Swapped out my old Victron MPPT on the narrowboat – worth it?

Been through something similar on a static setup rather than a narrowboat, but the principle's the same — older Victron MPPTs are solid but the newer SmartSolar range with proper Bluetooth monitoring is a different world once you've used it.

The VictronConnect app alone makes it worth considering an upgrade. Being able to pull up your charge history, state of charge trends, and catch any absorption/float issues without crawling into a locker is genuinely useful, especially on a boat where access is awkward at the best of times.

That said, I'd push back slightly on "worth it" depending on your panel array size. If you're running under 400W, an older 75/15 or 100/20 that's still doing its job properly is hard to justify replacing on performance grounds alone. The monitoring argument is real, but you can partially address that with a Victron BMV-712 on the battery side if the MPPT itself is healthy.

Where I have seen genuine gains reported is when people move to a unit with a higher voltage input ceiling — particularly if they've added panels since the original install and are now pushing the limits of what the old controller can handle efficiently.

A few questions worth thinking about:

• What's your panel wattage and configuration now vs. when the old unit was installed?
• Are you on lithium (Fogstar Drift etc.) or lead-acid? The lithium charging profiles on newer units are noticeably better
• Any actual faults or just itchy upgrade fingers? 😄

Would be interested to hear what specific model you swapped from/to and whether the real-world amp numbers changed at all.

@Chalky12 yeah the Bluetooth side is a game changer on the water tbh. My SmartSolar 100/30 talks straight to the VictronConnect app and I can check state of charge from the towpath without even stepping aboard.

Old MPPT I had was doing the job fine but flying blind gets old fast, especially when you're mooring somewhere unfamiliar and not sure what the panels are actually pulling.

One thing worth noting — pair it with a Cerbo GX if you want proper logging over time. Helped me spot a dodgy connection on my 200W Renogy panels I'd never have caught otherwise.

@BenJohnson95 and @Chalky12 — both valid points, though I'd add that on a narrowboat the SmartSolar's temperature compensation really earns its keep. Engine bay temperatures fluctuate wildly compared to a static setup, and having the controller adjust charge voltage accordingly protects your batteries properly rather than just chucking the same voltage at them regardless of conditions. I ran a older 75/15 for years on a friend's cruiser and we were almost certainly undercharging through winter without realising. The newer units paired with a battery temperature sensor make a genuine difference to battery longevity. Worth the upgrade cost if you're planning on staying aboard long-term in my opinion.

@Chalky12 done similar in a van conversion and honestly the SmartSolar range is decent but I'd not rush to ditch a working older unit just for Bluetooth. If your existing MPPT's hitting its numbers, it's hitting its numbers.

That said — one thing nobody's mentioned — the VictronConnect app logging is genuinely useful if you're trying to size a setup properly or troubleshoot a dodgy panel. I was chasing a yield problem for weeks before the data made it obvious.

Only caveat: make sure your firmware's actually up to date before assuming the new unit's performing better than the old one. Seen a few people make that swap and not realise the old controller just needed an update.

Good points all round here. One thing nobody's mentioned yet — if you're doing any serious cruising and mooring in different orientations, the SmartSolar's adaptive charging algorithm handles variable input conditions noticeably better than the older units in my experience. Worth factoring in alongside the Bluetooth convenience. @RetiredChef26 raises a fair point on temperature compensation too, especially over winter moorings where battery performance drops off anyway. That said, @LuckySkipper's caution is sensible — if your existing unit is genuinely performing well and your bank is healthy, the upgrade case gets thinner. I'd say the sweet spot is when you're already looking at a system refresh more broadly rather than swapping the MPPT in isolation.