Anyone else running lithium on a narrowboat? Sharing my setup and a few headaches

I've been living aboard a 57ft trad stern narrowboat on the Kennet & Avon for about eighteen months now, and last spring I finally ripped out the old 440Ah flooded lead acid bank and replaced it with a 200Ah 12V LiFePO4 from Fogstar. Paired it with a Victron SmartSolar MPPT 100/30 feeding two 175W panels on the roof, and a Victron Orion-Tr Smart DC-DC charger off the Beta 43 engine alternator. On paper it all looked tidy.

The main headache I keep running into is the DC-DC charger limiting me to about 18A charge current when the alternator's doing its thing — which is fine for pottering, but on longer cruising days I feel like I'm not making the most of the engine hours. I've seen some folks running two Orion units in parallel to double the current; has anyone done that on a narrowboat install specifically, or is there a better way to get more amps in while underway?

The other thing catching me out is the solar dropping right off in winter. Two panels laid flat on the roof isn't exactly ideal — I know that — but tilting them isn't really practical with bridges and tunnels on the canals. I'm getting maybe 10–15Ah on a grey January day, which barely covers the fridge and a bit of LED lighting. Wondering whether a third panel in the same footprint is worth it, or whether I'd be better off looking at higher-efficiency panels like the SunPower-cell options.

Happy to share full system diagrams if anyone's interested. Curious what others on continuous moorers or liveaboards are running, and whether anyone's cracked the winter generation problem without resorting to a genny every other day.

@BerlingoWanderer sounds like you cut off mid-sentence there — curious what you replaced it with!

I made the same swap on my 60ft semi-trad about three years ago now. Pulled out a tired bank of Trojans and fitted 200Ah of Fogstar Drift lithium. The difference in usable capacity is night and day — obviously — but the thing nobody warned me about properly was the alternator situation.

Running lithium straight off the engine alternator without a proper DC-DC charger nearly cooked my alternator within the first month. The batteries just take everything you offer, no taper. Fitted a Victron Orion-Tr Smart 30A after that — sorted it completely.

The other narrowboat-specific headache: BMS disconnecting at low temperatures during a cold snap on the Llangollen last January. Worth checking your battery's low-temp cutoff spec before winter cruising.

@BerlingoWanderer @RetiredNurse looks like you're both mid-sentence 😄 curious what you both ended up with!

I'm on a static caravan rather than a narrowboat so slightly different world, but running Fogstar Drift cells in a DIY 200Ah 12V bank and the difference over lead acid is just night and day honestly.

One thing I will say — if you're on a boat, BMS choice matters even more I reckon. Moisture and vibration aren't kind to dodgy connections. Victron SmartShunt for monitoring is worth every penny, you actually know your state of charge rather than guessing.

Do either of you run a DC-DC charger off the engine? That's where I see liveaboards trip up most — alternator dumps into lithium without proper current limiting and you're asking for trouble.

Haha seems like this thread is cursed — everyone's getting cut off mid-post 😄

Anyway, van rather than boat here so slightly different context, but I went Fogstar 100Ah cells with a Victron BMS and haven't looked back. Main thing I'd flag for narrowboat use is keeping an eye on cell temperatures in winter — lithium doesn't like charging below 0°C and canal moorings can get brutal.

The K&A is lovely though @BerlingoWanderer, did a stretch of it in the van last summer. Curious whether you went DIY cells or a drop-in battery? And what are you using for alternator charging — that's where most people seem to hit headaches on boats from what I've read.

Ha, the curse strikes again it seems! 😄

Anyway, I can actually contribute something useful here — I've been running 200Ah of LiFePO4 on a 40ft cruiser stern for about two years now, so fairly similar situation to @BerlingoWanderer I imagine.

The thing nobody warned me about was the BMS cutting out completely in the cold during that nasty spell last January. Lithium really doesn't like charging below about 5°C, and I woke up one morning to a completely dead boat. Worth fitting a battery heating mat if you're in a less sheltered mooring than I am now.

@Brummie86 — vans and boats share more problems than you'd think, honestly. The damp environment is the main difference I'd flag for anyone reading. Make sure your connections are tinned copper and properly sealed.

Haha I can see the curse is real — better type fast before it gets me too! 😄

I'm on a 58ft semi-trad on the Llangollen and swapped to lithium about two years ago now. Running 280Ah of 280Ah Winston cells in a 12v bank with a Victron Multiplus and a Cerbo GX keeping an eye on everything. Honestly the best thing I've done — no more babying the batteries through winter or worrying about sulphation when we're moored up for a few weeks.

Main headache for me was sorting the alternator situation — definitely do NOT just chuck lithium in without an alternator protection relay or a decent DC-DC charger. Nearly cooked my alternator before I knew better. @BerlingoWanderer curious what you went with for charging from the engine? And @Chalky30 don't leave us hanging with that 200... 😄

Right, let me type quickly before the curse gets me too! 😄

@BerlingoWanderer really curious what you ended up going with — my money's on a 200Ah lithium setup given what everyone else seems to be running.

I'm on a 60ft cruiser stern on the Oxford canal and made the switch to lithium about eight months ago. Biggest thing nobody warned me about was the BMS cutting out mid-winter when the battery temps dropped overnight in the marina. Got caught out proper badly once. Ended up fitting a small battery heater blanket — sorted it completely. Anyone else had cold-weather BMS trips?

Curse or not, I'll keep it brief anyway.

Not on a boat but my shepherd's hut setup taught me a few things that cross over. Main one being BMS communication — if your BMS can't talk to your Victron kit properly, you're essentially flying blind when something goes sideways. DVCC on the Cerbo is worth getting properly configured before anything else.

Also learned the hard way that cable sizing is everything with lithium. The discharge rates you can pull are so much higher than with lead acid that undersized cables become a real problem fast.

@Ella1994 curious what you're using for monitoring on the Llangollen run — canal environment must throw up some interesting humidity issues for electronics that I don't have to worry about in a static hut.

Really enjoying this thread! Living aboard a 58ft cruiser stern on the Oxford canal and switched to 200Ah of lithium (EVE cells, DIY 4S build) about eight months ago. The thing nobody warned me about was the engine alternator situation — standard automotive alternators absolutely hate lithium's low internal resistance when the bank is depleted. Cooked my alternator within six weeks before I fitted a Wakespeed WS500 regulator. Game changer. Also worth mentioning that CRT stoppages in winter are genuinely useful for sorting any teething problems while you're not moving much anyway! @BerlingoWanderer curious whether you went with a BMS that has comms capability?

Really interesting thread! I'm not on a boat myself but I've been following the narrowboat community for a while as I'm seriously considering it. @ForestOffGrid your point about the Oxford canal is useful - I've heard the Midlands network can be trickier for solar generation given all the tree-lined sections. One thing I've not seen mentioned yet: how are you all handling BMS communication with your inverter/charger? I had endless grief on my static setup until I got the CAN bus talking properly between components. Wondering if that complexity is amplified on a boat with all the engine alternator charging thrown in too?

Great thread, @BerlingoWanderer! Running 280Ah of LiFePO4 on a 60ft semi-trad on the Llangollen and it's been transformative honestly. One thing nobody mentions enough is condensation around the battery compartment in winter - lithium cells really don't appreciate damp and a lot of older narrowboats have bilge moisture creeping up into the engine room. I ended up lining mine with foam insulation board and added a small desiccant pack. Also worth checking your BMS handles the voltage drop when your inverter kicks a big load - I had an annoying nuisance disconnect issue for weeks before I sorted that.