Nissan LEAF - General

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522 posts

Ultimate Geek
+1 received by user: 320

#3013585 23-Dec-2022 19:34

When I was using a Leaf to commute 5 days a week I used a smart plug to cut off charging when it would be ~70% charged, but only on Fridays. On Sunday I had the smart plug turning back on to get the battery to 100% and I let it charge to 100% on Mon-Thurs. My idea was to not leave in at 100% over the weekend but to have a full charge by the time I needed to drive to work. I was doing a 72km return trip and most of that was 100kph, so in winter I didn't have a huge amount left from my 24kWh battery when I got home. I doubt that the battery would have suffered much from being at 100% for a few hours, probably a lesser factor in battery deterioration than calendar aging or simply running the battery through a bunch of charge cycles. I bought the car when it was 2 years old and used it for 5 years and it still had >70% SoH on the battery and still was making the 72km trip just fine.

lmnop

22 posts

Geek
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#3013702 23-Dec-2022 23:18

100% charging is mainly a concern when the battery is maintained at a high temperature after it is charged.

When at high charge levels, don't park somewhere where the asphalt is hot under the car and/or the car is in direct sunlight. THAT is the sort of thing that is going to severely curtail battery life. Moreso the hot asphalt cooking the battery from below.

GV27

5978 posts

Uber Geek
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#3014919 29-Dec-2022 07:01

Any tips for polishing out light scratches from the entertainment unit on the ZE1? It seems the slightest swipe will leave a small mark.

John225

11 posts

Geek
+1 received by user: 3

#3019482 10-Jan-2023 13:21

GV27:

The GOM is near useless in the wet... but I've only driven it in the wet and I've yet to do the tyre pressures, which will be tonight's job.

The 2020/2021 refreshed screen is really good but there is already a bit of wear on the screen itself from just being used as a touch screen. Hopefully by the time it's really unusable I'll have some options for what I can swap it with.

GOM is even more inaccurate in the wet when the car becomes a bit less aerodynamic.

You could try and get a glass screen protector.

MarkH67:

When I was using a Leaf to commute 5 days a week I used a smart plug to cut off charging when it would be ~70% charged, but only on Fridays. On Sunday I had the smart plug turning back on to get the battery to 100% and I let it charge to 100% on Mon-Thurs. My idea was to not leave in at 100% over the weekend but to have a full charge by the time I needed to drive to work.

I use the charge timer to charge my car to 80% just before I leave for my work commute. When I get to work it has discharged to about 60%. So it sits around at work at 60%. When I get home it is around 40%. I disable the charge timer, then charge the car and time the charge so that I can enable the charge timer when the car reaches 60%. Then the car will stop charging until the charge timer starts it at about 5am, and it will reach about 80% SOC when it is time to depart for work. This way the car spends most of the time at about 60% SOC and excursions above or below this SOC are brief. Charging the car takes about an hour per 10%, or 6 minutes per 1%, so it is quite easy to work out the time required to reach 60%. This becomes a bit less in winter when it is cold, so I tend to over charge my set points a bit in winter. My work commute is quite a bit shorter than yours MarkH67.

GV27

5978 posts

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#3019569 10-Jan-2023 14:04

John225:

You could try and get a glass screen protector.

Finding one locally that fits the 9" Nissan Connect Nav screen is proving hard so I'll nab one from Buyee.

Been quoted 500 GBP for the 6.6kw PDM + shipping which I'll take as soon as they get one in stock. It will transform the usefulness of the car overnight.

MarkH67

522 posts

Ultimate Geek
+1 received by user: 320

#3019602 10-Jan-2023 15:04

John225:My work commute is quite a bit shorter than yours MarkH67.

Well, mine WAS 36km each way for 72km total. Now it is 6 minutes walk each way, so I don't even need a car to get to work. I'm now using micro-mobility to get around most of the time.

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GV27

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#3020736 13-Jan-2023 07:52

John225:

You could try and get a glass screen protector.

Yup, I think this is the way to go. I'm going to have to get a cut-down tablet hydrogel one to fit as I'm worried anything else will damage the screen and there's no readily available 9" ones - the local Leafs are an 8 inch screen, from what I can tell.

GV27

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#3022478 17-Jan-2023 06:09

So it looks like the new Nissan Note in Japan has the same 9" Connect screen but with a different housing shape.

I've found a screen protector on Buyee that will cover the touchscreen itself, it's not going to be possible to get one to cover the whole unit including volume knobs due to the angled edges on the Note. But it will do for now.

