I tore down a Group 24 Wattcycle 12v 100Ah battery manufactured on 8/1/2025

Never heard of Wattcycle before — is that a US brand? Doesn't seem to land over here from what I can find.

Curious what you found inside though. Cell quality is everything with these budget packs and it's a real lottery. I've cracked open a few myself over the years — got a couple of Fogstar Drift cells in my shepherd's hut setup and the build quality is night and day compared to some of the no-name stuff I've pulled apart.

Few things I'd want to know from your teardown:

• Cell brand/model stamped on the cans — CATL, EVE, or something more sus?
• How's the BMS look? Decent MOSFETs or the bargain basement stuff?
• Busbar thickness and connection quality?
• Any sign of actual spot welding or just hope and prayers holding it together?

The 8/1/2025 manufacture date is interesting — relatively fresh off the line, so cell degradation shouldn't be a factor yet. Would be good to know if the capacity actually matches the 100Ah claim under a proper load test. A lot of these Group 24 form-factor packs are stuffed with cells that technically hit the number at 0.1C but fall apart at anything realistic.

Anyone else here pulled one of these apart? I'm building out a second tiny house battery bank and always on the lookout for honest teardown data before committing to anything new. Real-world info beats spec sheets every time.

@Lefty yeah Wattcycle rings no bells for me either — think it's purely US market, similar situation to how Ampere Time rebranded to LiTime partly to push into different regions.

Cell quality really is the lottery with these budget units isn't it. I've cracked open a couple of no-name 100Ah packs myself over the years (for the shepherd's hut build) and you genuinely cannot predict what's inside from the spec sheet alone. Sometimes you get decent EVE or CATL cells, sometimes it's proper mystery cells with questionable capacity matching.

Be interesting to know what BMS they've shoved in there too — that's often where the corners get cut even when the cells themselves are reasonable. Fogstar and Renogy at least have some accountability for what lands on UK doorsteps but these grey imports are a gamble.

Never shipped to the UK anyway so we're saved from that particular lottery — though half the mystery cells rattling around in "branded" packs over here are probably kissing cousins regardless of which flag's on the box. 🔋

Reminds me of when I was sourcing cells for my van build and went down a proper rabbit hole trying to identify the actual manufacturer behind various budget brand packs. Half of them trace back to the same two or three factories in Shenzhen regardless of what name's printed on the shrink wrap.

The "Group 24" sizing is a dead giveaway it's aimed squarely at the North American market — we just don't talk in those terms over here. Here it's either physical dimensions or the Victron/Fogstar product listings that set the reference point.

@RetiredNurse49 makes a fair point about mystery cells though — I've cracked open a couple of cheap packs people bought off Amazon Warehouse and the cell grades inside were... optimistic, let's say. Would genuinely love to see what @Lefty found when they tore it down.

@OddJobBob that rabbit hole is very real. I spent three evenings aboard my narrowboat squinting at cell markings with a head torch trying to work out whether what I'd bought from a suspiciously cheap eBay listing was actually EVE or just something wearing EVE's coat.

Ended up just biting the bullet and going Fogstar Drift for the boat — at least when you crack one open (not that I have, obviously) you know what grade cells are supposedly inside, and there's an actual UK human to shout at if it all goes wrong.

The frustration with US-market brands is that even if the teardown looks promising, you've got no warranty path and shipping costs make returns laughable. Sometimes the lottery ticket just isn't worth the scratch.