Issues after 40kWh cell swap and can-bridge install on 2016 Nissan Leaf (AZE0)

[TwisterKalo]

I have a 2016 Nissan Leaf (AZE0) that recently had a cell swap to a 40kWh battery. The BMS is still the original Nissan one. After installing the can-bridge and battery, and clearing the issues with Leaf Spy Pro, we were able to drive the car.

The problem is that, with the can-bridge (this one: Can-Bridge on Aliexpress), the mileage doesn’t adjust correctly, and the battery life bars remain the same as before (they haven’t updated), although Leaf Spy Pro shows a SOH of 96%.

Another issue I’m having is that, when I accelerate to full throttle, the car shuts down and throws an error that I have to clear using Leaf Spy Pro (otherwise, I can’t turn the car back on). The same thing happens if I brake hard. I suspect it might be related to the regeneration system, since if I put the car in Neutral and brake hard, it doesn’t shut down.

Has anyone experienced something similar or have any idea what might be going on? Could it be that the program we uploaded to the can-bridge wasn’t the correct one, or is there another step we’re missing?

Any help or advice would be greatly appreciated. Thanks!

 

[MikeinPA]

Interesting. You say there are now 40 kWh modules from the 40 kWh Leaf that have been loaded into a 24 kWh Leaf battery shell, but retaining the 24 kWh BMS? And installed back into a 24 kWh Leaf ? No CAN bridge is needed if the BMS is the original BMS!

1. The BMS may need some time to update capacity--although it may not be able to cope with more than about 28 kWh. This is what others who know a lot more have reported.
2. If your clearing codes, what are they? The codes are very likely related to the shutdowns. So look the codes up or report them here.
3. But back to the top comment--if there is a 24 kWh BMS in a 24 kWh Leaf--no CAN bridge needed!

Does it work without the CAN bridge?

Also, please do let us know what happens. One really simple pathway to refurbishing a 24 kWh leaf would be to put some aging 40 kWh modules that are at 70% capacity or less into the 24 kWh shell. The BMS should be able to handle this, and it's basically making an old dying 24 kWh Leaf into a new 30 kWh Leaf.

 

[TwisterKalo]

Interesting. You say there are now 40 kWh modules from the 40 kWh Leaf that have been loaded into a 24 kWh Leaf battery shell, but retaining the 24 kWh BMS? And installed back into a 24 kWh Leaf ? No CAN bridge is needed if the BMS is the original BMS!

1. The BMS may need some time to update capacity--although it may not be able to cope with more than about 28 kWh. This is what others who know a lot more have reported.
2. If your clearing codes, what are they? The codes are very likely related to the shutdowns. So look the codes up or report them here.
3. But back to the top comment--if there is a 24 kWh BMS in a 24 kWh Leaf--no CAN bridge needed!

Does it work without the CAN bridge?

Also, please do let us know what happens. One really simple pathway to refurbishing a 24 kWh leaf would be to put some aging 40 kWh modules that are at 70% capacity or less into the 24 kWh shell. The BMS should be able to handle this, and it's basically making an old dying 24 kWh Leaf into a new 30 kWh Leaf.

It is not cells from a Nissan Leaf, I order them from a battery supplier. And my Leaf was 30kWh, and yes, it is the same BMS. Anyways, when do I need a CAN bridge? Only when the BMS is different?
1. I'll give time to the CAN bridge to see if it gets better.
2. Image (I have been doing some research and believe that the car goes into neutral when accelerating or braking hard because the battery has a lower discharge and delivery capacity than the original battery. So if I accelerate to the maximum the engine asks for 100kwh but we can only deliver about 40kwh and the car understands that it is not well and for safety, it puts it in neutral. The only thing I have to do is enter the Leaf Spy Pro and delete the EV/HEV alarm, turn it off and on again)
3. But the new cells are 40kWh, or it doesn't matter?

Yes, it works without the CAN bridge.

So, what I have done is just not good, and maybe a bottle neck?

 

[MikeinPA]

First, if the BMS is still the original BMS--you do not need a CAN bridge.

The P317D is, as you suggested, related to motor power. From the repair manual: "The estimated torque value from the traction motor inverter to VCM remains greater/smaller than the torque command value from VCM to the traction motor inverter for the specified time." OR "The difference between the estimated power consumption calculated based on a torque value from VCM to the traction motor inverter and the actual power consumption calculated based on a high voltage battery voltage and current is 54 kW or more."

