Leaf hardware with batteries from another car?

[Alibro]

Hi guys
Last year I bought a Gen1 Leaf with the HV battery removed and stripped the Leaf of all hardware before scrapping the shell.
Project thread is here. viewtopic.php?f=11&t=971
Since then I acquired a Leaf BMS and more recently an e-Golf battery pack.

My question is will a Leaf BMS work with the batteries out of an e-Golf?

I know the cell count is wrong but I could add two 4S modules to bring the cell count up to 96.
This would give the added benefit of more range, more power, more speed and if the Leaf hardware likes the Golf cells then Charging, BMS, and DC-DC would be sorted.
Or would it?

Any thoughts guys?

The reason I'm asking now is I have the option of purchasing another e-Golf pack, the same age and similar mileage to my current one, so I could take the bits I need and sell the rest, so the extra battery modules would cost a lot less than buying them individually. Having half stripped the pack I have I now know why the sellers charge so much for the modules compared to the full packs. It's a lot of work.

Thanks in advance.

[Extremetaz]

At a hardware level, I can't think of any reason why the Leaf BMS wouldn't play nice with the Golf modules (or anything else assuming the NCM voltage range). In terms of software though there will be a lot of nuance, particularly if you're expecting to use that BMS directly with the rest of the leaf system you have.

At the very minimum you'll have to pair the new LBC to the existing VCM in order to get the drivetrain to 'accept' the battery pack. You can have a friendly garage do that or you can get the EVs Enchanced OBD tool for the job.

You have an early Gen leaf which means that only the 24 and 30kWh LBC will work in this fashion however and of those LBC's then, if you're using a 24kWh variant you'll be limited to about 85Ah in the pack (IIRC) as those LBC's loose their mind if they see any more than that AFAIK.

Assuming that's all acceptable, then the next issue you have is that battery management (Charge, Discharge, SoH calcs) in the Nissan LBC will all be based on their original packs. This isn't to suggest that they'll necessarily do any damage to the golf modules, but it's not out of the questions and at the very least they're unlikely to be optimal - that being said, it will certainly work for a while at least.

On the other hand, if you're using a later series LBC which is happy with high capacity packs, then it's not going to talk to your early series VCM - at all.

So bottom line, you're likely going to require a MITM between the LBC and the VCM no matter what you do.
This will give you full control over how the VCM and charger interpret any messages coming from the LBC, which means you can tailor charge and discharge profiles, and revise SoH and any other metrics as you see fit.

As for the terminal voltage of the stack, it's likely that you can terminate even with the short stack by simply tying any remaining terminals together so that they all see the same voltage. Again, this may lead to some funky error messages from the LBC but at a hardware level I'd expect it to be just fine.

[Alibro]

Thanks for the reply, I think you just confirmed what I already suspected.
Since asking the question I've learned that upgrading a Leaf from 24kWh to 30kWh is a lot more complicated than just replacing the pack so it's no surprise that using a Golf pack would require more than just plugging it together. I guess I was hoping for an easy way to get charging, DC-DC and BMS working and it won't be as simple as that.
I have already decided that a BMS is not essential short term as the pack is perfectly balanced now so should be OK for a while.
This means I can continue the build but will probably take BMS wires out of every cell so that if I need to I can rig up an aftermarket BMS in the future. In the meantime I'll keep the Golf BMS (integrated into the battery modules) connected as SimpBMS may at some stage be upgraded to enable balancing.

Thanks again for the answer and hope the stuff you got off me is all still good.

[Extremetaz]

I have already decided that a BMS is not essential short term as the pack is perfectly balanced now so should be OK for a while.

It is if you intend to use the stock VCM - it won't engage the Battery contactor block without say-so from the LBC.
That means no go, and no charging.

[Alibro]

Yeah I had already figured the bms would be essential to charging. As for 'going' I hadn't been planning to use the Leaf electronics in stock form. I was intending to go DIY for that but have to admit I still have to figure that out.