The 40KWH Battery Topic

[LeafyMaple]

Newbie, here wondering if someone seasoned would be willing to interpret these cell voltage readings from my local Nissan dealer:

CELL VOLTAGE 78, 3921 mV
CELL VOLTAGE 79, 3910 mV
CELL VOLTAGE 80, 3920 mV
CELL VOLTAGE 81, 3908 mV
CELL VOLTAGE 82, 3919 mV
CELL VOLTAGE 83, 3911 mV
CELL VOLTAGE 84, 3920 mV
CELL VOLTAGE 85, 3916 mV
CELL VOLTAGE 86, 3739 mV
CELL VOLTAGE 87, 3910 mV
CELL VOLTAGE 88, 3918 mV

It was briefly explained to me that the 3739 reading indicates a problem in at least one cell?
I have a follow up appointment for them to further investigate and perform the repair. I'm told wait times on this can be unpredictable.
I welcome your insights.

Probably better to have started a separate topic (I'll let the moderator decide), but it looks like you definitely have a weak cell. Would be better to have some context (SoC?) and even a LeafSpy graph, but a 200 mV difference in small sample is not good.
FWIW, "unpredictable" wait times is an understatement. First you have to get Nissan to agree/admit it's bad enough to trigger a warranty replacement...and then you have to wait for them to send the dealer a good module. It's a full day job (if you had to pay for it yourself).

Thanks, Stanton.
SoC was 74%
The dealer has acknowledged that it is a warranty issue and we've scheduled the repair.
Your explanation helps me understand better. Thank you.

 

[hornstudio]

We sold the car and next owner is waiting to finally fix the problem at Nissan.

Buyer sent me an unbelievable video: he has got 78% SOC and goes on German autobahn with like 70mph and empties the battery in a few seconds to " - - - " and 0 bars. After he leaves the exit the SOC fills back to 76%. Fantastic video.

 

[rogersleaf]

Passing 85K miles and 4 years, 5 month service. Interesting to note the AHr's and SOH stats are slowly dropping but the GID count is relatively constant and changes in usability/range is not noticeable.

LS stats:
AHr... 98.79
SOH... 85.58%
Hx... 83.75%
SOC... 99.0% and 432 GID
403.72v cells balanced between 4.204 and 4.207v
odo... 85,165
43 QC / 2229 L2’s

Going past 90,000 miles now...
LS stats:
AHr... 97.07
SOH... 84.09% (still showing 12 capacity bars)
Hx... 82.58%
SOC... 99.2% and 426 GID
403.42v cells balanced between 4.201 and 4.203v
odo... 90,259
43 QC / 2401 L2’s

 

[Oostenrijker]

Prices of used 40kWh in the Netherlands have really dropped substantially: bought mine 2019 with 171.000km's, for € 18650 and now there are 2020's with less than 40.000km's available for the amount I paid. Just the thing is, my trade in value is so bad. I found out online, it's about € 9000 so half of what I paid. Considering I have battery issues, I really hope that Nissan is going offer a solution. My understanding, is that the Nissan dealer is in discussion with Nissan.

I hope, I don't need to seek legal help, but we have something in the Netherlands called the dispute committee: that would cost € 127 totally, and if they would decide in my favour. Than its binding for the Nissan dealer.

 

[hornstudio]

@ Oostenrijker What mileage do you have on your LEAF? We also have a LEAF with almost the same LeafSpy curve with the big dent in the first half of the cell packs.

We drove it until the car stopped last week and fully charged it slow and are getting 210km with 150.000km on odo meter. Fair enough though.

​

 

[HerdingElectrons]

Just checking in to 'happily' report that my SOH losses have massively stalled as my car has crossed 5 years back in Sept and is about to cross 80K miles on the clock!

[url=https://imgur.com/485otk1] [/URL]

 

[Oostenrijker]

@ Oostenrijker What mileage do you have on your LEAF? We also have a LEAF with almost the same LeafSpy curve with the big dent in the first half of the cell packs.

We drove it until the car stopped last week and fully charged it slow and are getting 210km with 150.000km on odo meter. Fair enough though.

​

Currently almost 189.000km, but I bought it with 171.000km. Only I did not have Leafspy. Can you show your Leafspy?

