Battery temp management for new leaf

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Powersurge: Your post has got to be amongst the most absurd on heat related degradation I've heard here ever since maybe 2013. But at the same time, I can understand why you're making such statements as you weren't on MNL back in May 2012 (you joined in Oct 2015) and if your Leaf was bought or leased as new in Dec 2014, you have a lizard battery (best so far) Leaf. Also, you have the benefit of very reduced degradation in winter and a not blazing hot climate like Phoenix. (Example Phoenix crazy temps at http://www.mynissanleaf.com/viewtopic.php?p=306687#p306687.)

If you had a pre-4/2013 Leaf and lived in Phoenix or Texas or a hot part of So Cal and compared notes w/those in mild climate climates like those in Oregon or the Seattle area, you'd think differently.
powersurge said:
I think all this worry and complaint about battery cooling and deterioration is all a myth that some are using to either discredit the Nissan company or for Nissan to blame battery deterioration on temperature rather than time. If all members recall their past experience, they may see my point.
...
Let's step back. Nissan in the past made claims like the ones at http://www.mynissanleaf.com/viewtopic.php?f=30&t=22446&p=469608&hilit=percent+perry#p469608 (70 to 80% remaining after to year life, we don't need thermal management, etc.)

We first started seeing capacity bars being lost in May 2012 with http://www.mynissanleaf.com/viewtopic.php?f=30&t=8802, that ballooned into an over 785 page thread. http://www.mynissanleaf.com/viewtopic.php?f=30&t=9694 is a summary. There ended up being a lot of noise in the Phoenix local media, on MNL and elsewhere. TonyWilliams w/the help of other folks here ran a range test, results at https://web.archive.org/web/20130115102522/http://www.mynissanleaf.com/viewtopic.php?p=228326 posted on Sept 18, 2012 (first deliveries of Leaf were in Dec 2010). Leaf had only been out ~21 months and yet we already had 1 to 4 bar losers and no capacity warranty either. So... 30+% loss in under 2 years vs. 10????

Some of the Phoenix Leafers had their cars collected by Nissan temporarily for testing. TickTock actually met w/Nissan engineers on this.
http://www.mynissanleaf.com/viewtopic.php?p=230478#p230478
http://www.mynissanleaf.com/viewtopic.php?p=230575#p230575

It seems like the above and an unbeknownst to us Klee class action lawsuit forced Nissan to provide a retroactive 5 year/60K capacity warranty: http://www.mynissanleaf.com/viewtopic.php?t=13192.

You've also ignored literature stating capacity loss reduction is worse at higher temps (e.g. http://batteryuniversity.com/learn/article/how_to_store_batteries, but that's not the same chemistry used in the Leaf). There are numerous chemistries (http://batteryuniversity.com/learn/article/types_of_lithium_ion), some more sensitive to high temps than others.

http://www.mynissanleaf.com/viewtopic.php?f=30&t=9694 has a quote from Charles Whalen
the LiMn2O4 chemistry, that both GM and Nissan are using in the Volt and Leaf, being the most heat sensitive and having the shortest life at higher ambients)
I personally know 2 folks in my part of the Bay Area who lost 4 bars on their '11 or '12 Leaf in time to get their battery replaced under capacity warranty. There are many more.

As for cycling vs. temp: http://www.greencarreports.com/news/1089091_owner-of-100000-mile-nissan-leaf-electric-car-to-be-honored-monday commutes 130 miles/day in his Leaf. He has to charge fully on both ends but he lives in a cool climate.
http://www.mynissanleaf.com/viewtopic.php?f=27&t=12781 - at ~2 year mark, he lost 1 bar at 76K miles. Compare that to the <21 month old Phoenician Leafs w/WAY less mileage but blazing heat that were down 1-4 bars.

https://www.facebook.com/groups/seattlenissanleaf/permalink/1597025036995594/ in the mild PNW lost his first bar on his '13 at 92.7K miles.

