The 62kWh Battery Topic

[watchdoc]

Watchdoc,

You can see statistics from my quarterly full discharge tests by looking at my November 29, 2021 post. The battery still has 93% of its original energy storage capability after 27 months and 38,000 miles of use. The range estimated by the DTE (distance to empty, aka guess-o-meter) display varies a lot, depending upon recent driving conditions. Since the energy storage is 93% of original, range is 93% of original (assuming the same efficiency).

Are you still able to achieve the EPA rating of 215 miles at your current SOH?

I guess a better question might be How long will the Leaf 62 mainstain it's EPA rating?

Has anyone produced a graph that correlates SOH to range?

 

[SageBrush]

Has anyone produced a graph that correlates SOH to range?

It is proportional

 

[watchdoc]

Has anyone produced a graph that correlates SOH to range?

It is proportional

So you're saying a car with 90% SOH would have lost 10% of it's EPA rated range and thus only be able to go 193.5 miles instead of 215?

For some reason, I thought the buffer helped maintain range but I guess I'm not understanding the purpose of the BMS adjustments and how it manages the "usable" portion of the pack.

 

[knightmb]

So you're saying a car with 90% SOH would have lost 10% of it's EPA rated range and thus only be able to go 193.5 miles instead of 215?

For some reason, I thought the buffer helped maintain range but I guess I'm not understanding the purpose of the BMS adjustments and how it manages the "usable" portion of the pack.

Doesn't seem to be that way for me, anecdotally. My Leaf is down to 92% SOH but the capacity has remained above +56 kWH so my range is still identical to when I bought it and it's going to be +2 years old come March of this year. The SOH ticks down by the hundreds 0.01 every day, but the capacity seems to remain identical, so I'm not really sure what formula Nissan is using to calculate SOH. :?

 

[LeftieBiker]

Some of the apparent retention of range is likely the driver learning how to drive the car more efficiently as it loses capacity. Can you folks look at your efficiency numbers over time? Still, I doubt that it's all because of that, so it certainly does raise questions about the buffers, and about just what SOH means these days...

 

[watchdoc]

I'm kinda surprised there hasn't been more discussion on the subject as I'm still awaiting delivery of my SV+ and I've been biding my time learning about the 62 Kwh packs.

The videos about AESC's NCM 523 chemistry and how cells are stacked in the packs is very interesting. It's also interesting to me how they stacked so many more cells in the rear of the pack where it gets the hottest!! The new module cases are more open compared to the "sardine can" style module cases which I assume aides in cooling.

 

[danrjones]

I'm kinda surprised there hasn't been more discussion on the subject as I'm still awaiting delivery of my SV+ and I've been biding my time learning about the 62 Kwh packs.

The videos about AESC's NCM 523 chemistry and how cells are stacked in the packs is very interesting. It's also interesting to me how they stacked so many more cells in the rear of the pack where it gets the hottest!! The new module cases are more open compared to the "sardine can" style module cases which I assume aides in cooling.

I know my 40 pack gets really hot, and stays hot, for about 6 months. Still have full battery bars - for now. SOH 87.45

 

[SageBrush]

Has anyone produced a graph that correlates SOH to range?

It is proportional

So you're saying a car with 90% SOH would have lost 10% of it's EPA rated range and thus only be able to go 193.5 miles instead of 215?

Yes

But keep in mind that 'usable' in this context means range until turtle because that is the way EPA tested the range. Nissan may be playing with range until low battery charge alerts, and that may change as the battery loses capacity.

The point is this: if turtle occurs at e.g 2.6v cell voltage, that 2.6v does not change as the pack ages

 

[watchdoc]

Seems kinda weird. So it's only rated for 215 miles when it's delivered and immediately starts losing range with every day/mile it's owned or driven. This sounds like a class action lawsuit waiting to happen. I had always assumed, apparently wrongly, the BMS managed the buffer to maintain a useable amount of the battery that would equate roughly to the EPA mileage rating that Nissan advertises.

Also, since time is such a factor in SOH for Leaf batteries it sounds like a Leaf that has been sitting on the lot for 6 months to a year would no longer achieve it's EPA rating??

 

[watchdoc]

I'm kinda surprised there hasn't been more discussion on the subject as I'm still awaiting delivery of my SV+ and I've been biding my time learning about the 62 Kwh packs.

The videos about AESC's NCM 523 chemistry and how cells are stacked in the packs is very interesting. It's also interesting to me how they stacked so many more cells in the rear of the pack where it gets the hottest!! The new module cases are more open compared to the "sardine can" style module cases which I assume aides in cooling.

I know my 40 pack gets really hot, and stays hot, for about 6 months. Still have full battery bars - for now. SOH 87.45

Your pack stays hot for 6 months????? How many miles do you have on your 40?

 

[danrjones]

I'm kinda surprised there hasn't been more discussion on the subject as I'm still awaiting delivery of my SV+ and I've been biding my time learning about the 62 Kwh packs.

