Shepherd's hut build — what battery capacity did you actually end up needing?

Planning the electrical side of my shepherd's hut and going round in circles trying to size the battery bank properly. Currently leaning toward 200Ah of lithium (probably Fogstar Drift cells) with a couple of 200W panels and a Victron MPPT, but I keep second-guessing whether that's enough for full-time weekend use plus the odd week away.

Typical loads would be: LED lighting, a 12V compressor fridge (~40Ah/day estimated), phone/laptop charging, and maybe a small Victron inverter for the occasional power tool or kettle. No immersion heater or anything daft. UK weather means I can't always count on solar doing much November through February.

For those who've actually been living out of a cabin or hut setup — did your original estimate hold up, or did you end up wishing you'd gone bigger from the start? I've heard "double what you think you need" so many times it's basically a meme at this point, but 400Ah feels like overkill for a weekend hut.

Also curious whether anyone's running a small wind turbine alongside solar to help with the winter deficit — the site gets reasonable exposure and I've been eyeing up a 400W unit to complement the panels.

@BatteryWez the "going round in circles" feeling is so familiar — I spent three weeks on spreadsheets before just committing and learning from reality.

200Ah sounds reasonable on paper but the thing that caught me out wasn't the big loads, it was the parasitic stuff — the Victron BMV monitor, the router if you're running one, LED drivers that never fully sleep. Those quietly chewed through maybe 15-20Ah overnight before I'd even switched a kettle on.

For a shepherd's hut I'd genuinely push toward 280Ah minimum if you can stretch the budget. Fogstar Drift cells are solid — I've got their 100Ah units in the van and they've been properly reliable through two winters on Exmoor.

Also worth asking: what's your charging source? Solar alone changes the calculation massively versus having a hookup fallback.

SandyViking | 847 posts | ⚡ Solar nerd, Orkney

@BatteryWez 200Ah lithium is a reasonable starting point but honestly it depends heavily on what season you're using the hut. My off-grid setup taught me that summer sizing and winter sizing are completely different conversations — shorter days mean your panels aren't replenishing anywhere near as fast.

What's your heating situation? If you're running any electric heating at all, double whatever you're planning. Electric blanket overnight alone surprised me with how much it chewed through.

Fogstar Drift cells are solid value — no complaints there from what I've seen on here.

One practical tip: whatever capacity you settle on, design your cable routing and enclosure to accommodate double that from the start. Expanding a battery bank is much easier when you've not boxed yourself in physically. Shepherd's huts are tight spaces!

@BatteryWez worth thinking about what your worst case day actually looks like rather than the average. I sized my garden office on averages and got caught out every January.

For context — I ended up at 300Ah (Fogstar Drift) for a space with similar loads to what you're describing, but honestly the bigger revelation was adding a second smaller solar string facing west. Doubled my afternoon harvest without touching the battery.

One question nobody seems to ask: are you planning any EV charging from the hut circuit, even occasional top-ups? That changes the maths dramatically and might mean you want expandability built in from day one rather than bolting it on later.

What's your solar array size looking like? Battery capacity in isolation is almost meaningless without knowing what's feeding it.

DalesSolar | 1,203 posts | ☀️ Yorkshire Dales | Fogstar fan

@BatteryWez one thing nobody's mentioned yet — how many consecutive bad weather days do you need to survive without running a generator or feeling anxious? That's what actually dictates my battery sizing recommendations more than daily consumption figures.

In the Dales I plan for 3 cloudy days minimum, often 4-5 in winter. With 200Ah you're essentially betting on decent solar recovery every couple of days, which is fine spring through autumn but can get stressful December-February.

What's your heating situation? If it's a wood burner with no electric pump then your loads are probably manageable on 200Ah. Add an electric blanket, a decent 12V compressor fridge, and a laptop and you'll likely wish you'd gone 300Ah fairly quickly.

Fogstar Drift cells are solid choice by the way, no complaints from me.

LauraGraham72 | 312 posts | 🏡 Shepherd's hut owner, Shropshire

@BatteryWez I went through exactly this with my hut two years ago and ended up at 280Ah after initially planning 200Ah — genuinely glad I upsized. The thing that caught me out was guests. When it's just me I'm quite disciplined, but the moment someone else stays they're charging multiple devices, leaving lights on, wanting the hairdryer... completely changes your consumption picture overnight.

Also worth considering whether you'll ever want to rent it out commercially, because that changes everything. Holiday let guests are a completely different animal to personal use!

The Fogstar cells have been solid for me for what it's worth. Just make sure you're not regularly dipping below 20% — that's where I'd budget from rather than the full 200Ah nominal capacity. @FormerMariner's worst-case-day approach is exactly right. 🙂