Batman

Mad Scientist
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#3022488 17-Jan-2023 07:39

MarkH67:

When I was using a Leaf to commute 5 days a week I used a smart plug to cut off charging when it would be ~70% charged, but only on Fridays. On Sunday I had the smart plug turning back on to get the battery to 100% and I let it charge to 100% on Mon-Thurs. My idea was to not leave in at 100% over the weekend but to have a full charge by the time I needed to drive to work. I was doing a 72km return trip and most of that was 100kph, so in winter I didn't have a huge amount left from my 24kWh battery when I got home. I doubt that the battery would have suffered much from being at 100% for a few hours, probably a lesser factor in battery deterioration than calendar aging or simply running the battery through a bunch of charge cycles. I bought the car when it was 2 years old and used it for 5 years and it still had >70% SoH on the battery and still was making the 72km trip just fine.

i have tried charging the car and discharging, to all sorts of levels, over a 2 year period. makes zero difference to degradation in my car at least. so i just gave up and charge to 100%. did not degrade any faster or slower.

i have concluded based on that, degradation is a lottery, as much as how you treat the battery, if not more lottery than treatment.

HarmLessSolutions

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#3022496 17-Jan-2023 08:25

Batman:

MarkH67:

When I was using a Leaf to commute 5 days a week I used a smart plug to cut off charging when it would be ~70% charged, but only on Fridays. On Sunday I had the smart plug turning back on to get the battery to 100% and I let it charge to 100% on Mon-Thurs. My idea was to not leave in at 100% over the weekend but to have a full charge by the time I needed to drive to work. I was doing a 72km return trip and most of that was 100kph, so in winter I didn't have a huge amount left from my 24kWh battery when I got home. I doubt that the battery would have suffered much from being at 100% for a few hours, probably a lesser factor in battery deterioration than calendar aging or simply running the battery through a bunch of charge cycles. I bought the car when it was 2 years old and used it for 5 years and it still had >70% SoH on the battery and still was making the 72km trip just fine.

i have tried charging the car and discharging, to all sorts of levels, over a 2 year period. makes zero difference to degradation in my car at least. so i just gave up and charge to 100%. did not degrade any faster or slower.

i have concluded based on that, degradation is a lottery, as much as how you treat the battery, if not more lottery than treatment.

The rate of charge is more pertinent in regard to rate of degradation I suspect. Home AC charging at 7kW (or even 11kW) has a much lesser effect than Rapid DC charging, particularly when done in conjunction with higher discharge rates such as during a longer journey when both things cause the battery temperature to rise substantially. Heating of the battery is what does the most damage and isn't mitigated by any active cooling system as it is in other EVs.

https://www.harmlesssolutions.co.nz/

John225

11 posts

Geek
+1 received by user: 3

#3022623 17-Jan-2023 11:42

MarkH67:

When I was using a Leaf to commute 5 days a week I used a smart plug to cut off charging when it would be ~70% charged, but only on Fridays. On Sunday I had the smart plug turning back on to get the battery to 100% and I let it charge to 100% on Mon-Thurs. My idea was to not leave in at 100% over the weekend but to have a full charge by the time I needed to drive to work. I was doing a 72km return trip and most of that was 100kph, so in winter I didn't have a huge amount left from my 24kWh battery when I got home. I doubt that the battery would have suffered much from being at 100% for a few hours, probably a lesser factor in battery deterioration than calendar aging or simply running the battery through a bunch of charge cycles. I bought the car when it was 2 years old and used it for 5 years and it still had >70% SoH on the battery and still was making the 72km trip just fine.

Batman:

i have tried charging the car and discharging, to all sorts of levels, over a 2 year period. makes zero difference to degradation in my car at least. so i just gave up and charge to 100%. did not degrade any faster or slower.

i have concluded based on that, degradation is a lottery, as much as how you treat the battery, if not more lottery than treatment.

Since battery SOH varies so much by ambient temperature, it would be difficult to accurately pinpoint battery degradation rates quickly due to various charging regimes. My car when I got it was about 6 years old and battery SOH had declined to just bellow 80%. This would correspond to an average degradation of about 3.3% per annum. I haven't quite got to the 2 year anniversary of purchasing it yet but annual degradation looks like it will be about 1.6% under my charging routine. Still not fantastic. The car had pretty much been exclusively fast charged in Japan (1500 fast charges) and I pretty much exclusively slow charge it. I also generally use less than 50% of its capacity between charges. I'm not sure I could call 50% shallow cycling. 1500 charges over 6 years is about 250 per year. There are about 250 working days per year, so probably a daily commuter vehicle in Japan. From its odometer it would have done less than 50km per charge in Japan. It's highly likely it wouldn't have been charged over 80% most of the time. MarkH67, 30% degradation over 7 years corresponds to more than 4% per annum. I would consider the battery done at around 60% SOH. My car was degrading faster per km than yours when it was in Japan.

