Take an amp meter and put it on the positive cable after shutting off everything and see if there is any draw if so does it amount to anything significant enough to take the batteries down overnight. Do you know the age of the batteries? Are they agm, gel of flooded? Is it really cold where you are?
Brad & Karen & Mena
Coach Name BIG BLUE
1988 40 ft 8v92 TA
2012 Toyota FJ Cruiser,1990 Jeep Cherokee 4/WD now a desert rat
25 ft Haulmark trailer
730 watt solar panels, Full timing.