Anyone else struggling to get decent solar yield in January? Sharing my numbers this week

I've got a 400W panel setup on my static shed build — two 200W monos wired in series going into a Victron MPPT 100/30 and a 200Ah lithium. This past week in Yorkshire I've been lucky to scrape 150–200Wh on a clear day, and yesterday with full overcast I got a pathetic 40Wh total. Panel angle is fixed at about 35°, which I know isn't optimal for winter but tilting steeper isn't really an option with my current mount.

I'm running a 12V system and the main loads are a small 12V fridge (roughly 30Wh/day when it's cold), LED lighting, and charging phones/laptop. Most days I'm just about keeping up, but a run of grey days like this week has me dipping into reserves more than I'd like. I've got a backup B2B charger ready to hook up to a vehicle but I'd rather not rely on it.

Curious what other people's actual January yield numbers look like — panel size, location, angle — just real figures rather than theoretical. Also wondering if anyone's experimented with a steeper winter tilt and whether it made a meaningful difference in these low-sun months, or if the diffuse light situation just makes angle almost irrelevant when it's properly overcast?

@Spider6 that's pretty much par for the course in January — even down south I'm pulling similar numbers on good days. Worth checking your panel angle if you haven't already; I tilted mine to around 60–65° for winter and picked up a noticeable improvement over the standard 30° roof mount. Low sun elevation means steep tilt pays dividends this time of year.

Also double-check your Victron app for any absorption/float time data — sometimes the battery's already topped from a previous day and the MPPT is just sitting in float, which skews your yield figures downward and makes it look worse than it is.

400W in Yorkshire in January is always going to be modest. I budget roughly 100–150Wh/day as my baseline expectation and treat anything above that as a bonus.

@Spider6 same story up here — I've got 600W on the cabin roof and January is just brutal. What's your panel angle? I tilted mine steeper over winter (around 60°) and picked up a noticeable improvement, maybe 15–20% more on clear days compared to when they were at the summer angle. Low sun elevation means a flatter array is genuinely wasted potential this time of year.

Worth checking your Victron app history too — sometimes the yield figures look grim but you realise most of the loss is just cloud hours rather than poor system efficiency. If your absorption/float voltages are being hit by midday on clearer days, the system's doing its job fine.

@Spider6 my garden office panels spent most of last week generating enough electricity to power my disappointment, and not much else.

@Spider6 January in a shepherd's hut is genuinely humbling — I've got 320W on mine and last week I was seeing maybe 80–120Wh on the grey days, which barely keeps the Victron comms ticking and the 12V lighting going. Had to run the Honda 2200i for a couple of hours mid-week just to top things up properly.

One thing that made a noticeable difference for me was a proper clean of the panels — surprising how much grime and that fine green algae build-up kills output even on what passes for a bright January day. Worth checking if you haven't done it recently.

@NickBennett 😄 powering your disappointment is about right for this time of year.

@Spider6 those numbers don't surprise me at all for Yorkshire in January, to be honest. Worth checking your actual solar hours though — I use a pyranometer app and we're talking maybe 1.5–2 peak sun hours on a clear winter day up north, sometimes barely half that on overcast days. So 150–200Wh from a 400W array is actually pretty reasonable when you do the maths.

What I'd focus on is minimising overnight losses from the battery rather than chasing better yield — tighten up your loads, check your Victron is set to ECO mode, and squeeze every bit out of what you are generating. January's just grim, that's the truth of it. @NickBennett's disappointment-powered setup sounds about right for most of us this time of year! 😄

@Spider6 those numbers don't surprise me at all for Yorkshire in January — solar is very much a fair-weather friend this time of year! One thing worth checking is your battery's state of charge first thing in the morning. If you're starting each day already reasonably topped up from the day before, your MPPT may actually be throttling back earlier than you'd expect, which can make your yield figures look worse than the panels are actually capable of. Also worth logging your peak watts mid-day even briefly — sometimes you'll catch a decent spike around noon on a clear day that makes the overall Wh figure look misleading. Hang tight, February makes a noticeable difference in my experience. 😄

@Spider6 those figures are pretty much what I'd expect for Yorkshire this time of year, honestly. January UK solar is brutal — you're looking at maybe 1–2 peak sun hours on a decent day, and that's if you're not getting the low-angle shading issues that catch a lot of people out. Have you tried tilting your panels steeper? Around 60–70 degrees in winter can make a noticeable difference versus a summer angle. Also worth logging your yield daily on PVOutput if you're not already — really helps you spot patterns and set realistic expectations through the dark months.

@Spider6 honestly those numbers are pretty normal for January — don't panic! I've got a similar setup on my garden office and I just plan around it this time of year. A few things that help me: keeping panels wiped down (frost residue kills output), and if you can tilt them steeper for winter that makes a real difference. Low sun angle in Yorkshire means every degree counts. I also run a small Fogstar battery so I'm not drawing it right down on the grim days. February onwards it picks up noticeably — hang in there! 🌤️