The videos about AESC's NCM 523 chemistry and how cells are stacked in the packs is very interesting. It's also interesting to me how they stacked so many more cells in the rear of the pack where it gets the hottest!! The new module cases are more open compared to the "sardine can" style module cases which I assume aides in cooling.

I know my 40 pack gets really hot, and stays hot, for about 6 months. Still have full battery bars - for now. SOH 87.45

Your pack stays hot for 6 months????? How many miles do you have on your 40?

I think I'm just over 12.5k. Not many. The heat is from the summer here. Last year we hit 119F one day. It simply takes on the average temp plus a few degrees from use and charging. There simply is no cooling built into the pack.

 

[watchdoc]

I know my 40 pack gets really hot, and stays hot, for about 6 months. Still have full battery bars - for now. SOH 87.45

Your pack stays hot for 6 months????? How many miles do you have on your 40?

I think I'm just over 12.5k. Not many. The heat is from the summer here. Last year we hit 119F one day. It simply takes on the average temp plus a few degrees from use and charging. There simply is no cooling built into the pack.

I don't wanna get too off topic since you have a 40 and this is a 62 thread but when you say "stays hot for 6 months" what does that equate to on your battery temp guage?

 

[SageBrush]

It simply takes on the average temp plus a few degrees from use and charging. There simply is no cooling built into the pack.

Exactly

Unless the charging is DC, then you get to see impressive pack temperatures in a hot climate.

 

[danrjones]

I don't wanna get too off topic since you have a 40 and this is a 62 thread but when you say "stays hot for 6 months" what does that equate to on your battery temp guage?
[/quote]


I sit the entire summer (6-7 months here) in the first notch above middle, and large swaths of time I sit in the second notch and now and then the third notch. Third notch is usually the morning and afternoon after a charging session (almost always lvl 2 at home, 240 volts) and then for the next day or two before charging again it levels out on the second notch above middle. I charge about every 3rd night. I can't remember what those notches equate to, but I know my pack temps average well above 100 f during the summer.

 

[watchdoc]

I don't wanna get too off topic since you have a 40 and this is a 62 thread but when you say "stays hot for 6 months" what does that equate to on your battery temp guage?

I sit the entire summer (6-7 months here) in the first notch above middle, and large swaths of time I sit in the second notch and now and then the third notch. Third notch is usually the morning and afternoon after a charging session (almost always lvl 2 at home, 240 volts) and then for the next day or two before charging again it levels out on the second notch above middle. I charge about every 3rd night. I can't remember what those notches equate to, but I know my pack temps average well above 100 f during the summer.
[/quote]

Is your car garage kept?
I suppose these constant high ambient temps would help explain your 87% SOH after only 2 years and 13k miles. Here in eastern NC, we have very humid summers with temps rountinely in the middle to upper 90's but not many days over `100. I also plan to keep my Leaf in the garage.

 

[danrjones]

Is your car garage kept?
I suppose these constant high ambient temps would help explain your 87% SOH after only 2 years and 13k miles. Here in eastern NC, we have very humid summers with temps rountinely in the middle to upper 90's but not many days over `100. I also plan to keep my Leaf in the garage.

No, that would be even worse. It sits outside during the day because it has to, at my work. The only cooling it gets is at night when our temps drop into the 80's or even upper 70's when we are lucky. If I kept it in the garage, it wouldn't get below 90-100 at night.

Lefty (?) and a few others here have talked about or actually experimented with AC in their garage to cool the car / pack, but that feels wasteful (to me). YMMV.

 

[danrjones]

Also, it is worth pointing out there are others with 2018's in cooler climates that have almost the same SOH. Its hard to discern whether its mileage, heat or time.

 

[watchdoc]

Also, it is worth pointing out there are others with 2018's in cooler climates that have almost the same SOH. Its hard to discern whether its mileage, heat or time.

Are you refering to 40 packs or 62's or both?

 

[danrjones]

Also, it is worth pointing out there are others with 2018's in cooler climates that have almost the same SOH. Its hard to discern whether its mileage, heat or time.

Are you refering to 40 packs or 62's or both?

2018's were only 40s. But I think the 62's are following a similar pattern?

 

[watchdoc]

Also, it is worth pointing out there are others with 2018's in cooler climates that have almost the same SOH. Its hard to discern whether its mileage, heat or time.

Are you refering to 40 packs or 62's or both?

2018's were only 40s. But I think the 62's are following a similar pattern?

After reading all the pages of this thread, I haven't seen any 62's below 90% SOH but I'm sure there are out there by now. Based on the small sample size of stuff I've read, the 62's level off in the low 90's with many owners over 2 years and 30k miles. I'm pretty sure I read that the 40 and 62 packs both use AESC's 4th gen NCM-523 pouch cell chemistry but the BMS are obviously different. I wonder if getting rid of the "sardine can" style modules helps the 62's in some way??