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Re: How to Check Battery Capacity, Degradation and Range

Posted: Fri Nov 15, 2019 10:49 pm
by GaleHawkins
Thanks Lothsahn.

Figure 5 results for a non updated firmware mirrors what I am seeing at 3.5 years/low 20K miles after 750 charge cycles so maybe the software update is the factor in my case or at least one of the factors in my reported low SOH.

I need to find the variables used to estimate SOH because from the last time I recharged before today SOH has moved from 64.85% to 65.47% not that is a meaningful value change. This spring I will have more time to get the car to a qualified Leaf service center.

Some reported a DC fast charge has given them back one SOH bar and I want to understand how that could possible happen before I do the firmware update. Almost daily the results of using Leaf Spy Pro is moving my understanding of the traction battery function forward.

Re: How to Check Battery Capacity, Degradation and Range

Posted: Sat Dec 19, 2020 2:42 am
by GaleHawkins
GaleHawkins wrote:
Fri Nov 15, 2019 10:49 pm
Thanks Lothsahn.

Figure 5 results for a non updated firmware mirrors what I am seeing at 3.5 years/low 20K miles after 750 charge cycles so maybe the software update is the factor in my case or at least one of the factors in my reported low SOH.

I need to find the variables used to estimate SOH because from the last time I recharged before today SOH has moved from 64.85% to 65.47% not that is a meaningful value change. This spring I will have more time to get the car to a qualified Leaf service center.

Some reported a DC fast charge has given them back one SOH bar and I want to understand how that could possible happen before I do the firmware update. Almost daily the results of using Leaf Spy Pro is moving my understanding of the traction battery function forward.
As an update 13 months later I lost my 4 SOH bar 6 days after the above post. After Christmas holidays I dropped of car 30 Dec 2019 and after some resistance at division level the 40 kWh battery was installed and I picked it up 12 Feb 2020. It got totalled 7 Nov 2020 when a Toyota van shot through a red light. SOC was 89% and 5 weeks later and after running it hard 2 miles testing handling at interstate speeds SOC is at 88%. I am working on getting a parts car and they aren't cheap.

Strangely with the 12v battery disconnected SOH per Leaf Spy Pro stops declining. I plan to get 12v blade cut off switch to test if 12 volt battery being connected leads to faster degradation of traction battery when we get it back on the road.

Re: How to Check Battery Capacity, Degradation and Range

Posted: Thu Jan 21, 2021 8:49 pm
by Ragnar
Any updates on 2019 battery characteristics? I am looking at as used 2019. The first post in this thread talks about fast degradation in the 2018 pack.

Re: How to Check Battery Capacity, Degradation and Range

Posted: Fri Jan 22, 2021 11:59 am
by goldbrick
The 40kWh packs look OK, at least to me. They seem to drop in a non-linear but similar manner on most of the cars monitored here. Also, AFAIK, there are no verified cases of a 2018+ car that has lost a capacity bar yet, in any climate or use case.

Re: How to Check Battery Capacity, Degradation and Range

Posted: Fri Jan 22, 2021 12:03 pm
by LeftieBiker
It looks like there is one case of this, but so far only one.

Re: How to Check Battery Capacity, Degradation and Range

Posted: Fri Jan 22, 2021 1:07 pm
by alozzy
For details on a 40 kWh pack that's had issues, see this post:

https://www.mynissanleaf.com/viewtopic. ... 20#p597396

That's an outlier though (taxi, with many DCFCs)

Re: How to Check Battery Capacity, Degradation and Range

Posted: Fri Jan 22, 2021 7:58 pm
by DougWantsALeaf
While they had a popped cell, they actually were still at 12 bars.

Re: How to Check Battery Capacity, Degradation and Range

Posted: Fri Jan 22, 2021 8:04 pm
by goldbrick
Indeed. On the one hand, it's a bit scary to see that cell. On the other hand, it shows how robust the Nissan design is, in that it can tolerate that kind of wear and change but still work as designed, and hopefully still be safe. I have no idea how close that cell is to causing a problem but the fact that it was still operating as normal indicates it isn't completely fragile.