Anyone else running Fogstar Drift cells in a garden office setup?

Been running a 280Ah 12V LiFePO4 bank in my garden office for about eight months now — four Fogstar Drift 280Ah cells in a 4S configuration with a Daly 100A BMS. Genuinely impressed with the cells themselves, no complaints there. The BMS, however, has been a bit of a headache.

The issue is cell drift over time. Started with all four sitting within 5mV of each other, but after a few months of daily cycling I'm seeing cell 3 consistently lag behind by around 30–40mV at the top of charge. The Daly is balancing, just... slowly. Active vs passive balancing — should've thought harder about that before buying.

Considering swapping the Daly out for a Victron Smart BMS or possibly a JK BMS (heard good things about the active balancing on the JK at that price point). Main constraint is I'm running this through a Victron MPPT 100/30 and a MultiPlus 12/1600, so ideally want something that plays nicely with the Victron ecosystem via VE.Can or at least Bluetooth monitoring.

Has anyone made this switch, particularly going from Daly passive to JK active on a similar capacity bank? Did it actually sort the drift, or is there something else going on with the cells?

@LesPhillips similar setup in my shepherd's hut — though I went with 8 cells in a 24V configuration rather than 12V. The Drift cells have been solid, no complaints after about a year.

One thing worth checking if you haven't already: cell top balancing before you first connect the BMS. I didn't do it properly on my first build and had the Daly throwing balance errors for weeks until I sorted it manually.

Also the Daly 100A is fine but if you're running anything with a decent surge draw — inverter, kettle etc — you might find it trips. I eventually moved to a JK BMS which handles peaks much better and the active balancing is genuinely noticeable.

What are you using for charging, solar or mains hookup?

@LesPhillips 280Ah at 12V feels like you're limiting yourself tbh. Fine for lighting and a laptop but the moment you chuck a decent inverter on it you'll be sagging voltage under load.

@TerryScott72 has the right idea going 24V — I did the same with my static, runs far more efficiently and the cable sizing becomes less of a headache.

One thing worth watching with the Daly BMS — they're fine until they're not. Had one drop out on me mid-winter, not ideal. Looked at upgrading to a Victron-compatible unit but the cost is eye-watering.

What's your solar input situation like? Garden office with trees nearby can be a nightmare for partial shading killing output.

GrumpyHermit | Posts: 847 | Location: Scottish Borders

Running a very similar 24V setup to @TerryScott72 in my workshop — though I went with a JK BMS rather than the Daly. Night and day difference in terms of active balancing and the Bluetooth monitoring is actually useful rather than just a gimmick.

One thing worth mentioning to @LesPhillips — at 12V you'll be pulling significant current for anything remotely demanding. What's your inverter situation? I'd be curious what loads you're actually running through it day-to-day in a garden office context. Heating in winter is where most people get caught out with undersized setups.

The Fogstar cells themselves seem solid enough. Mine are approaching 18 months with no drama whatsoever.

@LesPhillips the Daly is functional but worth knowing it's a weak point in that setup long-term. The passive balancing current is quite low — around 30–50mA typically — which means any cell drift that develops will take an age to correct, especially as capacity increases with cycling.

For a static garden office install I'd seriously consider swapping to an active balancer alongside it, or eventually migrating to a JK BMS which has proper active balancing built in. The JK also gives you proper Bluetooth monitoring without needing a separate shunt.

@TerryScott72 24V was the right call for anything above 200Ah in a fixed install — cable losses alone make 12V a compromise at that scale.

I've run Fogstar Drift cells in my van build for 14 months now. Top-balancing them properly before first use made a noticeable difference to how evenly they've aged.

Really useful thread this. @LesPhillips eight months is a decent proving period — good to hear they're holding up.

One thing worth flagging that I don't think anyone's mentioned yet: keep an eye on your cell voltage spread during the first few full cycles after any period of sitting idle. I found my Drift cells needed a good few charge/discharge cycles to properly settle before the BMS passive balancing could do its job properly. Initial spread looked a bit alarming but tightened up nicely after a week or so of regular use.

Also worth checking your BMS low-temp cutoff settings if you haven't already — garden offices can get brutal in January and LiFePO4 really doesn't want to be charging below about 5°C. Might be worth a small heating pad on a thermostat if you're not already running one.

WezBrown66 | Posts: 213 | Location: West Yorkshire

Nice one @LesPhillips, good to see a proper long-term update rather than someone posting after two weeks and calling it proven!

I've got a similar garden office setup but went 24V with eight Drift 280Ah cells — been running since last spring with a JK BMS rather than the Daly. Active balancing makes a noticeable difference, particularly heading into winter when the cells are sitting at lower states of charge for longer periods.

One thing worth keeping an eye on with any garden office setup is temperature. I added a small thermostatically controlled heat mat under the battery box once temps started dropping — LiFePO4 really doesn't like charging below about 5°C and the Daly won't necessarily protect you there depending on how it's configured.

What's your solar input situation looking like over winter? That's usually where these setups get tested properly.

Been running Drift cells myself — though mine are in a 48V bank feeding a Victron Multiplus for whole-house backup out here in Kent. What I'd add from experience is that the cell matching matters more than people realise at build time. Spent an afternoon with a multimeter checking internal resistance before I assembled mine, and eight months on, the balance is still remarkably tight. @LesPhillips if you haven't logged your individual cell voltages under load from day one, start now — it's the only way you'll catch a drifting cell before it becomes a problem.

Great thread, cheers @LesPhillips. I've got a similar setup in my garden office — 280Ah 16S at 48V rather than 12V, mainly because I wanted to run a small inverter without the cable gauge getting silly. Eight months sounds about right for when you really start trusting the cells through proper seasonal variation. Curious what you're seeing on winter capacity — I noticed maybe a 6-8% drop during the cold snap in January but nothing dramatic. Also worth mentioning the Fogstar customer support has been decent in my experience, which you don't always get with budget cells.