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  #1979519 19-Mar-2018 08:38
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Cybnate:
Unsure how realistic L1/L2 number is as I had only 380 L1/L2s when I got it. Couldn't have charged it 1,250 times since as that would count for 4 times a day or so. Anyone else also seeing skewed L1/L2 numbers in Leaf Spy?


Apparently the Leaf counts a timer-based charger twice - once when you plug it in, and another when it starts charging. Of course, that doesn’t account for all of your four charges a day stat, but it makes me feel this number is meaningless. Kind of interesting and valid at the point of purchase, in terms of ratio of slow to fast charges perhaps, eg ours had 64 slow to 536 quick, giving a fair indication as to how it had been typically charged.

My six-year-old loves plugging in and unplugging our Leaf just for the sake of it, so that plus we always charge with a timer means I just ignore the Leafspy charging stats. (Actually using Leafspy far less now anyway, as I don’t like the feeling of seeing the SOH drop over time, especially now it measures to two decimal places! I appreciate the advice I’ve received from others - just drive and enjoy the experience...)

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  #1979553 19-Mar-2018 09:25
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jonathan18:
Cybnate:
Unsure how realistic L1/L2 number is as I had only 380 L1/L2s when I got it. Couldn't have charged it 1,250 times since as that would count for 4 times a day or so. Anyone else also seeing skewed L1/L2 numbers in Leaf Spy?


Apparently the Leaf counts a timer-based charger twice - once when you plug it in, and another when it starts charging. .....

 

My understanding of L1/L2 counter is as follows: it is a counter of High Voltage Relays openings. It is important as HV DC Relays wear more than AC relays (because of the ARC). At higher charging currents ARC is bigger and possibly more of the fast chargers would wear relays more.

 

That is why Dealership Scanner (Consult) has ability to reset those numbers to zero when the block of relays is changed.

 

Point being - L1/L2 is related to, but not necessarily proportional to the ODO, duration or amount of charge.

 

P.S. I have a number of reports of DC relays failures in traction batteries (not Leafs, but design is the same).





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  #1979566 19-Mar-2018 09:38
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pogo: So... instead of all the doom & gloom about degrading batteries, I was wondering if anyone has any updates about modifying Leafs to use Android Auto or Apple Car Play?


That’s all in the head unit. In S models you can just pop a CarPlay unit in as a replacement with a double din Nissan mounting kit. Any car audio place should be able to do that for you.

On X and G cars (or UK) you will lose the timer functionality but it can also be done.

Basically it’s cheap and easy on a S model but probably not worth it on other models.

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  #1979569 19-Mar-2018 09:41
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I know some people have been experimenting with installing it in the X and G models so that you don't lose the head unit... I don't want to lose the timer functionality, as I'm with flick and we have very cheap electricity overnight.



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  #1980015 19-Mar-2018 17:22
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paulchinnz:

 

One limitation of the flipthefleet data is that their analysis doesn't take potential covariates into account. Perhaps 30 kWh owners are more likely (than 24 kWh owners) to go for long distance drives with fast charging and ergo stress their batteries with higher temperatures.

 



That is definitely me. I do a fair number of long trips with lots of fast charging. That said, my battery is holding up as one would expect with my usage patterns. I'm over 62,000 km in 2 years and 4 months since manufacture and my battery was 91% SoH this morning.   

I'd also be interested to see a breakdown between Japanese 30kWh LEAFs and UK 30kWh LEAFs. The summers in the UK just aren't as hot as they are in Japan.  

Some people definitely have had problems with heat and degradation.  No doubt about it. 





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  #1980018 19-Mar-2018 17:26
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happyfunball:
paulchinnz:

 

And by the way, that published paper isn't peer reviewed (https://www.preprints.org/manuscript/201803.0122/v1) - all well and good if it has been submitted for review, but the paper resulting from that hasn't appeared yet as far as I know.

 



So you think the battery degradation is a result of peoples driving patterns? On radioNZ the interviewed scientist said the likelihood of that was ‘vanishingly small’.


