Nissan LEAF - General

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1618 posts

Uber Geek

#1997831 17-Apr-2018 14:12

I've noticed that on the 24kw cars that the battery declines to ~90% SoH quite rapidly, then the rate of decline slows down. (the 12th bar on the battery gauge represents a larger % of SoH in order to linearize the scale). I've often though that they drop to ~22kw so rapidly that it would be more truthful to think of them as 22kw batteries.

Given that the 30 Kw batteries are still fairly new to the market, I wonder if they are still in this initial stage of rapid decline and simply haven't reached the point where they plateau and their decline slows. If so, this whole situation may be nothing to stress about. Perhaps Nissan has incorrectly estimated the point at which they plateau and correspondingly not set the 11 to 12th bar threshold correctly.

It might take another couple of years of using the 30Kw batteries to accurately establish their true characteristics.

happyfunball

287 posts

Ultimate Geek

#1997836 17-Apr-2018 14:16

PhantomNVD: But I’d love to get a 30kw 2016 for the price of a 24KW 😉

If you buy it in Japan and import it yourself, thats exactly what you can do right now :)

kingdragonfly

11211 posts

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#1997895 17-Apr-2018 15:11

I'm sure this has been asked 10,000 times, but is imported Japanese Leaf dashboards have an English language option?

SaltyNZ

8237 posts

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2degrees

Lifetime subscriber

#1997897 17-Apr-2018 15:16

kingdragonfly: I'm sure this has been asked 10,000 times, but is imported Japanese Leaf dashboards have an English language option?

The dashboard does - i.e. what is directly above the steering wheel. The stereo head unit in the centre console does not. You can pay ~$1500 to have them replaced though.

iPad Pro 11" + iPhone 15 Pro Max + 2degrees 4tw!

These comments are my own and do not represent the opinions of 2degrees.

kingdragonfly

11211 posts

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#1997899 17-Apr-2018 15:18

Is that a standard double DINN stereo?

SaltyNZ

8237 posts

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2degrees

Lifetime subscriber

#1997902 17-Apr-2018 15:23

I think it is in the lowest spec model, but it's a specific Clariion one for the higher spec ones. It doubles as the control display for all the car functions too. I might get mine replaced at some stage - despite watching about five dozen YouTube videos, I cannot find the right option in the hidden service menu to reset my clock so it's going to be wrong for the next 6 months.

iPad Pro 11" + iPhone 15 Pro Max + 2degrees 4tw!

These comments are my own and do not represent the opinions of 2degrees.

FireEngine

1223 posts

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#1997910 17-Apr-2018 15:29

tripper1000:

I've noticed that on the 24kw cars that the battery declines to ~90% SoH quite rapidly, then the rate of decline slows down. (the 12th bar on the battery gauge represents a larger % of SoH in order to linearize the scale). I've often though that they drop to ~22kw so rapidly that it would be more truthful to think of them as 22kw batteries.

Given that the 30 Kw batteries are still fairly new to the market, I wonder if they are still in this initial stage of rapid decline and simply haven't reached the point where they plateau and their decline slows. If so, this whole situation may be nothing to stress about. Perhaps Nissan has incorrectly estimated the point at which they plateau and correspondingly not set the 11 to 12th bar threshold correctly.

It might take another couple of years of using the 30Kw batteries to accurately establish their true characteristics.

Did you look at the graphs in the report? In a couple of years (ie around the 4yr mark), the 30kwh is likely to decay to some 40% SoH - half of what Nissan predict at the 5yr point. Thats not going to be fixed by a fine-tuning of the indicator IMHO.

Regards FireEngine

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gulfa

321 posts

Ultimate Geek
Inactive user

#1997927 17-Apr-2018 15:48

FireEngine:

tripper1000:

I've noticed that on the 24kw cars that the battery declines to ~90% SoH quite rapidly, then the rate of decline slows down. (the 12th bar on the battery gauge represents a larger % of SoH in order to linearize the scale). I've often though that they drop to ~22kw so rapidly that it would be more truthful to think of them as 22kw batteries.

Given that the 30 Kw batteries are still fairly new to the market, I wonder if they are still in this initial stage of rapid decline and simply haven't reached the point where they plateau and their decline slows. If so, this whole situation may be nothing to stress about. Perhaps Nissan has incorrectly estimated the point at which they plateau and correspondingly not set the 11 to 12th bar threshold correctly.

It might take another couple of years of using the 30Kw batteries to accurately establish their true characteristics.

Did you look at the graphs in the report? In a couple of years (ie around the 4yr mark), the 30kwh is likely to decay to some 40% SoH - half of what Nissan predict at the 5yr point. Thats not going to be fixed by a fine-tuning of the indicator IMHO.