This article has some good insights into why batteries degrade. https://batteryuniversity.com/article/bu-808b-what-causes-li-ion-to-die

The sweet spot of 3.92V per cell, I think corresponds to about 62% SOC in a leaf. Early Leaf's chemistry is LMO, and this is particularly sensitive to temperature. The article would seem to indicate that time spent at high or low SOC degrades the cells faster, particularly time at high SOC when also at high temperatures. This could be why Nissan supplies replacement cells at about 50% SOC, this will be for maximum shelf life. I wonder if the detrimental effects of repaid charging are due solely to the heat generated in the process. The discharge rates in early Leaf's is going to be fairly high due to the small battery. There is not much you can do about that without significantly altering the way you drive.

This article has some good information on shallow cycling. https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries.

If you divide the 10% DOD cycles by 10 to get equivalent full cycles, you can see that the batteries lifetime capacity is 2 or 3 times as much by shallow cycling. Note; that big battery EV's are going to have lower discharge rates and are going to shallow cycle their batteries more often than small battery EV's. Both of these things will prolong battery life.

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HarmLessSolutions

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#3022726 17-Jan-2023 13:43

This owner's well monitored case study is interesting for a couple of reasons.

Firstly he is managing to maintain a steady SoH by his charging strategy and minimal distances travelled, which while possible in his situation is probably not practical usage for most Leaf owners.

Secondly the scatter graph (from Flip The Fleet) show that battery degradation accelerates as the car ages and SoH declines. I imagine this will be the result of owners maximising battery charging limit and extent of discharge as the range declines. This is definitely so in our case as the battery range declines to the point that anything less than a full (100%) charge has become less than we require for a return trip during our usual travels.

https://www.harmlesssolutions.co.nz/

John225

11 posts

Geek
+1 received by user: 3

#3022760 17-Jan-2023 14:37

HarmLessSolutions:

Secondly the scatter graph (from Flip The Fleet) show that battery degradation accelerates as the car ages and SoH declines. I imagine this will be the result of owners maximising battery charging limit and extent of discharge as the range declines. This is definitely so in our case as the battery range declines to the point that anything less than a full (100%) charge has become less than we require for a return trip during our usual travels.

I May have to rethink my charging routine. It looks like the stable SOC is much lower than I've been assuming. Staying entirely below 40% wont work for me though.

I've put accelerating degradation down to increasing cell divergence as the pack ages. The weakest cell determines pack capacity and gets exercised hardest as the pack is cycled. As you've pointed out usage patterns don't change as the battery ages and capacity declines, so the pack tends to gets cycled deeper as it ages which accelerates the degradation of the weaker cells in particular.

Even if you require 100% SOC you can still minimize time at that SOC if your use pattern is predictable.

smac

338 posts

Ultimate Geek
+1 received by user: 40

#3022765 17-Jan-2023 14:44

John225:

I May have to rethink my charging routine. It looks like the stable SOC is much lower than I've been assuming. Staying entirely below 40% wont work for me though.

I've put accelerating degradation down to increasing cell divergence as the pack ages. The weakest cell determines pack capacity and gets exercised hardest as the pack is cycled. As you've pointed out usage patterns don't change as the battery ages and capacity declines, so the pack tends to gets cycled deeper as it ages which accelerates the degradation of the weaker cells in particular.

Even if you require 100% SOC you can still minimize time at that SOC if your use pattern is predictable.

That's the situation I'm facing I think, my overall battery performance is being smashed by a few rogue cells. I really don't want to fork out for a whole swap yet, but I'm guessing getting a few swapped is going to cost similar to getting a whole battery swapped, because the whole thing still needs to come out. Anyway know some rough numbers?

afe66

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#3022814 17-Jan-2023 16:10

smac:
John225:

I May have to rethink my charging routine. It looks like the stable SOC is much lower than I've been assuming. Staying entirely below 40% wont work for me though.

I've put accelerating degradation down to increasing cell divergence as the pack ages. The weakest cell determines pack capacity and gets exercised hardest as the pack is cycled. As you've pointed out usage patterns don't change as the battery ages and capacity declines, so the pack tends to gets cycled deeper as it ages which accelerates the degradation of the weaker cells in particular.

Even if you require 100% SOC you can still minimize time at that SOC if your use pattern is predictable.

That's the situation I'm facing I think, my overall battery performance is being smashed by a few rogue cells. I really don't want to fork out for a whole swap yet, but I'm guessing getting a few swapped is going to cost similar to getting a whole battery swapped, because the whole thing still needs to come out. Anyway know some rough numbers?

You are probably not in Dunedin but the head of automobile electrics at the polytech at one stage ran a EV repair course which included how to remove pack and ID poor cells and replace them. I did the first introductory course yrs back on electrical safety.

Possible your local polytech elect engineering school might do similar

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