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

Running a 200W Renogy panel on my motorhome through last winter and honestly it was touch and go some months, so curious whether others have had similar experiences.

My setup is a single 100Ah AGM leisure battery — so not huge — and even with that relatively modest bank I found January and February particularly brutal. On a clear day I'd see maybe 2–3 hours of usable sun at best, which on a 200W panel gives you somewhere around 400–600Wh if you're lucky. Sounds reasonable until you factor in cloudy days where output drops to practically nothing.

A few things I'm wondering:

• Does panel orientation and tilt angle make a meaningful difference in winter months? I've read that steeper angles help capture the lower sun but never properly tested it
• Is the battery chemistry relevant here — would a LiFePO4 like a Fogstar Drift hold charge better over winter than my AGM, or is that a separate conversation?
• At what point does it make sense to add a second panel versus upgrading the battery bank?

The honest answer from my experience is that 200W probably isn't enough if you're relying on solar alone through December and January in the UK — I ended up running a hook-up or running the engine more than I'd have liked. But I was also running a compressor fridge constantly, which is hardly a light load.

Would love to hear from anyone who's managed to stay genuinely solar-independent through a UK winter. Particularly interested if you're further north than the Midlands, where I suspect the numbers get even tighter.

@WattAMess25 — welcome to the forum, really glad you've posted this because it's a question that trips up a lot of people starting out!

The short answer: 200W can work, but winter in the UK is genuinely brutal for solar yields. You're potentially looking at only 1–2 peak sun hours on a grey December day, meaning realistic output closer to 200–400Wh — assuming no shading or panel soiling losses.

Key factors worth checking:

• Panel angle — a steeper tilt (50–60°) recovers meaningful output in winter
• MPPT vs PWM controller — if you're on PWM, you're leaving efficiency on the table
• Battery state — AGMs really dislike sitting below 50% for extended periods

From my own static caravan backup setup, I found adding even a modest second panel made a noticeable difference November through February specifically.

What's your typical daily consumption looking like?

@WattAMess25 200W is borderline at best in winter, honestly. UK December/January you're lucky to get 2 peak sun hours on a good day — often less. That's maybe 300-400Wh on paper, less once you account for panel angle, temperature losses, and a dirty screen.

With a 100Ah AGM you've got roughly 50Ah usable, so if you're pulling any meaningful load in the evenings it'll creep down week by week.

Few things that actually help:

• Tilt the panel — even propping it to 60° in winter makes a noticeable difference
• Check your MPPT is properly configured for AGM charge curves
• Consider whether upgrading to lithium (like a Fogstar Drift) would give you more usable capacity rather than throwing more panels at it

What's your actual daily consumption? That's the number that really matters here.

@WattAMess25 the AGM part is working against you as much as the panel size. AGMs want a proper full charge regularly or you'll sulphate the plates over winter — and with 2 peak sun hours on a good January day, you're rarely pushing enough current to satisfy the absorption stage fully.

I ran a similar setup on my narrowboat backup system two winters back. The maths looked fine on paper: 200W ÷ 12V = ~16.7A theoretical. Actual harvest? Closer to 6–8A average through December once you factor in cloud cover and low sun angle losses.

Switched to a Fogstar 100Ah lithium and the equation changed completely — lower voltage threshold, accepts charge faster, tolerates partial state-of-charge far better. If swapping chemistry isn't an option, a small shore power trickle charger running alongside would genuinely save that battery's lifespan.

@TorJake is right about the AGM, and I'll add something nobody's mentioned yet — tilt angle matters enormously in winter.

My cabin panel sits flat-mounted. Same wattage, completely different story once I propped it to around 60° for the low winter sun. Picked up a noticeable difference almost immediately.

@WattAMess25 if your Renogy is flush-mounted to the motorhome roof, you're losing a significant chunk of what little December sun there is before it even reaches your battery. Even a basic tiltable bracket made a difference on my motorhome setup.

200W can be enough for modest loads, but only if everything else is optimised — angle, clean panels, decent cable runs, a proper MPPT controller. Cut corners on any of those and you're fighting a losing battle come January.

@RustyTinker what angle are you actually running yours at then? I've got a 200W panel on my static caravan — flat-mounted, no tilt at all — and I've always wondered how much I'm losing because of it.

Also does anyone know if it's worth bothering with a proper MPPT controller if the panel output is already that low in winter? I've got a basic PWM on mine at the moment. Fogstar sell some decent lithium options and I've been half-thinking of ditching the AGM altogether but not sure if that solves the winter generation problem or just masks it a bit.