Nissan LEAF 30-kWh Battery Degrades More Rapidly Than 24-kWh Pack


Analysis of 1382 measures of battery State of Health (SoH) from 283 Nissan LEAFS has detected a faster rate of decline for 30 kWh variants than for the original 24-kWh LEAFs.

That’s the big takeaway from a recently reported study.


Of course, there’s more to it than just that though. The study states:

“At two years of age, the mean rate of decline of SoH of 30 kWh Leafs was 9.9% per annum (95% uncertainty interval of 8.7% to 11.1%; n = 82). This was around three times the rate of decline of 24 kWh Leafs which at two years averaged 3.1% per annum (95% uncertainty interval of 2.9% to 3.3%; n = 201).”

On the upside, findings suggest that high use of DC fast charging had little impact on battery SoH.

The study concludes by suggesting that the rate of decline in the 24-kWh version of the LEAF is acceptable, but suggests that the 30-kWh pack declines too rapidly to be considered within normal  parameters.

Myall, D.; Ivanov, D.; Larason, W.; Nixon, M.; Moller, H. Accelerated Reported Battery Capacity Loss in 30 kWh Variants of the Nissan Leaf. Preprints 2018, 2018030122 (doi: 10.20944/preprints201803.0122.v1)

Myall, D.; Ivanov, D.; Larason, W.; Nixon, M.; Moller, H. Accelerated Reported Battery Capacity Loss in 30 kWh Variants of the Nissan Leaf. Preprints 2018, 2018030122 (doi: 10.20944/preprints201803.0122.v1)

The abstract from the work titled “Accelerated Reported Battery Capacity Loss in 30 kWh Variants of the Nissan Leaf” states:

Analysis of 1382 measures of battery State of Health (SoH) from 283 Nissan Leafs (“Leaf/s”), manufactured between 2011 and 2017, has detected a faster rate of decline in this measure of energy-holding capacity for 30 kWh variants.

At two years of age, the mean rate of decline of SoH of 30 kWh Leafs was 9.9% per annum (95% uncertainty interval of 8.7% to 11.1%; n = 82). This was around three times the rate of decline of 24 kWh Leafs which at two years averaged 3.1% per annum (95% uncertainty interval of 2.9% to 3.3%; n = 201).

For both variants there was evidence for an increasing rate of decline as they aged, although this was much more pronounced in the 30 kWh Leafs. Higher use of rapid DC charging was associated with a small decrease in SoH. Additionally, while 24 kWh cars with greater distances travelled showed a higher SoH, in 30 kWh cars there was a reduction in SoH observed in cars that had travelled further.

The 30 kWh Leafs sourced from United Kingdom showed slower initial decline than those from Japan, but the rate of decline was similar at two years of age.

Improvements in the battery health diagnostics, continuous monitoring of battery temperatures and state of charge, and verification of a fundamental model of battery health are needed before causes and remedies for the observed decline can be pinpointed.

If the high rate of decline in battery capacity that we observed in the first 2.3 years of a 30 kWh Leaf’s lifetime were to continue, the financial and environmental benefits of this model may be significantly eroded. Despite 30 kWh Leafs accounting for only 14% of all light battery electric vehicles registered for use on New Zealand roads at the end of February 2018, there is also the potential for the relatively poor performance of this specific model to undermine electric vehicle uptake more generally unless remedies can be found.

Myall, D.; Ivanov, D.; Larason, W.; Nixon, M.; Moller, H. Accelerated Reported Battery Capacity Loss in 30 kWh Variants of the Nissan Leaf. Preprints 2018, 2018030122 (doi: 10.20944/preprints201803.0122.v1)

Myall, D.; Ivanov, D.; Larason, W.; Nixon, M.; Moller, H. Accelerated Reported Battery Capacity Loss in 30 kWh Variants of the Nissan Leaf. Preprints 2018, 2018030122 (doi: 10.20944/preprints201803.0122.v1)

Myall, D.; Ivanov, D.; Larason, W.; Nixon, M.; Moller, H. Accelerated Reported Battery Capacity Loss in 30 kWh Variants of the Nissan Leaf. Preprints 2018, 2018030122 (doi: 10.20944/preprints201803.0122.v1)

Myall, D.; Ivanov, D.; Larason, W.; Nixon, M.; Moller, H. Accelerated Reported Battery Capacity Loss in 30 kWh Variants of the Nissan Leaf. Preprints 2018, 2018030122 (doi: 10.20944/preprints201803.0122.v1)

Myall, D.; Ivanov, D.; Larason, W.; Nixon, M.; Moller, H. Accelerated Reported Battery Capacity Loss in 30 kWh Variants of the Nissan Leaf. Preprints 2018, 2018030122 (doi: 10.20944/preprints201803.0122.v1)

Let’s hope Nissan has rectified this with the new 40-kWh LEAF and then soon the 60-kWh version.

There’s a wealth of meaningful discussion on the findings presented in this study at the source link below. You’ll find a full PDF version of the study there too.

Source: Preprints

Categories: Nissan

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114 Comments on "Nissan LEAF 30-kWh Battery Degrades More Rapidly Than 24-kWh Pack"

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This is pretty bad, if true. It’s hard to believe that decline of the 30 kWh pack can actually be worse than the 24 kWh. If that remains true at some point the 30 kWh pack will drop below the 24 kWh pack in terms of usable capacity.

