We have an Ablemail on our Carthago, I am planning to use the SW2 to switch on the charging when the leisure batts are below the normal trigger point - I do it manually at the moment but will forget to check at some point..... Not sure if I will use the user defined load output on the solar 100/50 or one of the Cerbo GX relays to do it. My van is in a storage site so I have Victrons Connect/VRM apps and monitor the batteries through that.So I'm thinking let the Ablemail do it's job and wire the relay output of the BMV to a larger relay to switch the input to the solar regulator. Then set the relay to switch on connecting the solar when the battery is at 40% SOC and to switch off when the battery is at 80% SOC.
If I don't fit the BMV and go for a Smart Shunt I could use a voltage comparator to do the same job.
The second option is to fit a changeover switch to the output of the solar regulator and switch it over to the starter battery when parked up at home, so the solar just maintains the starter battery.
Next problem is the fridge as the Victron regulator does not have an AES output.
So I'm thinking of using either the BMV relay or a voltage comparator to switch a 12v signal to the S+ on the fridge when the battery is at 100% SOC and to switch off when the battery is down to 50% or 60% SOC. Also I will fit a 24 hour timer inline so the AES connection will only be active from say 7 am to 4 pm (depending on the time of year) with it switching on & off in one hour blocks. That should preserve the battery and save a bit of gas.
The fridge is something I have thought about as well, at the moment we just leave the multiplus inverter on, and the fridge is wired to the inverter so defaults to 240v, the solar just keeps topping up the batteries, not an efficient process, but so far the B2B has kept up while driving, but in the cooler wetter months we have mostly been on sites with ehu so not sure how this will work in the summer when we are off grid - will be a pain having to monitor it so it will be good to hear how you end up doing it...