A guess on my part is the new cells or wiring are not capable of supplying enough current. In this case, you would either see severe voltage sag on the cells, or voltage sag related to current losses in the wiring. Either case should scare you silly. The Leaf draws up to 400 amps (Plus models even more). If the cells/modules and wiring are not engineered for this--you will be overheating one or both of these components and risk fire.

But back to the CAN bridge--does the fault occur if the CAN bridge is absent?

 

[cornbinder89]

kwh rating is the amount of power a battery can deliver over time, kw is the instantaneous power.
SO a 24kwh Leaf pack can deliver 80 kw for a short burst, but that reduces how long the power will last.

It would seam that your 40kwh cell pack can not provide enough instantaneous power when the vehicle is under heavy load.
Most likely your new cells were designed for solar power storage not vehicle use. In power storage the loads tend to be light but long, rather than vehicle loads which can peak quite high, but for less time.
I agree with MikeinPA, you are trying to draw more current than the battery or wiring can handle and the voltage dips and the controls sense a problem.
It is also likely the cause of your display not "updating" it is "seeing" the voltage drop off under load and cuts the est miles as it is seeing an inability to supply the current requested.

 

[TwisterKalo]

First, if the BMS is still the original BMS--you do not need a CAN bridge.

The P317D is, as you suggested, related to motor power. From the repair manual: "The estimated torque value from the traction motor inverter to VCM remains greater/smaller than the torque command value from VCM to the traction motor inverter for the specified time." OR "The difference between the estimated power consumption calculated based on a torque value from VCM to the traction motor inverter and the actual power consumption calculated based on a high voltage battery voltage and current is 54 kW or more."

A guess on my part is the new cells or wiring are not capable of supplying enough current. In this case, you would either see severe voltage sag on the cells, or voltage sag related to current losses in the wiring. Either case should scare you silly. The Leaf draws up to 400 amps (Plus models even more). If the cells/modules and wiring are not engineered for this--you will be overheating one or both of these components and risk fire.

But back to the CAN bridge--does the fault occur if the CAN bridge is absent?

A friend came to the same conclusion that the cells aren't capable of supplying enough current. We don't believe it is the cables because we used the original ones. We need to order new cells with better capacity for charge and discharge. And yes, the fault occurs with or without CAN bridge.

 

[TwisterKalo]

kwh rating is the amount of power a battery can deliver over time, kw is the instantaneous power.
SO a 24kwh Leaf pack can deliver 80 kw for a short burst, but that reduces how long the power will last.

It would seam that your 40kwh cell pack can not provide enough instantaneous power when the vehicle is under heavy load.
Most likely your new cells were designed for solar power storage not vehicle use. In power storage the loads tend to be light but long, rather than vehicle loads which can peak quite high, but for less time.
I agree with MikeinPA, you are trying to draw more current than the battery or wiring can handle and the voltage dips and the controls sense a problem.
It is also likely the cause of your display not "updating" it is "seeing" the voltage drop off under load and cuts the est miles as it is seeing an inability to supply the current requested.

Yes, we believe this is our problem. I have been driving the car for a few days now and haven't turned it off while driving (because I accelerate very slowly). I believe when I charge it from a low % to max, I'll get some update, or I hope so.

 

[cornbinder89]

Before you buy new cells, look at the their charge/discharge graph. Make sure they can be discharged at the rate the cars inverter can draw.

 

[nlspace]

Disconnect the PTC Heater. If it has a defect then it may be pulling down the voltage from the HV traction battery.

The VCM thinks that your traction battery has degraded capacity to 5 capacity bars (2 red bars plus 3 white bars), so call it 12 to 15 kWh available.

But VCM is sending confusing information to the dash in thinking you can get 90 miles of driving range. That's not gonna happen on a 5-bar laef.

Monitor traction pack battery voltage graph and current on LaefSpy while driving to see voltage sag when doing WOT acceleration. If it drops below the Low Voltage limit, then it will set the turtle mode, or fall back to a fail-safe mode.

 

[TwisterKalo]

Before you buy new cells, look at the their charge/discharge graph. Make sure they can be discharged at the rate the cars inverter can draw.

