Anyone else running Fogstar Drift LiFePO4 on a narrowboat? Curious about BMS settings

Been running a 200Ah Fogstar Drift 12V on the boat for about eight months now. Mostly happy with it — charges well from the alternator via a Victron Orion-Tr Smart and tops up nicely from 400W of solar on the roof. No drama so far.

What I'm not sure about is whether my BMS low-temp cutoff is set sensibly for a canal boat situation. We're moored up in the Midlands and last winter the battery locker got properly cold — I think I saw 3°C in there at one point. The Drift's built-in BMS is supposed to handle this but I never actually confirmed what the cutoff threshold is.

Also thinking about adding a second 200Ah unit in parallel for EV charging when we're on shore power. Running a small Type 2 setup off a Victron Multiplus 2000. Anyone done similar and had issues with the two units balancing properly over time?

@DaiBennett not a narrowboat setup here but running two 200Ah Drifts in a garden office with a Victron MultiPlus — broadly similar BMS characteristics so worth comparing notes.

Main thing I'd flag: the Drift's internal BMS is fairly conservative on the low-voltage cutoff, around 10V if I recall correctly, but the useful capacity ends well before that. I've got my Victron set to a 12.0V low-voltage disconnect rather than relying on the BMS as a backstop — treating the BMS as emergency protection only, not active management.

On the alternator side, what absorption voltage are you running through the Orion-Tr? The Drift datasheet suggests 14.2–14.6V. I'd sit at 14.4V personally — gives a proper full charge without stressing the cells. Anything much above 14.6V and you'll likely see the BMS disconnect mid-charge, which is hard on the alternator.

Hey @DaiBennett, yes! Running a single 200Ah Drift on our 57-footer since last spring and really pleased with it. One thing worth checking — I've got my absorption voltage set to 14.2V rather than the full 14.6V that some chargers default to. The Drift seems perfectly happy with that and you're not flogging the cells unnecessarily on a daily cycle. Also worth making sure your low voltage disconnect on the BMS is set a touch conservatively, maybe 11.8V rather than the absolute floor — gives you a buffer if you're drawing hard through an inverter. What's your typical daily consumption looking like? We do mostly leisure cruising so ours sits at decent state of charge most of the time, which LiFePO4 handles beautifully. Curious whether you've had any issues with the alternator charging cutting out unexpectedly — had a funny moment with that early on.

@DaiBennett same setup here — 200Ah Drift on a 58ft trad stern. One thing worth checking is your Orion-Tr absorption voltage. I had mine set a touch high initially and the BMS was occasionally kicking in during long cruising days. Dropped it to 14.2V and it's been solid since.

Also worth setting a proper tail current in the Victron app rather than relying purely on time — the Drift BMS seems happier that way in my experience.

What's your charge disconnect threshold set to on the BMS side? Mine's at 14.6V and I've never had it trip.

Hey @DaiBennett, great to see more narrowboaters going with the Drift — solid choice. One thing I'd flag specifically for boat life is keeping an eye on your low temperature cutoff settings if you're leaving her unattended over winter. LiFePO4 really doesn't like being charged below 5°C and a moored boat can get surprisingly cold overnight even in autumn.

Also worth checking your cell balance periodically if you're doing a lot of partial cycles from the alternator — short runs between locks can mean the cells never quite get a proper top balance. I tend to do a deliberate slow charge to full from shore power every few weeks just to keep things tidy.

What's your current charge voltage set to on the Orion? That makes a big difference with these cells.

Great thread! @DaiBennett, one thing nobody's mentioned yet — worth keeping an eye on your resting voltage after a long mooring with minimal load. LiFePO4 can sit at a deceptively healthy-looking voltage while actually being a touch lower in real state of charge than you'd expect, especially in colder canal temperatures over winter. The Drift handles it fine, but if you've got any 12V appliances with low-voltage cutoffs set for lead-acid, they might trip earlier than anticipated. Might be worth reviewing those thresholds. Eight months in is also a good point to check your cable connections are still properly torqued — vibration from the engine and general boat movement can work terminals loose over time, which causes resistance and heat. Nothing dramatic, just good practice!

Really useful thread this — been lurking on this exact topic as I'm considering the same setup for my 62ft cruiser stern.

@DaiBennett one thing I'd add that nobody's touched on yet is temperature compensation during winter mooring. If you're leaving the boat unattended through a cold snap, the Drift's BMS will protect against charging below 0°C, but it's worth making sure your Orion-Tr is actually seeing that cutoff signal rather than just blindly pushing charge. Had a friend with a similar install where the two weren't communicating properly and the charger was essentially fighting the BMS.

Have you got the Victron and the Drift talking via the BMS connector, or are you relying on voltage-based protection only? Makes a real difference to how reliably the system behaves when temperatures drop on the cut.