Hi.
As the title says, i know it is possible, but is it a safe and viable way for me to charge the battery bank while i'm not present at the cabin?
I will attach my homemade wiring diagram which is still a work in progress. The part i am concerned about is the wiring between the MPPT and the battery switch.
In theory a properly programmed system can be left unattended.
You have fusing in place. I assume you mean the main bank there, there is more than one battery in the picture, and the mppt is connected on the battery side if I am understanding your diagram correctly. (So the battery switch is just cutting off the rest of the system normally it cuts the battery off from everything both charge and discharge)
If you leave it in float service there should be no really heavy charging just maintaining a level. So maybe make sure gas won't build up, and they won't run dry.
Couple other comments.
16mm² is overkill from the panel to the mppt. And then 4mm² underkill from mppt to the batteries. Personally I would have those two gauges swapped around. But would prefer 6mm² on the solar side since you want to upgrade.
