The 40KWH Battery Topic

danrjones said:

I'll be blunt, I'm glad I'm getting rid of it later this year. I don't really want to try and sell it with a bar missing.

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You sound more optimistic than I would be that the car will have 12 bars after another hot summer.

DougWantsALeaf said:

My charging regimen is now DC charging only on a trip when needed (sad for my NCTC), keep battery between 30% and 70% unless driving far.

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20 - 80% routine is also probably fine, but you are certainly right to only DCFC when needed. I take this battery nanny-ing one step further and only charge soon after a drive in the winter (before the battery gets cold) and in the AM in the summer so that the car battery does not sit at a high SoC for long and has had a chance to cool down overnight. Oh, and the car is parked in the shade at home and rarely sits on hot asphalt for any length of time when being used.

Our 8 year old LEAF has an 83 SOH and loss of 1.25 Ahr/year the past two years, so I'd like to think we are doing well by her and the degradation rate will not increase.

That's great for a 2013 Leaf.

SageBrush said:

danrjones said:

I'll be blunt, I'm glad I'm getting rid of it later this year. I don't really want to try and sell it with a bar missing.

Click to expand...

You sound more optimistic than I would be that the car will have 12 bars after another hot summer.

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Yes I know but no choice. I don't want to pay back the CA rebate, so technically I must keep the vehicle for a total of 2.5 years.
not sure they really check but I don't feel like taking the chance. And the end of the year usually has good deals anyway.

but man the SOH keeps dropping....

This AM down to 87.82% with still less than 9200 miles.
I'd post a graph but images here require being hosted elsewhere, correct?


Now there is some good news: The warranty is still has 6 years left, so Nissan may be giving someone a new battery later.

SageBrush said:

DougWantsALeaf said:

My charging regimen is now DC charging only on a trip when needed (sad for my NCTC), keep battery between 30% and 70% unless driving far.

Click to expand...

20 - 80% routine is also probably fine, but you are certainly right to only DCFC when needed. I take this battery nanny-ing one step further and only charge soon after a drive in the winter (before the battery gets cold) and in the AM in the summer so that the car does not sit at a high SoC for long.

Our 8 year old LEAF has an 83 SOH and loss of 1.25 Ahr/year the past two years, so I'd like to think we are doing well by her and the degradation rate will not increase.

Click to expand...

Rate will probably increase as the capacity drops but sounds like its holding up well. Have you lost a bar yet?

danrjones said:

Now there is some good news: The warranty is still has 6 years left, so Nissan may be giving someone a new battery later.

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I had the same thought

DaveinOlyWA said:

Rate will probably increase as the capacity drops but sounds like its holding up well. Have you lost a bar yet?

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One bar down.

I was actually thinking that the rate should decrease as capacity is lost, and IIRC Nissan expected the same. What actually happens in the fleet is probably pretty variable since there are multiple degradation pathways. My capacity loss graph appears to follow the 'less as time goes on' pattern but I'm not willing to call it yet with confidence because of confounding factors that include living in 3 different climates, a probable battery reset before I bought the car at age 3 years, and markedly reduced use during Covid.

SageBrush said:

DaveinOlyWA said:

Rate will probably increase as the capacity drops but sounds like its holding up well. Have you lost a bar yet?

Click to expand...

One bar down.

I was actually thinking that the rate should decrease as capacity is lost, and IIRC Nissan expected the same. What actually happens is probably pretty variable since there are multiple degradation pathways. My capacity loss graph appears to follow the 'less as time goes on' expectation but I'm not willing to call it yet with confidence because of confounding factors that include living in 3 different climates, a probable battery reset before I bought the car at age 3 years, and markedly reduced use during Covid.

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I wish my trend line was as predictable. Nissan messed with the BMS algorithm and still not understanding what they are aiming for but does look like they went the GOM route and is now showing us what they want us to see and not a true reflection of the battery state.

