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

I've been slowly converting my 58ft narrowboat over to lithium over the past year or so, and I'm at the point where I've got 400Ah of 12V LiFePO4 (four 100Ah Winston cells wired in parallel) paired with a Victron MultiPlus 12/3000/120. Charging comes from a 60A DC-DC charger off the engine alternator and a 400W solar array on the roof — two 200W panels in series feeding a Victron SmartSolar 100/30. Works brilliantly when the sun's out in summer, but obviously that's not always a given on the canals.

My main headache right now is winter charging. I'm a continuous cruiser so I do run the engine regularly, but I'm finding the DC-DC charger isn't keeping up on shorter runs of an hour or two. I've got the Orion-Tr Smart 12/12-30 and it just doesn't shift enough amps fast enough when the cells are sitting at 40–50% SOC after a cloudy few days. I'm wondering whether it's worth adding a second Orion in parallel or swapping out for the 12/12-60 isolated unit.

Has anyone else dealt with this on a boat — specifically the conflict between wanting to protect the alternator and actually getting a decent charge in a reasonable amount of time? I've read the arguments for and against a bigger alternator with an external regulator (Wakespeed WS500 gets mentioned a lot) but the engine on mine is a 35-year-old Lister SR2 and I'm a bit nervous about loading it up heavily. Curious what others have done, particularly those cruising through winter on older engines.

@EwanPowell92 interesting setup! One thing I'd flag with parallel Winston cells — make sure you've got individual fusing on each cell's positive terminal before they connect to your busbar. Parallel LiFePO4 without per-cell fusing is a thermal runaway waiting to ruin your boat day 😅

On the marine side specifically, the condensation issue is real. I run my Victron SmartShunt and BMS wiring through conduit with desiccant packets near the connectors — narrowboats are essentially floating humidity chambers.

Also worth considering: what's your charging topology? Engine alternator into lithium without a proper DC-DC charger (like a Victron Orion-Tr Smart) will hammer your alternator into an early grave — lithium's near-zero internal resistance essentially becomes a dead short from the alternator's perspective when cells are depleted.

What BMS are you running across the four cells? Active balancer or passive?

@EwanPowell92 not on a boat myself but I've got a similar parallel LiFePO4 setup for my garden office and the damp/condensation issue is real even on land. I ended up boxing my Fogstar cells in a vented enclosure with a small desiccant pack — made a noticeable difference.

One thing I'd look at is your BMS comms in that environment. Moisture got into one of my connectors and was throwing false low-voltage alerts for weeks before I tracked it down. Worth hitting every JST connector with some dielectric grease.

What are you using for charging — alternator with a DC-DC charger, or shore power only? Curious whether you've got a Victron Orion-Tr in the mix, as that seems to be the go-to for narrowboats from what I've seen on here.

Fair bit of crossover between van and boat electrics so hopefully useful — I run 280Ah of LiFePO4 in my van and condensation is absolutely a killer if your battery compartment isn't ventilated properly. LiFePO4 is way more tolerant than lithium-ion but the BMS boards still hate prolonged damp.

One thing specific to narrowboats though — engine bay vibration. @EwanPowell92 are your cells properly secured with compression foam between them? Winston cells in particular can develop hairline stress fractures on terminals if they're rattling about on tick-over for hours. I'd check your terminal torque periodically, especially after longer cruising stretches.

Also worth considering a Victron BMV-712 if you haven't already — the Bluetooth monitoring is handy when the batteries are tucked away in awkward bilge-adjacent spaces.

Great thread, @EwanPowell92! Narrowboat life and lithium is a brilliant combination but definitely has its quirks.

One thing worth mentioning that nobody's touched on yet — thermal management in winter moorings can be a real issue with LiFePO4. If you're on the cut through January and February and the boat sits unused for a few days, those cells really don't want to be charged below about 0°C. Worth checking whether your BMS has low-temperature charge cutoff built in, or adding a battery heater mat if you're in a particularly exposed mooring.

Also, with Winston cells specifically, I'd keep an eye on cell-level voltage drift over time — they can develop imbalances more noticeably than some other brands in my experience. Are you doing regular manual balance checks or relying entirely on the BMS? What BMS are you running?

Great thread @EwanPowell92 — been running LiFePO4 on my 62ft cruiser stern for about 18 months now so a few things I've picked up that might help.

One thing nobody's mentioned yet: pay close attention to where your BMS is physically mounted. Mine was tucked fairly low in the battery box and I had a couple of mysterious shutdowns before I realised it was getting occasional spray from the bilge pump outlet. Moved it higher and wrapped the connections with self-amalgamating tape — sorted completely.

Also worth investing in a decent battery monitor with logging (I use a Victron BMV-712) so when something odd does happen you can actually look back at what the voltage and current were doing. Saved me hours of guesswork diagnosing a dodgy connection on my shore power setup last winter.

Really interesting thread — I'm in the planning stages of a lithium setup on my narrowboat so this is timely.

Quick question for @EwanPowell92 and @DougDixon56 — how are you handling battery heating in winter? I'm worried about charging LiFePO4 below 0°C when moored up for extended periods. Are you relying on the engine bay ambient heat keeping temps above freezing, or have you added dedicated heating pads?

Also wondering whether anyone's gone with a Victron SmartShunt for monitoring or found something better suited to the narrowboat environment? I've been looking at the Victron ecosystem generally but costs add up fast.

Four Winston cells in parallel is giving me flashbacks to the time mine decided to have a cell-level argument mid-cruising the Llangollen — get a proper Victron BMS that actually talks to your alternator or your engine will be doing all the work and none of the benefits. 🚤⚡