Yes, I'll buy 60kWh with those specs. thanks

 

[cornbinder89]

You are looking at the spec's that show how much they can store, and not how fast they can deliver. If you only look at kwh specs, you'll be right back where you are now.
You need to look at max discharge/ recharge rates, something that is hard to find.

 

[TwisterKalo]

You are looking at the spec's that show how much they can store, and not how fast they can deliver. If you only look at kwh specs, you'll be right back where you are now.
You need to look at max discharge/ recharge rates, something that is hard to find.

Yes, I know. These 40kWh cells were a test because I had them with me for another project. Now that I have tested them I'm 100% sure the C is the problem. The new 60kWh will be fine. Thanks.

 

[MikeinPA]

Yes, we believe this is our problem. I have been driving the car for a few days now and haven't turned it off while driving (because I accelerate very slowly). I believe when I charge it from a low % to max, I'll get some update, or I hope so.

Thank you for reporting back! Amazingly, about 90% of people posing questions here never follow up. Leaves us all wondering.

 

[MikeinPA]

Yes, I know. These 40kWh cells were a test because I had them with me for another project. Now that I have tested them I'm 100% sure the C is the problem. The new 60kWh will be fine. Thanks.

Here is one issue. The Nissan Leaf BMS (properly called the Lithium battery Controller (LBC)) is more complex than a simple BMS that monitored cell voltages and does balancing. I believe it contains a battery model that is closely matched to the actual cells. The reason for this is the cells are going to vary a lot from charge to charge due to temperature, aging, charge rate and other variables (lithium Ion cells are complex in terms of chemistry), so the Nissan EEs made the BMS smart enough to estimate SOC (and other things) from the model. Unfortunately, if you put 60 kWh of cells with a 30 kWh BMS, the BMS will be confused and start throwing faults. An EE on this forum called it "wraparound" which to me sounds like some cumulative amps value in the BMS exceeds what the BMS believes is possible and just say to heck with it and goes back to zero. Any way, the 30 kWh BMS should be able to handle about 115% of 30 kWh or so, based on what I have seen on other forums.

There are some mythical "reprogramming the BMS" fixes for this--but I don't believe in them, and if I did, I would be horrified at someone mucking about in the BMS firmware. There are also some CAN bus fixes that are supposedly able to adapt a 30 kWh BMS to much high amounts of kWh--I do not know enough about whether this would be possible, but would certainly involve some very fast footwork in the CAN bridge (lookup tables going both ways), as well as some strange artifacts on the dashboard.

What cells have you adapted? if your were able to reuse the harness, I am wondering if you are making modules from scratch that fit the Leaf format?

 

[jorno23]

Do you use CAN bridge software from Dala, or does the software you use come from the seller of your new cells? The pictures you provided show the same hardware Dala uses for upgrades with original Nissan batteries. I'm using such a CAN bridge, too, in an AZE0 upgraded to 40kWh with a battery from a ZE1. Works perfectly.
But as Dala wrote sept 8th on his closed Discord forum: "This software CANNOT be used for chinese cell upgrades. I tell people this every week."
So this might be the reason for your problems.
Dala's information on Leaf upgrades and flashing CAN bridges with his open source software is found here:
https://github.com/dalathegreat/Nissan-LEAF-Battery-Upgrade

 

[TwisterKalo]

Aquí hay un problema. El BMS del Nissan Leaf (denominado correctamente Controlador de batería de litio (LBC)) es más complejo que un BMS simple que monitorea los voltajes de las celdas y realiza el balanceo. Creo que contiene un modelo de batería que coincide estrechamente con las celdas reales. La razón de esto es que las celdas van a variar mucho de una carga a otra debido a la temperatura, el envejecimiento, la velocidad de carga y otras variables (las celdas de iones de litio son complejas en términos de química), por lo que los EE de Nissan hicieron que el BMS fuera lo suficientemente inteligente como para estimar el estado de carga (y otras cosas) a partir del modelo. Desafortunadamente, si coloca 60 kWh de celdas con un BMS de 30 kWh, el BMS se confundirá y comenzará a arrojar fallas. Un EE en este foro lo llamó "wraparound", lo que para mí suena como si algún valor de amperios acumulados en el BMS excediera lo que el BMS cree que es posible y simplemente diga al diablo con eso y vuelva a cero. De todos modos, el BMS de 30 kWh debería poder manejar aproximadamente el 115 % de 30 kWh aproximadamente, según lo que he visto en otros foros.