So far no one besides Nissan is showing this sort of serious decline in battery capacity. I definitely would not *buy* a new Nissan Leaf until this has clearly been rectified. Lease is another story since you’re passing the buck back to Nissan, and used ones are so cheap that they might still be worth looking at despite the issues

I have a used Leaf myself. I haven’t actually observed much decline during my time owning it, but I don’t drive that much, only charge to 80% and park it under a car port out of the sun.

As someone who’s been an owner of both a 2013MY/24kWh and a 2016MY/30kWh LEAF, i can absolutely attest to accelerated degradation of the 30kWh pack compared to the 2013 / 24kWh model. I’m in Austin, TX so it is a bit warmer here. But that means both versions of the LEAF were subjected to the same warm climate and the 2013/24kWh version fared much better. Our 24kWh LEAF went 25k miles before losing it’s first bar. The 30kWh LEAF lost it’s *second* bar at 18k miles, and according to the battery SOH it’s close to losing it’s 3rd bar at 21k miles. This study is claiming about 3x faster degradation of the 30kWh pack but here in Austin I’m seeing closer to 4x degradation. To add insult to injury: The 30kWh LEAF is far less energy efficient than the 24kWh version. I actually download the full trip data / drive history details from the NissanConnect web services on a daily basis, so i can actually track energy efficiency by day, month, year. Our 2013 / 24kWh LEAF averaged: 4.18 miles/kWh Our 2016 / 30 kWh LEAF averages: 3.73 miles/kWh So as of right now with less than 2 years on… Read more »
Interesting, and I’m sorry for you! However, there are many caveats to be aware of. What you experience in Austin may be different in Kristiansand, Norway, where I live. In fact, if you read that “study” (it is a preview, never published, not peer-reviewed, run by students, and based on “measurements” from LEAF Spy that the authors themselves state they have done nothing to verify, with unknown precision and, worse, unknown accuracy) one of the things discussed is precisely that the two packs appear to have very different temperature sensitivity. Since Austin is very likely hotter than the homeplace of the average car participating in this study (based on volunteers enrolling who go to a web site and punch their numbers) Even with all the weaknesses, short of intentional cheating it is hard to see how the data could be anything like this unless there was a real underlying difference in the packs. One mystery is the graphs showing at what SOH(1) the cars lost the first bar, second bar and so on. As you can see, some lost the first bar at 90%, but others at well below 80%. My own hypothesis is that the car is calibrated to… Read more »

Oops, unfinished business:

> Since Austin is very likely hotter than the homeplace of the average car participating in this study (based on volunteers enrolling who go to a web site and punch their numbers)

… we should unfortunately expect you to experience even more rapid degradation than the average 30 kWh pack in the study.

SOH is not battery capacity. For measuring battery capacity use the GID.

what SOH represents is somewhat uncertain, perhaps its an inverses function of cell resistance. As the SEI layers form the SOH reduces down from 100%

If Nissan (or Tesla) is having any level of ‘formation’ occur while vehicles are on the road, then the SOH will be reducing. SOH is a useful measurement, but its simply the wrong measurement for capacity loss analysis.

GIDs for capacity.
SOH for regen/charge acceptance/turtle mode power.

“My car, a 2012 SL imported from the US and now living in Norway”

That is probably why the degradation has slowed….

Just more evidence that improper battery cooling design is the root cause here.

I have a 2011 LEAF that I unfortunately bought new, and it is down 31%. This is with babying the battery, in the relatively tame weather of the SF bay. Many are blaming the lack of TMS, yet I drove a Fit EV for 3 years, and never noticed a significant decrease in battery capacity. I lease a VW e-Golf now, and in over 30 months, no detectable degradation. Neither of these cars have TMS. So I must conclude this is a *Nissan* problem, more so than a TMS problem. Maybe TMS would solve it, but it seems to me that in my climate, it’s not TMS that is necessary, it is *not-a-Nissan* that is necessary.

I have a 2012 Leaf in NC and am down to 4 bars with 86k. I will never buy another Leaf and I actually had a sign printed for the back of mine which says “go green, buy an EV, just not a Nissan leaf”

How about this summary: both sized battery packs are GARBAGE. And Nissan still doesn’t offer a true thermal management pack. I can’t speak to the 30 kWh packs, but my 24 kWh degradation has been horrible. Best part is the degradation really took off just AFTER it went out of warranty- so good job on that timing Nissan. Maybe in a year or two I’ll still be able to drive to the mailbox and make it home without re-charging..

What I like about this article is the statement, “Let’s hope Nissan has rectified this with the new 40-kWh LEAF..” With known better options now (Bolt, used Teslas, etc) why would anyone in their right mind roll the dice on Nissan again?

I’m in complete agreement with you. It’s almost as if Nissan is single handedly trying to destroy the reputation of EVs with their crappy batteries. This will definitely have an impact on people’s perception.

I’m in the same boat as you. I’m at 68% state of health with 3 months left on the warranty and I know my car isn’t going to make it. It will drop the 4th bar a couple months after and I’ll be left with a car that is almost completely useless to me. I would characterize the degradation of my 2013 24kWh Leaf battery as abysmal. It’s unbelievable to me that Nissan managed to do even worse on the 30kWh version.

I plan to trade in my Leaf for my Model 3 and will never consider another Nissan after that.

By the way nice write up Eric! Love to see all the data.

You probably have the old, pre-Lizzard 24 kWh battery.

The Lizzards have much better capacity retention but started only shipping in 2014.

Unfortunately, both the 30 kWh and the 40 kWh packs use different chemistry than the Lizzard.

