing i should note. Car had been running for only 5 min from cold and i could'nt even touch the alternator it was that hot after only five mine.

Cheers Dave

[red truck]

Check the condition of the terminal on the end of thick wire, where it attaches to the back of alternator. They were not soldered to the wire, only crimped. The connection gets crappy, creates a resistance and will get very hot.
The alternator is trying to pump out max amps, but it can't get through the bad connection. Will damage a good alternator if you keep driving it.
The plastic coating of the wire will look hard and burnt close to the terminal.
All you need to do is cut the terminal off close, clean up the copper wire and solder a new terminal on, should be just enough wire to reach.
Very common problem since VN, right up to VT.