As I posted at http://www.mynissanleaf.com/viewtopic.php?f=6&t=24023&p=496269&hilit=phoenix+contrast#p496269 a pointer to http://www.mynissanleaf.com/viewtopic.php?p=473995#p473995, this guy is in Phoenix.
elec7ric said:
I got my new 2013 SL (manufactured 5/2013 ) on 9/30/2013. Lost my first bar 5/2015, second bar 9/2015, third bar 5/2016 and forth bar 8/23/2016 (31,400 miles). First 21 months mostly charged L1/L2 to 80% (home and work). My drive was 55 miles round trip with about 75% highway. As capacity started to go away, I had to charge more often to 100%, however, I tried my best to keep it fully charged as little as possible (extreme Phoenix temperatures).
My 5/2013 built '13 that I bought used in July 2015 STILL has all 12 capacity bars and I'm past 49,2K miles. From Leaf Spy, I am getting close to losing 1 bar (SOH at around 86%, Hx at around 83.92%)

The 6/2013 built '13 Leaf I leased for 2 years, I have a screenshot of the stats near turn in. On 7/23/2015, was at AHr: 58.57, SOH: 89%, Hx: 88.89%, odo: 23,342 miles. It had 12 bars at turn in.

I also have a screenshot of the 5/2013-built '13 Leaf I'm driving now on 7/16/2015 showing AHr: 60.15, SOH, 91%, Hx: 92.12%, odo: 23,850 miles. It had 12 bars when I purchased in July 2015 and still does now.

We later discovered that it seems '13 Leafs built 4/2013 and later do MUCH better in terms of degradation than pre-4/2013 built Leafs.

GerryAZ in Phoenix has also given a comparison of how his lizard battery is doing vs. previous ones: http://www.mynissanleaf.com/viewtopic.php?p=499072#p499072 and http://www.mynissanleaf.com/viewtopic.php?f=27&t=24407&p=502456&hilit=11+bars+2011#p502456.

Prior to lizard battery announcement (http://www.mynissanleaf.com/viewtopic.php?f=4&t=17168), Nissan was talking about a "hot" battery in testing that's more heat resistant. At http://www.mynissanleaf.com/viewtopic.php?t=23983, I pointed to a paper at http://www.nec.com/en/global/techrep/journal/g12/n01/pdf/120112.pdf (Leaf batteries are made by AESC, a JV between Nissan and NEC, soon to be sold to a Chinese company) which discusses degradation depending on temp and a newly developed cell (maybe the lizard battery?) that degrades less at high temps.

Some folks that got replacements before the "hot"/lizard battery was available were supposed to get coupons for another swap to the better "hot" battery. Some pointers at http://www.mynissanleaf.com/viewtopic.php?p=499828#p499828.

You should monitor http://www.mynissanleaf.com/viewtopic.php?f=30&t=23606 on the disappointing 30 kWh batteries. There are already 1 to 4 bar losers (usually in hotter climates). There are somewhere between 2 and 4 4 bar losers that we know of. You can't blame this stuff on cycling vs. what GerryAZ has already done in Phoenix on his '15 lizard battery.

You should also monitor all the other battery degradation threads. You will see a very strong correlation between hotter climates (doesn't need to be Phoenix-level) and worse degradation.

Below's a Sacramento lizard battery car, for instance. It's no surprise that it's already in worse shape than my 5/2013 built Leaf.
http://www.mynissanleaf.com/viewtopic.php?p=504601#p504601
http://www.mynissanleaf.com/viewtopic.php?p=504665#p504665
 
WetEV said:
Arrhenius's law.

Batteries have unwanted side reactions that degrade the chemistry of the cell. Roughly every 10C the rate of these reactions will double. So if your battery gets 10C warmer for a day, then it degrades as much as two normal days in your climate. Or if you are American, 14F warmer.

So does it matter? Yes, but not very much unless you do this a lot. As I've started to take trips like this more frequently, I'm no longer in contention for the 100k miles on a 24kWh battery before losing the first bar competition. Oh, and I'm not disappointed in how fast my battery is aging. The battery isn't "crappy", but isn't the best choice for vary hot places.
Every 10C is 18F more

Phoenix is a poster child for heat related battery degradation but there is a large swath of the US that has an ambient average annual temperature 10C higher than Seattle. And ever more problematic, summers that are 20C hotter than Seattle are common. This works out to a large community of LEAF owners that are seeing (as expected by Arrhenius' law) 2.5-3x faster degradation than you.

And by the way, Seattle has another advantage besides low average ambient: the generous rain keeps the roads cool. So while I agree entirely that a LEAF can have a somewhat reasonable life in Seattle or similar climate, most of the US is LEAF inhospitable.
 
