2016-2017 model year 30 kWh bar losers and capacity losses

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jbuntz said:
samrovner said:
It's crazy to think I dropped two more bars in that short of a duration.
Sam, you lost bar 3 and 4 in 2 months?

Yep, pretty much. The good news is that the dealer ordered my new battery today and I am hopeful that this battery pack was an anomaly. Still so happy I decided to lease again like my 2013 leaf. Almost bought this one.

Also pretty stoked because they said I can watch the work get done. Something fascinates me about seeing the battery swap done.
 
johnlocke said:
It appears that battery degradation is a function of ageing and ambient temps. Mileage doesn't appear to be related. Because of the way that Nissan implemented the capacity loss bars most people haven't noticed the loss yet. What we seem to be seeing is that people who bought in early 2016 and live in hotter climates are seeing the most degradation. What I'd be curious to know is who has a 2016 and lives in a warm climate like Phoenix or Dallas and hasn't seen major degradation? Is this a limited problem with a few cars or is it endemic to the 30 KWH battery? Cars reporting losses seem to be across a wide spread of purchase dates so a bad batch of batteries doesn't seem likely but is still possible.

Degradation happens under several scenarios but the big one in most of these is the TIME @high SOC combined with heat.

Neither high SOC or heat "alone" is anywhere near that significant. It has to be all 3 to see packs going that fast. But 30 kwh packs don't have the range to do 80% charging in most cases. Nissan should have done the 90% like Tesla (and everyone else)
 
Anybody ever consider the possibility of the extra cells crammed into the same space as the 24 kW pack, hence Reducing the cooling ability as the batteries are much closer together, thereby causing the unexpected premature degradwtion?
 
smnewport said:
Anybody ever consider the possibility of the extra cells crammed into the same space as the 24 kW pack, hence Reducing the cooling ability as the batteries are much closer together, thereby causing the unexpected premature degradwtion?

Extra cells would produce higher voltage that the car couldn't use. What they've done is use the same number of cells, with more capacity per cell. The cells may be slightly larger, but mainly they just hold more energy per cell. I suspect that the chemistry that Nissan used to get that higher energy density is less heat and age tolerant than the previous two generations of cells.
 
I wondered if the 30kwh pack is actually just the 24kwh pack with different parameters in the software, so it's stressed more and hence degrades faster.
 
SageBrush said:
johnlocke said:
It appears that battery degradation is a function of ageing and ambient temps. Mileage doesn't appear to be related.
True in a practical way, since these are all low mileage cars.
Yes but many are 20,000 miles or less. I'm at 36,000 miles and am down two bars. I'm pretty sure that there are 2016's with even higher mileage than mine out there. If mileage was a factor, I'd expect the high mileage cars to be clustered together with similar bar losses. That doesn't appear to be the case. Age combined with location seems to be a better predictor. I'd still like to hear from people in Arizona, Texas, and Florida who have 2016 30 KWH cars who don't have battery degradation. Some loss is inevitable but by Nissan's estimates a two year old car with 25,000 miles on it should only have a 5% loss (based on Nissan's estimate of 80% capacity at 100,000 miles and eight years old for a typical owner). Until we hear from those with minimal losses we won't have a real picture of the problem.
 
LTLFTcomposite said:
I wondered if the 30kwh pack is actually just the 24kwh pack with different parameters in the software, so it's stressed more and hence degrades faster.
No, if this were the case, you'd see much higher voltages when charged to 100% and/or discharged to turtle. But they are the same.
 
johnlocke said:
SageBrush said:
johnlocke said:
It appears that battery degradation is a function of ageing and ambient temps. Mileage doesn't appear to be related.
True in a practical way, since these are all low mileage cars.
Yes but many are 20,000 miles or less. I'm at 36,000 miles and am down two bars. I'm pretty sure that there are 2016's with even higher mileage than mine out there. If mileage was a factor, I'd expect the high mileage cars to be clustered together with similar bar losses. That doesn't appear to be the case. Age combined with location seems to be a better predictor. I'd still like to hear from people in Arizona, Texas, and Florida who have 2016 30 KWH cars who don't have battery degradation. Some loss is inevitable but by Nissan's estimates a two year old car with 25,000 miles on it should only have a 5% loss (based on Nissan's estimate of 80% capacity at 100,000 miles and eight years old for a typical owner). Until we hear from those with minimal losses we won't have a real picture of the problem.
I was not clear, I meant that any car below below 100k miles is low mileage, so we lack sensitivity to declare that mileage is not in play.
 
smnewport said:
Anybody ever consider the possibility of the extra cells crammed into the same space as the 24 kW pack, hence Reducing the cooling ability as the batteries are much closer together, thereby causing the unexpected premature degradwtion?

