Anyone else using Fogstar Drift lithium on a narrowboat? How are you getting on?

Fitted a 200Ah Fogstar Drift last spring as my main house bank. Running it alongside a 200W Renogy panel on the roof and a Victron SmartSolar 100/30. Canal cruising so the engine charges it too via a Victron Orion DC-DC.

Been pretty happy overall but noticed it struggles a bit in winter — shorter days, more overcast, and I'm running the inverter more for the laptop and lighting. Not dropping below 20% but it's closer than I'd like. Wondering if a second 200Ah in parallel is the sensible move or if I'm better off just adding more solar.

Anyone on a narrowboat with a similar setup — what's your battery capacity and how do you manage winter power? Curious whether 400Ah is the sweet spot or if people are running even bigger banks.

Not on a narrowboat myself — I've got the Drift in my off-grid cabin setup — but the chemistry is identical so my experience should translate.

Mine's been running about 18 months now alongside a Victron SmartSolar and I've been genuinely impressed. The self-heating feature earned its keep last winter when temps dropped properly low here in Scotland.

One thing worth checking @Fogstar_Guy — make sure your Victron absorption/float voltages are dialled in correctly for LiFePO4. Default profiles can be a bit aggressive. I run absorption at 14.2V and float at 13.5V which keeps the BMS happy.

Also worth enabling the battery protect function on the SmartSolar if you haven't already. Narrowboat life with engine charging and solar can sometimes cause weird state-of-charge readings if the parameters aren't set right.

@Fogstar_Guy really solid choice pairing that Drift with the SmartSolar — the Victron/Fogstar combo is well-proven.

One thing worth double-checking: make sure your SmartSolar profile is set to lithium rather than the default AGM preset. Sounds obvious but I've seen people running them undercharged for months without realising.

Also, with engine charging via your alternator, I'd strongly recommend a Victron Orion-Tr Smart DC-DC isolator rather than a split charge relay. Standard relays will hammer a lithium BMS with uncontrolled current, particularly on a warm engine. The Orion limits input beautifully and handles the voltage differential properly.

On my Vivaro conversion I run similar — Fogstar Drift 100Ah, Victron MPPT, and an Orion for vehicle charging. The BMS has never tripped in anger.

How many amp-hours are you typically pulling daily? That'll help assess whether the 200W panel is keeping pace.

@Fogstar_Guy not a narrowboat here but running a Drift in my cabin so same ballpark really. One thing worth keeping an eye on — the BMS can occasionally trip if your alternator throws a voltage spike during engine charging. Worth fitting a battery-to-battery charger (B2B) between the alternator and the Drift rather than charging direct. Victron Orion-Tr Smart is the obvious choice and plays nicely with the rest of your setup. Probably overkill if it's been fine so far, but narrowboat alternators can be a bit agricultural with their output. Just something I'd consider before winter when you're relying on it more.

Great thread! I've got a 200Ah Drift on my 57-footer and it's been brilliant. One thing I'd flag specific to narrowboat life that hasn't been mentioned — keep an eye on your alternator charging setup. The Drift's BMS will disconnect if it gets unhappy, and if you've got a standard split-charge relay setup, that sudden disconnect can spike voltage back to your alternator. Worth fitting a Victron Orion or a proper DC-DC charger between the alternator and the battery if you haven't already. @Fogstar_Guy what are you using for your engine charging side? That's the bit I'd prioritise getting right on a boat. Solar's fairly forgiving but alternator charging needs a bit more thought with lithium. Mine's been rock solid since I sorted that side of things — over a season of continuous cruising with no complaints.

Not a narrowboat either but running a Drift 200Ah in the motorhome and a second one in the cabin, so decent sample size across different use patterns.

One thing I'd add that nobody's mentioned — cold soak performance. Left the cabin bank unattended over a cold snap last January, temps dropped to around -4°C overnight. The BMS did its job and blocked charging until things warmed up, which is exactly what you want, but worth factoring into your morning routine if you're wanting to get underway early.

Also @Fogstar_Guy — if your alternator charging isn't going through a proper DC-DC charger like a Victron Orion, the Drift's BMS can occasionally cause headaches with older alternators. Not always an issue but worth double-checking your setup before winter cruising.

Got a pair of Drift 200Ah batteries on my 62-footer wired in parallel giving me 400Ah — been running them since late 2023 with zero complaints.

One thing nobody's mentioned: tunnel transit and the low-light stretches of some northern canals in winter genuinely hammer your solar yield. I've got a Victron SmartShunt logging everything and the data is eye-opening — some days I'm getting barely 20-30W average through a full day. Engine alternator becomes the real workhorse November through February.

Worth making sure your split charge relay or B2B charger is properly rated if you're doing long engine runs — I upgraded to a Victron Orion-Tr Smart 30A after frying a cheap relay. The Drift cells seem perfectly happy taking a decent charge current from it.

@OGG_Power curious what your alternator setup looks like on yours?

Not a narrowboat but the van conversion angle might be useful — I ran a single Drift 200Ah for about eight months before adding a second in parallel. One thing worth flagging that nobody's mentioned: balance the batteries at identical SoC before paralleling them up. I made the mistake of connecting one at 80% and one fully charged and got a pretty alarming inrush current spike. The Drift's BMS handled it, but it's not a habit worth forming. Also worth checking your bus bar ratings if you're running 400Ah+ — the cheap ones @MrBodge65 might have originally spec'd for a lead bank won't cut it.