Anyone else running Fogstar Drift lithiums on a narrowboat AND a van — worth the faff of mixing setups?

Just swapped out my tired AGMs on the boat for a pair of Fogstar Drift 100Ah 12V lithiums and honestly the difference is embarrassing — I was running out of juice by 9pm before, now I'm barely touching 40% by midnight watching Taskmaster reruns on the inverter.

Now I'm eyeing up my campervan (2018 Transit Custom, currently a sad single 110Ah AGM under the bed) and wondering whether to just go Fogstar again for consistency, or whether a different chemistry or brand makes more sense in a vehicle that actually moves and vibrates a lot more than a canal boat gently bumping a towpath.

The boat runs Victron MPPT and a BMV-712 which I'm obsessed with, so tempted to do the same in the van — but is it overkill for weekend trips vs. living aboard?

Has anyone actually run the same battery brand across two completely different setups, and did keeping things "uniform" save your sanity or just mean you bought twice as many of the same cables you still can't find?

PanelTina | 847 posts

@VickyWard oh the AGM-to-lithium moment is properly eye-opening isn't it! I've got a single Drift 100Ah in my van and I keep telling myself I don't need a second one... then I run the kettle twice and reconsider 😅

Worth flagging for anyone considering both applications — the charge profile requirements do differ a bit between a narrowboat setup (where you're often relying on engine alternator charging) and a van. Make sure your alternator-to-battery charging is going through a proper DC-DC charger on the boat rather than direct connection, the Drifts will thank you for it. The van side is generally more straightforward with a B2B already in the mix.

What solar are you running on the boat? Curious whether you've managed to keep it simple across both setups or ended up with completely different kit on each.

@VickyWard running Drift 100Ahs on my van roof setup and they've been solid for about 18 months now. One thing worth knowing if you're juggling two setups — the Drift cells are pretty forgiving on partial state of charge, so you don't need to stress about keeping both systems at 100% when they're sitting idle.

On the boat specifically, watch your charging profile if you're using a traditional alternator setup — worth grabbing a Victron Orion DC-DC to protect the cells properly rather than just chucking alternator voltage straight at them. Might already know this but caught a few people out on here before.

What BMS are you running on the boat bank?

@VickyWard running Drifts on both my narrowboat and the van conversion here — the crossover is actually brilliant once you get your head around it.

Main thing I'd flag: your charge profiles need to be identical across both setups or you'll drive yourself mad troubleshooting. I run Victron SmartSolar on the boat and a Renogy Wanderer on the van, both set to 14.6V absorption / 13.6V float, synced via the Victron Connect app where possible.

The boat setup does throw one extra wrinkle — shore power charging via a B2B isolator can confuse things if your alternator profile isn't lithium-spec'd. Caught me out first season.

Biggest win though? Both banks talk the same language, so spare cables and connectors are interchangeable between the two. Sounds minor but when you're moored somewhere awkward at 11pm it's genuinely lifesaving.

SomersetCamper | 312 posts

@VickyWard great timing on this thread! I've been running a Drift 100Ah in my van for about eight months and just added a second for the boat last spring, so I can speak to exactly this.

One thing I'd flag that nobody's mentioned — if you're moving your MPPT or charger settings between the two setups, double-check your absorption voltage profiles match what Fogstar recommend. I got lazy once and carried over van settings to the boat without checking and charged a bit aggressively for a week before I caught it. No drama thankfully, but worth being diligent when you're juggling multiple installs.

Also the weight saving vs AGMs genuinely changes how the boat sits in the water — tiny thing but I noticed it immediately. Daft detail but it made me smile!

@VickyWard running Fogstar Drifts across my boat and shepherd's hut here — the real faff isn't the batteries, it's convincing yourself you don't need a third setup somewhere equally impractical.

One thing nobody's mentioned: if you're paralleling Drifts across two separate systems at any point, make sure your Victron BMV is reading each bank independently — learned that the embarrassing way when my shepherd's hut showed a cheerful 100% SOC whilst quietly being completely wrong.

Also worth noting the Drift's built-in BMS is reasonably tolerant, but it's not a substitute for a proper Victron BMS if you're doing anything clever with shore power on the boat side. Keep it simple and they're genuinely brilliant value for the money.

NotAnElectrician48 | 847 posts

@VickyWard funny you should ask — I've got a Drift 200Ah on the boat and a 100Ah wedged behind the passenger seat in the Transit. The thing nobody warned me about is keeping your BMS settings consistent between the two setups, especially if you're moving a charger between them temporarily (don't ask). Once I stopped being lazy about that it's been dead reliable. The capacity difference to AGM is genuinely embarrassing isn't it — like finding out you'd been driving with the handbrake on for three years. 😄

Great thread @VickyWard! I've got Drifts in my van and was seriously considering the same swap on a mate's narrowboat so this is timely.

One thing worth flagging that I haven't seen mentioned — if you're running both setups off solar, watch your charge profiles carefully when temperatures drop in winter. Lithiums don't like being bulk charged below about 5°C, and a narrowboat sat in a marina overnight can get properly cold down in the battery compartment. Worth checking your MPPT has a proper low-temp cutoff or adding a battery management sensor if it hasn't already.

The Drifts themselves have built-in BMS protection but better not to rely solely on that. Sorted mine with a Victron SmartSolar and it's been faultless since. Not specific to Fogstar but catches a lot of people out switching from AGMs for the first time.

Run Drifts on both my narrowboat and motorhome — the key thing nobody mentions is getting the charging profiles sorted per setup. Van alternator needs a proper DC-DC (running a Victron Orion-Tr Smart), whereas on the boat I'm using a Victron MPPT from roof panels. Once both are dialled in properly, the batteries themselves behave identically across both installs which is actually dead handy for fault-finding.

@Turbo43 the narrowboat swap is straightforward if your mate already has a decent BMV or SmartShunt — don't skip the monitoring side, it's where lithiums really earn their keep.

@PanelBuff is right about charging profiles but I'd add — the bigger headache on a narrowboat vs a van is your alternator charging setup. Boats often have ancient split-charge relays that'll just confuse a lithium BMS. Chucked a Victron Orion-Tr Smart DC-DC isolator on mine and it sorted everything cleanly. Van was simpler because modern B2B chargers are everywhere now.

Running two Drift 100Ah in parallel on the boat currently — solid 8 months in, no drama. Just make sure your BMV-712 or similar is actually calibrated properly or your SOC readings will lie to you constantly.