Anyone else running solar on a narrowboat? What's actually working?

Finally got round to fitting 2x 175W Renogy panels on the roof of my mate's narrowboat last summer. Paired them with a Victron SmartSolar 100/30 and a pair of Fogstar 100Ah lithium batteries. Setup's been solid but we're scratching our heads on a few things.

Main issue is the roof layout — curved profile means the panels aren't sitting flat and we're losing maybe 10-15% efficiency compared to what the spec sheet suggests. Anyone found decent low-profile tilt mounts that work on a narrowboat without snagging on bridges?

Also wondering about winter performance on the cut. Trees overhanging the towpath basically kill output for hours at a time. Thinking about adding a small wind turbine as a supplement but not sure if that's more hassle than it's worth on a 57ft boat. Anyone done a hybrid setup?

ShaunHamilton | 847 posts

@DownsWanderer Nice setup! Victron and Fogstar is a solid combination for a narrowboat. One thing worth checking is your panel tilt angle - flat mounting on a roof loses you a fair bit of efficiency, especially in winter when the sun's low. Even a 10-15° tilt makes a noticeable difference if you can engineer a frame that doesn't catch the wind under bridges!

Also, are you running a battery-to-battery charger from your engine alternator as backup? On the cut during a grey week in November you'll thank yourself for it. I use a Victron Orion-Tr Smart 12/12-30 alongside my solar and it keeps things topped up nicely when cruising through the Midlands canal network where trees shadow the roof constantly. What's your daily consumption looking like?

Been running 3x 200W panels on my narrowboat for two seasons now, also with a SmartSolar — the 100/50 in my case. Few things I'd add:

Shading is brutal on canals. Trees, bridges, moored boats alongside — it kills output constantly. If you haven't already, wire your panels in parallel rather than series. Takes the sting out of partial shading significantly.

Also worth checking your MPPT absorption voltage is dialled in correctly for the Fogstar cells. Victron's default lithium profile is a bit conservative out the box — I run mine at 14.2V absorption, 13.5V float and it's been solid.

One thing that surprised me — engine alternator charging via a Victron Orion DC-DC charger made a bigger difference than the extra panel I added. Canal speeds mean you're often motoring anyway.

Not a narrowboat myself — garden office setup here — but the Victron + Fogstar combo is exactly what I run and it's been rock solid.

One thing worth flagging for narrowboat specifically: keep an eye on your cable runs. Boats get a lot of vibration and I've seen people mention connections working loose over time. Worth checking crimps and terminals every season.

Also curious what @DownsWanderer is seeing for actual daily yield on those 175W panels. On a narrowboat roof the tilt angle is pretty much fixed and fairly shallow — wondering if that's noticeably hurting output compared to an optimised ground mount situation.

DorsetCruiser | 1,204 posts

Great thread! I've got 3x 200W panels on my 57ft trad stern and honestly the biggest lesson I learnt was panel placement — anything near the cratch or stern gets shadowed by trees when you're moored up, which absolutely kills output if you're not using optimisers or separate strings.

@CaddyProject curious whether you're running your panels in series or parallel? On a narrowboat roof the shade issue can be brutal and I switched to two separate MPPT inputs after losing half my harvest one summer just from overhanging canal-side willows.

Also worth mentioning to @DownsWanderer — keep an eye on your Fogstar BMS temperature readings through VictronConnect if you haven't already. Winter mooring can push lithiums into charge lockout earlier than you'd expect on colder nights. Good setup though, Victron kit on water is hard to beat.