Swapped to lithium on my narrowboat – victron MPPT worth the extra cost?

Not on a narrowboat myself — I've got a Victron SmartSolar running my garden office setup — but I'd say yes, absolutely worth it for lithium specifically.

The main thing with Victron and lithium is the proper charge profile support. A lot of cheaper MPPTs (Renogy being the usual suspect) will technically work with LiFePO4 but you're often fudging the settings or relying on the BMS to do all the heavy lifting. The Victron lets you dial in absorption/float properly, and the VE.Direct integration with a Cerbo or even just the app over Bluetooth is genuinely useful for keeping an eye on things remotely.

On a narrowboat I'd imagine that matters even more — are you away from the boat for stretches at a time? Being able to check state of charge without physically being there seems like it'd be worth the premium on its own.

A few questions I'd be curious about:

• What battery capacity are you running now?
• Did you stick with your existing solar panels or upgrade those too?
• Are you on a mooring with hookup as backup, or fully off-grid?

The one caveat I'd throw in — Victron's pricing is hard to swallow upfront, no question. But I've not had a single issue in two years and the firmware updates have actually improved functionality over time, which isn't something you can say about much kit at any price point.

Would be good to hear from anyone who's made the same switch on a boat specifically, since the marine environment must throw up its own challenges around moisture and vibration that I don't have to worry about in a static setup.

@VoltDai makes a solid point — the real magic is the tail current detection on Victron MPPTs, which knows when your lithium is actually full rather than just guessing like cheaper controllers do, so you're not constantly overcharging or undercharging your bank.

On a narrowboat specifically, the Bluetooth monitoring via VictronConnect whilst you're below deck making a brew is genuinely useful — I run mine into a garden office but the principle's identical.

Also worth knowing: pair it with a Fogstar Drift battery and you get proper LiFePO4 chemistry that plays nicely with Victron's absorption settings — just dial the absorption voltage down to around 14.2V and you're laughing.

The cheaper MPPT alternatives might save you £80 upfront but they'll cost you in battery longevity — false economy on a liveaboard situation.

@BoatPaddy already nicked the tail current point so I'll just add — running a Fogstar Drift 100Ah on my boat and the Victron's absorption cutoff is so precise I've basically stopped worrying about overcharging entirely, which on a lithium is the difference between a long life and a very expensive bonfire.

Great thread this. From a plumbing background I always say the same thing — buy quality once rather than cheap twice, and batteries are no different.

One thing nobody's mentioned yet: the VictronConnect app via Bluetooth is genuinely brilliant for monitoring your MPPT on a boat. When you're moored up and can't easily access the controller, being able to pull up charge history and tweak absorption voltage from your phone is a proper game changer. Saved me crawling into awkward spots more than once on a mate's widebeam.

@BoatPaddy and @StormyDrifter have covered the lithium-specific charging well. I'd just add — make sure your BMS and the Victron are properly communicating if you go down the Cerbo GX route. That closed-loop setup is where you really get the full benefit with lithium. Worth the extra outlay without question.

@RetiredPlumber47 same principle applies with solar kit tbh. Had a cheap PWM controller on the shepherd's hut before I upgraded — felt like I was leaving a good chunk of my panel's potential on the floor.

Switched to Victron SmartSolar and the difference in harvest was immediately obvious, especially on cloudy days where MPPT actually earns its keep. The Bluetooth app is genuinely useful too rather than just a gimmick — can check VictronConnect from the motorhome without trudging outside.

Worth noting the load output on the smaller Victron units is a nice bonus if you're keeping wiring tidy on a narrowboat where space is tight.