But then again, their SW skills have been questionable in the past and guessing like last time, nothing will change until someone figures out what is wrong and starting complaining.

DougWantsALeaf said:

That's great for a 2013 Leaf.

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Yeah, and I'd llke to take some credit but I honestly think Nissan batteries have lousy QC so for all I know I was lucky and got a good pack.

I agree with you that I can't tell, as most stories are anecdotal regarding battery care vs. Long term battery life.

I do like the "battery lottery" terminology from the Tesla forums though as there does seem to be an aspect of luck involved too.

SageBrush said:

DougWantsALeaf said:

That's great for a 2013 Leaf.

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Yeah, and I'd llke to take some credit but I honestly think Nissan batteries have lousy QC so for all I know I was lucky and got a good pack.

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Not buying that. I have found that most EVers don't tell all when explaining their charging habits. You are simply more aware of what needed to be done and found ways to do it easily. Later versions w/o custom charge settings just encouraged people to think "Nissan took care of it" so I don't have to w/o realizing Nissan was the ONLY manufacturer w/o custom charge settings. They deluded themselves into thinking it didn't matter.

You really wouldn't believe what people do under the impression they are being a "good EVer" and then recommending it to new EVers.

DaveinOlyWA said:

SageBrush said:

DougWantsALeaf said:

That's great for a 2013 Leaf.

Click to expand...

Yeah, and I'd llke to take some credit but I honestly think Nissan batteries have lousy QC so for all I know I was lucky and got a good pack.

Click to expand...

Not buying that. I have found that most EVers don't tell all when explaining their charging habits. You are simply more aware of what needed to be done and found ways to do it easily. Later versions w/o custom charge settings just encouraged people to think "Nissan took care of it" so I don't have to w/o realizing Nissan was the ONLY manufacturer w/o custom charge settings. They deluded themselves into thinking it didn't matter.

You really wouldn't believe what people do under the impression they are being a "good EVer" and then recommending it to new EVers.

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I obviously *think* I know ways to prolong battery life or I wouldn't be doing them, but Doug is right: anecdotes just do not mean much. In part because conditions vary from car to car and from climate to climate; in part for the reasons you mention; and in part I suspect because of wide variation in battery quality from the factory.

I do agree that some of the things that owners do in the name of battery protection make me shake my head. Closed garages in hot climates is a leading example. How would my battery look today if I had started out with a poor quality battery and then carried out all my 'good' behaviors ? I don't really know, but I doubt I would be happy with my battery.

I am by no means trying to say that 'good' behaviors are a waste of time -- far from it. I am saying that we should all be humble in drawing too strong a conclusion how much any one strategy or explanation explains (or does not explain) the car battery health. All we really know, based on battery research and large group analysis, is that heat , fast charging, prolonged high SoC, and Li plating are all degradation accelerants and when present at the same time their effect is greater than their sums. Specifics are lacking, so all we can do is minimize exposure to these risks within the context of keeping the car a useful device for our use cases.

danrjones said:

SageBrush said:

danrjones said:

I'll be blunt, I'm glad I'm getting rid of it later this year. I don't really want to try and sell it with a bar missing.

Click to expand...

You sound more optimistic than I would be that the car will have 12 bars after another hot summer.

Click to expand...

Yes I know but no choice. I don't want to pay back the CA rebate, so technically I must keep the vehicle for a total of 2.5 years.
not sure they really check but I don't feel like taking the chance. And the end of the year usually has good deals anyway.

but man the SOH keeps dropping....

This AM down to 87.82% with still less than 9200 miles.
I'd post a graph but images here require being hosted elsewhere, correct?


Now there is some good news: The warranty is still has 6 years left, so Nissan may be giving someone a new battery later.

Click to expand...

My adjustment FINALLY finished over the weekend. Seems like this one took forever, and it hurt.

SOH: 87.40%
AmpHr: 100.89
Hx: 102.85%


BMS took away over 2.5%. That actually is the biggest adjustment I've had.

