The 40KWH Battery Topic

Well, all I can go on is the data I have. Here is the web photo of the supposedly empty 40 kWh Leaf on leaf spy.

Leaf spy shows 9.8% remaining on empty - so I think given the numbers I had, that's interesting.
My daily or semi-daily correction certainly has increased since it got warm.
Until I can prove otherwise, I'm going to assume I do indeed have a bit over 10% degradation.

Sorry if I'm late with the post but https://cleantechnica.com/2020/01/26/2018-nissan-leaf-60000-mile-update/ from Jan 26, 2020 said

Using an OBD-II Bluetooth dongle and the LeafSpy Pro app, the battery state of health is 86.8%.
...
Given that this car has been in the desert Southwest for nearly all of its life, those numbers are actually not that bad. About half of these miles were in the Phoenix, Arizona metro area, and the rest in and near El Paso, TX. Fast charging was also used regularly, so there were many times when the battery pack’s temperature got quite hot

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IIRC, this person during their Uber/Lyft driving was the one putting ice thru the service plug hole in the rear seat area hump (normally covered by a plastic panel) to bring down battery temps/sensor temps.

edit: Seems right: https://mynissanleaf.com/viewtopic.php?p=546024#p546024.

DougWantsALeaf said:

the ongoing debate on the 62kW discussion is whether the SOH shown is true battery capacity, or capacity given to the user.
...

One belief is that Nissan starts with a 3-4% buffer on the battery (say 2-2.5kW)

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You talking about kWh?

DanJones, are you Lemon-Tea Leaf?? I thought you went with a Kona.

DougWantsALeaf said:

DanJones, are you Lemon-Tea Leaf?? I thought you went with a Kona.

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No that's not me. I found it online searching for a leafspy shot if an empty 40 pack.

danrjones said:

Does anyone have a leafpy reading for SOC at zero usable range?

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I did from some testing I did awhile back. Let me see about getting that uploaded to the internets. And I also showed about 9.2% via LeafSpy with dashes where the remaining mileage would normally be on the dash

HerdingElectrons said:

danrjones said:

Does anyone have a leafpy reading for SOC at zero usable range?

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I did from some testing I did awhile back. Let me see about getting that uploaded to the internets. And I also showed about 9.2% via LeafSpy with dashes where the remaining mileage would normally be on the dash

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Thanks! I guess this also means one must define what "empty" means. Are the dashes when you hit turtle mode? My idea was to assume Nissan is holding back 4 of the 40 kWhs, therefore, when you hit "empty" you can take that as the bottom for your calculation. But then everyone may treat empty as slightly different - 0 miles on the GOM. Or turtle mode. Or when the car refuses to move. I'd argue empty is when you hit turtle since turtle isn't a super useful car but YMMV. But It should really be empty when Nissan won't let you use the hidden portion of the battery.

One can do some sensitivity analysis on my previous calculation. I have two pieces of data for empty - rounding them we can say 10% SOC and 9%. I'll also toss in 8% just to see what that would do. (Reminder my data was at 5% usable and that equated to 10% on Leafspy so I'm using that and adjusting)

(miles driven/Eff = kWh used -> kWh used/battery % used = usable batt capacity -> usable batt cap / original usable = remaining capacity)

(Empty is 10% SoC) 126/4.1 = 30.7 kWh -> 30.7/0.95 = 32.3 kWh -> 32.3/36 = 89.7%
(Empty is 9% SOC) 126/4.1 = 30.7 kWh -> 30.7/0.94 = 32.7 kWh -> 32.7/36 = 90.8%
(Empty is 8% SOC) 126/4.1 = 30.7 kWh -> 30.7/0.93 = 33.0 kWh -> 33.0/36 = 91.7%

Further I'm not confident on my 4.1 miles per kWh number, so we can re-run the analysis using some variations with that as well.

(Efficiency 4.1) 126/4.1 = 30.7 kWh -> 30.7/0.95 = 32.3 kWh -> 32.3/36 = 89.7%
(Efficiency 4.4) 126/4.4 = 28.6 kWh -> 28.6/0.95 = 30.1 kWh -> 30.1/36 = 83.7%
(Efficiency 3.8) 126/3.8 = 33.2 kWh -> 33.2/0.95 = 34.9 kWh -> 34.9/36 = 96.9%

Seeing this data I'd argue that the bottom SOC makes a difference but having the correct efficiency into my calculation makes a much larger difference, and I'm not confident on that 4.1 number. I'll need to repeat the experiment but reset my trip meter and write down the readings from MyLeaf app for each trip in the experiment.

For me, "empty" on a Leaf as either turtle comes on or car will no longer move are close enough. User inaccessible capacity is useless to the user.