I think that's what many of us will be interested in. That 4-5 yr period. It is hoped by then Nissan will have addressed the problem

FireEngine

1223 posts

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#1997936 17-Apr-2018 16:03

gulfa:

I think that's what many of us will be interested in. That 4-5 yr period. It is hoped by then Nissan will have addressed the problem

I'd certainly be reading the warranty fine-print if I had or was in the market for a 30kwh. Expect resales values to be hit, hard and soon.

Regards FireEngine

frankv

5680 posts

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Lifetime subscriber

#1997940 17-Apr-2018 16:06

FireEngine:

Did you look at the graphs in the report? In a couple of years (ie around the 4yr mark), the 30kwh is likely to decay to some 40% SoH - half of what Nissan predict at the 5yr point. Thats not going to be fixed by a fine-tuning of the indicator IMHO.

If you look at the Y axis scale in the report, you'll see that it starts at about 65%. I figure that the 30kWh batteries will be about 70% in another 2 years, if they continue to degrade at the current rate.

FireEngine

1223 posts

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#1997960 17-Apr-2018 16:20

frankv:

If you look at the Y axis scale in the report, you'll see that it starts at about 65%. I figure that the 30kWh batteries will be about 70% in another 2 years, if they continue to degrade at the current rate.

Yep the Y scale starts at 65% in both graphs, doesn't mean you can't estimate off the screen below that. 70% in two years time? IMHO thats way optimistic, straight line extrapolation gives almost exactly 65% at the 4yr mark but the curve is still a curve, it would need to reverse its curve pretty quick to not be around the 40-50% mark at the 4 yr point - and remember that is still a full year shorter than the Nissan 5yr estimation point

Regards FireEngine

frankv

5680 posts

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#1997982 17-Apr-2018 16:58

It's a curve guesstimated in some ineffible way to approximate the known data points, whose accuracy is unknown. Depending on how many polynomial coefficients you use and how you smooth the data, the curve can turn this way or that. Without the information on how that curve was calculated (and the justification for choosing to do it that way), any extrapolation is questionable.

Having said that, I'd avoid a 30kWh Leaf for now.

zenourn

271 posts

Ultimate Geek

Trusted

#1997991 17-Apr-2018 17:35

frankv:

It's a curve guesstimated in some ineffible way to approximate the known data points, whose accuracy is unknown. Depending on how many polynomial coefficients you use and how you smooth the data, the curve can turn this way or that. Without the information on how that curve was calculated (and the justification for choosing to do it that way), any extrapolation is questionable.

Having said that, I'd avoid a 30kWh Leaf for now.

Most of this detail is in the paper: It's a second-degree polynomial estimated by a hierarchical Bayesian model (allowing coefficients to vary by car). It was selected over a linear model via model comparison (WAIC). At this stage there is no evidence that a more complicated model offers a superior fit.

I agree extrapolation is questionable and is why I didn't have any extrapolations in the paper. I've now got a couple more months of data and a second-degree polynomial fit still appears reasonable. Longer term I wouldn't be surprised if the shape of the curve changed and a hierarchical Gaussian process will then provide a better fit.

GV27

5898 posts

Uber Geek

#1998004 17-Apr-2018 18:26

Earlybird pricing on 30kwh Leafs on TM have now dipped to below premium 24kwh prices.

tripper1000

1618 posts

Uber Geek

#1998352 18-Apr-2018 10:24

FireEngine: Did you look at the graphs in the report? In a couple of years (ie around the 4yr mark), the 30kwh is likely to decay to some 40% SoH - half of what Nissan predict at the 5yr point. Thats not going to be fixed by a fine-tuning of the indicator IMHO.

Yeah, I did, and I noted that they didn't relate decay or SoH to KM's, or the rate of being driven (unless I missed a graph?). A few things about the report that struck me were that it was primarily NZ based and therefore is (naturally) on imported vehicles, which it self will causes bias through selection. If you are using the graphs to extrapolate future decay, the way we import and use the cars will artificially stack the results in favour of older cars.

I am interested if a Leaf dealer can confirm or deny the follow theory:

1) We generally don't bother importing cars with poor battery SOH, so all the older 24 Kw's in NZ are the cream of the crop with better than average batteries, where as the 30kws are so new, not enough time has lapsed pre-import to sort the good from the bad and so both good and bad 30kw's have been imported. The batteries can contain latent conditions that affect their future decline such as variations in manufacture, through to how the previous owner drove and charged them, and weather they came from the milder south of Japan or harsher north of Japan, and weather they were parked out doors or protected in a garage.

2) I reckon kiwis use these cars heaps more and heaps harder than the Japanese - we typically import low KM examples and then rapidly pile on the Kms. This (if true) will produce skewed statistics when graphing SoH vs years. Due to averaging out the results, a recently imported 2013 model with lows Kms and good SoH will look a lot better on those graphs than a 2016 30kw with low kms and good SoH even if 10,000kms of use is producing identical decline of SoH in both cars.

I don't think I'm barking up the wrong tree. Can you see a flaw in my logic?

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