SageBrush said:
edatoakrun said:
Why do those who have such serious anxiety regarding battery temperatures in passively manged packs keep buying LEAFs, and continue sharing their insecurities on this forum?
Not insecurities, disappointment with how fast the battery is aging.
Should they have known how crappy the battery is before purchase ?
Perhaps, but now they are doing their part to save others from the same fate. You know, to reduce your annoyance.
Actually, edatoakrun is asking a fairly good question. Yes, a substantial case can be made for rapid battery degradation in pre 4/13 (primarily '11 and '12) LEAFs in places like Southern Arizona. And providing information to potential buyers on the actual performance of new battery pack formulations is certainly a useful thing to do. But dedicating an entire website to endless tirades about worst case degradation of the '11/'12 battery packs is getting a bit tedious. For those who don't want a passively cooled EV - don't buy one. And for those who don't like the way Nissan dealt with the situation - scratch them off your list. Going to have to move on sooner or later.
 
Dooglas said:
Actually, edatoakrun is asking a fairly good question. Yes, a substantial case can be made for rapid battery degradation in pre 4/13 (primarily '11 and '12) LEAFs in places like Southern Arizona. And providing information to potential buyers on the actual performance of new battery pack formulations is certainly a useful thing to do. But dedicating an entire website to endless tirades about worst case degradation of the '11/'12 battery packs is getting a bit tedious.
It's not even the worst case. I wish I could find the thread where I asked '11 and '12 Leaf batteries essentially, how many '11 or '12 Leafs will still be on their original batteries and have at least 70 to 80% of original capacity. I got a couple answers of 0.

The 30 kWh batteries are NOT holding up well either (http://www.mynissanleaf.com/viewtopic.php?f=30&t=23606) w/somewhere between 2 and 4 4 bar losers beside a bunch of 1 to 3 bar losers. So, it is a legitimate concern to wonder how well the 40 kWh packs will hold up w/no active cooling.
 
Sagebrush,

I disagree with your statement that "most of the US is LEAF inhospitable" because I have driven nearly 100,000 miles on electricity in the brutal heat of Phoenix. It is true that the traction batteries deteriorate faster here, but 12-volt batteries in the LEAF last longer than typical for gasoline or Diesel engine cars. There is almost no routine maintenance required on the LEAF (just annual battery checks, routine inspections, and brake fluid flush every 2 years). Gasoline and Diesel engine vehicles require more frequent maintenance to cope with the heat here vs. cooler climates so there are trade offs.

It will be interesting to see what Nissan does about the 30 kWh batteries that appear to be losing capacity faster than the 2015 "lizard" batteries.
 
GerryAZ said:
It will be interesting to see what Nissan does about the 30 kWh batteries that appear to be losing capacity faster than the 2015 "lizard" batteries.
Well, one thing they certainly will do. They will honor the current extended battery warranty, whatever happens with battery capacity thru time.
 
cwerdna said:
It's not even the worst case. I wish I could find the thread where I asked '11 and '12 Leaf batteries essentially, how many '11 or '12 Leafs will still be on their original batteries and have at least 70 to 80% of original capacity. I got a couple answers of 0.
Hmmm, You asked how many '11 and '12 LEAFs are still on their original battery pack and have 70% to 80% of original capacity. And 2 people responded by guessing none?!? What were the other guesses? How is that useful?
 
Dooglas said:
cwerdna said:
It's not even the worst case. I wish I could find the thread where I asked '11 and '12 Leaf batteries essentially, how many '11 or '12 Leafs will still be on their original batteries and have at least 70 to 80% of original capacity. I got a couple answers of 0.
Hmmm, You asked how many '11 and '12 LEAFs are still on their original battery pack and have 70% to 80% of original capacity. And 2 people responded by guessing none?!? What were the other guesses? How is that useful?
I wish I could find the thread. It was intended to be a poll. It illustrates how far short Nissan fell short of their claims (see http://www.mynissanleaf.com/viewtopic.php?f=30&t=22446&p=469608&hilit=percent+perry#p469608).

I doubt very many (if any) in the mild Pacific NW at 10 years on an '11 or '12 Leaf that's still on the original pack will have 70% capacity remaining.

