1999 tahoe. 200 amp fet isolator. 1- 12 volt regular wet starter battery. I- 12 volt auxiliary AGM battery. My set up worked just fine for 6 months and a good many miles. Now will work only intermittently ...allows charge at startup..then shuts down. some miles down the road..or ...does not allow alternator engagement on initial start -up....have replaced what I now know was a good 95 amp alternator with 140 amp alternator and its doing the same thing.... So can not trust the vehicle to drive anywhere....Victron customer service has been no help .60 dollar an hour shop is frustrated.with this ........as am I.....will have no choice but to remove the unit if unable to determine what is going on. Again..worked very nicely for a good while before this issue arose ...any thoughts appreciated. thisissue must have happened to someone ....out there