I guess, if it looks like mine: you also got weak cell's. The state of my battery pack is only becoming worse. Just now I went to my parents, just a 8km trip and there is one road that after the roundabout I need to speed up to 70km/h.

And then I saw again, drop my dash SoC by several percentage. Like about 5 or 7 I guess, to climb back up again. Been looking at Leafspy while driving, and the colder it gets. The worse the battery issues become.

If you are at 150.000km, I would advise you to start reporting any battery issues you experience to the dealership. Once you are over the 160.000km, getting a replacement battery under warranty might be hard.

Not necessarily impossible, if you have some kind of warranty like used car warranty? But I have understood, that's not really a thing in countries like the USA or Canada. That's more a thing in The Netherlands, or other countries in Europe.

I still don't know what's going happen with my Leaf, but one thing is clear: I do have batter issues. The other day I also recorded my dash SoC dropping 10% while hard acceleration.

 

[hornstudio]

As I said I have a video which empties the battery from 78% in half a minute and refills to 76% from a e-NV200 I sold. Nissan needs to rework the battery once more.

As I said before, I suggest Nissan to do a software upgrade that makes the BMS read way slower than it does now to solve this problem. Only highspeed highway rides will still be a nightmare.

 

[hornstudio]

Following file is when I stuck in traffic on 22/12/2023.

Thank god some pedestrians came by and pushed my LEAF into safe position to refill. I still had 2,8kWh in the pack, usually a new LEAF should die with 0,6kWh inside or less.

 

[hornstudio]

After refill.

 

[LeftieBiker]

That certainly looks much better - nothing alarming at all...

 

[Oostenrijker]

Following file is when I stuck in traffic on 22/12/2023.

Thank god some pedestrians came by and pushed my LEAF into safe position to refill. I still had 2,8kWh in the pack, usually a new LEAF should die with 0,6kWh inside or less.

That looks quite bad: believe me, it will only get worse, because weak cells don't disappear. No matter how frequently you charge to 100% which is bad as well, and might make your pack fail even sooner.

Nissan don't need to update their BMS: you got a bad battery, that's why the dash SoC acts up. If Nissan updates the BMS, then it's only masking problems.

 

[GaleHawkins]

Just checking in to 'happily' report that my SOH losses have massively stalled as my car has crossed 5 years back in Sept and is about to cross 80K miles on the clock!

[url=https://imgur.com/485otk1] [/URL]

Your cell balance is impressive. Nissan replaced our 2016 Leaf SL 30 kWh in Feb 2020 at 25K miles under warranty.

The 40 kWh battery SOH is down to 90.81% after 20K new miles of use over the past 4 years.

It got totalled Nov 2020 and we bought a 27K mile mint inside and out 2015 Leaf SV from Virgina that was totaled due to electrical problems for a parts car. Dealing with long covid it was late 2022 before we finished rebuilding our 2016 using the front cap, windshield and air bags from the 2015 SV. Was hoping to use the 2015 24 kWh battery for solar storage but it's still in the parts car.

My wife drives the Leaf to work when she doesn't ride in with me. In the 11 months since getting Model Y we have put over 20K miles on it. Due to physical limitations I use FSD daily and for cross country trips.

Thanks again for the details on the health of your 40 kWh pack. Had Nissan come out with the 40 and 62 kWh packs in 2015 the EV landscape might look very different today.

 

[hornstudio]

I had 2x LEAF 30kWh in my hands. One was sold to my wifes colleague with ONE damaged cell, totally dead - driven hard daily - cell recovered completely.

We had a 30kWh LEAF for 2 years with 2 weak cells - driven hard - mountains - they recovered and could not be found later on.

You can cure weak cells if you wake them up.

 

[HerdingElectrons]

Your cell balance is impressive. Nissan replaced our 2016 Leaf SL 30 kWh in Feb 2020 at 25K miles under warranty.

The 40 kWh battery SOH is down to 90.81% after 20K new miles of use over the past 4 years.

It got totalled Nov 2020 and we bought a 27K mile mint inside and out 2015 Leaf SV from Virgina that was totaled due to electrical problems for a parts car. Dealing with long covid it was late 2022 before we finished rebuilding our 2016 using the front cap, windshield and air bags from the 2015 SV. Was hoping to use the 2015 24 kWh battery for solar storage but it's still in the parts car.

