Tiny house EV charging off-grid — anyone actually done it without bankrupting themselves?

Finally bit the bullet and wired up a proper off-grid setup for my tiny house — 4× Fogstar Drift 200Ah LiFePO4 batteries, a Victron MultiPlus-II 5000VA, and 3kW of panels on the roof. Running nicely for the house loads, no complaints.

The problem is the Nissan Leaf sitting outside looking at me judgementally. Charging it overnight would absolutely batter the battery bank — rough sums say even a slow 3.2kW EVSE would drain my 800Ah usable capacity in a few hours before dawn.

Currently thinking about a timed charge using only solar surplus mid-afternoon with a Victron ESS assistant keeping the grid (well, my Honda EU22i) as backup. But it feels like I'm flogging a generator just to charge an EV, which somewhat defeats the point.

Has anyone cracked EV charging in a genuinely off-grid setup — panels, storage, realistic UK winter sun — without just running a genny all the time or taking out a second mortgage on more batteries?

PYW_VanLife | 312 posts

@RetiredElectrician74 Cracking setup — the Fogstar Drift cells are solid bang for your buck. One thing worth considering: set your MultiPlus charge current low overnight if you're running ESS mode, otherwise you'll hammer your SOC trying to top off the EV and leave yourself short for morning loads.

I run a similar Victron setup in my van and charge a small e-scooter off it — the key lesson was patience. Treat the EV like a low-priority load, not an urgent one. Solar surplus charging only, let it trickle over several days rather than forcing a session.

What inverter assistant are you running? If you're not using the scheduled charging assistant already, that's your first port of call — makes a massive difference to managing peaks sensibly.

Del6 | 847 posts

@RetiredElectrician74 Nice one — that MultiPlus-II 5000VA should handle a decent charging session without breaking a sweat. The key with EV charging off-grid is really watching your state of charge before you plug in. I'd strongly recommend setting up a schedule in VictronConnect so it only charges when the batteries are above say 60-70% and solar input is genuinely covering the load. Otherwise you'll be hammering those Fogstars pulling from storage constantly.

What car are you running? A Type 2 at 3.6kW single phase is about the realistic ceiling here — anything faster and you'll be draining faster than you're generating on a decent day. Granny charger as backup for lean periods too. Curious what your typical daily mileage looks like as that'll dictate whether this is genuinely workable day-to-day.