Charging problem

Friend turned up saying he had flat battery & belt squealing this camper has always been rather strange with charging, leisure battery problems, leave parked for a week wont start.
Checked before latest fail, for poor connections as suggested, checked for current drain when switched off, charge seemed good on start, both batteries newish, always suspected the ZIG
Anyhow checked belt seemed worn so replaced with his spare, started van  belt sounded like a siren, checked belt  result burnt hand, the belt pulley were red hot after 30\40 seconds, removed belt Alt turned easily no rough feel, no play, belt on like a replay of previous,
Had left the ammeter in circuit it was showing 90AMPS no wonder the belt was unhappy, remove belt & alternator went to mate who has a test rig & it was producing crazy current we checked Alt stator windings shot.
Replaced unit now ok, we reckon it has being going faulty for a fair while, should help MPG as well

I would suspect the fault started with a shot regulator.
However after an experience of one failing if the split charge relay device is one of these SmartCom self sensing things - I would check it is operating correctly - especially the "break" operation. One I had went a little skew-wiff and took out the leisure battery.
I now have a manually triggered split charge relay the operating signal taken from the side light circuit - so whenever the lights are on the Leisure battery is charging - turn off the lights breaks the split charge circuit.
Jon

Hi jon01
Since posting i have dissected Alt the alternator, the diodes in reg all pass test  the coils are the only thing that seem U\S .
I think this is one of those once or twice in a lifetime problems been it the trade for 40 years & cant remember it before, talked to a auto electrician friend of the same or longer vintage he said he thinks he can remember one other occurrence years ago,  the split charger is a ZIG.
Been running a month since trouble, all ok now
I tend to use 2 R4a Relays for split charge but with AC hook up it becomes a little more difficult