There was a similar thread covering those Leafs but with 80% remaining after 5 years: http://www.mynissanleaf.com/viewtopic.php?f=27&t=16236.
 
powersurge said:
I think all this worry and complaint about battery cooling and deterioration is all a myth that some are using to either discredit the Nissan company or for Nissan to blame battery deterioration on temperature rather than time. If all members recall their past experience, they may see my point.

Except for those hot climates where daily temperatures are over 100 degrees, the reported posts on battery temperature are irrelevant. If posters are complaining that their battery temperatures have "spiked" up to 100 or even 112 degrees, their complaints are totally trivial. First, if you are driving in a 70-95 degree ambient temperature (and the car's battery is working hard to propel you at high speed), what is so terrible if the battery temperature goes up to 100-110 degrees? That temperature is just slightly above your normal body temperature. If you touch something with that temperature, then you would hardly perceive that it is hot at all... Maybe a bit warm. I cannot imagine that that temperature would DEGRADE any rechargeable battery. Man, my Samsung cell phone gets so hot that it burns in my pocket at times, and it still continues to work fine for years. In my opinion, battery temps of 120-140 degrees would be more damaging than at 100 degrees.

Second, this is my theory of what is happening. I have used rechargeable batteries since the 1970s in all types of products, and the following NEVER changes. Rechargeable batteries do an amazing job of holding and giving out electricity, with many cycles of discharge and charging. Truth is that rechargeable batteries have still not progressed that much. The lifetime of a cordless drill battery (my closest comparable battery to EV batteries) only last 2-4 years before they do not hold a charge.

So, it is my "conspiracy theory" belief that (except the crazy people that buy Leafs and live in desert and tropical climates) all battery deterioration that people report is a NORMAL expression of the battery's normal lifetime. Think of it, my battery has over 1500 charging cycles and is still (for now) strong. THAT is amazing. Of course, Nissan would never "to your face" tell you that their batteries are strong for only 2-3 years and go downhill from there. No one would ever consciously buy their cars then. SO.... It is easier to blame high battery temperatures (caused by users), which give us users the "fantasy" that we can extend the life of our cars with careful use. Its like the TV commercial fantasy that if you eat probiotics and organic food, you will live to 120...

I, personally, voluntarily took the plunge with my Leaf and hope that by the time my battery needs to be excised, batteries will either last longer or will have greater capacity. I really think that Leaf owners should consider themselves as trailblazers who are testing out the future technology of our planet. They should not be considering themselves as "discriminating consumers" that EXPECT all their products should work perfectly, like their continued fantasy that their world should be also perfect.
Nissan has repeatedly offered the information that "the battery is expected to last for the life of the car and should retain typically 80% of the original capacity after 8 years or 100,000 mile of operation." They said that about the original Leaf, the revised 24KWH model, and even put it in writing for the 2016 and newer 30KWH models. See the 100,00 mile battery warranty for more info. Nowhere has Nissan ever stated that the car is unsuitable for hot climates or that it should only be considered for light to moderate use.

No one has ever proved why the battery deteriorates in warm climates, only that it does. No has ever proved that the excessive loss of capacity is limited to early 2016 models ( bad batch theory). Most of the 2016 and 2017 models simply haven't been on the road long enough to draw any meaningful conclusions. DCFC doesn't seem to have any meaningful correlation nor does high numbers of L2 charges.

If the manufacturer warrants the drivetrain and battery for 100,000 miles why shouldn't I believe them? Why should I expect to be a guinea pig for their manufacturing processes? I don't think that it is unreasonable to expect any car to last for 150,000 miles and a well built car to last for 200,000+ miles with reasonable maintenance. Average life expectancy for cars in California is about 15 years. Do you really believe that the average Leaf is going to come close to that without a couple of battery changes?
 
I wonder how Powersurge would explain the sudden jump in pack longevity that occurred in April of 2013...? Before then it was ""normal" for packs to lose several capacity bars over just three years in all but the very coolest climates. Then, starting in 4/2013, bars were retained in all but the hottest climates, with first bar loss yet to occur in many of these cars (including mine), and with others losing just one bar about now. Perhaps some sort of mass migration of Leaf drivers Northward in April of 2013?
 
johnlocke said:
If the manufacturer warrants the drivetrain and battery for 100,000 miles why shouldn't I believe them?
Why shouldn't you believe the manufacturers warranty? Well, I'd say you should as it is a legally binding commitment.
 