The 30 kWh degradation looks pretty bad and that doesn’t bode well for the 40 kWh.

“Nissan is single handedly trying to destroy the reputation of EVs”

For Leaf owners, battery degradation. For other EV drivers, by offering free charging and severe taper with DCFC due to lack of TMS.

Well, John, I can’t afford a Tesla or a Bolt. I am on my third Leaf and I have never had any battery degradation as far as I could see. I lease rather than buy so I have never had to worry about it. All three Leafs have been wonderfully reliable which is huge with me. I have been tempted by the Bolt but the fact that
chevrolet doesn’t pass on the 7500 dollar federal credit kills it for me.

If you can afford a $30k Leaf, not sure how a $37k Bolt (probably more like 33-34k with current deals) is out of your price range.

to bro1999

It is all about the 7500 dollar federal credit. When you lease a Leaf you get the credit. When you lease a Bolt GM Financial takes the credit.

I don’t know about the Bolt specifically, but I think it depends on the dealer and how you negotiate. I got the credit on my Volt at Criswell in Maryland.
You don’t ask, you don’t get.
And you have to be willing to walk away.

To ziv

I have tried to deal with several dealers in the Seattle area and have had to walk away from all of them. They say it is a policy from Mary Barra.

“They say it is a policy from Mary Barra.”

Ummm I don’t think Mary Barra personally sets policy on lease terms. XD

If and when Bolt sales start to sag, then you will see better lease terms. Bolt and Tesla sales are strong enough that they don’t need to significantly drop the pricing. GM does pass part of the rebate value on into the residual value of the car, but not the full amount.

Of course, you can pick up a slightly used Bolt and your rebate is already factored in! But if you can’t afford it then the leaf is a good alternative. Besides, as long as you are leasing a leaf, who cares what happens to the pack? It’s Nissan’s issue now.

That is an irritating response from the dealers, Corvus. I think you are right to tell them to pound sand.

Current lease incentives for a Bolt pretty much suck. If you aren’t in a CARB state, there are 0 incentives. Since the Bolt is in demand, GM Financial pulled back lease incentives.
If you can wait till the summer, there should be much better lease deals on Bolts. Still won’t be as good as CA deals, but better than they are now.

I bought my 2017 Bolt on 3/10/18 and got what I considered a pretty good deal. I did walk away fromo what they said was what they would do. A few hours after they saw what I would do, they called and agreed to my offer.

That willingness to walk away is very valuable, especailly when you actually mean it.

Sounds like unjust enrichment to me. File a complaint online with the Washington State Attorney General’s Office. Watch how fast you get the tax credit.

Waste of time. GM Financial owns the leased car. It can choose how much to pass on to the leasing customer. Currently, it ain’t much for a Bolt.

Yeah, spending ten minutes filling out an online form, and then likely having the dealer cave and hand over the tax credit is a huge waste of time.

Wrong on several counts.
The PURCHASER of the vehicle gets the credit – if you’re leasing, that ain’t you.
And the dealer never gets the credit and doesn’t even have it to “hand over” to you. The finance company that purchases the car and leases it to you, by law, is entitled to the credit. It is not “yours”, you have no right to it, and the AG or anyone else can’t make someone give you something you are not entitled to.

The leasing company ALWAYS gets the credit. That’s the way the tax code is written.
GM Financial has not been applying te entire &,500 as a CCR, but that does not mean you aren’t benefiting from it. Since you lease, the only relevant factor is your monthly payment (most add up any prepayment/”down” to get a true monthly cost). That they apply part of the credit to keep the residual artificially high (which lowers your payment the same as a CCR) makes no difference to you. If you live in CA or another State that taxes the amount applied as a CCR, doing it this way actually saves money.

And you are not locked in to leasing thru GM Financial, there are other leasing companies that will apply the entire amount as a CCR – but your payments will be much higher since the typically assign a residual of around 30-35%.

The 2015 leaf was closer to 18.5k all in.

If you can afford three Leafs, you can certainly afford a Bolt, even factoring in tax credits. Just save longer. Then you’ll have an EV that will last considerably longer and be better use of your dollars.

On a lease, sure. Especially since even if it degrades 30%, it still should be getting the same range as the 30kWh versions. But I agree, buying is definitely dicey.

Exactly. Nissan claimed they fixed this in 2013 with the “lizard battery”. Nope. Here it is 2018, same story. And it’s not just lack of TMS. There is clearly something about the batteries Nissan uses, or the way they manage them. Other non-TMS cars do NOT have this issue, at least in mild climates (based on my direct experience).

I was considering renting an EV for a trip to Hawaii. Rental company has a couple of 2015 LEAFs. Owner indicated that both are down two bars already. This is more than 22% degradation in two years! Hawaii is warm, but it is not Phoenix. Nissan EV depreciation will remain the highest in the industry.

This research confirms that buying a Nissan EV is a large risk, especially if one keeps their cars longer than just a few years. It also makes buying a used Leaf a risk, granted the prices can be quite low, but realistically you need to price in the cost of a new battery as well.

I certainly would not be willing to roll the dice on the new 40-kWh Leaf’s battery and it’s lack of TMS, Nissan has a lot to do if they want folks like me to consider them as a purchase option. This research is hard evidence that their track record up to this point is shoddy.

I bought my Leaf used last year at 30k miles with 12 bars. It lost one at ~37k, now closing in on 52k with 11 bars still, so I doubt I’ll need to worry about replacing the pack anytime soon.

