Battery Degradation of a high mileage Leaf

[DougWantsALeaf]

It does feel like the adjustments have become smaller over time.

 

[granlundii]

From the research I have seen and discussed with experts, some of the recommendations on charging are not true. Actual list should be more like this:
- Avoid frequent quick charging
- Avoid frequently charging to 100%. Never leave the car at 100% for many days.
- Keep the car cool (easier said than done)

Low SoC seems to actually reduce the degradation, as opposed to many recommendation on the internet.

Degradation seems to slow quite a lot after loosing the first 10-15 %, so that is nice.

Mine Nissan Leaf is soon 11 years old (early 2014 model), now with a SOH of 81 %. Admittingly, the degradation is reduced to some extent here in Finland due to us having only 2-3 warm months per year...

 

[sineadeworc]

Hello there,

I recently bought a second hand Nissan Leaf Tekna from 2019 and now it almost has 180.000km's on the odometer. In the beginning I didn't wanna bother with Leaf Spy, and still I don't use it actively.

However I have found out some interesting things: the degradation with a Nissan Leaf is mostly time based, so no matter if your Nissan Leaf from 2018/2019 has driven 180.000km or 50.000km totally. The degradation is atleast going be 11% after 4 years.



Mine however has a degradation of 15% roughly: a month ago it was still 16% but now the SOH is all of a sudden higher, which I kinda expected. The previous owner was a leasing costumer, who drove a lot.

That didn't scare me off buying a high mileage Nissan Leaf: because it saves quite some money, and the state of the car is almost as new. It also has no issues at all, and I still manage to drive more than 200km on a full battery.



The only think I found out today is: when the SOC gets below 10% it often would start dropping very quickly, in comparison to the drop from 100% to 10% which goes normal.

Basically it's a bit unstable: 8 out of the 96 battery cells, that are displayed in Leaf Spy are supposedly "Weak Cells" and I did some searching about this.

It seems to be quite common with high mileage EV's: and I have already driven the Leaf to 0% several times. Where I witnessed, that the SOC would drop first from 8% to 5% for example. And finally to 0% which increases the range anxiety. But then all of a sudden, it would jump back to 3% for example.

The explanation would most likely be: below 20% SOC the battery cells aren't that balanced anymore, and the BMS might try to balance it more. But in the end it's the weakest battery cell, which will activate turtle mode when one of the cells gets below 3volt?

I'm not sure about it: but just searching on Google, I can see it's not something unique for only Nissan Leaf. It does occur at Ioniq's as well, despite those EV's having a higher SOH usually.

So getting a highly mileage Nissan Leaf is totally fine: but don't trust blindly on Leaf Spy. Because according to Leafspy, I still had 16.9% SOC left. But I have no idea, when Turtle Mode will actually kick in?

But I still had 6kWh left in my battery, which should be in theory enough for another 50km's. Because my average consumption is 12.3kWh/100km.



Today I actually did 11.7kWh/100km and from 100% until 0% I drove 227.7km. But it includes some city driving of the last few days, as I charged to 98% on Monday.

My 2021 leaf has 136000km, I recently got a leafspy the car % started fluctuating drastically in recently. On one journey started 100% 220km, after just 36km it started was at 85%, seconds later 58% 40% 25%10% then 5% and 0% but was still driving ok, until the tortoise mode came on, speed dropped and had no acceleration and would only go 60km/hrs. Then the % started going up, all the way to 58% but still in tortoise mode. I was afraid to stop to see it would reset, I case it wouldn't start again, so when I got to my destination I switched it off and on and it did reset, that has happened a fea times since

 

[DaveinOlyWA]

My 2021 leaf has 136000km, I recently got a leafspy the car % started fluctuating drastically in recently. On one journey started 100% 220km, after just 36km it started was at 85%, seconds later 58% 40% 25%10% then 5% and 0% but was still driving ok, until the tortoise mode came on, speed dropped and had no acceleration and would only go 60km/hrs. Then the % started going up, all the way to 58% but still in tortoise mode. I was afraid to stop to see it would reset, I case it wouldn't start again, so when I got to my destination I switched it off and on and it did reset, that has happened a fea times since

You have a failed cell.

 

[DaveinOlyWA]

From the research I have seen and discussed with experts, some of the recommendations on charging are not true. Actual list should be more like this:
- Avoid frequent quick charging
- Avoid frequently charging to 100%. Never leave the car at 100% for many days.
- Keep the car cool (easier said than done)

Low SoC seems to actually reduce the degradation, as opposed to many recommendation on the internet.

Degradation seems to slow quite a lot after loosing the first 10-15 %, so that is nice.

Mine Nissan Leaf is soon 11 years old (early 2014 model), now with a SOH of 81 %. Admittingly, the degradation is reduced to some extent here in Finland due to us having only 2-3 warm months per year...

Comment; why charge the car up to 100% then not drive it? "several days at 100%?" Reality states if you are charging beyond your immediate need plus a buffer then you are overcharging. Be it 100% or 75%. The lower, the better.

"Degradation slows after 10-15%" Does it? Or is the BMS manipulating data to make you think that? Or does it take the BMS that long to adjust the pack to your driving needs? If not, how do you explain "increases" in capacity? (A physical impossibility btw...)