Nissan Leaf BMS

[janosch]

I changed only batteries, not BMS or other parts in battery box.

It sounds like you did a 40kWh upgrade? Surprised the 40kWh cells fit into the 24kWh box without changes.

Best forum member to talk to is dala https://dalasevrepair.fi/

I think you will need:

• 40kWh BMS
• dalas 40 -> 24 CAN bridge

and with that fitted the Leaf should understand the bigger battery.

[Jacobsmess]

Ok, so anyone got a TLDR; for how to use the leaf BMS from a 40kWh pack? One arrived today, I suspect I'm going to have to do some digging. I've read a lot so far but nothing super conclusive for my tired brain.

Can I just hook up 12V, Gnd, CanH and CanL and get data via a Bluetooth dongle and leafspy lite? Is there some documentation on which cells connect where on the BMS cabling?

Thanks

[Jacobsmess]

I 've attached the wiring diagram from the 2013 BMS that I used in my car.

Ok so this is a great start for wiring things up, although interestingly my LS11 connector has an extra wire that's not shown on this diagram on pin 11.

[Jacobsmess]

The BMS cannot limit anything, it only measures voltage and current and it will balance the cells 24/7 as long as it receives +12V on pin 5 (BAT) of the round connector, which is wired to pin 12 of the LB11 connector.
Also, all 96 pairs of cells need to be plugged in obviously.
The BMS will only communicate when there is 12V on either IGN (pin 4 round connector, pin 6 or 7 of LB11, for old/new BMS) or CHG IGN (Charging) which is located on pin 21 or 31 (old/new battery type), pin 5 of LB11.

Source: https://www.diyelectriccar.com/threads/ ... ost-871641

[Jacobsmess]

A question, will the BMS report voltage for just 1 cell for testing purposes? It would be nice to have it setup spitting out CAN and then connect cells one by one and see the voltages show up on leaf spy.

[johu]

No, all cells must be connected

[ianlighting]

I am considering getting new CATL modules for a project that is based on Nissan Leaf and Resolve EV. These would be 4s1p x24 modules and total 63kWh.

Are there any options for getting hold of a Leaf 62kWh BMS? I don’t want to buy an entire second hand battery pack.

[Jacobsmess]

I am considering getting new CATL modules for a project that is based on Nissan Leaf and Resolve EV. These would be 4s1p x24 modules and total 63kWh.

Are there any options for getting hold of a Leaf 62kWh BMS? I don’t want to buy an entire second hand battery pack.

They come up on eBay from time to time. I'm not sure the 62kwh pack has been reversed engineered but I think a 24kwh or 36kwh BMS should work fine. The 42kwh is a little more tricky apparently

[ianlighting]

They come up on eBay from time to time. I'm not sure the 62kwh pack has been reversed engineered but I think a 24kwh or 36kwh BMS should work fine. The 42kwh is a little more tricky apparently

I have 24kWh BMS. So to be clear, it should work ok with the larger capacity if wired correctly? That’s good info, thanks. If it’s at least worth a go I will get into it in due course.

I did look on eBay. I have seen 1x 62kWh complete battery pack for £8800! No thanks but no separate BMS. So reusing my spare 24KWh would be a good option. I had assumed they were matched to the factory shipped model / capacity.

[Jacobsmess]

I have 24kWh BMS. So to be clear, it should work ok with the larger capacity if wired correctly?

I believe so. Alibro here has used the 24kWk leaf BMS with VW modules. You may need to reinterpret the messages with an Arduino or something similar but I'm a bit out of my depth from here on.

[ianlighting]

I believe so. Alibro here has used the 24kWk leaf BMS with VW modules. You may need to reinterpret the messages with an Arduino or something similar but I'm a bit out of my depth from here on.

Well I’ll report back if I’m successful. Or not….!

[Marat]

Reprogramming the unit is necessary, otherwise the factory firmware will only process 22KWh, and this is in the case of a wear data reset.
BMS 40KW sees a maximum of 115Ah, and requires a different current sensor.

[ianlighting]

Reprogramming the unit is necessary, otherwise the factory firmware will only process 22KWh, and this is in the case of a wear data reset.
BMS 40KW sees a maximum of 115Ah, and requires a different current sensor.

Ah, ok. That’s sounds more like what I expected, even though I am coming from a pretty low-knowledge starting point, so I am deferring to those with more experience at this stage.

I doubt I am able to reprogram the Leaf BMS. Unless there are methods that others have used previously that can be easily followed?

If not, that takes me back to the starting point of needing a factory built 62kWh BMS, which I expect will be hard to find.

I’ll keep poking about to see what options exist for my project. I’ll dig into what was referred to with @alibro”s project to see if that’s an option.

More inputs welcome