Nissan may have a massive warranty-claim problem soon. Per the IEVs article link below, Nissan warranted the 30 kWh battery to 70% capacity at 8 years (96 months) or 100,000 miles.

Since they’re mostly “sold” on subsidized leases they’ve likely already paid for the problem.

May I remind you that there is a world outside of the US? Hardly *any* of the LEAFs in Norway are leased, and I doubt the lease share is high in Europe overall. And currently Nissan is selling 3x as many of these babies in the EU as they are in the US.

However, I don’t think they are sitting on a warranty bomb here. The numbers seem to show degradation is highly sensitive to temperature, and the problem will be greatly reduced in Europe compared to the US (where EVs are disproportionately popular in hot climates).

The warranty may not apply to business buyers who buy a fleet and then lease it to physical persons, and then Nissan has the US covered as well as the EU…. a sly move, if this was all calculated.

Instead of giving one of the option of replacing a crummy battery with another crummy battery, why not just make a good one to begin with, with active liquid cooling and see how that goes.

Why isn’t Nissan in the Tesla battery consortium?
This issue is SOLVED by better battery chemistry.
Who is the supplier of these batteries?

Nissan sold off its battery division (AESC) to a Chinese company.

Yes – the main issue is the chemistry of the batteries, not thermal management as many cry out.

Tesla’s batteries don’t even start active cooling until they pack gets well above 30C. And then it let’s the pack get up to 50C.

Even in moderate climates where batteries rarely get above 30C, LEAF batteries degrade at a rate far faster than what I consider acceptable. Batteries should last the life of the car (150k miles, 10 years) in most circumstances before losing more than 30% capacity.

The only time active cooling should be necessary is in very hot climates (sustained and regular temps over ~40C/100F+) or when quick charging multiple times a day.

Well said.

I think in 5 years, high volume economy EVs won’t have a TMS, because they’ll use chemistries that can handle 45C without issue. They already exist.

The main issue is most definitely the lack of active cooling system. The real problem, according to what I’ve read, is when the battery gets hot and stays hot for 24 hours or more, or fast-charging when the battery is hot. That’s what degrades it the fastest. (High humidity while charging when the battery is warm is also a problem.) With only passive cooling, the battery takes a long time to cool down, so stays hot much longer than it would with an active cooling system. Also, when using a DC fast charger, the lack of active cooling means the battery heats up a lot. If the car is driven an extended distance right after DC fast charging, as happens on an extended trip, then it likely won’t cool off so long as the car is still being driven. If you have any doubt the latter is true, then read this report from a 30 kWh Leaf driver in the UK: On a recent quick two day trip from Scotland to Cheltenham and back I managed to get south without any battery overheating problems, possibly because traffic was heavy. Coming back the next evening, with the outside temp at 18C,… Read more »

If you all are interested in the technical reason why Nissan batteries are degrading so quickly there is a really informative YouTube video of professor Jeff Dahn giving a talk on the subject. He is an expert on battery longevity and was hired by Tesla a year or so ago to make their batteries even more long lasting.

It boils down to Nissan choosing the worst battery chemistry for heat related degradation and then choosing not to thermally manage the battery. This is a deadly combo that is resulting in rapid degradation for their customers. The fact that they haven’t corrected either of these I’ll advised engineering decisions 8 years in is really quite astounding.

Do you have a link for that one?

Of course DC fast charging had little impact on charging since it’s throttled back. Sheesh.

on overall degradation of the battery. Since they throttle charging back when the battery is too warm as it would cause more rapid degradation of the pack. That last is according to Nissan.

That’s only for the ’18 Leafs, as since Nissan sold off its battery division to a company that required it be more strict with warranty replacement costs, thus the very conservative charging profile Nissan went with for the ’18 Leaf that easily neuters fast charging rates.

This is the review from the guy that did the Bolt battery teardown.

My ’11 LEAF was only QCd a dozen or so times and I live close to the coast in Southern California. I still needed a new battery after 5 years.

QC or not, Nissan keeps on putting batteries with very high rates of capacity loss in the LEAF.

You’d think that the bean-counters at least would have prevented this with the 30kWh LEAFs since they have an 8 year warranty in the USA now. At the very least, one would expect them to be better, not worse than the 24 kWh LEAFs.

They are going to shell out a ton of money for replacements.

They’ll repurpose them into light poles and probably even just start putting refurbs in as warranty replacements.

On a positive note for IEV’s standing in the EV community, this technical study referenced and cited a 2015 IEVs’ technical article reviewing BMW’s, Tesla’s, and LG’s battery thermal management systems by fellow mechanical engineer and frequent-contributor George S. Bower.

Leaving aside what I think of Leaf’s batteries with no active temperature management, the study raises some questions …. the team has used LeafSpy to collect data. This comment sums up pretty much what I thought …

Comment: To my understanding are the numbers publish based on the SOH value reported by LeafSpy.
I believe this value is an undocumented value and it is not clear what it stands for.
It must be a different value than Nissan is using, otherwise my Leaf shall not show a full health scale, bur0t LeafSpy shows SOH 81% at my 30 kWh Leaf.
Either SOH or the value shown by Nissan are wrong.

In another words, who the heck knows how LeafSpy calculates SoH???

The fact that 30kWh is not dramatically better than the original, is what I would expect (with no profound change to the design), but it’s quite unlikely that Nissan would replace it with a pack performing that much WORSE (as the study suggests) than the original one.

I think the study is simply flawed.