Wow, that is a big drop given your limited miles. When is the last time you charged to 100%?

On the same breath, this 2020 M3 owner who posted today is down 12% with not many more miles, so who knows what's expected. (Not meant to be a trolling comment, just that many evs show a range of loss in first couple years).

https://teslamotorsclub.com/tmc/threads/how-i-recovered-half-of-my-batterys-lost-capacity.204712/page-26

DougWantsALeaf said:

On the same breath, this 2020 M3 owner who posted today is down 12% with not many more miles, so who knows what's expected. (Not meant to be a trolling comment, just that many evs show a range of loss in first couple years).

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The Model 3/Y is known to develop calibration errors with certain home charging routines, so unless you have good reason to think that the LEAF correction is also a calibration error, your attempt to imply that Tesla EVs also suffer LEAF level battery degradation is wrong.

DougWantsALeaf said:

Wow, that is a big drop given your limited miles. When is the last time you charged to 100%?

On the same breath, this 2020 M3 owner who posted today is down 12% with not many more miles, so who knows what's expected. (Not meant to be a trolling comment, just that many evs show a range of loss in first couple years).

https://teslamotorsclub.com/tmc/threads/how-i-recovered-half-of-my-batterys-lost-capacity.204712/page-26

Click to expand...

I charged up very close to 100% back on the 19th (?) of February because i had to drive for service at my dealer. Didn't quite hit 100% I believe it was 98%. But I basically never charge 100%. I would guess the previous time was 5, maybe 6 months prior. I've been otherwise keeping it between 30 and 70ish percent.

Ok, so you have been babying the battery. Not sure then what might be driving the loss (real or bms). The fellow in Japan with a 40 just hit 100K miles with lots of DC charges and just over 3 years with SoH of 84% (still 12 bars). This bms is still a bit of a mystery as usage cycle doesn't seem to explain the outcomes.

Sage, yes many (but not all),see some artifical loss due to calibration.

DougWantsALeaf said:

Ok, so you have been babying the battery. Not sure then what might be driving the loss (real or bms). The fellow in Japan with a 40 just hit 100K miles with lots of DC charges and just over 3 years with SoH of 84% (still 12 bars). This bms is still a bit of a mystery as usage cycle doesn't seem to explain the outcomes.

Sage, yes many (but not all),see some artifical loss due to calibration.

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Other than ambient temp, I've tried. Interesting to read someone else's story here of charging to 100% every day.

And who knows, maybe the BMS does need to see a full charge more often. I don't know.

3 years 25K miles, down 11.21%, Not too bad I guess. Of course that's if the BMS reading is correct.

Due to popular request added a mileage column

I keep the charge level between 30 and 70% and no DC charging.

DougWantsALeaf said:

Sage, yes many (but not all),see some artifical loss due to calibration.

Click to expand...

You are grossly uninformed. When a change in charging routine improves the reported range, it is called a calibration issue. Instances where an increase in reported range are not reported are of uncertain cause, of which battery degradation is one possible explanation. The ONLY confident way to document battery degradation is by showing a reduction in energy required to charge from a low SoC to a high SoC under similar battery conditions.

A less accurate but not-bad approach is calculate the energy that leaves the pack as the SoC drops from a high to a low level. This is some variant of Wh/distance*distance but the Wh/distance meter can be tricky or inaccurate

LeafSpy or LeafSpy Pro has a screen that shows power into the pack during charging. You can use that to ~ calculate capacity. It is approximate because battery resistance is ignored and pack hysteresis is a can of worms. See
http://www.wind-works.org/cms/index.php?id=84&tx_ttnews%5Btt_news%5D=3887&cHash=0c4d4be8e984be6345356511f9d73202#:~:text=At%204%20miles%20per%20kWh,Leaf%20on%20a%20full%20charge.&text=Leaf%20Spy%20uses%20an%20On,your%20car%20into%20the%20shop.