Cells from a used Nissan Leaf pack — worth testing individually or just bin them?

Honestly, don't bin them without at least running a basic capacity test first — you could be throwing away perfectly good cells. Leaf packs are lithium manganese oxide chemistry (well, blended NMC/LMO depending on the generation), and they can hold up surprisingly well if the pack wasn't thermally abused.

What I'd do:

1. Separate the modules — the Leaf uses paired cells in flat pouch modules, so you're working with those rather than individual cylindrical cells
2. Check voltage on each module first — anything badly out of balance or sitting below ~3.5V per cell equivalent needs a closer look before you even bother capacity testing
3. Run a proper charge/discharge cycle — I use an iCharger for this sort of thing, log the actual Ah you get back against the rated capacity

From my own narrowboat build I picked up some second-gen Leaf modules (the 40kWh pack generation) and after testing I'd say roughly 80% of modules from a used pack are still usable for stationary storage, even if they're not suitable for EV duty anymore.

The ones to bin are anything showing cell-level voltage divergence during discharge, physical swelling, or capacity below 70% of nameplate.

If you've got a decent BMS like a Daly or JK unit you can monitor cell-level behaviour once they're in a battery build too, which gives you early warning of any rogues.

What generation Leaf is the pack from? Makes a difference — the older 24kWh packs can be quite degraded by now but the 40kWh and 62kWh modules are often cracking value secondhand.

@Boycie dead right — I pulled 24 cells from a gen1 Leaf last spring and 19 of them still had >85% capacity, which is now happily running my shed via a Victron SmartShunt and Fogstar cells as backfill for the duff ones.

A cheap RC hobby charger with discharge testing mode is your best mate here — the iCharger or even a basic ISDT will tell you what you've actually got before you commit to a BMS.

Worth noting: Leaf cells are pouch format, so watch for any swelling like a hawk — a puffed pouch is the one you do bin without guilt.

Good thread. One thing worth adding — before you even get to capacity testing, do a resting voltage check on every cell first. Anything sitting significantly below ~3.6–3.7V after a full charge cycle is worth flagging immediately as a likely dud; saves you wasting time on a full capacity test.

For the actual capacity test, an iCharger or a decent active load setup will give you far more reliable figures than a basic hobby charger. I did something similar when I was scoping out a second-hand pack for my static caravan setup — the variance between cells from the same module was surprisingly wide.

Also worth noting: Leaf cells tend to suffer from uneven degradation across the pack because they're passively cooled. Cells from the centre modules often test worse than those on the edges. Factor that into how you group them if you're building a DIY bank.

@BlownFuse good shout on the resting voltage check — what threshold are you actually using to discard at that stage? I've got a knackered Leaf pack sitting in the garden office right now and I want a proper decision tree before I start pulling it apart.

Specifically:

• Below X volts = skip entirely?
• Above Y volts = proceed to capacity test?
• Anything in between = ???

Also worth asking — what's the minimum capacity you lot consider actually usable for a static storage build? I'm not putting these on a boat where weight and density matter, just supplementing my office setup, so presumably I can tolerate cells that @VE_Electric might reject for a vehicle application.

Is there a decent cell-level capacity tester that won't cost more than the cells are worth? The SkyRC MC3000 gets mentioned a lot but I'm not sure it handles the Leaf cell format.

@DodgyMechanic anything below 3.5V at rest after 24hrs off charge goes straight in the "probably haunted" pile — though I've nursed a few dodgy ones back with a careful slow charge and they've been fine in my static van battery bank ever since, running through a Victron SmartShunt so I can actually see which cells are being awkward.

@BorderVanLifer "probably haunted" is doing a lot of work there 😄

Worth adding that resting voltage alone doesn't tell the full story — I've had cells sitting at a perfectly respectable 3.7V that showed catastrophic internal resistance when I actually load-tested them. Grabbed a secondhand Leaf pack last year for the van build and ran every pouch through a proper discharge cycle with a DC load tester, logging capacity at C/5 rate. Anything below roughly 75% of rated nameplate capacity got binned regardless of resting voltage. Some cells that looked fine on the multimeter were effectively dead weight.

If you're serious about reusing them, an EBC-A20 or similar programmable charger/discharger is worth every penny — you'll get actual mAh figures rather than guessing. Internal resistance measurement via a dedicated meter (I use a YR1035+) adds another useful data point alongside capacity.