While that is a good point, there are also multiple reports of people in warm and hot climates in the USA losing capacity bars very quickly to the point of losing 4 and qualifying for warranty replacement.

IMO the easiest way to estimate the total capacity of the pack without relying on the cars computers is to measure the energy required to recharge from empty to full. At the very least you could do this to confirm that the BMS data matches reality on a statistically significant number of cars without pulling the pack apart and measuring capacity directly using specialized equipment.

I am aware of the issues experienced in hot climates. But the report claims something way beyond the general understanding of the issue … and bases it on data from some app where nobody knows how the app really arrives at SoH figures. I can see where people find the app useful for things, but to use it as backbone for a study of this sort, is just not very wise, if you ask me.

Studies are conducted targeting a specific results that the sponsors want.

I own 30kwh Lear for over a year. No noticebke degradation.
Thermal management is a scape goat to pick on Nissan.
Leaf is a practical working electric car at an attractive price point.
May not be suitable for dpecs naxis

What is “dpecs naxis”?

SoH is not calculated by LeafSpy, it is reported by the LEAF’s BMS. With 30 kWh batteries, 81% SoH is displayed as 12 capacity bars on the dashbord. You’ll go down to 11 bars when SoH gets to around 77%. Look at the second chart near the top of this page, that shows the relationship between SoH and battery capacity bars.


Too many people don’t realize how much Nissan games the capacity bars. They don’t realize that an 8% drop in indicator bars is actually a 15-20% drop in battery capacity! The battery pack will be down to 60% or less before that fourth bar drops.

Don’t know about the 30kWh but from what I read about the 24kWh, the first bar loss takes twice the battery percentage loss compared to the other 11 bars.

I hate to defend Nissan as I do believe their batteries need to be better. However:

Other manufacturers don’t prominently display the battery capacity like Nissan does. So I guess at least they are showing people the state of the battery up front.

The first bar is the only one ‘gamed’ and I believe that’s because you always get an initial calendar ageing loss in the first year or two pretty much regardless of how much the battery is used. So I think it’s fair the give the first bar a bit extra. Presumably other manufacturers don’t count that initial calendar aging as part of the capacity or their chemistries don’t suffer so much from it.

I agree that it’s nice Nissan gives people battery health up front, but it’s unfortunate Nissan is using deception as a tactic to minimize perceived capacity loss.

this ^^^^

Same with ‘perceived range’, where Nissan games the state of charge of the battery in such a way that the GoM shows much higher range when the battery is nearly full. Which is the case when people are making a test drive.

From 100% SoC to ~80%, you’ll lose the percents fairly slowly, and the GoM shows you an incredible range. But as soon as battery SoC dips below that 80%, the percents fly off and ‘available’ range drops like a stone. And available range is not an extrapolation of recent driving, but some theoretical “if you now drop your speed to 80 km/h and draft behind a truck, you might be able to cover this distance”.

From about 5% SoC, the meter jumps to —, so in essence, that last 5% is not actually usable.

And then they widely advertise the totally unrealistic, unachievable NEDC range.

In terms of “marketing”, Nissan is the worst of the bunch.

“…you always get an initial calendar ageing loss in the first year or two pretty much regardless of how much the battery is used. So I think it’s fair the give the first bar a bit extra. Presumably other manufacturers don’t count that initial calendar aging as part of the capacity or their chemistries don’t suffer so much from it.”

It’s actually not calendar life, it’s miles driven (or more accurately, the number of times the battery is put through charge/discharge cycles). Calendar life is actually a separate and somewhat unrelated limitation on li-ion batteries.

It’s the nature of the beast that li-ion battery packs in BEVs lose capacity more rapidly in the first few tens of thousands of kilometers distance of driving than they do later. It’s not just Nissan’s battery chemistry, as you can see from this graph of Tesla Model S capacity loss over distance:

Are there similar statistics from other BEVs to compare to this? Has there been any information about the battery composition/chemistry of the new 40kwh compared to the 30kwh?

Tesla batteries degrade at about 1/3 the rate of the Nissan 24 kWh – they’re very good.

To be fair, a lot of that has to do with Tesla battery packs having a much higher capacity, so they get cycled less frequently over the same distance as the Leaf’s smaller battery pack.

That’s why I find it shocking — assuming it’s true — that the Leaf’s 30 kWh battery pack is degrading faster than the 24 kWh packs. It should be the reverse!

To be fair to Nissan, I had a Renault Zoe for 3 years, with a very small battery (23 kWh) and it showed absolutely zero loss after 3 years and 90k km.

The Nissan battery simply sucks.

It’s not just the bigger pack leads to less intensive cycling. After all, plenty of Tesla vehicles get used in demanding back to back to back DCFC scenarios using most of the battery each time. It is also that the base capacity degradation of the chemistry is lower, the chemistry is far more heat tolerant, losing very little additional at 50 degrees C versus 25 degrees C, and the pack is activity thermal managed even when the car is parked. The vampire drain mostly goes towards the BMS when all energy conservation settings are enabled.

It is a travesty that any professional reviewers recommended the Nissan Leaf or other BEVs with high cell degradation (Kia Soul EV). Many of those reviews should be revisited and the 2018 models should have a big warning that the vehicle manufacturer has not cared about cell degradation in the past.

(⌐■_■) Trollnonymous

and that’s why I no longer recommend the Leaf to friends and family.

Cool, they used R and ggplot 🙂 I will contact the authors regarding additional analysis, in particular looking at the 24kWh’s by year should be interesting, if they haven’t done so already.

