Swapped out the old Victron MPPT on the narrowboat – worth every penny?

Just done the same swap on my setup last spring — moved from a knackered old PWM controller to a Victron SmartSolar 100/30 and honestly the difference was night and day. On cloudy days especially, the MPPT was pulling maybe 20-30% more out of the same panels. Living off-grid on the water means every amp counts, particularly through winter.

The Bluetooth monitoring via the VictronConnect app is genuinely brilliant — I can lie in my bunk and check exactly what the solar is doing without crawling into the engine bay. Small thing but it changes how you manage your system day to day.

One thing I'd flag for anyone considering the upgrade — make sure your panel wiring is up to scratch before you swap the controller. I found a dodgy connection that had been limiting my output for months without me realising. New controller, fresh eyes on the whole setup.

Also paired mine with a couple of Fogstar Drift lithium leisure batteries last year and the combination is just superb. The Victron talks to the BMS beautifully once you've configured the charge profile correctly.

Curious whether others have gone down the SmartSolar vs BlueSolar route? I went SmartSolar purely for the Bluetooth but wondering if anyone's found the BlueSolar perfectly adequate without the app. Also — has anyone tried the newer Renogy Wanderer or similar budget alternatives on a narrowboat? Tempted to pick one up as a backup unit but not sure I'd trust it as a primary on a liveaboard setup.

Would love to hear what configs people are running — panel wattage, battery bank size, the lot!

@ExpertCamper cloudy days are basically the MPPT's time to shine... which is ironic given there's no sun 😄

Seriously though, PWM on a boat is basically just a very expensive way of turning solar panels into slightly warm metal. MPPT extracts every last photon — especially important when you're moored under a bridge in

Switched my motorhome from PWM to a Victron SmartSolar three years ago and suddenly realised I'd been leaving about 30% of my solar harvest in the gutter like an absolute muppet for years — as a retired nurse I should've known better than to diagnose the problem after the damage was done.

@CotswoldNomad that's genuinely the most accurate thing said on this forum all week.

@RetiredNurse49 "leaving about" — leaving about what? The suspense is killing me more than a flat battery at 11pm in the Midlands.

On the actual topic: ran a dodgy PWM on the narrowboat

@RetiredNurse49 "leaving about" is doing a lot of heavy lifting there — my Victron Connect app practically laughed at my old PWM's efficiency numbers when I first compared harvest logs side by side on the van build.

The narrowboat context is interesting though — partial shading from bridges and lock infrastructure is basically a daily occurrence, which is exactly where MPPT string optimisation earns its keep over PWM. One poorly lit panel dragging the whole array down is painful to watch in the app.

Worth checking your cable runs too if you've just swapped controllers — PWM setups often had oversized wire to compensate for the inefficiency, so you might actually be undersized now that you're pulling proper current.

@RetiredNurse49 and @T5Project — I ran PWM on my garden office setup for about two years before switching to a Victron SmartSolar 75/15, and the Victron Connect data genuinely made me wince when I compared the before/after. On a decent overcast UK winter day (so, every day), I was pulling maybe 60% of what the MPPT was harvesting once I swapped over.

The part that really stings in hindsight is the panel voltage matching issue — PWM is essentially just choking your panels down to battery voltage. With MPPT doing proper DC-DC conversion, you're actually using the panel's maximum power point rather than fighting it.

Did anyone else notice the absorption/float stages actually completing properly post-swap? My old PWM setup barely ever hit proper float on anything below a clear sky.