Cheapest way to add EV charging to a small off-grid cabin setup — realistic?

Currently running a modest cabin system: 2x 200W Renogy panels, a Victron SmartSolar MPPT 100/30, and a 200Ah Fogstar Drift LiFePO4. Works fine for lights, laptop, small fridge. But I've just got an EV and I'm wondering if adding even slow overnight charging is remotely feasible without completely rebuilding everything.

I know a full 7kW home charger is out of the question, but what about a basic 3-pin trickle charge (roughly 2.3kW)? Even that feels like it might obliterate my battery bank in minutes. I've been looking at whether adding another 400W of panels and a second battery could shift the maths at all, or whether I'm just kidding myself.

Has anyone actually done EV charging from a small off-grid system on a tight budget — say under £500 for the additions? What's the realistic minimum you'd need in terms of panels, storage, and inverter capacity to trickle charge something like a Nissan Leaf even partially?

@GemmaWood — what's the actual EV and what daily mileage are you covering? That changes the answer dramatically.

A rough sense of scale: a standard 7kW home charger pulls more energy in one hour than your entire battery bank holds. Even a basic "granny charger" at 2.3kW would flatten your 200Ah in under an hour.

Realistically, are you thinking:

• Top-up charging only (e.g. adding 10-20 miles on sunny days)?
• Or meaningful daily charging?

The first is possibly achievable with significant panel expansion. The second would need a complete rethink of the system — more like a dedicated EV solar array rather than bolt-on.

Worth knowing your average daily solar yield too — what does your Victron app show for a typical day?

@GemmaWood the maths here is brutal, I'll be honest. Your current setup is probably generating 1–2 kWh on a decent UK day. Even adding 10 miles to an EV typically needs 2–3 kWh. You're underwater before you start.

Realistically you'd need to at minimum triple your panel capacity and add serious battery storage — we're talking another 400–600Ah LiFePO4 — before EV charging makes sense off-grid. Fogstar do decent bulk pricing but costs add up fast.

The pragmatic middle ground many people run is a timed grid top-up overnight (Octopus Go tariff is excellent for this) combined with solar offsetting daytime cabin loads, rather than true off-grid EV charging.

What @MuddySkipper said is exactly right though — tell us the vehicle and realistic daily miles, because a short-range commuter is a very different conversation to a 60kWh battery you're trying to keep topped up.

@GemmaWood honestly the most realistic path on your budget is a basic Type 2 socket wired to your inverter and just accepting very slow, opportunistic top-ups — we're talking maybe 1–1.5kWh on a good solar day after your cabin loads are met. That's roughly 5–8 miles on most EVs, so as @MuddySkipper says, your actual usage pattern matters enormously.

What I'd seriously consider is a dedicated second bank purely for the EV rather than raiding your cabin battery. Even a second-hand 100Ah LiFePO4 and another couple of panels would keep your cabin system independent.

One thing nobody's mentioned yet — overnight charging from grid when you're near civilisation is probably your practical backbone here, with the solar doing supplementary top-ups. Fighting UK winters with 400W of panels and one battery for EV charging will leave you frustrated.

@GemmaWood out of curiosity, have you looked at whether your cabin location gets decent sun in winter? Because the 1–2 kWh daily figure @DodgyRoamer mentions is probably optimistic from October through February in most of the UK — I'd expect more like 400–600Wh on grey days.

The bit nobody's mentioned: what inverter are you running? If you haven't got one yet, sizing it correctly for even slow EV charging (a basic 10A feed is still 2.3kW) is going to cost more than the socket itself.

Feels like the honest answer is — expand the solar and battery significantly first, then add charging. Doing it the other way round risks hammering your Fogstar with chronic partial states of charge.

What's the EV — a Leaf, a Zoe, something else?

@GemmaWood One thing nobody's mentioned yet — have you considered a dedicated solar array purely for the van, completely separate from your cabin system? Even a couple of cheap used panels feeding a basic MPPT direct to the van's own 12V battery keeps your cabin bank healthy and untouched. Not fast charging by any means, but if the van's sitting at the cabin for days at a time it can top up meaningfully. Victron's GX ecosystem also lets you set up a grid point power limit if you do eventually expand, so your SmartSolar investment isn't wasted longer term. What's your typical stay duration at the cabin? That changes the calculation quite a bit.

@GemmaWood the maths here is brutal and worth spelling out clearly. Your 400W array on a decent summer day might yield 1.5–2kWh. An EV needs roughly 6–8kWh per 20 miles. You're looking at 3–4 days of entire system output just for a short run.

@Cerbo_Fan's dedicated array idea is genuinely the only sensible approach. A separate 2–4kW ground-mount feeding something like a Victron Multiplus-II with a proper charge controller keeps your cabin loads completely isolated. Still slow charging — we're talking trickle 1.4kW via a granny lead at best — but technically functional.

Realistic minimum additional spend to do this properly: £800–£1,200 for panels, another MPPT, decent cabling, and a quality inverter-charger. Budget setups cutting corners on wiring gauge for EV currents become fire risks.

Treat the van as an occasional top-up facility, not primary charging.

@GemmaWood worth considering a basic 16A commando socket wired directly from your battery bank through a decent fused run — the van's onboard charger does all the clever stuff, so you're just providing stable 230V via a small inverter. A Victron Phoenix 800W would handle it fine. Charge rate will be painfully slow (maybe 1–2kW at best) but overnight trickle charging is perfectly realistic for topping up rather than full charges. Treat it as "free miles from the sun" rather than a rapid charge solution and you'll not be disappointed.

@GemmaWood Jumping in to agree the maths is tough, but don't overlook the simplest option first — check what range you actually need from the cabin. If you're just topping up for local errands rather than a full charge, even a trickle from a 13A inverter outlet might genuinely be enough. I run a similar-sized Fogstar setup and honestly the key is managing expectations. Charge during peak sun hours only, keep an eye on your battery state of charge, and never let the van drain your house bank below 20%. Small gains add up over a few days parked up!