My wife drives the Leaf to work when she doesn't ride in with me. In the 11 months since getting Model Y we have put over 20K miles on it. Due to physical limitations I use FSD daily and for cross country trips.

Thanks again for the details on the health of your 40 kWh pack. Had Nissan come out with the 40 and 62 kWh packs in 2015 the EV landscape might look very different today.

Thanks! I purchased a 16A L2 Charger that I use for summer charging & full charge cell balancing because my understanding is slowing down the charge rate allows the BMS more time to balance the pack up to a point.

 

[Astral]

I bought my 2018 40kw Leaf 9 months ago. It had 87.4% SOH at the time. Since then I have put on 11000 kilometers on it and the SOH actually went up a bit. So yeah I can confirm that around the 5 year mark the SOH seems to stabilize nicely.

 

[rogersleaf]

Going past 90,000 miles now...
LS stats:
AHr... 97.07
SOH... 84.09% (still showing 12 capacity bars)
Hx... 82.58%
SOC... 99.2% and 426 GID
403.42v cells balanced between 4.201 and 4.203v
odo... 90,259
43 QC / 2401 L2’s

Just adding a note that over the past weekend I traded this 40KWh LEAF for an Ariya. So my own final numbers were 91,500 miles at 84% SOH.

Interesting to note they used LeafSpy to check the car on trade-in…

 

[aneesh84]

Just adding a note that over the past weekend I traded this 40KWh LEAF for an Ariya. So my own final numbers were 91,500 miles at 84% SOH.

Interesting to note they used LeafSpy to check the car on trade-in…

How much did you get for the leaf?

 

[knightmb]

My wife finally tortured her 2018 Leaf down to 11 bars. For reference, she absolutely does not make any effort to take care of the battery. She drives it like it will somehow run forever no matter how she treats it. I've been watching her EV stats for almost a year now. I thought she would drop the first bar at 85% SOH, but then it went and left, still 12 bars, then 84%, then 83%, so finally looks like 82% is the magic number to drop the first bar, in a Gen 2 Leaf I guess.

 

[Bombastinator2]

We need a place to post battery info, temperature observations, and other things relating to the new 40kwh pack. There are a few stats scattered in other topics, but having this one should make it easier to keep track of them. Links to the other posts would be a good idea.

When I went to pick up my 2018 SL the other evening, I took advantage of my salesman's need to finish up with other customers to take a quick LeafSpy reading. Here are the main stats (I'll try to post a snap of the screen later):

SOH: 99.59

Hx: 99.48

AH: 114.97

The pack looked extremely well balanced - no shunts at all, IIRC, and all the voltages close. SOC was 95% or so.

New item by Leftie Biker

Moving on to pack temp observations, I have a suggestion: since the temp gauge is a little...subjective to read, it might be best, when LeafSpy isn't available, to estimate the readings as a percentage, with the far left side of the virtual bar gauge being "0%" and the far right, at the end of the red zone, as 100%. Using that metric, I started the car this evening with the ambient temp at 86 or 87F, a huge rise after a morning low of 46F. The pack was still fairly cool, and I would estimate the gauge was reading "40%" along the scale - somewhat to the left of the middle. I also used an infrared touch-less thermometer to read the exterior (Scarlet) body temp (112F) and a digital thermometer I'd left in the backseat to measure the interior (black/grey seat covers and white trim) temp, which was 104.5F. All of this means little of course, because the pack, with its large thermal mass, hadn't warmed to anywhere near ambient.

It might also be interesting to get other readings of steel body panels (with color noted) in full sun, and interior temps with windows both closed and partially open, along with gauge and LeafSpy readings. One comparison I was able to make today was of my Scarlet Ember Leaf's body in full sun (112F), vs my housemate's "Sea Mist Pearl" (very light green/blue) Prius PHEV (99.5F) also in full sun, behind my car. I'm kind of wishing I'd gone with another Brilliant Silver Leaf after all...

Yours is all blue whereas mine is blue and red. I don’t understand how to read the app. I’ve got a 2019 with around 20k on it. Is mine bad? Is there anything I can do if it is bad? What does this chart even mean?