The 40KWH Battery Topic

[LeftieBiker]

The histogram visually represents both the voltages of each module, and the differences between them. That "25mv" means that your cells, even though they look awful in the histogram, are pretty close together in voltage and capacity. The red just means that they were receiving charge at the moment the reading was taken. Don't worry about them unless you get odd symptoms at low states of charge. If so, take another reading at 10-20% charge

 

[cwerdna]

Not sure if anyone posted this already but https://medium.com/@eTaxidriver/aná...l-nissan-leaf-40-kwh-tras-5-años-d2080401ce1e is from Sept 26, 2023 of 40 kWh Leaf taxis in Spain. Unfortunately, it's in Spanish but you can have your browser or Google Translate translate for you.

There is a mention of this (translated):
"The only car in the study that had already lost two bars. Outside of the study we have 3 colleagues who have lost 2 bars, most around 180,000km."

 

[Bombastinator2]

Not sure if anyone posted this already but https://medium.com/@eTaxidriver/análisis-de-las-baterías-del-nissan-leaf-40-kwh-tras-5-años-d2080401ce1e is from Sept 26, 2023 of 40 kWh Leaf taxis in Spain. Unfortunately, it's in Spanish but you can have your browser or Google Translate translate for you.

There is a mention of this (translated):
"The only car in the study that had already lost two bars. Outside of the study we have 3 colleagues who have lost 2 bars, most around 180,000km."

So Spanish Spanish rather than Mexican spains? Iirc they read the same, though Spaniards sound like they’re lisping

 

[leafthesis]

Long shot, does anyone know what the name of the connector connecting the battery and the inverter? The complete harness has item number 297A6-5SA1A, but I'm looking for the name of only the connector connecting to the battery.

For example, the connectors and harness is seen here: https://www.ebay.com/itm/195804984466

 

[Bombastinator2]

Long shot, does anyone know what the name of the connector connecting the battery and the inverter? The complete harness has item number 297A6-5SA1A, but I'm looking for the name of only the connector connecting to the battery.

For example, the connectors and harness is seen here: https://www.ebay.com/itm/195804984466

“Battery cable”? More than 1 part, generally.

 

[leafthesis]

“Battery cable”? More than 1 part, generally.

Yeah, I found only the harness so far. I guess you're right, they only sell them in a package.

Another question if someone's into standalone use of the 40 kWh battery. I have only the battery (not the full car, so no VCM etc.) and I'm trying to get the BMS to balance the cells, but it won't do it. I read on many forums that the "Nissan Leaf 40kWh BMS is actively balancing the cells all the time, even during charging", however this doesn't seem to be the case for me. I'm reading the values off the CAN-bus on 0x7BB, which allegedely reports the status of the balancing resistors, but all the bits are 0s, confirming my suspicion that the BMS is not doing any balancing.

I'm wondering if somehow it refuses to do balancing if it can't communicate with the VCM? Maybe there's way to force the BMS to start balancing by sending some CAN-bus messages? Glad to hear any suggestions for what to try.

 

[Ronin78PL]

Hello community, I'm writing from Poland. I would like to show you the results of my car, which I have been driving since new, and ask whether I fit into the statistical average for the SOH Leaf 40? The car is 10 months old (10.000 mil / 16.500 km) and the average energy consumption over the entire distance is 13.1 kWh/100 km

 

[Bombastinator2]

Yeah, I found only the harness so far. I guess you're right, they only sell them in a package.

Another question if someone's into standalone use of the 40 kWh battery. I have only the battery (not the full car, so no VCM etc.) and I'm trying to get the BMS to balance the cells, but it won't do it. I read on many forums that the "Nissan Leaf 40kWh BMS is actively balancing the cells all the time, even during charging", however this doesn't seem to be the case for me. I'm reading the values off the CAN-bus on 0x7BB, which allegedely reports the status of the balancing resistors, but all the bits are 0s, confirming my suspicion that the BMS is not doing any balancing.

