Shepherd's hut solar setup — is 400W enough for year-round use?

Finally got the hut wired up properly last month. Running a 400W Renogy panel into a Victron SmartSolar 100/30 MPPT, with a 200Ah Fogstar Drift LiFePO4 as the battery. Powers lighting, a small 12V compressor fridge, phone/laptop charging, and a little Govee fan. Summer's been brilliant — barely touched 50% DoD.

Worried about winter though. We're in the Midlands so peak sun hours drop off badly around December/January. Last year I had a cheap PWM setup and it was constantly flat by mid-morning. The Victron is obviously miles better but I'm still wondering if I should add another 200W panel before the bad weather hits.

Anyone running a similar-sized system through a UK winter in a cabin or shepherd's hut? What's your typical yield looking like in December — are we talking 1-2 kWh on a good day or even less? Considering whether a small wind turbine would complement it better than more panels given how grim and grey it gets.

PennineBoater | 312 posts

@WillWebb nice setup, Fogstar Drift is a solid choice. The honest answer is: it depends entirely on your winter location and what you're running. Up here in the north, December and January can be brutal for solar — you might genuinely see only 30-50% of your expected generation on many days, and that's assuming the panels aren't buried under snow or sitting under persistent cloud for a week straight.

The 200Ah LiFePO4 gives you decent buffer, but I'd strongly consider adding a small DC-DC charger so you can top up from a vehicle if needed, or even a tiny wind turbine if the site's exposed enough. What's your rough latitude and is the hut your permanent residence or occasional use? That changes the answer considerably.

CornishExplorer | 847 posts | Cornwall

@WillWebb Nice setup! The Victron/Fogstar combo is solid. My honest take — 400W is fine for summer, but Cornwall winters have taught me some hard lessons. December and January are brutal; you're looking at maybe 1-2 peak sun hours on overcast days, so realistically pulling 400-800Wh on a good winter day.

My suggestion would be to track your actual consumption now while conditions are decent, then stress-test your assumptions against a proper shade/winter shading calculator.

One thing worth considering is a small wind turbine supplement if you're in an exposed spot — wind often picks up exactly when solar drops off.

What's your daily consumption roughly? That'll tell us whether 200Ah is going to leave you comfortable or anxious come February. The battery capacity might actually be your limiting factor before the panels are.

Chalky | 1,204 posts | Array

400W in a UK winter is basically just a polite suggestion to the clouds ☁️ — done the same in my shepherd's hut and by January I was rationing like it was wartime. Slapped a second 200W panel on the south-facing roof and suddenly the Victron stopped sending me sad numbers. The Fogstar Drift will handle the storage no bother, but you can't store what you're not generating — worth checking your hut's roof pitch too, steeper angle pays dividends December through February when the sun's practically underground.

CotswoldExplorer | 203 posts | Cotswolds

@Chalky 😂 brutal but accurate — my garden office setup taught me that lesson the hard way.

@WillWebb the bit nobody mentions: panel orientation matters massively in winter. A fixed 400W at 35° pitch loses a chunk vs tilting seasonally. Even adjusting twice a year (summer/winter angles) can add meaningful harvest.

Also worth checking your SmartSolar app data after a few grey weeks — Victron logging is genuinely useful for spotting patterns. If you're regularly hitting 20% state-of-charge by morning, that's your warning sign before anything dramatic happens.

A small generator for backup isn't failure, it's just sensible UK realism. Tiny house folk figure that out pretty quick too. Your 200Ah Fogstar will handle it fine long-term though — LiFePO4 doesn't mind the partial cycles like lead-acid would.

LDVConvert | 412 posts | Array

The panel-to-battery ratio is worth scrutinising here. 400W feeding a 200Ah bank is actually reasonable sizing, but your real constraint is the 100/30 MPPT — that's 30A output, so you're already at the ceiling of what the controller can handle from 400W at 12V nominal. If you ever expand the panel array, you'll need a larger controller first.

More critically for year-round tiny house use: what's your actual load in Wh/day? A small fridge alone will chew 300-500Wh daily. Stack that against December irradiance in the UK (often sub-1 peak sun hour) and 400W might genuinely struggle mid-winter without either:

• A secondary charging source (Victron's Orion DC-DC if you're near a vehicle, or a small generator)
• Aggressive load-shedding November through February

What's powering the water heating situation, if anything?

KateMitchell73 | 847 posts | Yorkshire Dales

@WillWebb nice setup to start with, but I'd echo what @LDVConvert is hinting at — that panel-to-battery ratio gets punishing in December/January up here. Last winter I tracked my 320W array and genuinely averaged under 40Wh on several consecutive days during that grey stretch in January. Your Fogstar's a brilliant battery choice though, so at least you're not losing capacity to the cold like you would with AGM. My honest suggestion: look at adding even a small 100W panel on a secondary south-facing mount if you've got the roof space. The Victron will handle it fine. What's your typical daily consumption looking like? That'd help work out whether you've actually got a problem or whether 400W suits your use case well enough. 🌤️