Quote by relay racer
In the real cold weather there around January I had plugged in every evening for 3-4 hour’s and started the engine every morning for 5 mins making sure I had unplugged before starting engine
Between one charge and the other I disconnect both the engine batteries and the two leisure batteries (I have two in parallel).
All my campers have always been equipped with batteries disconnect switch.
Personally, for years, I have connected the camper to the EHU for 24/36 hours every six weeks.
This is enough to recover the self-discharge of the batteries, both the engine and the leisure ones (new I have two in parallel).
Instead of useful, I believe harmful, to turn on the engine for a few minutes, not even enough to bring the oil to operating temperature.
Even the manufacturers advise against doing so.
Max