Anyone actually running a van system on reclaimed 18650 cells? Worth the hassle?

Been going back and forth on this for a few weeks now. Converting a Sprinter and trying to keep costs down — proper Fogstar or CALB cells would obviously be ideal but I'm looking at £400-600 just for a decent 100Ah LiFePO4, which is a chunk of my whole budget.

Spotted a load of laptop battery packs and old power tool batteries on eBay and Facebook Marketplace, some blokes selling tested 18650 cells for 50p-£1 each. Done some reading and in theory you can build a reasonable 12V 100Ah bank for well under £150 if you're patient with testing and sorting cells. Running a BMS from Daly or similar (£20-30 on AliExpress) and bus bars you can fabricate yourself.

The obvious concerns are capacity variance, dead cells degrading the whole pack, and the sheer time involved in testing hundreds of cells with a charger/discharger like a Opus BT-C3400. I've got the time, just not sure if I'm being naive about the failure rate or fire risk. Already got a Victron SmartSolar 75/15 sorted and a basic 175W panel, so it's really just the battery where I'm trying to cut corners.

Has anyone here actually run a reclaimed 18650 pack in a van for more than a season? What failure rate did you see, and would you do it again?

Done it. Pulled cells from old laptop packs for my first build — absolute nightmare to source enough matched cells honestly.

The testing alone took weeks. Every cell needs capacity testing, IR checking, anything sketchy gets binned. You'll waste probably 40-50% of what you pull depending on source.

Bigger issue for van life though — 18650s really want a proper BMS that handles cell-level balancing, not just pack-level. That adds cost back in.

If you can source pulled EV module cells (Nissan Leaf modules especially) you're in much better territory. Proper prismatic cells, already matched, easier to work with. Check eBay and some of the EV salvage places — sometimes proper bargains.

For a Sprinter build I'd personally say the faff isn't worth it vs waiting and buying decent Fogstar cells outright.

Hey @FenlandVanLifer! Running reclaimed 18650s in my Transit for about 18 months now — cells pulled from old laptop packs mostly. Honestly? It's absolutely worth it if you're patient with the sorting process. The key is having a proper capacity tester (I use a SkyRC MC3000) and ruthlessly binning anything below 80% rated capacity. Group your cells tightly by capacity and internal resistance or your pack will be dragged down by the weakest ones.

Realistic expectation though — budget an extra 15-20 hours for testing and spot welding. The actual cell cost is pennies but your time isn't free.

What's your target capacity? That'll determine whether 18650s are even practical versus sourcing one decent secondhand LiFePO4 brick. Sometimes the maths doesn't stack up once you factor in the BMS properly.

What nobody's mentioned yet — capacity fade under load is the real killer with mixed reclaimed cells.

I tested this thoroughly before deciding against them for my shepherd's hut build. Cells that bench-tested at 2,000mAh individually were delivering maybe 60% of that under a sustained 10A draw. Fine for a laptop cycling gently. A van inverter pulling 20-30A? Different story entirely.

The maths stopped making sense once I factored in the cell-level fusing wire, proper nickel strip, a decent spot welder, and the hours of sorting/testing. Fogstar Drift cells came out surprisingly close in total cost once I was honest about my time.

That said — @RenogyKing's 18 months of real-world data is genuinely useful. What's your actual usable capacity vs theoretical, out of curiosity? That number tells the whole story.

Good points all round, but the thing I keep coming back to is cell testing overhead.

For my shepherd's hut build I priced up a proper 18650 tester (the OPUS BT-C3100 or similar) plus the time to sort, grade and reject cells — you're easily 15-20 hours in before you've assembled anything. On a van where you need meaningful capacity, multiply that significantly.

@SteveBurns99's point about capacity fade is exactly why I'd be nervous doing this in a moving vehicle — you can't just nip under the bed easily when something starts performing oddly.

Have you looked at Fogstar Drift cells as a middle ground? Not reclaimed, but their 18650s are decent price-per-Wh and you know what you're getting from the start. Might close the budget gap without the gamble.

@FenlandVanLifer the bit everyone glosses over is cell matching — shove mismatched internal resistances into a pack and your BMS will be crying before you've even left the driveway.

Grabbed a proper cell analyser (Opus BT-C3100, dead cheap) before building my narrowboat bank and rejected roughly 40% of the cells I'd sourced — which rather demolished the "budget" argument I'd made to myself.

The maths only pencils out if you're getting the donor packs completely free — old power tool batteries from a scrappy, that sort of thing — otherwise a Fogstar Drift LiFePO4 is honestly closer than you'd think once you factor in your time, a decent spot welder, nickel strip, and the inevitable BMS replacements.

Not saying don't do it, just go in with a spreadsheet rather than optimism.