Hmmmm - I was under the impression that the connection between the MPPT controller and battery can be maintained without any problems when the solar panels are disconnected. The thermal breaker between the controller and battery is for overload protection.But, with no solar connected to the battery, its also good to install a disconnect between the controller and the batteries. Its my understanding that the controller can be affected when there is no solar connection but with the batteries connected. Other folks may have other opinions, but it makes the system easy to work on. I used a Blue Sea 30 amp breaker.
(Our set up is just like your photo and we don't trip the thermal breaker when the panels are disconnected.)