I'm wondering if somehow it refuses to do balancing if it can't communicate with the VCM? Maybe there's way to force the BMS to start balancing by sending some CAN-bus messages? Glad to hear any suggestions for what to try.

If it’s a bare battery you’re likely using it as a powerwall or something and it is likely something someone already pulled out of a car because it had problems. No telling what.

 

[leafthesis]

If it’s a bare battery you’re likely using it as a powerwall or something and it is likely something someone already pulled out of a car because it had problems. No telling what.

Thank you for your reply, I was actually about to give an update myself as I figured it out.

I was working on the reassembly and hadn't properly fixed the BMS to the battery structure. This probably resulted in the BMS reporting insulation-error and subsequently it goes into protection mode and stops all balancing (thanks to Wolf Tronix and his excellent Youtube-videos debugging the balancing chips).

After I secured the BMS properly everything works as expected!

 

[cwerdna]

TIL of . I've not had a chance to study it yet.

 

[knightmb]

Hello community, I'm writing from Poland. I would like to show you the results of my car, which I have been driving since new, and ask whether I fit into the statistical average for the SOH Leaf 40? The car is 10 months old (10.000 mil / 16.500 km) and the average energy consumption over the entire distance is 13.1 kWh/100 km

Looks good so far, but not enough miles to really say just yet about the lifetime health of the battery. The SOH is something that can go up and down over the life of the Leaf, so we always warn not to get too obsessed with watching the values change daily as a predictor of battery life or failure. The balancing voltage of all the cells tends to be a better indicator that the health is good over time.

 

[Oostenrijker]

I'm increasingly seeing more and more reports, about owners who's battery pack has died: one thing these cases have in common are swollen battery cells, probably due to fast charging and I would say perhaps also fast driving? It seems to me the Nissan Leaf is having serious reliability issues, concerning the battery pack. But who is to blame? The owners who do the fast charging, or Nissan for allowing to fast charge as much as you want?

We all know about Rapid Gate: it served a purpose, to reduce the fast charging speed to minimize heat damage to the battery cells. Customers weren't happy, because Nissan advertised it could do 50kW fast charging. So Nissan released an update to fix Rapid Gate kinda, which allowed faster charging. Well if you ask me? That might have been the worse decision Nissan could have made!

The battery pack lacks any form of active cooling, so the only way to avoid the temperature rising to fast and to high: is by slower charging. However Nissan doesn't allow the user, to setup a custom charging speed. Let's say 20kW would be safe enough, to keep the temperature down? Maybe sometimes just limit it to 11kW whether you got the time. But you don't have a choice in this: it's either the full 45kW, or not fast charging at all. And while travelling would take longer, by slower charging: your battery pack would last longer.

I don't do any fast charging anymore and people sometimes would call it strange, but after reading all these stories: I'm even more convinced, that fast charging should be avoided at all cost and only be done very a short time. Perhaps max 15mins? As we are seeing evidence now, that more and more Leaf owners are having there Leaf battery breaking down and many are not in warranty anymore.

 

[Ronin78PL]

I do only 230V and (20.000km - one year) if You drive slow mileage is good for L40

 

[Oostenrijker]

Mine showed a few weeks ago also more than 300km.

 

[knightmb]

But who is to blame? The owners who do the fast charging, or Nissan for allowing to fast charge as much as you want?

I would blame both actually. It seems that a lot of "used" Leaf often have a history of some accident that is known due to insurance claims or not because the owner paid out of pocket to fix any visual damage. My own Leaf (2020) was rear-ended by a full size pickup truck that destroyed the front of the truck, gave me a back ache for a week and myself had to get insurance to pay over $5K in repairs for the rear. I do often wonder if that accident has caused any issues for my battery, mainly in shifting or stressing the cells in a bad way. I may never know or I might have an issue tomorrow due to this, just no way to know exactly.

Nissan has the BMS track how many times you charge the battery, what type of charging (L1/L2 vs. DC Fast Charge) along with a battery health based on data tracking of various measurements. That's all good when you have a Leaf that has never taken a direct hit from something. The BMS doesn't record how many times the battery has experience G forces above normal and from which direction, etc. Maybe due to how new EVs are, that "tracking" didn't make sense but now it might as it could be an unknown source of warranty claims for Nissan and many other EV manufactures as well.