Existen algunas soluciones míticas para este problema, como la "reprogramación del BMS", pero no creo en ellas y, si lo hiciera, me horrorizaría que alguien estuviera hurgando en el firmware del BMS. También existen algunas soluciones para el bus CAN que supuestamente pueden adaptar un BMS de 30 kWh a cantidades mucho más altas de kWh. No sé lo suficiente sobre si esto sería posible, pero sin duda implicaría un trabajo muy rápido en el puente CAN (tablas de búsqueda en ambos sentidos), así como algunos artefactos extraños en el tablero.

¿Qué celdas has adaptado? Si pudiste reutilizar el arnés, me pregunto si estás haciendo módulos desde cero que se ajusten al formato Leaf.

Do you use CAN bridge software from Dala, or does the software you use come from the seller of your new cells? The pictures you provided show the same hardware Dala uses for upgrades with original Nissan batteries. I'm using such a CAN bridge, too, in an AZE0 upgraded to 40kWh with a battery from a ZE1. Works perfectly.
But as Dala wrote sept 8th on his closed Discord forum: "This software CANNOT be used for chinese cell upgrades. I tell people this every week."
So this might be the reason for your problems.
Dala's information on Leaf upgrades and flashing CAN bridges with his open source software is found here:
https://github.com/dalathegreat/Nissan-LEAF-Battery-Upgrade

Yes, I use Dala's software with chinese cells. But How do the car knows which cells are nissan or china?? Don't understand that part. They sent the same info to the car (voltage).

 

[Stanton]

Yes, I use Dala's software with chinese cells. But How do the car knows which cells are nissan or china?? Don't understand that part. They sent the same info to the car (voltage).

I don't think the car "knows" where the cells are made...but I'm sure Dala has analyzed/tested (some type of) Chinese product and knows they don't have the necessary specs/performance to do the job. One of those "you get what you pay for" kind of things.

 

[TwisterKalo]

I don't think the car "knows" where the cells are made...but I'm sure Dala has analyzed/tested (some type of) Chinese product and knows they don't have the necessary specs/performance to do the job. One of those "you get what you pay for" kind of things.

Ok, now I am on the same page.

 

[MikeinPA]

Yes, I use Dala's software with chinese cells. But How do the car knows which cells are nissan or china?? Don't understand that part. They sent the same info to the car (voltage).

It doesn't. Did anyone say that? But it can know when there is too much voltage sag in the pack, and I think this is what this item from the manual refers to: "The difference between the estimated power consumption calculated based on a torque value from VCM to the traction motor inverter and the actual power consumption calculated based on a high voltage battery voltage and current is 54 kW or more."

What cells have you placed in there?

 

[Evoto]

I have a 2016 Nissan Leaf (AZE0) that recently had a cell swap to a 40kWh battery. The BMS is still the original Nissan one. After installing the can-bridge and battery, and clearing the issues with Leaf Spy Pro, we were able to drive the car.

The problem is that, with the can-bridge (this one: Can-Bridge on Aliexpress), the mileage doesn’t adjust correctly, and the battery life bars remain the same as before (they haven’t updated), although Leaf Spy Pro shows a SOH of 96%.

Another issue I’m having is that, when I accelerate to full throttle, the car shuts down and throws an error that I have to clear using Leaf Spy Pro (otherwise, I can’t turn the car back on). The same thing happens if I brake hard. I suspect it might be related to the regeneration system, since if I put the car in Neutral and brake hard, it doesn’t shut down.

Has anyone experienced something similar or have any idea what might be going on? Could it be that the program we uploaded to the can-bridge wasn’t the correct one, or is there another step we’re missing?

Any help or advice would be greatly appreciated. Thanks!

HI ALL I'M WE ARE DOING BATTERY UPGRADING FOR NISSAN LEAF AND BMW I3 WE DON'T HAVE ISSUES OUR CARS RUNNING SMOOTHLY IF YOU NEED ANY ADVICE TELL ME I'LL THERE TO HELP YOU