Anyone else struggling to keep a 100Ah lithium topped up on a cloudy week in Scotland?

Scotland in winter is basically a solar panel's worst nightmare — I've had weeks up north where my 200W roof array has barely pushed out 10–15Ah in a full day. Genuinely grim.

A few things that made a real difference for me:

Shore power when you can get it — even a few hours on a campsite hookup every couple of days keeps you out of trouble. Not very off-grid purist, I know, but it's pragmatic.

Driving charges more than you'd think — I've got a decent B2B charger (Victron Orion-Tr Smart) wired in, and even a 45-minute run to a supermarket can put 15–20Ah back in. If you're moving around anyway, use it.

Audit your loads ruthlessly — a 100Ah lithium sounds like loads until you add up a compressor fridge (35–40Ah/day), lighting, phone charging, a diesel heater fan... it disappears fast.

Worth asking — what's your actual battery? Some of the cheaper cells genuinely don't perform as advertised, especially in the cold. My Fogstar Drift 100Ah has been solid, but I've heard horror stories about unbranded cells dropping usable capacity noticeably below 10°C.

The honest answer is that 100Ah is quite tight for full-time van life in overcast northern conditions without reliable solar. A second battery would probably give you more peace of mind than chasing better panels.

What loads are you running day-to-day? Might be easier to pinpoint where the drain's actually coming from.

@BrambleElla yeah Scotland in winter is basically proving that solar is a supplementary source, not a primary one. People massively overestimate what panels actually deliver vs. rated output.

On my static up near the coast I've had similar — 200W array giving me barely enough to run the fridge overnight, let alone top up a 100Ah.

Honest solution? You need a secondary input. Either a decent shore power hookup with a Victron IP22 charger, a wind turbine (genuinely underrated up there), or at minimum budget for a small genny run every couple of days.

Solar calculations based on peak sun hours are near-useless above the central belt November–February. Plan for maybe 0.5–1 sun hour equivalent on overcast days and size your system around that, not the summer figures everyone quotes.

Really interesting thread — though I'm coming at this from a narrowboat angle rather than a motorhome, so take it with a pinch of salt!

One thing nobody's mentioned yet — have you looked at what your actual baseline consumption is on those grim days? I spent ages trying to solve a generation problem when really I had a sneaky phantom load draining about 8Ah overnight (turned out to be my inverter on standby 🤦‍♀️).

Also curious — what's your battery chemistry? I've got Fogstar Drift cells and apparently lithium holds usable voltage much lower than AGM, so are you actually running out or just reading low on a dodgy SoC gauge?

@DODGuy makes a fair point about solar being supplementary up there in winter — has anyone paired a small wind turbine alongside? Feels like Scotland's practically designed for wind generation 😅

@BrambleElla this is painfully relatable — my static caravan setup in the Peak District isn't Scotland but we had a run of about 9 days in November where my 400W of panels produced genuinely embarrassing numbers. Like, my Fogstar Drift 100Ah was basically laughing at me.

One thing nobody's mentioned yet — have you looked at your panel angle? In winter the sun's so low that even a slight tilt adjustment made a noticeable difference for me. Obvious in hindsight but I'd just left mine flat all year like an idiot 🤦

Also curious — are you running a proper MPPT controller? Renogy's basic PWM units are rubbish at squeezing anything useful out of weak winter light. Swapping to even a budget Victron SmartSolar was a genuine game changer for low-irradiance days.

What's your charging setup currently?

Relevant from my shepherds hut setup rather than a van, but the winter solar struggle is identical. I ended up fitting a small wind turbine alongside my panels — even on dead grey days there's usually some movement, and the two sources together have kept my Fogstar 100Ah reasonably healthy through some pretty bleak February weeks.

The other thing worth considering is a proper MPP Solar charge controller rather than a basic PWM unit — I was genuinely losing 20-30% efficiency before I switched. Made a noticeable difference on marginal days.

@DODGuy is right though — I now treat solar as supplementary October through March and plan my consumption around that. Running a small petrol generator for occasional top-ups isn't glamorous but it's realistic.