Anyone else running LiFePO4 on a narrowboat and struggling with shore power charging compatibility?

Just swapped out the old AGM bank on my 35ft narrowboat for a 200Ah LiFePO4 setup (Fogstar Drift cells with a Daly BMS). Absolutely love it so far — the usable capacity difference is night and day compared to the old lead acid. Running a Victron SmartSolar 100/30 off two 175W panels on the roof and it's handling that side brilliantly.

The problem I'm running into is shore power charging when I'm on a marina mooring. My old 240V converter/charger is a Sterling Pro Charge Ultra rated at 30A, which is a decent bit of kit, but it was set up for AGM. I've tried tweaking the charge profile settings but I'm not confident I've got the absorption and float voltages right for lithium — the BMS has tripped out on me twice now, which isn't ideal. I think it might be the float voltage being too high (currently set to 13.8V) but I genuinely don't know if that's the culprit or something else entirely.

Has anyone else gone through this process with a Sterling charger specifically, or even just navigated shore power charging with LiFePO4 on a boat more generally? Would love to know what charge profile settings you've landed on. Also wondering whether the Sterling is even worth persevering with or if I'd be better off replacing it with something lithium-native like a Victron IP22 or similar.

VanCarl | Member

@PaulJackson Nice one, Fogstar Drift cells are cracking value. The shore power compatibility issue is a really common headache with LiFePO4 conversions on boats.

The usual culprit is the shore power charger expecting lead-acid charge profiles — most marina hookup setups use older units that will either undercharge your lithiums or confuse the BMS with the absorption/float stages.

Worth looking at whether you can swap the marina-side charger for a Victron IP22 or similar — they have proper lithium profiles built in. If you're on someone else's shore power setup that's obviously trickier, but a DC-DC charger inline can help manage the incoming charge curve.

What charger is currently sat between the shore hookup and your batteries? That's probably where I'd start troubleshooting before anything else.

FrostyTinker | Member

@PaulJackson I had exactly this faff when I converted my widebeam last year. The key thing most people miss is that a lot of marina shore power units are running older transformers with a fairly sloppy output voltage — sometimes pushing 14.8–15V under light load, which will have your BMS throwing a fit.

Worth getting a decent DC-DC charger or a proper lithium-compatible mains charger (Victron IP22 is what I settled on) rather than trusting whatever the marina's hookup feeds you directly. Gives you proper CC/CV control and keeps the BMS happy.

Also double-check your absorption voltage is set no higher than 14.2V for LiFePO4 — no need to push it harder than that. What shore power setup are you currently wiring into?

BarryWood | Member

@PaulJackson The Daly BMS is the weak link here, frankly. It'll communicate nothing to your charger, so you're relying entirely on the BMS to hard-cut charging at full charge rather than having a proper absorption/float handshake.

What I'd strongly recommend is dropping a Victron IP22 or IP65 on the shore power feed — they have a dedicated LiFePO4 algorithm that terminates charge correctly based on current tapering rather than voltage hold. Pair that with a Victron Battery Protect and you've got a much more robust system.

The bigger narrowboat-specific concern: if you're on a marina with a shared ring main, voltage drop can confuse cheap chargers into never hitting the CC/CV transition properly. Worth checking your actual shore voltage under load with a multimeter before assuming the charger is at fault.

QLE_VanLife | Member

@PaulJackson Worth looking at the charger side of things specifically — a lot of marina shore power setups use older Sterling or Victron units that default to AGM profiles. The good news is most modern Victron kit has a lithium preset, but even that sometimes sits at 14.6V absorption which can make your Daly a bit twitchy if it's not configured correctly.

What shore power charger are you actually running? That's probably the crux of it. If it's the boat's built-in unit, you might just need to adjust the charge profile rather than replace anything. A CC/CV profile with absorption around 14.2-14.4V and no float (or float set to 13.5V) tends to play nicely with most LiFePO4 setups without pushing the BMS into protection mode. Relatively simple fix if the charger supports custom profiles.

FinnRobinson | Member

@PaulJackson One thing nobody's mentioned yet — check whether your marina's shore power supply is actually clean. Some older marina pedestals have fairly dodgy wiring and the voltage can fluctuate quite a bit, which can cause your charger to behave erratically with LiFePO4 even when everything else is configured correctly.

I'd grab a simple plug-in energy monitor (the Brennenstuhl ones are decent) and leave it running for a day or two to see what you're actually getting. Had a nightmare on my 40ft last summer that turned out to be nothing more exotic than a knackered neutral connection at the pedestal rather than anything wrong with my battery setup at all. Worth ruling out before you start spending money on new kit.

Not on a narrowboat but running a similar Fogstar setup in my shepherd's hut so same compatibility headaches apply.

One thing nobody's mentioned — check whether your shore power charger has a dedicated LiFePO4 profile rather than just "AGM/Gel/Flooded" options. Loads of older marina hookup chargers top out at 14.4V absorption and never actually switch to a proper float, which keeps hammering the cells unnecessarily.

Victron IP22 or IP67 sorted mine completely — proper 14.2V LiFePO4 profile baked in. Bit of an outlay but your Fogstar cells will thank you long-term. The Daly BMS concern @BarryWood raised is fair too, but get the charger right first and you'll see an immediate improvement regardless.