eBay $599 48V 100A LiFePO4 Lithium Battery 5120Wh 8DIP for Solar Storage Home Backup Power ???

Spotted one of these lurking in my eBay "watched items" for about three months before I came to my senses — if a 5120Wh LiFePO4 is cheaper than my last Tesco shop, something's telling porkies somewhere on that spec sheet.

The "8DIP" branding is doing a lot of heavy lifting for zero brand recognition, and that eBay listing photo looks suspiciously like it was generated by someone who's never actually seen a battery in real life.

My main concerns:

• BMS quality — these budget units often have a BMS rated for about 30 seconds of actual load before it waves the white flag
• Cell provenance — grade A CATL cells don't end up in a £470-ish battery, they just don't
• Cycle life claims — "4000+ cycles" on a mystery cell is basically fan fiction
• Support — seller's been on eBay since last Tuesday, apparently

For what it's worth, I've got a pair of Fogstar Drift 48V units in my static caravan setup paired with a Victron Multiplus, and the peace of mind alone was worth the extra spend. No thermal surprises, proper documentation, and they actually answer the phone.

That said — has anyone here actually pulled the trigger on one of these eBay specials and cracked it open? Genuinely curious what cells are rattling around inside. Could be a hidden gem, could be a garden shed fire waiting to happen.

Anyone done a teardown? 👀

@VanKen the "$599" alone should set alarm bells ringing — pricing in dollars on a UK eBay listing usually means it's a grey import or a dropship listing with no real UK presence behind it.

5120Wh for that price puts it well below even Fogstar's budget tier, and Fogstar are hardly expensive. The specs on those listings are almost always fictitious — cells rated at headline capacity under conditions that don't exist in the real world.

My motorhome build runs Victron with proper EVE cells, and even buying cells separately and building yourself you'd struggle to hit that price legitimately.

The 8DIP label means nothing I've ever seen standardised anywhere. Classic invented jargon to sound technical.

Three months in your watched list was three months of good instinct. Leave it there as a reminder of what to avoid.

@VanKen the real tell is "8DIP" in the title — that's not a standard battery specification, it's marketing fluff designed to make the listing look technical whilst meaning absolutely nothing, and any genuine manufacturer (Fogstar, Pylontech, even decent no-name cells) would cite actual cell chemistry, cycle count, and BMS discharge rating instead.

Five kilowatt-hours of quality LiFePO4 cells alone — before you've paid for a BMS, casing, or a bloke to bolt it together — costs more than $599 wholesale; the maths simply doesn't work unless they've stuffed it with rejected Grade C cells or, worse, rebranded old NCM chemistry in an LFP wrapper, which is a genuine fire risk rather than just a disappointment.

Victron-compatible kit from Fogstar starts around £800 for half that capacity and that's already considered good value.

@OldSailor78 classic case of "if it sounds too good to be true" — had a mate nearly pull the trigger on something similar for his shepherd's hut build last spring. Cells inside turned out to be second-life laptop pulls dressed up in a fancy case.

For context, a genuine 5120Wh LiFePO4 from somewhere like Fogstar is going to set you back considerably more than £599 equivalent. That's just reality.

The EV charging setup I'm running needed proper cells — skimping on the battery bank is the one place you absolutely don't want to find out you've been had, ideally not when something's on fire 🔥

Stick to suppliers who'll actually answer the phone when it goes wrong.

@VanKen the capacity claim is the real red flag for me. Genuine 48V 100Ah LiFePO4 cells at that energy density have a hard floor on manufacturing cost — you're looking at cell cost alone being north of that asking price when you work through the maths on quality prismatic cells.

I went through this rabbit hole when speccing my van build. Ended up with Fogstar Drift cells and a Daly BMS — not glamorous, but I can verify every cell's actual capacity.

With these eBay units, nobody's independently tested the actual usable Wh. "5120Wh" printed on a label means nothing without a proper discharge curve. I'd wager heavily on parallel strings of underspec'd cells hidden inside a convincing enclosure.

The absence of any certifiable BMS documentation is what would personally kill it for me — no UN38.3, no IEC 62619, nothing.

@DucatoSolar that's got me wondering — has anyone actually measured the real-world capacity on one of these when it arrives? Like, done a proper charge/discharge cycle with a decent meter?

I'm running a Fogstar Drift 48V at the moment and the rated vs actual capacity is pretty much spot-on, which is what made me suspicious of claims like this in the first place.

Is there any way to verify cell provenance before committing? Or is it basically pot luck what grade cells end up inside these mystery units?

Also curious whether the BMS on these budget packs would even talk to a Victron system via CAN or Modbus — has anyone tried integrating one, or does it just sit there as a dumb battery?