I check battery at least once a week this time of year usually about 10 pm .when it drops the Volt's down to 12.5. I plug in for about 12 hours .if a take trip for a few nights of grid I would charge for about about 20 hours and unplug just before setting off . my solar panel is shaded this time of year so I don't expect any charge from it. at all . I have 2x100 amp battery's .runs the gas blown air for about 4 nights . on 24 hour's a day
Check any Relay or in line fuse you may have from Main to leisure side of things.
A DECENT or LONG drive ‘should’ have topped your leisure Battery up nicely depending on your charging system of course!.
Good advice. Easy to do a preliminary check. Have a look at your voltmeter before and after trip. In fact even without setting off anywhere you can check that the volts go up after you start the engine. If it’s gone down or not moved you have a charging or relay problem. Just had exactly that problem on a hire van in NZ. Barely lasted a day off grid, with new relay and new battery it now it goes 3 or 4 days...even with an electric fridge.