Dooglas said:
SageBrush said:
edatoakrun said:
Why do those who have such serious anxiety regarding battery temperatures in passively manged packs keep buying LEAFs, and continue sharing their insecurities on this forum?
Not insecurities, disappointment with how fast the battery is aging.
Should they have known how crappy the battery is before purchase ?
Perhaps, but now they are doing their part to save others from the same fate. You know, to reduce your annoyance.
Actually, edatoakrun is asking a fairly good question. Yes, a substantial case can be made for rapid battery degradation in pre 4/13 (primarily '11 and '12) LEAFs in places like Southern Arizona. And providing information to potential buyers on the actual performance of new battery pack formulations is certainly a useful thing to do. But dedicating an entire website to endless tirades about worst case degradation of the '11/'12 battery packs is getting a bit tedious. For those who don't want a passively cooled EV - don't buy one. And for those who don't like the way Nissan dealt with the situation - scratch them off your list. Going to have to move on sooner or later.

My previous post was not accepted by a few. Well, I agree with these posters. Nissans will never publicly say this, but it is true.... PEOPLE IN HOT CLIMATES...... DO NOT BUY A LEAF.. That is all that needs to be said, an I am sure that half of the degradation complaints ill disappear...
 
powersurge said:
My previous post was not accepted by a few. Well, I agree with these posters. Nissans will never publicly say this, but it is true.... PEOPLE IN HOT CLIMATES...... DO NOT BUY A LEAF.. That is all that needs to be said, an I am sure that half of the degradation complaints ill disappear...
Your post at http://www.mynissanleaf.com/viewtopic.php?p=508929#p508929 was full of ridiculous assertions and hypotheses not based upon known data and science regarding lithium ion-batteries nor observations we've seen here on MNL since the car's been available.

Where is the line drawn about a "hot climate"? Phoenix and Vegas get blazing hot, yes. At what point is "not hot" where people should/are ok to buy a Leaf? These people lost 1+ capacity bars on the disappointing 30 kWh battery Leafs, as examples:
East Bay in CA: http://www.mynissanleaf.com/viewtopic.php?p=507326#p507326 (arguably one of his areas is hot while the other isn't that hot: http://www.mynissanleaf.com/viewtopic.php?p=507368#p507368)
Minnesota: http://www.mynissanleaf.com/viewtopic.php?p=505408#p505408
Minnesota #2: http://www.mynissanleaf.com/viewtopic.php?p=507624#p507624
Hawaii: http://www.mynissanleaf.com/viewtopic.php?p=507704#p507704 - down 3 bars. I've only been there twice and in the time I was there, it wasn't hot at all compared to where I live in CA. Perhaps it just doesn't cool down enough at night or in winter?
Layton, UT: http://www.mynissanleaf.com/viewtopic.php?p=508839#p508839
 
cwerdna said:
powersurge said:
My previous post was not accepted by a few. Well, I agree with these posters. Nissans will never publicly say this, but it is true.... PEOPLE IN HOT CLIMATES...... DO NOT BUY A LEAF.. That is all that needs to be said, an I am sure that half of the degradation complaints ill disappear...
Your post at http://www.mynissanleaf.com/viewtopic.php?p=508929#p508929 was full of ridiculous assertions and hypotheses not based upon known data and science regarding lithium ion-batteries nor observations we've seen here on MNL since the car's been available.

Where is the line drawn about a "hot climate"? Phoenix and Vegas get blazing hot, yes. At what point is "not hot" where people should/are ok to buy a Leaf? These people lost 1+ capacity bars on the disappointing 30 kWh battery Leafs, as examples:
East Bay in CA: http://www.mynissanleaf.com/viewtopic.php?p=507326#p507326 (arguably one of his areas is hot while the other isn't that hot: http://www.mynissanleaf.com/viewtopic.php?p=507368#p507368)
Minnesota: http://www.mynissanleaf.com/viewtopic.php?p=505408#p505408
Minnesota #2: http://www.mynissanleaf.com/viewtopic.php?p=507624#p507624
Hawaii: http://www.mynissanleaf.com/viewtopic.php?p=507704#p507704 - down 3 bars. I've only been there twice and in the time I was there, it wasn't hot at all compared to where I live in CA. Perhaps it just doesn't cool down enough at night or in winter?
Layton, UT: http://www.mynissanleaf.com/viewtopic.php?p=508839#p508839

those people are not suffering degradation due to heat, its simply a defective battery batch. You are missing one btw. He lives in the ultra hot region of Northwest Oregon.
 
those people are not suffering degradation due to heat, its simply a defective battery batch.

