[CanadaLT28]

I'll post this somewhere else If I must. I can't remember if I asked this question before but, as I am having a hard time getting a Leaf battery pack, I am looking at getting 2+ Volt packs and using them but the issue is, how does the leaf BMS recognize a bespoke battery pack? What do I need to do to get it to communicate?

 

[Kevin Sharpe]

how does the leaf BMS recognize a bespoke battery pack?

By default the Leaf BMS will only work with Leaf modules. If you change the chemistry (i.e. use a Volt pack) it's very unlikely the BMS will work.

Obviously you could reprogram the Leaf BMS firmware (as Wolf has done) but I think that is beyond most peoples knowledge and budget. Possibly an alternative path would be to commission Wolf to provide a CAN emulator that makes the Volt Battery 'look like' a Leaf Battery. I think the Volt BMS must have been hacked by now.

What do I need to do to get it to communicate?

Reverse Enginnering the Nissan Leaf BMS Serial Protocol...

 

[CanadaLT28]

If I remember correctly, Wolf said he wasn't ready with his system yet so who knows how well it works.



Volt packs are generally around $1200-1500 and leaf packs are more than double.


I would expect that both packs have been hacked by now. Enough people have eluded to it over the last few years but I just can't keep track of all the goings on.

 

[CanadaLT28]

WooHoo, I can see my thread again.

 

[CanadaLT28]

OK folks. I now have both a leaf pack and one volt pack. I would like opinions on whether to leave the leaf pack in its case and put the volt pack in custom battery boxes that fit the truck better OR take them all apart and attempt to merge them in such a way as to have cells work in parallel. I will get another volt pack if needed to make it work.

I will also see what Wolf has up his sleeve. Damian appears to have also done some magic with the volt BMS, or so I am told.

I'm hoping toget this right the first time, lol (fat chance, but I can hope)

 

[brian_]

I now have both a leaf pack and one volt pack. I would like opinions on whether to leave the leaf pack in its case and put the volt pack in custom battery boxes that fit the truck better OR take them all apart and attempt to merge them in such a way as to have cells work in parallel.

I'm not sure that I understand both alternatives.

Is the first option to parallel the entire Leaf pack (96S2P of 33 Ah cells) with the entire Volt pack? They have about the same nominal voltage, but different capacities and seem unlikely to load-share ideally. Or is the first option to use one at a time, switching between them?

Is the second option to reconfigure the Leaf pack to place modules in parallel and then series them into a 48S set, and reconfigure the Volt pack to put modules or more cells in parallel and then series them into another 48S set, then put all of that in series? With the different capacities this seems like a problematic configuration. Or, is the second option to parallel two Leaf cells with a set (3 if the earlier Volt pack, 2 if the later Volt pack) of Volt cells, then put those mixed-source groups in series?

Modules are easy to connect in parallel with other modules, but the Volt modules are big (lots of cells) so it doesn't get even close to cell level parallel connections. Reconfiguring Volt modules at the cell level requires cutting of welds and making some sort of clamped connections. The Leaf modules are only 2S, and because they have a "middle" terminal for the BMS they can be paralleled at the cell level with only bolted connections. But I'm guessing that you already know that...

 

[CanadaLT28]

I'm not sure that I understand both alternatives.

Is the first option to parallel the entire Leaf pack (96S2P of 33 Ah cells) with the entire Volt pack? They have about the same nominal voltage, but different capacities and seem unlikely to load-share ideally. Or is the first option to use one at a time, switching between them?

Is the second option to reconfigure the Leaf pack to place modules in parallel and then series them into a 48S set, and reconfigure the Volt pack to put modules or more cells in parallel and then series them into another 48S set, then put all of that in series? With the different capacities this seems like a problematic configuration. Or, is the second option to parallel two Leaf cells with a set (3 if the earlier Volt pack, 2 if the later Volt pack) of Volt cells, then put those mixed-source groups in series?

Modules are easy to connect in parallel with other modules, but the Volt modules are big (lots of cells) so it doesn't get even close to cell level parallel connections. Reconfiguring Volt modules at the cell level requires cutting of welds and making some sort of clamped connections. The Leaf modules are only 2S, and because they have a "middle" terminal for the BMS they can be paralleled at the cell level with only bolted connections. But I'm guessing that you already know that...

I should not be speaking in terms of cell level. My mistake.


I do know that there is a "middle terminal" for the BMS on Leaf modules and the first thought I had (and I don't know how realistic this is) would be to take X number of leaf modules and combine them with X number of Volt modules to make one larger grouping which could allow me to use only the Leaf BMS, and then S and P the groups to get the proper output voltage.


The Leaf is a 2014 pack as is the current Volt pack. The second option would be to get another Volt pack and try to make 1 pack of equal capacity to the Leaf pack and put it parallel with the leaf pack. The ultimate goal is to be able to use just one charger.


If there is a 3rd option I am all ears.

 

[brian_]

I should not be speaking in terms of cell level...

I do know that there is a "middle terminal" for the BMS on Leaf modules and the first thought I had (and I don't know how realistic this is) would be to take X number of leaf modules and combine them with X number of Volt modules to make one larger grouping which could allow me to use only the Leaf BMS, and then S and P the groups to get the proper output voltage.

Thanks, that's more clear - it's essentially the mixed-source groups that I listed last, but connected only at the module level.

