Nissan Leaf battery degradation data: 24 vs 30 kWh batteries

Nissan Leaf battery SoH data

In a recent study 283 Nissan Leafs manufactured between 2011 and 2017, had their SoH (State of Health) measured 1.382 times. The data is from 82 Nissan Leafs with 30 kWh batteries and 201 with the 24 kWh variants.

The measurements were made by using a OBD device and the Leaf Spy app.

 

The study has some interesting conclusions and I recommend you to read it (only 14 pages), but in this article I’ll focus on one:

  • 30 kWh batteries are more affected by charge/discharge cycles (distance traveled) while 24 kWh versions were more affected by time.

 

Why are 30 kWh batteries more affected by charge/discharge cycles?

It’s not surprising that the 30 kWh versions suffer more from charge/discharge cycles, since they are more often charged to 100 %. Remember that the option to limit the charge to 80 % was removed when the 2014 model year debuted (to game EPA range ratings). This means that none Nissan Leaf with the 30 kWh battery has this option.

If you want to improve your electric car battery lifespan, you should know that it’s better to charge to 80 % and discharge till 0 % than to charge to 100 % and discharge to 20 %. Nonetheless, if you can use the battery between a SoC (State of Charge) of 80 and 20 % even better… And if you really want to take care of your battery, try to use it only between 70 and 20 %.

Moreover, having the battery sitting at 100 % SoC is worse with the 30 kWh version than it’s in the 24 kWh variants. Because in the same conditions the 30 kWh battery will likely be hotter. In the 24 kWh battery pack, each module has 4 cells, while in the 30 kWh variant there are 8 cells per module. A more dense battery pack will dissipate heat more slowly.

 

Why are 24 kWh batteries more affected by time?

It’s also not surprising that the 24 kWh versions are more affected by time and older Leafs show much higher degradation levels, since the “lizard” battery only arrived in 2014 with the 2015 Nissan Leaf.

  • 24 kWh battery (model years 2011-2014): higher degradation levels
  • 24 kWh battery (model years 2015-2016): lower degradation levels (“lizard battery”)

While the “lizard” battery cells remained with LMO cathodes, they had the electrolyte improved to be more heat tolerant. Only in 2016, Nissan finally started using NCM cathodes in their battery cells with the introduction of the 30 kWh battery version.

 

Anyway, I think that this information is important if you plan to buy an used Nissan Leaf. Choose wisely.

Thanks “Leaf Owner” for the heads up!

 

 

More info:

https://www.preprints.org/manuscript/201803.0122/v1

This Post Has 27 Comments

  1. The information is useless, because the information given by Leaf Spy does not mean it’s the true. For example, in my case, i have about 38000km, and every time i use 2 or more QC, my SOH rises to 100%. After a few days, it goes to the 96~98%…

    There’s only an effective test that can tell the true: discharge the car until the low battery warning appear and then charge to 100%. Do this always using the same charging current. Whit these values, measure how much energy was needed to charge.

    1. While SoH isn’t 100 % reliable, I wouldn’t say it’s useless.

    2. You are right.
      The displayed SOH value is only a calculated value. Not exactly, but can be thought to: Ah”in”/Ah”nominal”.
      If you charge with “granny-cahrger” (10A), the BMS will get miscalibrated.
      If you start using it from edge to edge, then the BMS will “recalibrate”.

      I bought my first leaf in France, and had a trip to Hungary ~2.000kms. It was produced in August 2013, one of the first “Gen2” 24kWh. When I have sit in forst, the SOH was about 90% and the Hx was 88%. After 4 QCs (and depleting the battery 5 times) SOH raised to 100% and the Hx was _above_ 100%. After arriving home, I started to use the granny charger, and after 4 months, the SOH and Hx was both ~91%.

      An other fact (much more interesting):
      Here in Budapest we have a small taxi-fleet, of Leaf-s. 10pcs Visia 24kWh, produced in 2015-2016.
      Recently a driver had “measured” each one with LeafSpy.
      The most shocking result: after 105,756 kms and 2,234 QCs (and 75 L1/L2), SOH=93,31%, Hx=91,66%.
      Two thousand QC session.
      The others are mainly the same. (The lowest mileage was 75k km and the lowest SOH was 89%)

      I think, this fact simply annihilates the above “study”.

    3. I just wanted to show, that the SOH value depend very much on the mode of use, so if I don’t compare these habits, then my results will be worthless.

      And an other data:
      I bought a 30kWh Leaf (prod. date 2017.02) also in France, it was about SOH=96%, Hx95%. I have subscribed to LeafSpy as a beta-tester, and I received an update just when I was driving the new car. After that (and some QCs), SOH jumped to 102%, Hx=104%.
      :))))

    4. Leaf’s SOH is reliable. But for this it has to be well calibrated: The value of SOH, with mild temperatures and after several full loads and deep discharges (good calibration) is very reliable.

