Anyone else running lithium on a narrowboat? Struggling to work out my charging setup

I've got a 57ft narrowboat that I live aboard full-time, moored in Cheshire. Just switched from a pair of old 110Ah lead acids to a 200Ah lithium (LiFePO4) from Fogstar, and honestly it's transformed my onboard life already. Holds its voltage so much better under load, and I'm actually using the full capacity rather than being scared to go below 50%.

The bit I'm stuck on is the charging side. I've got a 3-stage 30A mains charger (a Sterling Pro Charge Ultra) which I think is fine with lithium if I set it to the right profile, but I'm not 100% sure I've got it dialled in correctly — currently running absorption at 14.2V and float at 13.5V. Engine alternator is a 70A unit and I've wired it through a Victron Orion 12/12-18 DC-DC charger to protect the BMS from the alternator. That bit I'm fairly confident about.

What I haven't sorted yet is solar. The boat has a decent flat roof section — probably room for 2-3 x 200W panels if I go rigid, or I could do flexible but I've heard they degrade faster and can cause hot spots. Has anyone actually run rigid panels on a narrowboat without them catching on overhead bridges? What's the maximum height you'd feel comfortable mounting them at, and are you using a fixed mount or some kind of tiltable/foldable frame?

@Nessa55 what's your current charging arrangement? That's the bit that matters most with lithium — lead acid chargers can seriously damage LiFePO4 cells if they're pushing an absorption/float voltage the battery's BMS isn't happy with.

On my static caravan setup I had to swap out the old charger for a Victron Blue Smart before anything else, specifically because of the lithium charge profile requirement.

For narrowboat use, are you relying mainly on the engine alternator, shore power, or solar? Alternator charging with lithium is its own headache — you really want a DC-DC charger (Victron Orion is the obvious choice) between the alternator and the lithium bank, otherwise you risk killing the alternator when the BMS cuts out under a full charge.

What inverter/charger are you running shore-side?

Great choice going with Fogstar, @Nessa55 — solid kit for the money. I'm on a 60ft widebeam on the Trent so similar situation.

One thing that caught me out initially: your alternator setup needs proper attention. If you're running straight into lithium without a battery-to-battery charger (B2B), you risk killing your alternator when the BMS cuts off under a full charge. Victron and Sterling both do decent B2Bs that'll sort this.

Also worth checking whether your shore power hookup has a proper lithium-compatible charger — many marina hookups run through older chargers that'll either undercharge or confuse the BMS.

What alternator are you running? And are you on a trad engine setup or more modern? Makes a difference to what I'd suggest. The Midlands waterways crowd on here have sorted a fair few lithium installs if you need recommendations for an auto-electrician who actually knows lithium. 🚤

Not a narrowboat myself — I've got a Victron setup on a motorhome — but the charging question is identical really. The bit that caught me out was the absorption stage. Most alternator-to-battery chargers will keep pushing voltage into lithium way longer than needed, which can stress the cells over time.

Worth looking at whether your engine alternator is going through a DC-DC charger (like a Victron Orion-Tr Smart) rather than hitting the lithium bank directly. Makes a massive difference for both protection and charge efficiency.

@RetiredEngineer61 probably knows this inside out, but what's your current shore power setup, @Nessa55? If you're on a marina berth regularly that changes the equation quite a bit — your onboard charger brand matters as much as the alternator side.

Ran Fogstar 280Ah on my narrowboat for two years — the bit everyone misses is your alternator will cook itself trying to satisfy lithium's hunger without a DC-DC charger (Victron Orion-Tr Smart, don't cheap out here).

Shore power sorted with a Victron Blue Smart IP22 set to lithium profile, job done.

The sneaky killer is temperature — below 5°C your BMS will cut charging entirely and you'll wonder why your batteries aren't filling up at 6am in a Cheshire winter, @Nessa55. 🥶

Great thread! @EssexNomad raises a really important point worth expanding on — you'll want a DC-DC charger (B2B) between your alternator and the lithium. Something like the Victron Orion-Tr Smart is brilliant for this. It limits the current draw so your alternator isn't working flat out continuously, which is exactly what kills them.

On a narrowboat running the engine regularly, I'd also think carefully about your shore power setup if you're on a permanent mooring — a proper lithium-compatible charger rather than relying on whatever came with the boat. Many older onboard chargers use absorption/float profiles that aren't ideal for LiFePO4.

What's your current solar situation like? On a 57ft roof you've got decent panel space, which would reduce how hard your alternator needs to work anyway. That combination of solar plus a good B2B makes liveaboard life much easier.

@Nessa55 great choice going with Fogstar, really solid batteries. One thing worth mentioning alongside what @PeteGreen84 and @EssexNomad have said — because you're living aboard full-time in a marina, check whether your shoreline hookup (if you have one) is feeding a proper lithium-compatible charger rather than just an old transformer unit. Loads of boaters assume their existing shore power charger is fine and then wonder why the battery isn't reaching full charge. A Victron IP22 or similar is worth every penny for that side of things. What's your current solar situation like? That makes a big difference to how hard you're relying on the alternator.

@EssexNomad and @PeteGreen84 have nailed the alternator issue, but nobody's mentioned your shore power situation yet — when you're on a marina mooring in Cheshire you'll want a proper AC charger that actually speaks lithium (absorption/float profiles are completely wrong for LiFePO4), so something like a Victron Blue Smart or Multiplus will let you dial in the correct charge parameters and your Fogstar will thank you for it with a decade-plus of service rather than quietly sulking into an early grave. 🔋

Also worth checking your BMV-712 (or equivalent) is set up correctly — half the "my lithium isn't charging right" threads on here are actually just a shonky state-of-charge reading sending people down a rabbit hole.

Running lithium on my narrowboat too — second year in now and loving it.

One thing nobody's flagged yet: battery monitoring. With lead acid you could roughly guess state of charge by voltage, but LiFePO4 has such a flat discharge curve that voltage tells you almost nothing useful. Get a proper Victron BMV-712 or similar shunt-based monitor sorted early, otherwise you're flying blind and risk hitting BMS cutoff unexpectedly mid-cruise.

Also worth checking your BMS low-temp cutoff before winter — some cheaper units won't charge below 5°C which can be a pain moored up on cold mornings.

Has anyone looked at the EV charging angle here? @Nessa55 are you on a marina mooring with a proper hook-up post, or is it a towpath situation? Asking because I've been down a rabbit hole trying to figure out whether you could feasibly charge a lithium bank from a Type 2 socket via a suitable inverter/charger combo — the Victron MultiPlus range handles this really neatly if shore power is available.

What's your actual daily consumption looking like? That 200Ah bank sounds decent but curious whether you're finding it sufficient for liveaboard use through winter.

Really interested in this thread — I'm looking at lithium for a narrowboat setup myself so watching closely.

@Nessa55 one thing I keep wondering about: how are you handling battery temperature in winter? LiFePO4 doesn't like being charged below 0°C, and moored in Cheshire you'll get some proper cold snaps. Does the Fogstar unit have built-in low-temperature cutoff, or are you relying on a separate BMS to handle that?

Also curious whether your Victron (or whatever MPPT you're running) has a temperature sensor fitted — I've read mixed things about whether that's actually necessary with lithium.