That's one possible explanation, but you don't have enough data to be sure about it. "Defective" implies that Nissan designed the battery correctly but made mistakes in the manufacturing process. If the electrolyte/electrode formula was no good in the first place, then that's a bad design that may have been corrected later on.
 
LeftieBiker said:
those people are not suffering degradation due to heat, its simply a defective battery batch.

That's one possible explanation, but you don't have enough data to be sure about it. "Defective" implies that Nissan designed the battery correctly but made mistakes in the manufacturing process. If the electrolyte/electrode formula was no good in the first place, then that's a bad design that may have been corrected later on.

Well we can think they changed directions from a course that appeared to be working to try something completely different along with the decision to not test that new course and it backfired on them... or not.

Now, these cells have to be cured and that takes time which means a "hurried toss out the bad and make a new batch before morning" option is not possible. So its either put out what you got or stop the assembly line for several weeks. This makes the decision maybe not the best but definitely quite understandable not to mention the degradation warranty covering 100,000 miles means they have a safety net in place.

Now, is the issue fixed? Probably. After all, it was not a formulation issue its simply a processing error. (my opinion only... at least until enough evidence comes in that will prove me right)

But lets go back to the heat thing. So how did people in very not hot places get 2 years worth of degradation in a few months? We have people in the North that have seen faster degradation in shorter time period than 2011 LEAFers saw in Phoenix.

Provide a statement addressing that
 
johnlocke said:
edatoakrun said:
...Why do those who have such serious anxiety regarding battery temperatures in passively manged packs keep buying LEAFs, and continue sharing their insecurities on this forum?
...I have a 22 mo. old car with 35,000 mi on it and only 73% of its original capacity!..
That is, IMO, extremely unlikely.

How did you determine the original and present capacity?

Owners of "24 kWh" pack LEAFs are fortunate to have the one BEV for which multiple studies on battery capacity loss have been conducted.

You are claiming that your pack has lost a higher percentage of initial capacity in 35,000 miles, than did the four 2012 LEAFs tested over 50,000 miles, subject to brutally high temperatures (all packs averaging over 100F for many months at a time) and the most punishing charge/discharge cycles.

https://avt.inl.gov/sites/default/files/pdf/vehiclebatteries/DCFC_Study_FactSheet_EOT.pdf

Full report here:

https://avt.inl.gov/sites/default/files/pdf/vehiclebatteries/FastChargeEffects.pdf

It would have required a monumental effort on your part to reproduce those extreme conditions in your relatively moderate climate.

When you state:

johnlocke said:
...I have a 22 mo. old car with 35,000 mi on it and only 73% of its original capacity!..
Do you really mean that is what your LBC says your capacity loss is?

And why do you want to believe that Nissan builds a pack with that poor durability, but also that the LBC report is infallible?

My LEAF has a march 2011 build date, over 56,000 miles in a climate only slightly less warm than yours in Summer, and all indications from recharge capacity and range tests are that my pack has now lost close to 20% of its initial capacity (see my six-year-report quoted below) while my LBC now reports over 33.5% capacity loss (44.03 AHr and 66.46%).

...After more than six years, I've never run out of Wh, and never really suffered from "range anxiety" (charge-site anxiety yes, frequently) and largely credit my never relying on my LBC for its estimates of remaining energy capacity or battery capacity loss, for this experience.

Instead of relying on the LBC, I prefer to use only high-integrity data sources, primarily AVTA test results:

https://avt.inl.gov/vehicle-button/2012-nissan-leaf

And parameters that can be measured accurately, kWh received from the grid, miles driven, and time.

Knowing the approximate nominal kWh available to LBW and VLB from my initial charge of "80%" or "100%", and watching the Nav screen m/kWh while I drive, I know both my nominal kWh used, and what are the approximate N kWh remaining wherever I drive, and can avoid all anxiety caused by the often "pessimistic" estimates from the LBC, of kWh remaining.

I also have a pretty good idea of what my LEAF's total and available battery capacity loss over time has been.

At six years and 52 k miles, my best estimates are:

My LEAF's pack had slightly under 19 kWh total capacity (as per AVTA test standards) and about 17 kWh available, when warm, at ~80 F.