I know we had earlier discussion about "reserve" and it's frankly nothing I want to even bother discussing. It's not clear to me that there's one universally accepted definition of "reserve" on a Leaf. If you asked me, I'd ask you "what do you mean by "reserve"?"

cwerdna said:

For me, "empty" on a Leaf as either turtle comes on or car will no longer move are close enough. User inaccessible capacity is useless to the user.

I know we had earlier discussion about "reserve" and it's frankly nothing I want to even bother discussing. It's not clear to me that there's one universally accepted definition of "reserve" on a Leaf. If you asked me, I'd ask you "what do you mean by "reserve"?"

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Good question, I guess I'd say the capacity of the battery that exists but I can't access. Management reverse! LOL

Yes I am also making an assumption that Nissan has locked away 4 kWh, because I have no other number to work with.

If I decided they locked away 2 kWh, or even nothing at all, the calculations are going to come out a lot worse in terms of degradation.
At around 5% remaining usable capacity I have only "used" 30.7 kWh (for my baseline calculation anyway), so if Nissan actually locked away nothing, that would put remaining capacity at about 76.7%. I haven't dropped any bars so I think that scenario is very unlikely.

danrjones said:

blank

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Finally got a chance to upload:

https://www.dropbox.com/sh/zlv2o826981pons/AADccdb0yLDQopQNEZvGj3zZa?dl=0

See the time stamps in the car dash(es) or app or iPad for timeline reference

And curiously I never hit "turtle" mode and the VLBW was in the middle screen NOT on the dash so it wasn't very obvious to me

Man - I’ve loved reading through this thread! But there’s this one thing.

I have a 30KWH battery in a 2017 SV.

QUESTION: Is there a separate 30KWH thread? I’ve searched repeatedly and cannot find it.

Apologies for asking a potentially dumb question.

THX!

RapmasterD said:

QUESTION: Is there a separate 30KWH thread? I’ve searched repeatedly and cannot find it.

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There are several like these:
https://mynissanleaf.com/viewtopic.php?f=30&t=23606
https://mynissanleaf.com/viewtopic.php?f=44&t=20924

My recommendation to browse MNL is to view via https://mynissanleaf.com/search.php?search_id=active_topics (hamburger menu in upper left > active topics). If search doesn't work well for you, Google and/or Bing for:
site:mynissanleaf.com (your keywords here w/o the ())

Thank you!

28 months and 20,100 miles. A large negative correction of 1.13% just a few days ago. Driving less, so not sure what's up. I was hoping that the battery degradation would remain flat with just slight losses each month. I only charge to 70% and no DC charges. It really feels like the battery degradation is mostly based on time. If I put 40K miles on with in the same time period the battery would be at the same place.

Someone needs to hack into the bms code to see what's really going on.

Still waiting for that mystical SOH increase.
This morning:

SoH: 89.67%
AHrs: 103.51
HX: 108.52
TEMP: 99.0 max 94.6 min
Just under 6500 miles.

Now entered the time of year where the battery will likely be above 90f until beginning of September. 111f here yesterday.

danrjones said:

Still waiting for that mystical SOH increase.
This morning:

SoH: 89.67%
AHrs: 103.51
HX: 108.52
TEMP: 99.0 max 94.6 min
Just under 6500 miles.

Now entered the time of year where the battery will likely be above 90f until beginning of September. 111f here yesterday.

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That is some low mileage!

That is some low mileage!

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I leased mine about 3 days before Dan, and my odometer reads 3,503, IIRC.

LeftieBiker said:

That is some low mileage!

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I leased mine about 3 days before Dan, and my odometer reads 3,503, IIRC.

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Death by a thousand paper cuts?

My in town isn't large enough to exceed about 20 miles a day. And my actual commute is about 2.5 each way. Even if the battery heavily degrades in the heat the car will do fine in town for years. Mileage might be irrelevant to degradation ...

danrjones said:

LeftieBiker said:

That is some low mileage!

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I leased mine about 3 days before Dan, and my odometer reads 3,503, IIRC.

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Death by a thousand paper cuts?

My in town isn't large enough to exceed about 20 miles a day. And my actual commute is about 2.5 each way. Even if the battery heavily degrades in the heat the car will do fine in town for years. Mileage might be irrelevant to degradation ...

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What is your SOC targets for charge/discharge? What "seems" to be common are LEAFs driven heavily that degrade slowly while other LEAFs driven very lightly degrade faster. On the latter, there was a lot of evidence suggesting the lack of custom charge settings being the a factor with more than a handful simply "plugging it in and forgetting it"

My 30 kwh LEAF with supposedly one of the worst batteries went 30,000 miles in 14 months and 2 days died with 100% SOH and ahr of 82.05 of max 82.34 or 99.6% of new capacity. Since I rarely charged to full, I don't know how close I was to the maximum GID count of 363 but guessing I wasn't too far off. I did 116 miles on a single charge in Jan 2 days before the accident