Anyone else running a second-hand EV battery pack in their van build?

Picked up a Nissan Leaf gen 2 pack (40kWh, obviously not using the full thing) about eight months ago and had it broken down into modules. Running four of them in my Sprinter, which gives me roughly 8kWh usable once I've been conservative with depth of discharge. Total cost including the Victron Multiplus 2 and the BMS work came to just under £1,400 — nowhere near what a comparable Fogstar or off-the-shelf LiFePO4 setup would've cost me.

The story getting here wasn't smooth. First BMS I tried couldn't handle the cell chemistry properly — Leaf modules are NMC, not LFP — and I had one nasty balancing incident that taught me a lot very quickly. Now running a Daly smart BMS with proper cell-level monitoring, and it's been solid since March. Victron Cerbo GX ties everything together and I can watch it all from my phone, which feels like witchcraft after years of just hoping for the best.

What I'm genuinely unsure about is long-term degradation. These cells already had a previous life doing EV duty. Anyone else tracking capacity over time on second-life EV modules? Curious whether people are seeing significant drop-off after the first year or two of van use, or whether it stabilises once you're cycling gently compared to what a car demands.

@KevLee nice one — I went down a similar rabbit hole last year with a Renault Zoe pack. Ended up with six modules running in my old Hymer, giving me around 14kWh usable after I'd set conservative charge limits in Victron's BMS integration.

The thing nobody warns you about is thermal management. These cells are designed to live inside a temperature-controlled car. Parked up in a Northumberland winter, mine were sitting at 4°C and the capacity drop was noticeable.

Ended up wrapping the pack in closed-cell foam and adding a small 12V heating mat on a thermostat — sorted it completely.

Also worth saying — the BMS situation with Leaf modules specifically can be a bit of a dark art. What are you using to monitor cell-level voltages? I'd not trust a basic BMS on second-life cells personally.

Interesting timing on this thread — I've been eyeing up Leaf modules for my static caravan setup where space isn't the constraint, but weight and second-life cost savings absolutely are.

One thing worth flagging: cell balancing history on these pulled packs can be a real unknown. If the previous owner ran the pack hard or had a duff BMS, you might have cells that look fine on surface voltage but diverge badly under load. Happened to a narrowboat mate of mine running salvaged Zoe cells.

@KevLee what BMS are you running with it? I've seen people pair Leaf modules with a Daly or even a Victron-compatible unit, but getting the cell count right for LFP-tuned inverters can get fiddly when you're working with NMC chemistry.

Also — anyone had grief with UK insurance declaring a build a write-off over non-OEM battery chemistry? Seems like a grey area that's only going to get messier.

Really glad this thread popped up — I've been running three Leaf gen 1 modules (the older 24kWh pack) for about 14 months now in my Transit and honestly the hardest part wasn't the electrical side, it was getting the BMS talking nicely to my Victron kit. Ended up using a Batrium unit which sorted it out a treat.

@HeatherSoul for a static setup you'll have a much easier time — thermal management is less of a headache when you're not bouncing down country lanes. Worth checking the capacity retention on whatever pack you source though, some of the older Leafs have had a rough life and the cells aren't always as advertised.

@KevLee what are you using for balancing across your four modules? That's where I see people run into trouble further down the line.

@HeatherSoul same boat here — got a static and a shepherd's hut I'm trying to sort power for. The static I'm less worried about space but the hut is tight.

Been looking at Leaf modules myself but honestly the BMS side puts me off a bit. You need something that actually understands the cell chemistry properly or you're flying blind. Seen a few people pair them with a Victron Lynx Smart BMS workaround but it's not exactly plug and play.

What's your solar situation? That changes the equation quite a bit for a static — if you're pulling decent charge current you really want the BMS dialled in properly before committing to second-hand cells you can't fully verify.