All Leaf modules are 2S. There are glued-together module pairs to the later packs, but you can still make the electrical connection at the single module level. Gen 1 Volt modules are 6S and (mostly) 12S; Gen 2 Volt modules are 12S and 16S... so each Volt module could be paralleled with a suitable number of Leaf modules.

My concern with this would be that with no connection between the cell-level connections of the Leaf BMS and the corresponding points in Volt pack, there would be no monitoring of any imbalance in the Volt pack; one cell group in the Volt pack could be charged too high or discharged too low and the Leaf BMS would not be able to warn about it. Of course there would also be no balancing of the Volt pack (maybe okay - that's a whole argument of it's own), and if the Leaf BMS balances the Leaf modules then those Leaf modules would be discharged a bit below the Volt module in parallel with them.

 

[CanadaLT28]

Lots of thought on this. If using Volt packs, I can get 3 of them in 3 rows under the truck easily and they are a LOT easier to come by than the Leaf packs. All that is needed is some way to communicate with Leaf brain. Using the Volt pack also gives me more confidence in the SOH of the batteries as they have not generally been abused.



The leaf can become powerwall.

 

[Duncan]

Do the Leaf and the Volt use the same chemistry?

I would be surprised if it was exactly the same - so they will have different charge/voltage curves

Connecting them at cell level would be a disaster

 

[brian_]

Do the Leaf and the Volt use the same chemistry?

The Volt (both generations) use "NMC-LMO Pouch" cells (by LG)
The Leaf was (at least originally) LiMn2O4 (LMO) with LiNiO2... no NMC.

No, the two are not matched. They are different chemistry choices to suit different performance requirements and different cooling systems.

I agree that this is another reason not to mix cells from both sources in parallel.

 

[CanadaLT28]

Sorry if I misspoke, I will not be using the Leaf batteries in truck at all, just the volt packs (3 if I can get them). I will use the Volt charger and BMS so that will be somewhat stand.
Obviously the Leaf control is fine for the motor and inputs but it will probably get confused with the batteries so what can I do there? I know people have done this before but I haven't found a "part that I can buy" to mesh the Leaf controller and Volt batteries/BMS

 

[CanadaLT28]

A few updates. I have sourced the complete front end for a T4 (Eurovan) and will be using it to put a second leaf motor (motor/inverter/charger/dc-dc etc) in the front as a front drive truck. I will still use the current motor and inverter on the back as is but only the motor and inverter.

This will give me a 4x4 capability. Oddly, the T4 suspension is rated as high as my LT suspension and with shock/bags, I can get a better capacity.

I have just bought Pauls board that allows me to configure the Leaf to be controlled as I wish. There is a lot about it that I don't know such as how I will interface with the Volt pack(s). There is currently no DC fast charge on this leaf and I want to put one on if possible.

Paul believes that I can just split the throttle signal between the two inverters as they are torque controlled motors. It remains to be seen if I can run the two inverters with one controller.



Any thoughts will be appreciated, of course.

 

[Tony Bogs]

Thanks for the pictures of the modified drive shafts.

 

[mainfuse]

Hi , new to this thread, we have put together a geo metro with a 2013 leaf drive train, using our vcu to control the CAN messages that run the inverter. I would like to get photos of builds that others are doing with these cheap leaf drives. we have plans to put one in a ski boat ,and a two motor 4wheel drive vehicle. up next will be my MAzda Miata. I am working on mating the motor to the transmission now. Clutch or no clutch is my question .thunderstruck motors
thanks Brian

 

[CanadaLT28]

Hi , new to this thread, we have put together a geo metro with a 2013 leaf drive train, using our vcu to control the CAN messages that run the inverter. I would like to get photos of builds that others are doing with these cheap leaf drives. we have plans to put one in a ski boat ,and a two motor 4wheel drive vehicle. up next will be my MAzda Miata. I am working on mating the motor to the transmission now. Clutch or no clutch is my question .thunderstruck motors
thanks Brian

Where are you Brian?

 

[mainfuse]

Santa Rosa, CAlif.
thunderstruck-ev.com

 

[CanadaLT28]

Ahh, I didn't see that link. In my case I am doing 4WD by using two complete Leaf drivetrains so I have no need for the clutch. Can't help you there.

 

[dbargaehr]

Ahh, I didn't see that link. In my case I am doing 4WD by using two complete Leaf drivetrains so I have no need for the clutch. Can't help you there.

Hi,

looking at using a leaf drive in my conversion. Any chance you can provide the dimensions on the motor case length? (and ideally the motor case diameter too)?

Also curious if you're integrating the Leaf's liquid cooling with the existing radiator, or doing something else entirely. I've subscribed to this thread, really excited to see how it turns out.

 

[CanadaLT28]

Hi,

looking at using a leaf drive in my conversion. Any chance you can provide the dimensions on the motor case length? (and ideally the motor case diameter too)?

Also curious if you're integrating the Leaf's liquid cooling with the existing radiator, or doing something else entirely. I've subscribed to this thread, really excited to see how it turns out.

I don't have the dimensions off hand but they are available somewhere on the tinterweb. I wil be using a VW passat rad (because I already have it) to cool the motors/inverters and to provide cooling to the Volt batteries. I have a separate heater to heat the batteries if needed.