Today I installed the RasBo on the boat and hooked it up to the BMV712. The cable I made worked perfectly so I'll be making up a much longer one for the MPPT. It connected just fine over the onboard wifi and the switch directly. Once I permanently mount it I'll make up a short Ethernet cable and leave it wired in. The logging doesn't seem as sophisticated as I had hoped, but that might just be me needing to learn. I was hoping to see a graph of current over time rather than voltage.
I've also separately been playing with a rPi electronics kit, I think there will be lots of uses for this on board once I get up to speed!