Narrowboat shore power vs solar in winter — worth the hassle?

Been running my narrowboat on a 400W Renogy panel setup with a Victron SmartSolar MPPT since last spring and honestly it's been brilliant through summer. Two 100Ah Fogstar lithiums, rarely dipped below 80% SOC. Dead chuffed with it.

Now we're heading into winter and the numbers are ugly. Getting maybe 30–40 minutes of decent sun a day when it's not overcast, panels are low on the cabin roof so angle is terrible, and I'm burning through power on the diesel heating controls, LED strips, and the 12V fridge. Sitting at the marina most of November means I could plug into shore power but it's £4–5 a night on top of mooring fees.

Thinking about whether a small inverter charger (Victron Phoenix or similar) would let me top up from shore power just enough to keep the batteries healthy without paying for a full overnight connection. Anyone done a timed/scheduled charge setup on the narrowboat to keep costs down? Or just accepted winter solar is basically decorative and paid for the hook-up?

Also curious if anyone's added a second panel angled differently to catch more winter sun — seen some boats with panels on the side hatch covers which seems clever but looks a bit Heath Robinson.

DaiWalker61 | 847 posts | Narrowboat & Off-Grid Enthusiast

@HeatherSoul Great setup through summer, but winter on the cut is a different beast entirely! Those Fogstar cells will handle the cold fine, but 400W will really struggle December through February — you're looking at maybe 1-2 hours of decent generation on a bright day, and that's optimistic on a cloudy canal heading north-south.

Honest suggestion: don't ditch solar, but seriously consider shore power as a backstop rather than a replacement. Most marinas charge pennies overnight and your Victron will happily manage the blend. Running your engine for 45 minutes daily gets expensive and tedious fast.

What's your typical mooring situation — moving regularly or staying put? Makes a big difference to whether shore hookup is even practical. Long-term continuous cruisers often just accept supplementing with a small Honda genny through the darker months. 🚢

BreezyMechanic | 312 posts | Shepherd's Hut & Static Caravan Tinkerer

Not a narrowboat owner myself, but I went through exactly this reckoning with my shepherd's hut last November. That Victron SmartSolar is genuinely earning its keep even on grey days — mine was pulling a respectable 40-60W on overcast afternoons when I'd written the day off entirely.

The honest truth though? I ran a short shore power feed to the hut from October through February and stopped fighting the physics. Two Fogstar 100Ah cells simply aren't a winter energy store, they're a summer luxury.

Worth pricing up a marina hookup just for the darker months rather than thrashing your batteries trying to recover from repeated deep cycles. @DaiWalker61 is clearly pointing the same direction. Shore power isn't surrender — it's sensible engineering for your latitude.

HappyBodger | 1,204 posts | Narrowboat & Renewable Energy

@HeatherSoul Worth adding that shore power doesn't have to be all-or-nothing. I run a small Honda inverter genny for a couple of hours on really grim December days rather than staying plugged in at a marina — keeps the lithiums topped up without the mooring fees.

One thing nobody's mentioned: check your Victron's low-temperature charge cutoff settings before the cold snap hits. Fogstars have built-in BMS protection, but it's worth making sure your MPPT is configured correctly so it's not trying to stuff amps in when the cells are near freezing.

Also, a decent battery monitor showing you realistic state-of-charge trends over a few days will tell you pretty quickly whether you're managing fine or genuinely struggling. Often it's not as bad as you'd fear!

NorfolkWanderer | 563 posts | Narrowboat & Coastal Living

@HeatherSoul One thing nobody's mentioned yet — your mooring location makes a massive difference in winter. Up on the Norfolk Broads I found that open stretches gave me surprisingly decent harvest even in December, whereas friends moored under tree canopies or hemmed in by lock cuttings barely saw 10% of rated output on overcast days.

Also worth considering a small wind turbine to complement the solar. The days when your panels are doing nothing are often exactly the days when there's a decent blow coming through. I added a 200W unit last November and the two sources genuinely complement each other through the grim months.

Shore power's a perfectly valid backup, but I'd exhaust the generation options first before paying marina rates regularly.