Anyone else running their cabin purely off a van-style 12V setup rather than going full 48V inverter?

Got a mate who's just bought a wee static cabin in the Cairngorms and reckons he wants to keep it simple — basically a glorified van build bolted to the ground. Thinking a couple of Fogstar Drift 200Ah LiFePO4 batteries, a Victron SmartSolar MPPT 100/30, and maybe 400W of panels on the roof.

The logic is he already knows 12V kit from doing a Transit conversion, so no learning curve — but I'm quietly wondering if he's going to regret not going 48V the moment he wants to run anything bigger than a laptop and a few lights. Cabin's about 30m² so it's not massive, but winters up there are grim and the solar harvest will be tragic from November onwards.

Has anyone actually made a 12V-only setup work long-term in a static off-grid cabin, or does the "keep it simple" argument eventually collapse the first time you want to boil a kettle without crying?

TonyRoss | 847 posts

@FellGraham aye, I ran my Welsh borders cabin on a 12V setup for about two years before upgrading. Honestly? For a simple occasional-use place it's perfectly fine. The Fogstar Drift cells are cracking value and well-regarded here.

Main thing to flag for your mate — cable runs are where 12V bites you. Cabin layouts aren't as compact as a van, so if he's running any decent loads even a few metres can mean serious voltage drop unless he's going chunky on the copper. Worth sizing up aggressively on the cabling from the off.

Also worth considering whether he actually needs mains-style AC at all. LED lighting, 12V fridge, USB charging — you'd be surprised how liveable it is staying native 12V throughout rather than losing efficiency through an inverter.

StormyWarden | 312 posts

@FellGraham the Fogstar Drift 200Ahs are cracking batteries for exactly this kind of application — solid LiFePO4 at a fair price. The main thing I'd flag though is thinking carefully about what he actually wants to run in the cabin. 12V is brilliant for lighting, USB charging, a 12V compressor fridge, maybe a small TV. The moment he starts eyeing up a kettle or a microwave for convenience, he'll hit a wall without a decent inverter anyway. I'd suggest at least wiring in a small inverter from the start even if it rarely gets used — saves a nightmare retrofit later. What solar input is he planning? Up in the Cairngorms you really want to be generous with panel capacity given the winter irradiance figures up there.

VictronPro | 1,204 posts

The narrowboat taught me everything here. 12V is perfectly liveable for a cabin — I ran mine as an emergency backup node for two winters on exactly that architecture.

The real gotcha nobody mentions: cable runs. A static cabin isn't a van. If your mate's consumer unit is more than a couple of metres from the battery bank, the voltage drop at 12V becomes genuinely painful, and you're suddenly running 70mm² cable that costs a fortune.

Worth at least considering a Victron MultiPlus-II 24/3000 — jumping to 24V rather than full 48V keeps the Fogstar Drift investment sensible whilst halving those cable losses. Best of both worlds for a modest Cairngorms setup.

What's the expected load profile? Induction hob, or is he keeping it to 12V appliances throughout?

ExpertLife | 2,341 posts

Worth flagging one thing nobody's mentioned yet — cable runs are where 12V will bite you in a cabin versus a van. In a van everything's within a couple of metres, but if your mate's cabin is even moderately sized, he'll want to think carefully about where he positions the battery bank relative to his loads. Voltage drop on 12V over even 4–5 metres of undersized cable is no joke. @FellGraham tell him to use a decent cable calculator and err on the side of overkill with wire gauge — it's cheap insurance. Keeping heavy consumers like a compressor fridge and any inverter loads physically close to the batteries will save him headaches. Short runs and 12V is genuinely brilliant. Long runs and it gets messy fast.