This is the schematic that I built for the campervan, the batteries can be recharged by solar panels, engine battery/alternator and shore grid.

Leisure battery is 200ah 12v, two solar panels 175w 21v connected in parallel (due MPPT Charger limit input to 25v, just to be safe).

The dual DC-DC MPPT Charger is capable of a max output of 50Amp (25 solar + 25 from engine battery) and have a full automatic load distribution that direct the charge to the engine battery once the leisure one is full.

Inverter size is 2000W with AC input priority to stop using the battery when connected to the main grid. More than enough for our needs, the main load will be the induction hob, with 1500W max power. (from Sterling Power… as soon they have it back on stock!)

Still looking for the AC-DC charger