That's about a 21% reduction from the 24 kWh Nissan specified, and ~18.5% lower than the average capacity Nissan actually delivered in 2012, according to AVTA testing of multiple LEAF packs...
http://www.mynissanleaf.com/viewtopic.php?f=27&t=23733&start=40

Back on-topic.

If any of you are really anxious (or even only concerned) about the "40 kWh" 2018 LEAF's "40 kWh" pack's passive thermal management, just don't buy one.

Unlike seven years ago when the LEAF was the only real option, there are now several decent BEVs out there with complex thermal management systems.

But I doubt that will still be the case in a few more years, as the path to obsolescence for ATM is already fairly clear, IMO.
 
edatoakrun said:
You are claiming that your pack has lost a higher percentage of initial capacity in 35,000 miles, than did the four 2012 LEAFs tested over 50,000 miles, subject to brutally high temperatures (all packs averaging over 100F for many months at a time) and the most punishing charge/discharge cycles.


If any of you are really anxious (or even only concerned) about the "40 kWh" 2018 LEAF's "40 kWh" pack's passive thermal management, just don't buy one.

Unlike seven years ago when the LEAF was the only real option, there are now several decent BEVs out there with complex thermal management systems.

But I doubt that will still be the case in a few more years, as the path to obsolescence for ATM is already fairly clear, IMO.

Johnlocke has a 30kwh pack, and is amongst a group of owners who are experiencing excessively rapid degradation, AND a modification of percentage-capacity-to-bar relationship. You should see his posting history before jumping to conclusions about what he has.

It's the results of his and other early 30kwh leaf owners that's calling into question the reliability of Nissan's new 40kwh battery packs.
 
Oils4AsphaultOnly said:
...Johnlocke has a 30kwh pack, and is amongst a group of owners who are experiencing excessively rapid degradation...
AFAIK, only rapid gid loss has been reported, and on only some of the packs.

Anyone reported actual recharge capacity test results for their "30 kWh" packs?

As I posted a month ago on the 2016-2017 model year 30 kWh bar losers and capacity losses thread:

http://www.mynissanleaf.com/viewtopic.php?f=30&p=506232

edatoakrun said:
If you want to find actual capacity loss on a "30 kWh" LEAF, I'd suggest you test your pack the same way you would for a "24 kWh" pack, albeit with far fewer of the test parameters and variables known, and with only a single (?) "30 kWh" pack having been tested by a high-integrity source.

The EPA test of a 2016 "30 kWh" LEAF (strangely...) shows the same 31.7807 kWh from a 240 volt EVSE required to recharge after both the city (UDDS) and highway cycle tests.

This could correspond to a ~30 kWh (total) pack, that is ~90% accessible, and recharges at ~85% average efficiency over the entire accessible capacity.

Monitor the kWh your pack accepts (and/or the charge time, and voltage) after similar depletion from fully-charged (240 V) pack, after a similar single-event full (to stop) discharge.

Results should be expected to vary a great deal with pack and ambient temperatures, which I don't know for the EPA tests (?)

I'd guess the EPA might test near the 70F to 80F range?

Anyone know?

In "24 kWh" LEAF pack tests, there is significant variation in charge accepted even for the same pack, in identical tests.

This is evidently due to the LBCs inaccuracy in determining the upper and lower charge limits.

You should expect the same in the larger packs, so do not expect a single test to be determinative.

Remember, you are not able to test total pack capacity, only the capacity your LEAF's LBC allowed you to access during the given charge/discharge cycle.

Repeat, to get a larger sample, and also to determine the accuracy or (inaccuracy) of your LBC in determining its upper and lower pack limits.


Certification Summary Information Report

Model Year 2016...

Test Date 03/11/2015

Test Procedure 81 - Charge Depleting UDDS

Recharge Event Voltage 240...

Recharge Event Energy (kiloWatt-hours) 31.7807...

Total distance (mile):166.410...

Test Procedure 84 - Charge Depleting Highway...

Recharge Event Voltage 240...

Recharge Event Energy (kiloWatt-hours) 31.7807...

Charge Depleting Range (Actual miles) 136.408...

Charge Time[sec]:20733...

https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=36671&flag=1

2017 MY certification appears to use the same test results:

https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=38806&flag=1
 
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