Fogstar Drift vs cheap Amazon cells — anyone actually tested both long-term?

Been running a 200Ah Fogstar Drift LiFePO4 in my static caravan setup for about 18 months now and honestly no complaints. Paired it with a Victron SmartSolar 100/20 and it just... works. Sits at around 95–100% most sunny days with my 400W of panels.

Thing is, my mate's gone and bought two of those unbranded 100Ah cells off Amazon — paid about £140 total — and they're still going strong 8 months in. Makes me wonder if I overpaid by going "reputable."

Has anyone actually run both side by side, or tracked capacity over a couple of years? I get that Fogstar has proper BMS protection and UK support, but at nearly 3x the price I want to know if that premium is genuinely worth it for a low-drain cabin setup rather than a van where you're hammering it daily.

Curious whether anyone's done a proper discharge test on older cheap cells to see if capacity has dropped noticeably — or if they've just failed outright.

Neil1982 | 847 posts

@WonkySkipper similar experience here mate. Had a Drift 100Ah for about 14 months alongside a cheap 100Ah "lifepo4" off Amazon (can't even remember the brand, some unpronounceable thing).

The difference in actual usable capacity was stark from day one — the Amazon cell was barely hitting 70Ah realistically. Started showing signs of cell imbalance around month eight, now it struggles past 50Ah. The Drift hasn't flinched.

Main thing I'd say is factor in the BMS quality. The Fogstar's internal BMS handles my morning kettle surge without drama. The cheap one used to occasionally drop off under load which caused me no end of head-scratching before I figured out what was happening.

Not saying budget cells are always terrible but you're often buying someone else's B-grade rejects. False economy in my experience.

LauraCole | 312 posts

Interesting thread! I went the opposite route initially — grabbed a pair of cheap 100Ah cells off Amazon about two years ago, proper no-name stuff. First one started showing dramatically reduced capacity around month eight, second one followed maybe three months later. Replaced both with a single Fogstar Drift 200Ah and honestly wish I'd just done that from the start.

The maths aren't as compelling as the cheap option looks on paper. Factor in replacement costs plus the time faffing about with warranty claims (spoiler: good luck with that on Amazon sellers), and Fogstar comes out well ahead.

@WonkySkipper what BMS are you running with yours? I've got the built-in one but wondering if anyone's added external monitoring on top — curious whether it's worth the extra spend at our sort of capacity levels.

BoatPaddy | 1,203 posts

Ran a dodgy Amazon special for eight months in my garden office before it puffed up like a sad Yorkshire pudding and died — swapped to a Fogstar Drift and haven't looked back since. The BMS on the cheap stuff is where it all falls apart; mine cut out constantly below 10°C which is basically every morning in this country. @LauraCole curious what cells you grabbed — some of the EVE-based ones from reputable sellers are decent, but genuine lottery otherwise. The Drift's built-in low-temp protection actually earns its keep over a UK winter paired with my Victron setup. Spend the extra £40-50 upfront or spend it twice later — your call, but my shepherd's hut conversion taught me that lesson the expensive way. 🔋