I don't see how it could be vanishingly small if heat was a factor. In NZ, the battery gets hot because the car is being driven for hours and fast charged repeatedly......otherwise the battery just does not get hot. 

If it is time only driving this degradation....then.....yeah....it would be independent of the driving habits. 

I probably need to read the paper closely. I don't know if they are saying time is the only factor. 





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  #1980026 19-Mar-2018 17:36
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Did this drive on Saturday. (2016 30kWh LEAF from the UK)

 

Auckland to Kaitaia and back on the same day..... 

 

Left Auckland at 5am. No traffic. Love it. Charged briefly at Kaiwaka and Raumunga (Whangarei) and then to Kerikeri. I got there just after 9. But then had to wait for the charger for a bit as it was in use. Plus that lead to me going to Countdown and having a wander about.....generally fluffing around.....and I was there over an hour and a half. Got to Kaitaia, via the East coast route, just after Noon. The actual charge in Kerikeri only took 20 minutes. 

 

It was warm up there on Saturday!! 26C after mid day. So LEAF was having trouble cooling down after 300+ km and 3 (two short, one long) fast charges. I charged to 95% at Kaitaia (108km back to Kawakawa), then had lunch and a walk around and left about 2pm. The battery was on 49C at that point..... acceptable.....but it had got to 54C near the peak of the charge and then the charger slowed down near the end and the battery cooled to 53C. Still too hot. So.... Lunch. :-)

 

Went South via SH1 this time and the Mangamukas. Not much traffic around. Generally did 80-85kph. Had lots of battery left. Forget exactly how much. 39%? Charged to 80% in Kawakawa. A BMW i3 turned up just as I was nearly done.

 

But the battery was now back on 54C (very briefly) and the day was still hot. After 10 minutes the battery was 52.5C and the only thing going to cool it was to drive..... But not too fast.

 

Soon after a cold front rolled through on the way to Whangarei and it started to rain torrentially. Like fast-wipers-can't-see-anyway. But it did help cool the battery down.

 

Got to Whangarei and the battery was on 49.9C. Lots of hills in there and heavier traffic meant I had to go faster up them. That kept the battery temp higher.

 

Hmmm. Ok. So went to the Northpower substation and AC charged at 32amp for two hours. My UK LEAF can add 25% per hour this way. After 2 hours my battery temp was down to 45.3C and my LEAF was 100% charged.

 

Good to go!

 

Out of Whangarei I got behind a 90kph Fonterra truck and 3-second-ruled it all the way to Warkworth and was still on 42%. The battery was now 44.1C. After 20% battery use, I'd gone just over 40km behind the truck at 90-95kph. It really makes a difference (dash pic below) to range. You can see the truck in the photo. That far.

 

I charged to 80% at the BP (wanted McDs!) after a short wait as a local was just finishing charging......

 

At they point my hottest pack was on 48C..... Which rapidly fell as I drove home. I got home just after 10pm. But it hadn't been a race. It was a really good day!

 

Summary: definitely doable drive in a day as long as you take a few hours to AC charge and fill the battery while cooling down. I've added a LEAFSpy battery graph captured when I got home. SoH up to just over 91%. But the battery is nice and warm, in the mid-40s / high 30s.









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  #1980101 19-Mar-2018 19:54
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Linuxluver:

 

I don't see how it could be vanishingly small if heat was a factor. In NZ, the battery gets hot because the car is being driven for hours and fast charged repeatedly......otherwise the battery just does not get hot. 

If it is time only driving this degradation....then.....yeah....it would be independent of the driving habits. 

I probably need to read the paper closely. I don't know if they are saying time is the only factor. 

 

 

You should read the study, its only a few pages long and well written by NZ scientists.  I suspect it answers most of your questions.

 

There are many suspected factors outside of time but they are small, the point of the study is that the 30 kWh cars are not holding up as well as the 24 kWh, not by a bit, but by a lot.

 

They took odometer readings into account in the study and pointed out that cars that drive more have a higher SOH, but the rate of decline is the same, as you would expect if high milage was inflating SOH.