Not cool, the 30kWh results. Although in our specific case it’s Nissan that took all of the gamble, b/c we leased our 2017 for 2 years at a very attractive price.

Also, at this pace the majority of 30kWh’s may be eligible for a warranty battery replacement. That will hurt. And yeah, they better come clean quick about what happened there and what’s the forecast impact on the 40kWh’s.

Holy cow; this probably nixes the Leaf 2.0 from my list, since no major changes were made in its battery.

My 12 Leaf had a SOH of 85% and 12 bars (barely) when the 3-year lease ended. And the range had dropped substantially.

I’m not completely convinced the issue is cooling, since my car lived in cooler Pennsylvania (no lizards). *Winters* were very hard on it, though. Chemistry has to be the main culprit.

75% after 6 years? OMG. That STINKS.
Our tesla is almost 5 years old and is still more than 93%.
If other EVs act like the leaf, no wonder ICE owners will scream.

Not picking on people who love the LEAF, but this battery performance obviously has gone from bad to worse, and it is to the point of being simply unacceptable for most. The only saving grace to me personally, is at some time I may pick up a 3rd EV (would be my 6th overall) used 30 kwh Leaf for under $1000. If it becomes common knowledge that the 30 kwh battery is this atrocious, the used price of that sorry car should drop through the basement. Agree with others that it is better to look at the used competition and simply walk away from Nissan. If Ghosn or whomever is in charge now releases these turd batteries without adequate testing, then anything they say in the future regarding the 40 kwh or even the 60 kwh batteries, is beyond suspect UNLESS THEY BUY THE IDENTICAL GM-DESIGNED LG POUCHES, and INDEPENDENT TESTING from maybe Prof. Kelly at Weber University is done (since he’s already learned to be distrustful of any Nissan statements) to make sure the performance of the battery assembly (temperature regulation, etc.) is basically equivalent to the BOLT ev/Ampera-e. My personal 22,000 mile over 1 year old BOLT ev… Read more »

whoa, repeat of wilting LEAF again?

A denser packed battery pack with more heat generated… hmmm what else can go wrong with it.

“denser pack with more heat generated”

Heat generation does not depend on how dense the pack is. Assuming the same internal resistance, heat is determinied by how much power you draw from it. The car and motor being the same, the power draw is equal and thus heat too.

This can be slightly different in fast charging however, where on average you’ll charge less frequently, but with the average charge taking a longer time. Total fast charging time should be the same.

A bigger, denser pack may or may not heat up at similar rates to the smaller one, but it will definitely be slower to cool down in the absence of active cooling.

(⌐■_■) Trollnonymous

Whatever happened to what was supposed to be the better “Lizard” battery?????

I think the Lizzard chemistry was only used in the 24 kWh pack.

The 30 kWh and 40 kWh packs are completely different chemistry.

The improvement proved to be rather over-hyped. Yeah, some improvement, but not nearly enough.

But this report makes me wonder if Nissan went from bad battery chemistry to worse, or at least mediocre chemistry to bad, with the change from the 24 kWh pack to 30 kWh.

25,000 miles on my 2015 S, 88% SOHm should hit 90% when the weather warms up more.

(⌐■_■) Trollnonymous

OK, these social media bar crap at the bottom is sucking up real estate on my browser.

I vote to get rid of this mess.

What I find completely mystifying is Nissan’s approach to this problem. We know they are trying to hit a price point so I’m not surprised they haven’t put in an active cooling system for the batteries. However, how the heck do you explain that when they released the 30kWh version of the Leaf they also:
1. Upped the warranty from 5 to 8 years
2. Removed the ability to charge to 80%.

Everyone knows that charging past 80% is hard on the batteries. It would cost them absolutely nothing to add that option back in and yet they chose not to. How can you explain that? Given the degradation rate they are going to end up warrantying the battery on every single 30kWh Leaf, so there is no way they are saving money here.

I cannot reconcile this complete incompetence in design with their huge experience designing electric cars. Is there any rational explanation for this behaviour?

Removal of the 80% “long life” charge option occurred starting with the 2014 model year, 2 years before the introduction of the 30 kWh battery. Supposedly the decision was driven by the EPA telling Nissan that they were going to revise the window sticker range estimate downward, because the EPA apparently thinks owners are too stupid to choose between two settings based on their needs.

Agreed that the VERY least Nissan could do to help the battery degradation problem is restore the 80% charge setting, but it has nothing to do with the switch to the bigger pack.

“Everyone knows that charging past 80% is hard on the batteries. It would cost them absolutely nothing to add that option back in and yet they chose not to. How can you explain that?”

Nissan should allow the driver to set the limit of charge to anything he wants. It is at least comprehensible from a marketing point of view — altho not honest — that Nissan eliminated the “charge to 80%” setting the early Leafs had, because removing the ability to charge less than 100% artificially inflated the EPA’s range rating.

But as you point out, it makes no sense at all when considering utility or longevity of the vehicle. To me, it’s a pretty strong indication that Nissan is a lot more interested in milking as many leases as they can out of the money they’ve already spent developing the Leaf, rather than spend any money on building a better model.

This is short-term thinking of the sort which has lead to the demise of all too many established companies in the era of “greed is good”. 🙁

According to that data I must have one of the best 30kWh LEAFs! I’m at 94% SOH after nearly 2 years. It only started at 98% when new! (UK based).
NZ climate not hugely different from UK so I don’t know what’s going on here.

