Anyone else finding their solar harvest absolutely dire this past fortnight?

Been running a 400W panel setup on my static narrowboat (two 200W mono panels, Victron MPPT 100/30, 200Ah AGM bank) and I've barely seen more than 40-50W coming through on most days this week. We're in the Midlands, and the low sun angle combined with what feels like permanent grey cloud cover has just hammered things. Yesterday the controller peaked at 62W around midday and that was genuinely a good day.

I know this time of year is rough and I've planned for it — running a small Honda EU22i to top up every couple of days — but I'm wondering if anyone has found practical tweaks that have actually made a noticeable difference. I've already tilted the panels up to about 55 degrees to chase the winter sun angle, which helped a tiny bit, but I'm still struggling to keep the bank above 70% SOC without the genny running pretty much daily.

Thinking about adding a third panel if I can find the deck space, or possibly looking at a small wind turbine given how breezy the canal has been lately. Has anyone gone down the wind route on a boat or static van setup in the UK and actually found it worth the hassle and cost?

Yeah it's grim. November in the UK, what did you expect though?

400W theoretical on AGMs that are probably half-dead from chronic undercharging isn't going to save you. Check your battery voltage under load — if it's sagging badly you've got bigger problems than cloud cover.

My shepherd's hut setup was pulling about 180Wh yesterday which is actually decent for this time of year. Panels tilted at 45° makes a real difference in winter — low sun angle means flat-mounted panels are basically ornamental.

@CliveMorris59 what's your panel tilt? Narrowboats are notorious for near-flat mounting which absolutely kills winter harvest. Even propping them up temporarily helps.

Also check the MPPT logs — Victron's app will show you if you're genuinely getting poor irradiance or if something's actually wrong with the setup.

FZO_Marine

@CliveMorris59 Completely feel your pain - narrowboat here too and it's been properly grim. Worth double-checking your panel angles though; this time of year a shallow tilt makes a massive difference. Also, have you checked for any condensation getting into connectors? Cold damp weather plays havoc with MC4 joints and can introduce enough resistance to seriously drag your figures down.

One thing I've noticed on my AGMs is they also just accept charge more slowly when the bank temperature drops below about 10°C - the Victron should compensate with temperature-compensated charging if you've got the sensor fitted, but if not, that's worth looking into.

Basically though, a fortnight of proper British murk is just... a fortnight of proper British murk sometimes. 😄 Roll on spring.

@CliveMorris59 Have you checked what your actual panel voltage is doing on those grey days? On a narrowboat you've also got the issue of trees and bankside structures casting shadows across the panels for much of the short day we've got right now. Even partial shading on series-connected panels hammers your output disproportionately.

Also worth having a look at your battery voltage first thing in the morning before any charge comes in - if your AGMs are dropping below about 12.0V overnight that'll tell you something useful about their condition regardless of the harvest.

The Victron app should give you a decent history to diagnose whether it's genuinely the weather or something else going on. What sort of daily consumption are you running at the moment?

ExTrucker32

@CliveMorris59 Worth having a look at your panel orientation mate - on a narrowboat you're pretty much stuck with whatever angle the roof gives you, but even shifting a portable panel up to 45° on a stand can make a surprising difference in low winter sun. Also, are you keeping those AGMs topped up with a shore power hookup when you can? At this time of year I'd be treating solar as a supplement rather than a primary source. I run a small Honda genny two or three times a week through November and December and just let the panels do what they can on top. Not glamorous but keeps the lights on! What's your typical daily consumption looking like?