Nothing in your statement is correct.

the cells are smaller and there is actually MORE space between the cells. A LEAF Tech says there is about a "two washer" larger gap than the older packs. The cells are simply newer and smaller, denser, etc.
 
LTLFTcomposite said:
I wondered if the 30kwh pack is actually just the 24kwh pack with different parameters in the software, so it's stressed more and hence degrades faster.

that is a thought I had as well but hard to say since the charging profiles are not really detailed.

The fast charge profile generates a LOT more heat than the 24 kwh packs. I never hit the red in 6 years on 24 kwh packs but my 2016 has been in the red like 2-3 dozen times and spent nearly 24/7 at 8-10 bars for a 3 week period this past Summer.

Wondering if something on the L2 was changed? If you notice the math on the 30 kwh packs comes up to slightly less than 30 kwh and the charge level was going to 97.7 and my previous LEAF only went to 97.3 (at least as far as I can tell from several screenshots of LEAF spy taken)
 
DaveinOlyWA said:
LTLFTcomposite said:
I wondered if the 30kwh pack is actually just the 24kwh pack with different parameters in the software, so it's stressed more and hence degrades faster.

that is a thought I had as well but hard to say since the charging profiles are not really detailed.

The fast charge profile generates a LOT more heat than the 24 kwh packs. I never hit the red in 6 years on 24 kwh packs but my 2016 has been in the red like 2-3 dozen times and spent nearly 24/7 at 8-10 bars for a 3 week period this past Summer.


Wondering if something on the L2 was changed? If you notice the math on the 30 kwh packs comes up to slightly less than 30 kwh and the charge level was going to 97.7 and my previous LEAF only went to 97.3 (at least as far as I can tell from several screenshots of LEAF spy taken)

That would explain the difference between my QC experience with that of lorenfb then! We're both in SoCal, yet he would only sees a few degrees temp rise during QC, while I saw over 20 degrees! We had different sized battery packs (with their associated chemistry differences).

So does that make me the canary in the coal mine for post mid-2016 30kwh leafs that HAVEN'T suffered premature degradation (in a "warm" region)?
 
So, I have a 2016 with just over 34k on it. I've got about 50/50 charging profile of L2 and L3 because some kid shuttling I did needed to have a quick turnaround.

My current SOH is 83%. Full details below. I'm wondering if a sequence of L2 charging would help recover any of that? And secondly, I charge L2 at 21A....does that change the degradation compared to charging at 14 or 16A?


Mfg 12/15 Del 1/16 11 Nov 2017 34442 mi Ahr 66.44 SOH 83% Hx 76.86%
 
DCFC in a 30 KWH car IS different than the older 24 KWH battery. You will see 106 amps up to 85-90% charge and a slow tapering thereafter. I've seen 40A at 95% and 15A at 98% on a EVGO charger. You are charging longer at a high rate and the current reduction at high charge is less than the older battery. It's no wonder the battery gets warmer.
 
Oils4AsphaultOnly said:
DaveinOlyWA said:
LTLFTcomposite said:
I wondered if the 30kwh pack is actually just the 24kwh pack with different parameters in the software, so it's stressed more and hence degrades faster.

that is a thought I had as well but hard to say since the charging profiles are not really detailed.

The fast charge profile generates a LOT more heat than the 24 kwh packs. I never hit the red in 6 years on 24 kwh packs but my 2016 has been in the red like 2-3 dozen times and spent nearly 24/7 at 8-10 bars for a 3 week period this past Summer.


Wondering if something on the L2 was changed? If you notice the math on the 30 kwh packs comes up to slightly less than 30 kwh and the charge level was going to 97.7 and my previous LEAF only went to 97.3 (at least as far as I can tell from several screenshots of LEAF spy taken)

That would explain the difference between my QC experience with that of lorenfb then! We're both in SoCal, yet he would only sees a few degrees temp rise during QC, while I saw over 20 degrees! We had different sized battery packs (with their associated chemistry differences).