Dala had a good example video of this when he purchased a 62 kWh used battery pack that no bad "history", only to find out that it was in an "unknown" accident that shifted some of the rear cells and caused a battery code due to something touching the outside of the case. Luckily for him, he was about to dissemble the battery pack to fix this issue. But imagine an EV owner without that kind of knowledge or shop to do those kinds of repairs. From their perspective, the EV was fine and then just "failed" without explanation. I can see why it can be frustrating to EV owners and to Manufactures if a warranty replacement is needed.

I think future EVs will need some sort of "impact" recording for the BMS to address those issues, just like some smart phones have a "drop" counter now for the same reason, when it comes to warranty repairs, etc.

 

[Oostenrijker]

@knightmb actually my previous Leaf, the high mileage one I wrote a lot about. Also had some damage at the front of the car, as it was documented by the dealer who marked it down in the maintenance book. But I discovered it, due to the damaged licence plate giving it away.

I did mention to the dealer who sold me the Leaf, that I was worried about that: but seeing how there was almost no trace of the damage? I assume, it wasn't a big damage most likely.

But I believe when you see battery cells being swollen, that's due to them being overheated multiple times and that could mean: the driver did a lot of quick charging, and overheated the battery pack multiple times. Seeing these cases, makes me wanna avoid quick charging completely.

As I got a way better Leaf now, than I did before. I haven't quick charged a single time anymore, and it hasn't been such a big issue. Because I either take the airplane, or I look for chargers where I can get 6.6kW by type 2.

 

[Jerther]

But you don't have a choice in this: it's either the full 45kW, or not fast charging at all

Hmmm, maybe the update you talk about didn't hit the 2018 models?

Here are two screen captures from our charging network app. The first was taken during winter (< 0C outside temperature) and is typical of all fast charging sessions I had. The other capture was taken during summer (>25C outside temperature) and it was the third fast charge of the day. Battery was in the red zone (I learned never to do that and never did again.)

I also had a session on another more expensive network once where it was -20C outside, at about 30% SOC, and the speed quickly went down to 11 kW (which is painfully slow, and at 20$/h is much more expensive per km than gasoline )

Anyway, in all cases the most I ever got on the 2018 was 45 kW but only for like 5 minutes.

So rapid-gate is a real thing on the 2018 at least.

 

[Oostenrijker]

Hmmm, maybe the update you talk about didn't hit the 2018 models?

Here are two screen captures from our charging network app. The first was taken during winter (< 0C outside temperature) and is typical of all fast charging sessions I had. The other capture was taken during summer (>25C outside temperature) and it was the third fast charge of the day. Battery was in the red zone (I learned never to do that and never did again.)

I also had a session on another more expensive network once where it was -20C outside, at about 30% SOC, and the speed quickly went down to 11 kW (which is painfully slow, and at 20$/h is much more expensive per km than gasoline )

Anyway, in all cases the most I ever got on the 2018 was 45 kW but only for like 5 minutes.

So rapid-gate is a real thing on the 2018 at least.

View attachment 4177View attachment 4178

The update wasn't released for all market's: Japanse Leafs didn't get it for example. I read they released it for the European market, perhaps also USA?

I wouldn't know? But I don't think it did any good, to the battery packs.

 

[jdcbomb]

2018 SL put into service 2019 JUN with 40K miles. SOH now at 87% exactly which fluctuates occasionally upwards. Max range still showing 149 to 151 mi locally and 140 mi with some highway driving.

 

[Bombastinator2]

2018 SL put into service 2019 JUN with 40K miles. SOH now at 87% exactly which fluctuates occasionally upwards. Max range still showing 149 to 151 mi locally and 140 mi with some highway driving.

So mine must be below that then. When I got it I had 145 and now it’s below that. Interesting. I wonder if my battery is unbalanced and if there’s anything I can do about it?