My 30kWh Leaf (10/15 build date) is currently showing 97+% SOH. at 20 k + So. Cal miles.
Over 200 fast charges and battery temps well over 120* F, on 1 k mile road trips, with multiple / consecutive (5+) fast charges.

LeafSpy Pro reads total useable capacity at 27.2 kWh currently. I figure actual battery degradation, at somewhere between 3-5% from the start of the 3 year/ 45k mi. Lease, almost 18 months ago.

My 2016 SL with about 19,600 miles on it shows according to Leaf Spy Pro to have a total capacity of 22.1 KWH and a SOH of 77.05%…..I have lost 2 bars already and i’m so angry about it and can’t wait to make Nissan give me a new battery. For reference I live in Texas and have fast charged over 400 times and level 1 and 2 charged 100 times.

My 2017 Leaf S is showing 86% SOH in Leafspy, after 6 months and 4500 km. It was showing that amount after 2 months and 2500km too. I’ve tried to keep the SOC below 80%, although I’ve had it over that probably a dozen times so far.

Either the dealers who had it before I leased it kept it charged at 100% constantly and it’s damaged, or it’s never been run down to 0% and the BMS hasn’t been calibrated yet.

You haven’t been down to Zero yet. No worries, and don’t be in a hurry to do so. Your range is still probably very close to 100 mi.

“NZ climate not hugely different from UK so I don’t know what’s going on here.”

Many people have expressed puzzlement over the disparity between how much or how little degradation is seen in the Leaf battery pack, even among those living in the same region or climate.

We can only speculate as to the cause. I note that it’s not just getting the battery pack hot that causes degradation; it’s the pack getting hot and staying hot, especially while charging, that causes degradation. Different people may have different driving habits that makes a big difference here, or — I’m engaging in pure speculation here — perhaps it’s that some people’s garages cool down a lot at night, while the car is charging, while others’ garages remain warm at night.

For those looking for a used Leaf with a good battery pack: in cooler climates look for a Leaf made between April of 2013 (earlier 2013 leafs use the old 2011 chemistry) and the end of 2015. The packs made in 2015 (the “Lizard pack”) are best, but even these will still degrade in heat. If you live in a hot climate, forget the Leaf altogether. Avoid pre-4/’13 (unless they have new batteries) and 2016-2017 Leafs!

Sage advise, from someone who obviously reads the mynissanleaf blog. Those blog testimonials really get the daytime ambient 100* F heat issue, off of the back burner, so to speak.

I can definitely attest to the rapid battery loss.

I bought a 30K Leaf 16 months ago and it seems to have lost more than 10% of it’s range. I have about 22K miles on it and I can barely get to work and back, which is only 66 miles. When it was new, I had about 30 miles of range left. Now, I sometimes have less than 10. I haven’t lost any bars yet, but I have definitely lost the range.

I live and commute at the beach and it never gets anywhere near 100 degrees. This is a huge disappointment to me, since I still have 20 months remaining on my lease. I hope I don’t have to plug it in every day at lunch.

That is sub-optimal. I have an early 2013 Volt and it is hard to compare, but it looks like this spring I have finally seen a change in my battery stats. I have always seen 10.3-10.4 kWh used when I fully use up the pack and switch to the genset. This spring I have seen 10.2 kWh used a couple times. So after 5 years I may have lost 1% of my pack capacity. Or not. When the weather warms up a bit more I hope the missing 0.1 kWh will return.
The problem with this is that of course I still get the same amount of miles in cold weather, 26-30 miles, and on warm days this spring I have seen my usual 44-46 miles of AER.

Mine isn’t doing so hot either…My 2016 SL with about 19,600 miles on it shows according to Leaf Spy Pro to have a total capacity of 22.1 KWH usable and a SOH of 77.05% and has lost 2 bars.

I bought it new May 2017 and it was build May 2016 so it had been sitting at the dealership for a YEAR in Texas heat constantly charged and barely touched. I purchased it with 300 miles on it. At this point i’m doing everything I can to kill the battery so I can get a new one already. I can get about 60 miles on the highway with a 100% charge which I am not okay with. Love the car, hate the battery technology Nissan settled with.

OMG. Can this be true? That is, true for the average case, not just a small non-representative sample. If it is, then how is it that the significantly more rapid aging escaped the notice of Nissan engineers? Did they not do accelerating aging tests before putting the 30 kWh battery pack into production?

Very troubling. Also troubling is that sales of the new Leaf are significantly higher than the previous model year. I wonder if new Leaf buyers really understand just how questionable Nissan’s battery tech is. 🙁


As I and others have mentioned, does anyone know if the 40 kWh pack has any meaningful differences from the 24 and 30 kWh packs? Sometimes the devil is in the details, so maybe the 40 kWh pack will be great – I just don’t know, but now I have no reason to believe it will be better.

To your point above about deep cycling – yes, that is a well-known cause of battery degradation. I’m wondering how much degradation data exists for the old (and rare) 40 kWh Tesla batteries.

A TMC posts says “It is estimated that there are about 400 S40’s out there. Some may have upgraded or traded in. The actual number is less.” (source below)

Statistics isn’t my area of study; how many data sets would we need for a representative sample? At any rate, given the low number of total units, I think it would be difficult to get a meaningful sample size of data for the Model S40 without the active cooperation of Tesla. I think that is very unlikely to happen. So far as I know, all the data that’s publicly available on Model S pack degradation has come from third party surveys.

