Right, here's a slightly niche one. I've got my shepherd's hut on a farm plot in Shropshire, and over winter I've been parking the motorhome alongside it and running both off the same 400W Renogy panel array and a pair of Fogstar 100Ah lithiums. The hut takes priority obviously, but the van sits there drawing maybe 5–10W on standby (fridge on low, alarm ticking over). So far so good — the Victron MPPT is handling the split charging via a DC-DC charger and I've not had a flat battery since October.
The bit I'm wrestling with is load priority when we get a gloomy January week. Last week we had three days of proper soup-fog — zero meaningful solar — and the hut's 12V loads (LED strips, a small pump, phone charging) were quietly nibbling the shared bank down to 40% before I noticed. The van was fine, but only because I'd manually isolated it. I'd rather have something automatic rather than relying on my memory, which is, shall we say, not my strongest feature.
Has anyone wired up a proper voltage-based load disconnect — something like a Victron BatteryProtect or similar — to automatically shed the lower-priority loads before the bank gets sad? I'm thinking set the hut's "optional" circuits to cut at 12.2V and leave the essentials (and the van's standby) protected down to maybe 11.8V. Does that logic hold up, or am I overthinking a two-battery bank with a length of wire and some optimism?
