Battery drain issue

Have had 4 or 5 occasions where alt performed perfectly. As alternator cooled to ambient temperature it would discharge battery. Disconnect battery and reconnect without doing anything else and fault disappears. Start vehicle and shut it off and it returns.
Reason for disconnect setup to not interrupt battery circuit after
Running engine.
My own caravan would discharge battery only when below freezing.
No fault in warm shop.
Glove box lights,radios,power antennas,trunk lamps,corroded wires under wet carpets,battery gases condensed on case missing fuse on seat belt pretensioner. I have spent endless hours chasing electrical issues. Bought some decent tools for it as well.
A non contact infra red thermometer found a few as well. Anything consuming power also produces heat.