Tesla never built any physical 40 kwh packs, rather they fullfilled those orders with a software limited 60 kwh pack. So, one would expect any 40 kwh Model S’s out there that haven’t been software upgraded to 60 kwh would probably have less battery degradation than the 60 kwh models, since they’ve never used anywhere near full capacity.

Wait wait wait
Can some one care to explain , how come other cars with no thermal management do well like ionic and golf. do not heat up when fast charged ? or run hard ?

They use different type of batteries. Different Chemistry, different power dissipation. Also, Golf carts rarely measure range loss.

By “golf” do you mean the VW e-Golf?

Here is what one article reports:

The company’s engineers have tested the e-Golf’s battery pack in places like Death Valley and Arizona, as well as cold-weather climates, and found no dramatic impacts on performance. VW’s Darryll Harrison recently told AutoblogGreen that the Panasonic lithium nickel manganese cobalt oxide cells used in the e-Golf had “the lowest self-warming tendency and the lowest memory effect of all cells tested. The need for a cooling system wasn’t there.”

Of course, this doesn’t mean that VW has given no thought to temperature issues. The company says it has developed a Battery Management Unit with an intelligent thermal control that allows the pack to remain within an optimal temperature window, and that waste heat is quickly directed into the chassis, away from the battery. (source below)

That reads a lot like a press release from VW, so I wouldn’t take all of it at face value. But it’s not hard to believe that VW chose a battery chemistry less susceptible to degradation from overheating than Nissan did.

Yes i meant e golf
The issue here is heat and not chemistry cannot eliminate that
Chemistry can reduce effects of heat.
But without active heat management , heat will build up eventually , by driving hard and quick charging.
If it happens in 2 charges in leaf , it will happen in 3 charges in ionic and e-golf. And eventually we all know, where that leads.

in case of e golf, they did not have the space to all that liquid cooling etc. They just squeezed the cells under the seat.

looks like VW has some nano technology where waste heat is quickly directed into the chassis, away from the battery. but heat and cold do not come back when its -20F or +50F outside . They achieve this without any thermal management systems. unfortunately , Tesla had no access to this physics defying tech.

It’s almost certainly not any sort of “nano” tech. It’s probably very basic engineering. For example, in the Bolt EV’s battery pack, there is an aluminum plate between each pair of cells; a plate which absorbs heat and carries it down to some sort of base plate through which coolant is circulated. Even if there wasn’t any liquid cooling, the aluminum plates would help with conduction carrying waste heat away from the cells, and would also help with spreading it out evenly, avoiding hot spots in the battery pack. Did Nissan engineer the Leaf’s battery pack for that kind of rapid passive heat conduction? I have no idea. But if Nissan did not, then that would certainly be part of why they have such problems with premature battery aging. As I said in a previous post, the real problem with heat is the battery getting hot and staying hot for an extended period of time; I’ve seen that time limit reported at 24 hours. If VW engineered its packs for better heat conduction away from the cells, then that may be at least part of why the e-Golf has not experienced the kind of premature aging that Leaf batteries have.… Read more »

“As I and others have mentioned, does anyone know if the 40 kWh pack has any meaningful differences from the 24 and 30 kWh packs? Sometimes the devil is in the details, so maybe the 40 kWh pack will be great – I just don’t know, but now I have no reason to believe it will be better.”

There is a list of changes to things like the anode and cathode composition, but others have observed that the chemistry still requires active cooling, which still isn’t there in the 40kwh pack. The best we can hope for is that the 40kwh pack degrades quickly ONLY when hot…

Nissan seems to have really screwed the pooch with this one. I can hardly believe that the 30 kwh packs are so bad. Nissan could take a massive hit on warranty replacements before it’s all over if the rate of loss keeps up.

The question is whether they are comparing the real remaining capacity or just 2 different SOH algorithms.

My real range declined in line with SOH.

Those scatter plots are pretty broad. It would be nice if they correlated health to more than one variable. Age in months is one measure, odometer miles and number of DCFC sessions would be good to know too.
Heck, include the number of L2 charges as well.

I own a 2016 30kwh Leaf. Age in months, is the one thing I can’t control. But there is a lot I can control with charging patterns.

Is it better to top it up each night, or drive it until it’s down to 20% or so and then charge it?

I’ve pointed out the following to the authors of the paper.

Their curves appear to have been constrained to be 100% state of health at 0 years of life. They do not have or do not show any data very near 0 years yet they are apparently happy to let that constraint effectively define the curvature of their curves.

To my mind, curves fitted without this constraint would be a better predictor of the actual trends in the data.

I would also remove all data points that were at or very near 100% because it looks to me as if the state of health measure is cut off at 100%. Many data points appear to be sitting just at 100%.

The basic conclusion of the paper is clear directly from the data and doesn’t rely on any curve fitting. Where curve fitting might be useful as in predicting future performance. However, I would have reduced confidence in the curves shown for the reasons outlined above.

Yes, it is hard to believe that a 2016 30kWh pack would degrade faster than a 2016 24 kWh pack. In fact, it is so hard to believe that it is not true. Nissan has found that the difference is due to a software error in the battery controller. That error is being corrected by software upgrade that is the subject of a current Nissan service campaign. (perhaps InsideEVs will want to revisit this article)

So what is actually involved to carry out the software upgrade the 30 kw cars, in NZ Nissan do not want to recognise imported Leaf cars so can we do the upgrade on line?

Nissan NZ are now offering this fix for NZ$115. Since they (Nissan NZ) never sold 30kWh Leafs in NZ, they weren’t really obliged to support them, but they were losing face by ignoring the issue completely up until now.