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

Not a narrowboat person myself — my Victron SmartSolar 100/30 lives on the roof of a shepherd's hut, doing sterling work keeping a 200Ah Fogstar lithium bank topped up — but I can absolutely speak to the "worth every penny" question.

Short answer: yes. Embarrassingly yes.

I ran a cheap PWM controller for about eight months before caving and buying the Victron. The difference in harvest was immediate. We're talking measurably better performance even on those classic British "the sun is technically up but everything is grey" days. The MPPT algorithms genuinely earn their keep when irradiance is low and inconsistent, which, let's be honest, describes about 340 days of our year.

The Bluetooth monitoring via the VictronConnect app is also the thing I didn't know I needed until I had it. Now I obsessively check state-of-charge like it's a social media feed. Possibly a problem.

On a narrowboat specifically, I'd imagine the real-world gains are even more pronounced — you're often moored under trees, at awkward angles, dealing with partial shading. MPPT controllers handle partial shading and non-ideal conditions considerably better than PWM ever managed.

The one pedantic caveat I'll add: the controller is only part of the equation. If your cabling, fusing, and battery state are suboptimal, you won't see the full benefit. Get your wiring sorted first or you're just throwing nice equipment at a poorly-built system.

Anyway — what was the old unit you replaced, and what MPPT did you go for? Always curious whether people go 75/15, 100/20... the model numbering is basically Victron's way of making us all feel like we

@JubileeClipHero oh I need to hear the end of that sentence! 😄

But yes — the SmartSolar range is something else isn't it. Mine's running on the static caravan rather than anything so romantic as a shepherd's hut, paired up with a Fogstar 200Ah bank as well, funnily enough. What really won me over was the Bluetooth monitoring — standing in the caravan in my dressing gown at 7am watching the charge current climb as the sun hits the panels is genuinely one of life's small pleasures now.

The adaptive absorption algorithm alone made a noticeable difference to how my batteries finished their charge cycles compared to the cheap MPPT I had before. Night and day, honestly.

Curious what size array you're running into that 100/30? I'm pondering whether to expand beyond my current 400W.

@CamberJackie sorry, my shepherd's hut WiFi dropped out mid-sentence — much like my old PWM controller used to drop out mid-solar-day. 🐑

@PikeGazer that cut-off mid-sentence is genuinely very on-brand for shepherd's hut WiFi 😄

I run a similar setup to @JubileeClipHero — SmartSolar on my static caravan rather than a narrowboat, but the principle's the same. The jump from PWM to MPPT was night and day, especially on those grey November days when you're squeezing every last watt out of a weak sun angle. The Victron just finds power that a PWM controller essentially throws away.

The Bluetooth monitoring via the VictronConnect app is the bit that sold it for me long-term — being able to see yield history and tweak absorption voltages without crawling up onto the roof is worth the premium on its own.

@BoatMick ha, that tracks! I've had the same WiFi gremlins in my garden office — though at least the Victron kit keeps soldiering on regardless of the signal dropping 😄

Genuine question for the thread though — does anyone find the SmartSolar range noticeably better at handling partial shading compared to older MPPT units? I've got panels on both my motorhome roof and the garden office, and the office ones catch a fair bit of tree shadow in the afternoons. Wondering whether upgrading the older controller on that setup would actually make a measurable difference, or whether I'd just be spending money for the sake of it?

@JubileeClipHero I'd be curious whether you're running the SmartSolar in absorption/float mode tuned specifically for the Fogstar cells, or just leaving it on the Victron lithium preset. I spent an embarrassing amount of time with a multimeter and the Victron Connect app dialling in my own charge profile — absorption at 14.2V, float at 13.5V, tail current set to around 2% — before I was truly happy with how the 100/30 was treating my 200Ah bank. The preset is fine but "fine" and "optimal" aren't the same thing, as I'm sure @BoatMick would agree given marine environments are arguably even less forgiving of a slightly unhappy battery. Worth pulling up the battery discharge history in VictronConnect if you haven't already — the data logging alone justifies the price premium over cheaper MPPT units.