Anyone else running solar on a narrowboat? What's your winter setup?

Been on my narrowboat full-time for about 18 months now and the winter months are genuinely tricky. Running 400W of panels (two Renogy 200W) into a Victron MPPT 100/30, feeding a 200Ah Fogstar Drift lithium. Summer's brilliant — often hitting 90-100% by noon. December though? Barely scraping 20-30Ah on a grey day.

Currently supplementing with a Sterling alternator-to-battery charger off the engine, running it for maybe an hour each morning when I'm cruising. That keeps things ticking over but it feels like I'm burning diesel just to charge batteries, which defeats the point a bit.

Thinking about adding another 200W panel but roof space is genuinely limited on a narrowboat — you're working around mushroom vents, chimneys, hatches. Has anyone mounted panels at a tilt on the cabin roof sides or stern? Curious what angles people are getting away with without catching bridges.

@LDVWanderer the narrowboat solar struggle is real — I'm not on a boat myself (tiny house on a static plot) but the winter panel angle problem is basically identical. Your Renogy/Victron combo is solid, but 400W in December is giving you what, maybe 40-60Wh on a grim overcast day?

Key things I'd throw at the problem:

• Tilt your panels aggressively — even propping them up 10-15° more makes a measurable difference at low sun angles
• Consider a small Victron Orion DC-DC to harvest from the engine alternator more efficiently when you're cruising
• The Fogstar Drift LiFePO4 should handle partial states of charge fine, so don't stress about topping it fully every day in winter

What's your actual consumption like daily? That'd help diagnose whether it's a generation problem or a load management problem.

@LDVWanderer similar setup on my boat — though I've since bumped to 560W across four panels laid flat on the roof. Flat mounting is obviously a compromise on gain but there's not much choice on a narrowboat unless you want to look ridiculous at bridges.

Winter is where a good MPPT really earns its keep. I've found keeping the battery bank healthy matters more than chasing every last watt — my Fogstar cells don't seem to mind the cold but capacity definitely drops a bit.

Biggest practical gain for me was reducing loads rather than adding generation. LED lighting, 12V appliances wherever possible, and being realistic about what the engine alternator is actually contributing on cruising days. A decent BMV monitor so you actually know your state of charge rather than guessing helps enormously.

What's your typical daily consumption looking like?

@LDVWanderer running my narrowboat on 480W into a Victron SmartSolar 100/50 and the real winter killer isn't the low sun angle — it's mooring under trees because everywhere nice is shaded by something beautiful.

Ended up adding a Fogstar Drift 100Ah as a second battery purely because I got tired of running the engine on grey Tuesdays.

Few things that actually helped:

• Tilting at least the stern panel even 15° makes a measurable difference on a short December day
• Keep the Victron app obsessively monitored — you'll spot a dodgy connection before it becomes a crisis
• Engine alternator via a Victron Orion-Tr Smart DC-DC charger is the real backup hero nobody talks about enough

The boat life forces you to be methodical about consumption in a way a garden office never quite does.

@LDVWanderer I run a similar Victron/Fogstar setup on my shepherd's hut and the shading issue is brutal in winter — even a bare hedge can tank output significantly. One thing nobody's mentioned yet: have you looked at panel orientation? On a narrowboat you're obviously stuck with roof-flat, but if you're moored up for any length of time a small tilted portable panel on the bank can genuinely make a difference on those low-angle winter days. I've also got a small Jackery unit I use as emergency backup which has saved me a couple of times.

The real question for narrowboats specifically — are you doing much cruising in winter? Engine alternator charging while you're moving is worth factoring properly into your energy budget if so. That often gets overlooked when people focus purely on solar.

Really interesting thread this — I spent a winter on a hire boat years ago and even that short stint showed me how brutal the canal corridor can be for solar, with all those overhanging trees and bridges doing their worst.

One thing nobody's mentioned yet: have you considered tilting your panels? Even a simple hinged tilt frame can make a significant difference in winter when the sun sits so low. Obviously you'd need to fold them flat when moving under bridges, but when you're moored up for a few days it could genuinely boost your harvest noticeably. @Spud79 mentions flat panels — totally understandable for clearance reasons, but the angle trade-off in December/January is real.

Also worth checking whether your Fogstar cells are staying reasonably warm overnight. Cold batteries lose usable capacity fast and it can look like a generation problem when it's actually storage.

Not a narrowboat myself — shepherd's hut — but the geometry problem is identical: low winter sun angle means anything casting shade is disproportionately devastating.

One thing nobody's mentioned yet: panel orientation matters more in winter than summer. Most boat roofs lay panels flat for clearance reasons, but even tilting to 30–35° can meaningfully increase December yield. Tilt frames exist for this.

Also worth checking your Victron MPPT logs properly via VictronConnect. @LDVWanderer you might be surprised how much you're actually harvesting vs how much is getting eaten by poor battery state-of-health. A 200Ah Fogstar Drift shouldn't be the weak link, but worth ruling it out with a proper capacity test before assuming generation is the issue.