I have had this problem both small (just one Victron SmartSolar 75/15 in a van) and large (large offgrid installation with Multiplus and Cerbo GX)
The problem is that you remove the battery because of an external reason, or the battery disconnects itself by the BMS, connected devices are still powered directly by solar. Which leads to unpredicting results. Not only from safety point of few, but also for the devices possibly not getting enough power and acting weird.
So in most cases you want the solar power to disconnect as well. I am thinking what the best way is to do this?
On my larger installation is a larger SmartSolar 250/85, which has a remote input (and no load output). This I want to let disconnect by a relais when the BMS kicks in and disconnects the battery. That way the system will go down. Is that the proper way? Perhaps there is an application note or some other document about this.
On the smaller system, the SmartSolar doesn't feature a remote input, so I should probably have a contactor/relay between solar and load output.