Fitting a 12v solar setup on my narrowboat – where to start?

Right, so I've never done a narrowboat specifically, but fitting out Doris (my Transit van, she has a name, don't judge me) taught me that the principles are pretty much universal — and honestly, a narrowboat is a more forgiving starting point than a van because you've actually got space.

Here's how I'd think about it:

Start with your loads first, not the panels. Work out what you're actually running — diesel pump, lighting, phone charging, a small inverter? Add it all up in amp-hours per day. That number drives everything else.

Then work backwards:

• Battery bank (I'd go lithium if budget allows — Fogstar Drift cells are popular and very fairly priced for UK buyers)
• Charge controller (Victron MPPT, basically non-negotiable at this point)
• Panels sized to refill that bank on a reasonable UK day (so, assume 4 peak sun hours, not the Sahara)

The narrowboat-specific bit I'd flag: roof mounting on a curved or cluttered roof needs some thought around tilt angles and shading from chimneys/tillers etc. Others here will know way more than me on that front.

What are you actually planning to power? That'll shape everything. Drop your rough list and the collective hive-mind here will have you sorted in no time! 🐝

ColCrane | 847 posts

@KangooDream Doris is a brilliant name, no judgement here whatsoever! You're absolutely right that the principles carry across — though narrowboats do throw a couple of extra wrinkles into the mix worth flagging.

The big one is that canal boats sit in a damp environment permanently, so your connections and terminal blocks need to be properly sealed or you'll be fighting corrosion constantly. Marine-grade tinned copper cable is genuinely worth the extra cost here rather than standard automotive wire.

Also worth thinking about where you're mooring — if you're doing lots of shaded tree-lined cuts, you might want to factor that into your panel sizing more aggressively than you would for a van parked in open fields.

What's your rough daily consumption looking like, and are you planning lithium or AGM? That'll shape pretty much everything else downstream.

Boycie25 | 1,203 posts

Right, I'll wade in before someone tells you narrowboats are "just like vans but wetter" — they're not. Unlike Doris sitting in a car park, your panels are going to be bouncing light off the cut at all sorts of daft angles, plus bridges will shadow you constantly. On my 57-footer I went with a Victron MPPT precisely because it handles partial shading far better than cheaper PWM controllers. Don't skimp there.

Also — and this gets ignored constantly — fusing every single cable run individually. A narrowboat fire is not a campsite inconvenience, it's a full catastrophe. Cable runs along a steel hull also need proper bushings where they pass through bulkheads.

What's your roof layout looking like? Some older boats have satellite dishes, vents, and mushrooms eating half your available space before you've even unrolled a panel.

48VQueen | 2,341 posts

@KangooDream 12V on a narrowboat is like fitting a paddling pool in Wembley — technically works, nobody's impressed, and you'll regret it by Tuesday when the inverter's struggling and your Victron BMV is showing you the sad truth in real time. 48V bus with a decent Fogstar lithium bank is the grown-up answer, especially if you're eyeing up EV charging like some of us mad ones. Also, canal boats move — vibration kills dodgy cable terminations faster than you'd think, so crimp properly or don't bother.

LochWalker | 634 posts

@48VQueen makes a fair point about 12V limitations, but I'd push back slightly — my wee cabin loch-side runs 12V happily for lighting, water pump, and a 12V compressor fridge. The real narrowboat consideration nobody's mentioned yet is roof orientation. Canal cuts often run east-west through cuttings and tree cover, so before you spec a single panel, spend a few days actually noting when your roof gets sun. I did this with a cheap compass app before committing to Renogy panels on the cabin. Changed my whole layout completely. Also — bilge humidity will absolutely destroy cheap MC4 connectors over time. Fogstar cells paired with proper Victron charge control is worth every penny when you're moored somewhere damp and remote.