So does that make me the canary in the coal mine for post mid-2016 30kwh leafs that HAVEN'T suffered premature degradation (in a "warm" region)?
It puts you in the running at least. But you are only a year old with one summer of hot weather. You are still down 5% overall. I'd like to hope the battery was improved somehow. 5% a year loss over 8 years will still put you at 60% though and might qualify for a new battery before the warranty ends.
 
Something tells me that there could be a market for an app that allows you to rewrite the state of health and status of the cells on a leaf battery array ;-)
 
Oils4AsphaultOnly said:
DaveinOlyWA said:
LTLFTcomposite said:
I wondered if the 30kwh pack is actually just the 24kwh pack with different parameters in the software, so it's stressed more and hence degrades faster.

that is a thought I had as well but hard to say since the charging profiles are not really detailed.

The fast charge profile generates a LOT more heat than the 24 kwh packs. I never hit the red in 6 years on 24 kwh packs but my 2016 has been in the red like 2-3 dozen times and spent nearly 24/7 at 8-10 bars for a 3 week period this past Summer.


Wondering if something on the L2 was changed? If you notice the math on the 30 kwh packs comes up to slightly less than 30 kwh and the charge level was going to 97.7 and my previous LEAF only went to 97.3 (at least as far as I can tell from several screenshots of LEAF spy taken)

That would explain the difference between my QC experience with that of lorenfb then! We're both in SoCal, yet he would only sees a few degrees temp rise during QC, while I saw over 20 degrees! We had different sized battery packs (with their associated chemistry differences).

So does that make me the canary in the coal mine for post mid-2016 30kwh leafs that HAVEN'T suffered premature degradation (in a "warm" region)?

Its a huge difference. On a 300 mile trip I stopped to grab some lunch and plugged into a 125 amp AV charger. It finished the charge in 28 mins running at 38 KW when it shut off at 94% and I started the charge at 10 TBs....
 
FWIW this three bar loser car in central Florida has only been fast charged once we know of; the day delivery was taken at the dealer. We don't know if it might have been fast charged other times before delivery. Hard to see how it could have been too significant.
 
LTLFTcomposite said:
FWIW this three bar loser car in central Florida has only been fast charged once we know of; the day delivery was taken at the dealer. We don't know if it might have been fast charged other times before delivery. Hard to see how it could have been too significant.

So, what's the going theory on the biggest killer of the 30kWh packs? Would the fact that I do 50/50 L2/L3 charging be the cause of an 83% SOH after 34k miles? I can tell you that I adhere to all the other battery upkeep guidelines - rarely charge to 100%, never store @ 100% and I'm in a pretty temperate climate - if not on the cooler side.

I'm actually headed down to the Nissan battery plant in TN at the beginning of December, so I'm hoping to get a chance to talk with some of the folks there.
 
johnlocke said:
DCFC in a 30 KWH car IS different than the older 24 KWH battery. You will see 106 amps up to 85-90% charge and a slow tapering thereafter. I've seen 40A at 95% and 15A at 98% on a EVGO charger. You are charging longer at a high rate and the current reduction at high charge is less than the older battery. It's no wonder the battery gets warmer.
There is not going to be much heat dissipation during a QC so the temperature increase will be related to heat released in the battery and its heat capacity. If it is true that the heat capacity of the 30 kWh battery is about 25% greater than the 24 kWh battery then one might expect the 30 kWh to be able to charge at a rate 25% faster than the smaller battery with similar temperature rise. That of course presumes that a lot of things otherwise remain constant, most importantly internal battery resistance.
 
ironmanco said:
LTLFTcomposite said:
FWIW this three bar loser car in central Florida has only been fast charged once we know of; the day delivery was taken at the dealer. We don't know if it might have been fast charged other times before delivery. Hard to see how it could have been too significant.

So, what's the going theory on the biggest killer of the 30kWh packs? Would the fact that I do 50/50 L2/L3 charging be the cause of an 83% SOH after 34k miles? I can tell you that I adhere to all the other battery upkeep guidelines - rarely charge to 100%, never store @ 100% and I'm in a pretty temperate climate - if not on the cooler side.

I'm actually headed down to the Nissan battery plant in TN at the beginning of December, so I'm hoping to get a chance to talk with some of the folks there.
Do you have any idea of battery temperatures after your QCs ?
 
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