  2. Good those batteries come with an 8 years warranty. The 24kWh had 5 years warranty only.

  3. Can you show us the same data for Tesla EVs?

  4. Very interesting data. I don’t remember exactly, but Tesla data are looking much more optimistic. And module design resulting in poorer heat management is not the only reason. I would say that in Panasonic cell MNC material can be of the higher quality. So maybe AESC (is the name still AESC?) needs better quality control…
    It could be one more reason to switch to LG Chem

    1. Panasonic for Tesla vehicles produces NCA chemistry cells.

  5. Interesting reading but some info is wrong:
    Both 24/30kwh batteries have 4 cells/module.
    And
    You have the alternative to set 80% charge limit also for 2014> cars: in Navi (for hi spec Teknas) or in combimeter (for Low spec Visias).
    (at least for Europe market) /: Henrik

  6. How do the bars shown in the display correspond to SOH for the 24/30 Leafs?

  7. Is the SOH calculated by the BMS or by leaf spy itself.
    That rate of capacity loss on the 30kWh leafs seems alarmingly quick
    Makes me think something hasn’t been correctly tuned for the larger pack

  8. Woah, this is kind of alarming. Glad I leased my 2017 Leaf instead of buying it. I got Leaf Spy in December, and it’s shown around 86% SOH fairly consistently since then, with battery temperatures between -10C and 5C. The alarming part of that is that is that the Leaf had 2500km on it in December, and now has 4500km on it, so it’s barely been used.

    Range available seems to be what one would expect, although it’s hard to tell because it’s winter here in Ottawa, so it’s mostly been city driving with the heater on, and snow tires on it. Temperatures take ~10-15% off the range, the snow tires take another 5-10%, and of course, the heater takes some too.

    Maybe I need to recalibrate the BMS somehow? I’m hoping that LeafSpy isn’t compensating for battery temperatures when it calculates the SOH.

    1. SOH is calculated by the BMS, not by LeafSpy.
      Here in (the sometimes warm) Europe, we see, that during winter, when it’s cold, then the BMS calculates differently, compared to a warmer day. My car had “almost constant” SOH during the cold, but when the battery temperature got above 12 deg Celsius, then it falled 3% (Between when I stopped the car at the evening, and when I started it next morning. Without charging at that night.)
      So the temperature is definietly taken into account, and not only a simple multiplier.

    2. Interesting MNMN. I’m going to eventually try to recalibrate the BMS according to what I read on some forum, which would be running it down to turtle mode, then charging to 100%.

      As well, I’ll see what it says when the temperatures around here finally get up to 15C.

    3. If the first “recalibration” fails, try it again, but do the charging with QC (and not at home). If you have time, then let it go above 80% (SOC). Then charge it to 100% at home, and let the balancing periods to happen.
      The ambient (outer) temperature is not too important. If all the temp sensors inside the pack show values above 5 deg Celsius, then you can charge without risk.

      1. Thanks MNMN. I’m not sure when I’m going to have time to retry. When the car was showing it was charged to 100%, Leafspy showed 24.3kwh capacity, which is 87% of the 28kwh that’s supposed to be there when new. Battery temperature was ~14C, so that should go up a bit when it’s warmer, but not much, maybe 25kwh.

        I first got LeafSpy at 2500km/4 months, and it already showed SOH at 86%, and stayed at 86% until I tried recalibrating. I ran it down to Turtle mode, then charged to 100% on L1. It’s now reading SOH 88%, at 5500km and 8 months, which is still a low outlier on this chart.

        I’ve only had this car over the winter, so no excessive heat, and I’ve rarely charged above 80% or gone below 30%. Only 2 DCFC sessions. One up to 50%, and another at 22KW up to 90%, both in below freezing temperatures.

        Glad it’s a lease, but that was the plan anyway. When the lease is up, there will be a bunch of better longer range options.

  9. I have 155000km (97000 miles) done in my e-NV200, in 23 months.
    SoH at 88, Hx at 83.7%. Battery capacity left – 18.3kWh.
    Battery rarely ever gets higher than 6 temperature bars, but e-NV200 has active cooling

    1. That’s great (in my opinion).
      Can you tell us, how many QCs and L1/L2 charging sessions were made till now?

    1. It is pretty remarkable to think (soon) future EV batteries will last 15-20 years, without too much chemistry change. Scientists will most likely improve that as well.

  10. “It’s also not surprising that the 24 kWh versions are more affected by time and older Leafs show much higher degradation levels, since the “lizard” battery only arrived in 2014 ”

    @Pedro Lima
    This makes no sense. Lizzard batteries should show much “lower” degradation levels, not “higher”.

    It would be really great to see a separate diagram for the 24 kWh “Lizzard” batteries (2014+) because I suspect, they would show much better values than the older ones.

    1. That’s exactly what I meant, but looks like I wasn’t clear. I’ll rephrase that part to make it more clear 🙂

      24 kWh battery (model years 2011-2014): have higher degradation levels
      24 kWh battery (model years 2015-2016): have lower degradation levels (“lizard battery”)

      This is why the study says that the 24 kWh batteries are more affected by time, since older Leafs didn’t had “lizard” batteries.

  11. Any updates? If the plotted line continued for 3 more months (Mar->Apr->May->Jun) it’d be at 80% by now. Is that what actually happened?

    If, as some suggest, this is just Leaf Spy being unable to “interpret” the health of the 30kWh batteries, then at some point the intepretation curve and people’s actual experience will diverge more clearly.

    Also, has Leaf Spy itself had any insights into how Leaf Spy performs with 30kWh batteries?

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