 

 


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  #1980176 19-Mar-2018 21:47
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happyfunball:

 

You should read the study, its only a few pages long and well written by NZ scientists.  I suspect it answers most of your questions.

 

There are many suspected factors outside of time but they are small, the point of the study is that the 30 kWh cars are not holding up as well as the 24 kWh, not by a bit, but by a lot.

 

They took odometer readings into account in the study and pointed out that cars that drive more have a higher SOH, but the rate of decline is the same, as you would expect if high milage was inflating SOH.

 

 

Yes, please read the study. I spent a lot of time on that report ;-)

 

One clarification: I found that at the population-level the 24 kWh cars that had traveled further had a higher SoH, while in the 30 kWh cars the opposite was true. In any case, the variation that distance traveled explained compared to age was tiny.

 

We still have a lot more work ahead of us. We have a funding application in to continuously monitor SoC, temp, SoH, charge current, odometer, etc, in cars so we can gain much better insight into the variation and provide guidance about how to best preserve battery health. Several papers indicate that for many formulations of lithium-ion that a high SoC at moderate temperatures for an extended period of time leads to capacity loss. We need to see whether this is important or not for the chemistry used in the 30 kWh battery.

 

 

 

 


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  #1980235 20-Mar-2018 07:14
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@zenourn - I appreciate the work flipthefleet have done in analysing the data and publishing the paper.

 

Can I please check in case you didn't see my previous post: can your data distinguish between these 2 drivers who both do 500 km a week that typically comprises:

 

Driver A = 30 km per weekday and 350 km on Saturdays with 2-3 fast charging events on Saturday only

 

Driver B = 70 km per day with 1 fast charging event every 2-3 days

 

Thanks in advance.


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  #1980533 20-Mar-2018 14:43
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https://www.consumer.org.nz/articles/nissan-leafs-not-going-the-distance

 

Worth reading 

 

Is there any overseas research showing or backing up this information?  I wonder if there are more Leafs that have done high KMs or miles than ours here in NZ?


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  #1980557 20-Mar-2018 15:32
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paulchinnz:

 

Can I please check in case you didn't see my previous post: can your data distinguish between these 2 drivers who both do 500 km a week that typically comprises:

 

Driver A = 30 km per weekday and 350 km on Saturdays with 2-3 fast charging events on Saturday only

 

Driver B = 70 km per day with 1 fast charging event every 2-3 days

 

 

For the majority of cars no, but for some of the cars I do have periods of much more fine-grained data available and can distinguish between these two cases. Part of the reason for our proposed continuous data collection study to be able to distinguish between cases like this (and many others). There is some insight from the more detailed data I've looked at so far but there is a need for a much bigger sample size to gain confidence in the results.


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  #1980564 20-Mar-2018 15:43
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gulfa:

 

Is there any overseas research showing or backing up this information?  I wonder if there are more Leafs that have done high KMs or miles than ours here in NZ?

 

 

There is no other overseas research that I'm aware of but then there isn't anyone else collecting data like us. However, there is a very long thread (over 900 posts) at http://www.mynissanleaf.com/viewtopic.php?f=30&t=23606 with many examples of reported capacity loss in the 30 kWh Leaf.


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  #1980690 20-Mar-2018 20:07
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Thanks @zenourn and keep up the good work.


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  #1980693 20-Mar-2018 20:20
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I just wonder whether it was a bit too early to release the "not peer reviewed" study about the "accelerated reported battery capacity loss in 30  kWh variants of the Nissan Leaf".

 

Consumer is already giving 30 kWh owners advice on how to deal with the situation despite the fact that the study states that:

 

"It is unknown what causes the accelerated reported battery capacity loss that we have observed in 30 kWh Leafs, but other research suggests plausible hypotheses for further test."

 

And also "It is not clear exactly what variation of NMC (nickel manganese cobalt) was used..."

 

I think that potential buyers of both the 30 kWh and possibly the 40 kWh Leafs are likely to be put-off by this incomplete research and about which Nissan hasn't yet made a statement.

 

It is hard enough as it is to convince people to buy EVs and the early release of this incomplete research perhaps doesn't help this situation.

 

 

 

 


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