Swapped out the old Victron MPPT on the narrowboat – worth every penny or am I imagining it?

Just replaced my SmartSolar 100/30 with a 150/45 on my 60ft narrowboat and genuinely can't tell if the numbers are better because of the controller or because we've had a decent spell of sunshine this past fortnight. Classic British timing, isn't it?

Running 400W of panels on the cabin roof (bit of shading from the chimney in the mornings, annoyingly) into a 200Ah Fogstar Drift lithium bank. The 150/45 is pulling noticeably more amps during the shoulder periods — early morning and late afternoon — but I'm not sure if that's the higher input voltage ceiling doing its work or just confirmation bias on my part.

Few questions for anyone who's done similar upgrades:

• Did you actually log before/after data or just go on gut feel?
• Is the VictronConnect Bluetooth worth the faff for day-to-day monitoring or do you end up ignoring it after a week?
• Anyone running a larger MPPT on a similar panel array — did you actually fill the extra headroom, or is it just future-proofing?

The install itself was straightforward enough, though cable routing on a narrowboat is never exactly fun with all that condensation to think about.

Tempted to add another 200W panel on the cratch cover but not sure the bank would even notice given how little we draw in summer. Wondering if anyone else has gone down that rabbit hole and whether it was actually worth it or just satisfying to look at more panels.

MaxYoung80 | 847 posts | ⚓ Narrowboat Lifer

@SparkyCaptain Ha, the eternal struggle – is it the kit or is it just Yorkshire finally seeing the sun for five minutes? 😄

Honestly though, the jump from a 30A to 45A controller will make a measurable difference if your panels were ever being curtailed on bright days. Worth checking your Victron Connect history – if the old unit was regularly hitting its charge current ceiling mid-morning, that's your answer right there.

I made a similar upgrade on my 57-footer last spring and the logs told the story pretty clearly. Peak harvest went up noticeably even on equivalent days.

Give it a couple of weeks of mixed weather and compare the daily yield figures. The data doesn't lie, sunshine bias or not! What's your panel setup – total wattage?

ExPostie86 | 312 posts | 🔋 Battery Botherer

@SparkyCaptain Log your voltage and current figures for a fortnight on each side of the upgrade — if the 150/45 isn't pulling noticeably more amps at the same irradiance, the sun's having you on. Had exactly this debate with myself on the narrowboat last autumn when I swapped controllers; turns out both things happened simultaneously like some cruel cosmic joke. The higher input voltage ceiling on the 150 genuinely does matter if your panels are strung in series though — the 100/30 was almost certainly clipping on bright mornings. Victron's VRM portal will show you historical harvest data if you've got the Cerbo or even just a cheap dongle, so the evidence is there waiting to grass you up.

NBW_VanLife | 203 posts | 🚐 Cabin Dreamer

@SparkyCaptain Mate, classic British solar problem — you upgrade the hardware and the weather immediately decides to cooperate just to gaslight you completely.

WillWebb | 156 posts | ☀️ Shepherd's Hut Tinkerer

@SparkyCaptain the 100/30 to 150/45 jump is significant on paper — that extra headroom on the input voltage matters if you're ever running panels in series. Had a similar "is it the kit or the weather" moment when I upgraded the MPPT on my shepherd's hut setup.

One thing worth checking in the Victron Connect app — look at your daily yield history graph going back before the swap. If you were regularly hitting the 30A ceiling on the old unit you'll see it flat-lining. That's your proof right there, nothing to do with sunshine hours.

What's your panel array wattage? If you're not close to pushing 45A you might just be enjoying a good June rather than a hardware win 😄