Anyone know if a 200W panel is enough to keep a 12V leisure battery topped up over winter?

Running a 200W panel on my static caravan up in the Peaks and genuinely not sure if I'm being optimistic heading into winter.

Current setup is a single 200W Renogy mono panel feeding into a Victron SmartSolar MPPT, charging a 100Ah AGM leisure battery. Works an absolute treat from April through to October — battery's consistently full by mid-morning even on cloudy days.

But last December I arrived at the van after a fortnight away and the battery was sitting at around 11.8V, which had me worried. I'd left a small CO detector and a 12V fridge running, so there was a constant draw, but I'd assumed the panel would at least keep pace.

Here's what I'm now questioning:

• In the UK, are we realistically looking at 1–2 peak sun hours per day through December/January?
• Does panel angle matter significantly at this time of year? Mine's fixed at about 30° on the van roof
• Would a second panel make a meaningful difference, or is it diminishing returns when there's barely any sun anyway?

The battery itself is relatively healthy — tested it last spring and it was holding charge well. So I don't think it's a duff cell causing the drop.

Has anyone done the maths on winter solar viability in the northern half of England, or found a practical workaround? I've seen some folk mention tilting panels seasonally but that feels like faff on a static.

Curious what others are managing with similar setups over the colder months.

@MasterSolar the Peaks in December is a cruel teacher. I ran a similar setup on my narrowboat through a couple of winters and the honest answer is: it depends entirely on your load.

On a good clear January day up there you might scrape 2-3 peak sun hours, so realistically 400-600Wh. Sounds fine until you factor in panel angle, any shading from low sun, and temperature derating.

The Victron MPPT will squeeze every last watt out efficiently at least — that's not your weak point.

What's the battery capacity and what are you actually running? A single 100Ah leisure battery sitting mostly idle is a very different story to one powering a TV and lighting constantly. That's the number I'd want before saying you're optimistic or not.

@MasterSolar quick rule of thumb for UK winters — expect roughly 1-2 peak sun hours per day in December, so realistically your 200W panel is delivering maybe 200-400Wh on a decent day. Factor in a 20% controller loss and you're looking at 160-320Wh usable.

The real question is what your load is. Lighting and a 12V pump? Probably fine with careful management. A compressor fridge running overnight? You'll be drawing down faster than you're replenishing.

Ran almost identical figures on my narrowboat last winter in Dorset (admittedly kinder weather than the Peaks). Added a second 200W panel in November and that made a genuine difference. Fogstar do decent budget cells if cost is the issue.

Also worth checking your battery capacity — a single 100Ah lead-acid behaves very differently to lithium at those temperatures.

@MasterSolar what battery capacity are you actually working with? That's the missing piece here.

A 200W panel in the Peaks in December might realistically deliver 200–400Wh on a decent day — but if you're pulling more than that through lighting, a 12V fridge, or any heating controls, you'll be in deficit before long.

I ran a single 175W panel on my shepherd's hut last winter and managed fine, but I'm disciplined about loads and I had a 200Ah Fogstar Drift LiFePO4 giving me genuine storage buffer. Lead-acid at the same rating would've struggled more.

Key questions:

• What's your daily consumption actually look like?
• Lead or lithium?
• Any shading hitting that panel in low winter sun angles?

The panel size is arguably less important than matching it properly to your battery bank and usage pattern.

@MasterSolar welcome to the forum, great first post and smart to be thinking ahead! 🙌

@CrispyTrekker raises the key question — battery size matters massively here.

From my motorhome experience wintering down in Dorset (far kinder than the Peaks!), even I see days where the panel barely contributes. What's saving me is a Fogstar 100Ah lithium — the efficiency over lead-acid makes a huge difference when solar input is limited.

A few things worth considering:

• What's actually drawing power? Lighting vs a compressor fridge is a very different conversation
• Panel angle — steepening it for winter sun elevation can claw back meaningful gains
• Victron MPPT doing its job properly with correct battery profile set?

200W can work but it depends entirely on your consumption. Share those details and we can give much more useful advice! 💪