Cheap 100Ah LiFePO4 options in 2024 — worth the risk or stick to Fogstar?

Fogstar Drift 100Ah keeps coming up as the go-to budget pick but it's sitting around £180-£200 now. Spotted a few no-name cells on AliExpress and some rebranded units on eBay for under £120. Tempting for the cabin backup setup but obviously a bit sketchy.

Currently running a single Fogstar 100Ah paired with a Victron SmartSolar 75/15 and it's been rock solid for 18 months. Want to add a second bank on the cheap — not cycling it hard, mostly sitting as emergency backup so cycle life isn't a massive concern.

Has anyone actually tested the £100-ish eBay units with a proper BMS? Wondering if the cells are reject grade or just unbranded EVE/CATL that are fine in practice. Seen a few threads on YouTube suggesting some batches are legit but hard to know what's actually landing in the UK.

Any horror stories or hidden gems from the last 6 months? Specifically after something with a decent built-in BMS rather than faffing with separate units.

@GlenWard had a similar dilemma last year with my motorhome build. Went Fogstar in the end and honestly the BMS has been solid through a Welsh winter — no drama.

The sub-£120 units are a gamble. Some are genuinely rebranded EVE or CATL cells and you'd never know, others are graded-out rejects with inflated capacity ratings. The issue isn't usually the cells themselves, it's the BMS quality at that price point.

Worth checking if the eBay sellers have any return history or UK-based warranty. AliExpress protection is basically worthless once you're past the dispute window.

If budget is tight, I'd sooner buy one good Fogstar than two cheap unknowns — series/parallel mistakes with dodgy BMS units can get expensive fast. Check the Fogstar refurbished listings too, occasionally drop to £140-150.

@GlenWard running a shepherd's hut full time so battery reliability actually matters to me day-to-day. Had a dodgy no-name 100Ah from eBay about 18 months back — BMS gave up after 4 months, wouldn't balance properly. Ended up binning it.

Fogstar Drift at £180-ish isn't glamorous but the warranty support is actually real, which counts for something. If you're dead set on cheaper, Docan cells via AliExpress can be decent if you're confident testing them yourself with a capacity checker on arrival — but that's extra faff most people don't want.

For a shepherd's hut or similar where you're not constantly monitoring it, I wouldn't gamble personally. The £60 saving disappears fast if you're replacing it inside a year.

@GlenWard the £60 saving sounds mint until 3am in February when your no-name cell decides it's had enough and you're googling "how to explain a battery fire to your insurance company" by torchlight 🔦

Running LiFePO4 on the narrowboat and the cabin — both Fogstar. Not because I'm flush

Hey @GlenWard, worth checking out Keheng and Timeusb as middle-ground options — both floating around £130-£150 for 100Ah and have decent QC compared to pure AliExpress lottery stuff. I've got a Timeusb in my shed setup running since March, no issues so far.

That said, one thing nobody's mentioned yet — check what the low-temperature cutoff is on any budget BMS. Plenty of cheap units start throttling or disconnecting below 5°C which is basically useless for a UK winter. Fogstar are upfront about their specs; with the unknowns you're often digging through broken-English datasheets trying to work it out. Sometimes the hidden cost isn't the battery failing catastrophically, it's just quietly underperforming all winter and you never quite getting the capacity you paid for.