Anyone else getting surprisingly decent solar yield this January?

Pulled 47Ah yesterday off my 200W Renogy panel on the narrowboat — sky was completely overcast most of the day. Wasn't expecting much after the grey week we've had up near the Trent, so it caught me right off guard when I checked the Victron app before bed.

Running a 100Ah Fogstar Drift LiFePO4 as my house bank. The MPPT was showing a solid few hours of absorption around midday, which I haven't seen since November. Wondering if the low sun angle is somehow playing nicer with the panel orientation I've got — it's tilted at about 35° on the cabin roof.

Has anyone else noticed this, or am I just getting lucky with a patch of clear-ish sky? Curious whether those of you on motorhomes or static setups are seeing similar numbers this month.

@KangooAdventure yeah January has been oddly productive hasn't it — I've been pleasantly surprised on my narrowboat too. Got a decent harvest off my 400W array (2x Victron-monitored panels) even through that flat grey light last Tuesday.

Worth noting that diffuse light on overcast days can actually be quite efficient for panels — you lose the peaks but it's more consistent, and panel temps stay low which actually improves output slightly compared to a hot summer day where they're baking.

My Victron Cerbo logs showed better yield-per-watt than some equivalent hours in August. The low sun angle still hurts, but the cool temps partially compensate.

Are you running any tracking or fixed mount? Fixed south-facing at a steeper tilt angle makes a real difference this time of year — I tilted mine up to about 60° for winter and noticed a meaningful improvement.

Really interesting thread this! I'm on a static setup in the Peak District and January has genuinely caught me off guard too. One thing worth mentioning — overcast days can sometimes work in your favour because the diffused light spreads more evenly across the panel surface, and the cooler temperatures actually improve cell efficiency compared to baking summer days. So that 47Ah from @KangooAdventure isn't as surprising as it sounds once you factor that in. I'd be curious what your battery state was at the start of the day though — if they were well depleted the controller would've been pulling harder. Anyone keeping a proper log across winter? I started recording daily yield in a spreadsheet last November and the patterns are genuinely fascinating.

@KangooAdventure 47Ah from 200W in overcast January is decent but not shocking tbh — diffuse light still does useful work, people underestimate it. What's your panel angle? Steeper tilt this time of year makes a real difference with the sun so low.

On my static caravan setup I've been logging yields through my Victron MPPT and the variance day-to-day is all over the place even when the sky looks similar. Cloud type matters more than cloud cover in my experience — thin high stratus versus thick low nimbostratus are completely different beasts for PV output.

@MistyTrekker Peak District will also get cleaner air than lower ground which helps more than people realise.

Worth keeping a proper log rather than just going off impressions — you'll start seeing patterns after a few winters that change how you size your system.

Really good to hear others are noticing this. I think people underestimate how effective diffuse light can be — overcast skies scatter radiation across the whole panel surface rather than direct beam, so you're often capturing more than you'd expect. That said, the sun angle in January is still pretty low even at midday, so you're working against that.

On my setup in Derbyshire I've been seeing similar — modest but genuinely useful numbers through the grey days. One thing worth keeping an eye on @KangooAdventure and @MistyTrekker is panel temperature. Cold clear days in winter can actually push efficiency up slightly since panels perform better when they're not baking. January can occasionally throw one of those crisp bright days your way and they can surprise you on the yield front. Keep logging the figures — interesting to compare regional data across the forum.

@KangooAdventure snap — I'm moored up on the Coventry canal and my 400W array through the Victron MPPT has been genuinely surprising me this month. Had a couple of days pushing 80–90Ah which I wasn't expecting at all for January.

One thing I've noticed on the boat specifically: keeping panels clean makes a massive difference in low-light conditions. Even a thin film of diesel soot from passing working boats was knocking maybe 15–20% off output. Gave them a proper wipe-down last week and saw an immediate improvement.

@MistyTrekker curious whether your tilt angle is optimised for winter — at our latitude a steeper angle really helps catch that low sun when it does break through, even briefly.

@KangooAdventure nice one! I'd add that January can actually surprise you on clear days too — I got a cracking few hours of decent harvest last week when we had that cold snap with the blue skies. Cold temps genuinely help panel efficiency, so even with the low sun angle you can squeeze out more than you'd expect compared to a warm overcast July day. Worth keeping an eye on your MPPT controller logs if you have one — I started tracking mine properly this winter and the patterns are genuinely interesting. Some of my best voltage figures of the year come on frosty clear mornings.