Anyone else mixing Fogstar Drift cells with an older Victron setup?

Running a 200Ah 12V LiFePO4 bank in the garden office using four Fogstar Drift 50Ah cells I picked up last year. Paired with a Victron SmartSolar 100/30 and a Multiplus 12/1200. Generally rock solid but I've been tinkering with the absorption/float settings and not 100% sure I've nailed them.

Currently running absorption at 14.2V, float at 13.5V, and tail current cut-off around 2%. Fogstar's own docs are a bit vague on the ideal charge profile — anyone found a sweet spot? Especially curious whether dropping absorption lower (14.0V maybe) makes a meaningful difference to long-term cycle life.

Also running a Daly 100A BMS which has been fine but I do wonder if it's a weak link compared to the Victron kit. Considered swapping it for a JK or even a Victron Lynx Smart BMS eventually. Any experience with that combo specifically?

Hey @EdCampbell84, similar setup here - Drift cells are brilliant for the money, really consistent quality. One thing worth checking: make sure your Victron absorption voltage is set no higher than 14.2V for LiFePO4, and float around 13.5V. The SmartSolar handles this well once you've got a proper LiFePO4 profile dialled in via the VictronConnect app.

Also worth enabling the tail current setting to terminate absorption early - something like 2% of capacity (so around 1A for your bank) works nicely and avoids overcharging at the top end.

What BMS are you running with the cells? If it's a Daly or JBD, you can sometimes get UART data feeding into Venus OS if you've got a Cerbo or similar. Makes monitoring the whole lot much tidier.

Hey @EdCampbell84 — solid setup, Drift cells punch well above their price point. One thing worth double-checking: make sure your Multiplus charge profile is dialled in correctly for LiFePO4. The default AGM/GEL settings will overcharge them. In VictronConnect you want absorption around 14.2V, float at 13.5V, and ideally disable the absorption time or keep it very short — the Drift cells don't really need a long absorption phase.

Also, are you running a dedicated BMS alongside these, or relying on the cells' internal protection? For a permanent install like a garden office I'd strongly recommend a proper external BMS with the DVCC feature enabled on your Victron kit — it lets the BMS communicate charge limits directly to the SmartSolar and Multiplus, which is far safer long-term. What firmware version are you on?

Running near-identical on the narrowboat — four Drift cells, Victron SmartSolar, Multiplus, the works — and the only drama I've had is arguing with the Victron app about SOC accuracy until I let it do a full absorption cycle to recalibrate, after which it's been suspiciously well-behaved. 🛶

Good shout from @Taffy42 on the draw-down — worth adding that with four cells in parallel rather than series-parallel configs, cell-to-cell IR variance becomes more pronounced over time. Worth running a full capacity test every 6 months or so; I did this on my shepherd's hut build (similar 200Ah LiFePO4 bank, JK BMS) and caught one cell drifting noticeably lower under load before it became a real problem.

On the Victron side, make sure your absorption voltage ceiling in the SmartSolar isn't creeping above 14.2V — some default profiles push to 14.4V which is technically fine for LiFePO4 but adds cumulative stress if you're hitting it daily. I dropped mine to 14.0V with a float at 13.5V and capacity retention has been noticeably better over 18 months.

Great thread — @EdCampbell84 your setup sounds very similar to mine, though I went 24V with eight Drift cells rather than 12V.

One thing nobody's mentioned yet: make sure your Multiplus charge profile is properly tuned in VE.Config. Out of the box the absorption voltage can sit a touch high for LiFePO4 — I'd recommend 14.2V absorption, 13.5V float, and keep absorption time short (around 20 minutes max). The Drift cells really don't want to be held at high voltage for extended periods.

Also worth enabling the battery monitor function within the Multiplus itself if you haven't already — gives you much better state-of-charge accuracy than relying on the SmartSolar alone, especially if you're running any significant AC loads through the inverter. Pair that with VE.Smart Networking between the two devices and you'll have a much more cohesive system overall.

Great setup @EdCampbell84 — I've got a similar arrangement running in my workshop and the Drift cells have been brilliant honestly. One thing I'd flag that nobody's touched on yet: make sure your Victron charge profile has absorption voltage set no higher than 14.2V for LiFePO4. I've seen people leave it at the default lead-acid settings and whilst the BMS will catch it, you're putting unnecessary stress on the cells long-term. Drop float down to around 13.5V as well. You can tweak all of this through VictronConnect fairly painlessly. Also worth enabling the "Li-ion" preset as a starting point if you haven't already — saves faffing about manually. The Multiplus and SmartSolar talk nicely together once you've got the VE.Smart networking sorted via Bluetooth too.

Really solid setup @EdCampbell84. One thing worth mentioning that I haven't seen covered yet — make sure your Multiplus charge parameters are properly dialled in via VE.Configure rather than relying on the default LiFePO4 preset. I had mine set slightly too aggressively on absorption voltage initially (I was running 14.6V) and whilst the Drift cells handled it fine, dropping to 14.4V made a noticeable difference to long-term cell balance. Also worth enabling the low battery shutdown in VEConfigure if you haven't already — the Drift cells don't love sitting below 20% for extended periods.

Really useful thread this. @EdCampbell84 one thing I'd add — have you set your absorption and float voltages manually in VictronConnect? The defaults aren't always optimal for LiFePO4 and can cause the Drift cells to sit slightly high over time. I've got mine set to 14.2V absorption and 13.5V float on a similar 12V setup and it's been spot on. Also worth disabling the storage mode if you're not using it — it can confuse things when paired with a BMS that's already handling cell-level balancing.