LEAFspy says Bad Cells?! :(

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Not sure if this was made clear, the red lines are cells shunting of bleeding off voltage to balance, unless there's a bad or weak cells message then it is showing those cells.
I noticed on mine and on someone else's that cell 1 & 48 were weak. These are at either end of the rear part of the pack. It makes me wonder if it is corrosion of the connection, pr if it is related to being at the outside edge, so temp, or air circ may be the issue.
 
Yes, I understand about shunts being red. The thing I didn't explain well enough in my original post was that LEAF spy actually colored the words and numbers red when it said @ the bottom that "cells 19 and 40 were "bad". I haven't been exercising the cells to much to low SOC lately, so it has been some time since cell voltages were so low to show weak cells, but the last time I did get the battery so low (a few new cells were registering as weak).

Just so you know, I do agree with previous comments in that the weak cells have plenty of useful life left in them to get me many more thousands of miles before something should be done to address the low cell voltages at low SOC.
 
JonO,

Have comments in this discussion laid your concerns to rest, or do you have any further thoughts about individual cells and their relationship with an overall healthy battery pack?
 
Motty; I'm just getting to understand the "weak cell" message, and have only recently received the LeafSpy Pro, and I don't normally run the pack that low before recharging. So, big picture, if those weak cells limit my range by even 15% it is a big concern. The nearest Level 3 is 130 km away, and the nearest Level 2 is about 115 km away. As it is, I can reach the Level 2 on a good day, but arrive with 1 or 0 bars, at maybe 40 to 20 gid. On the return trip the last 30 km are bush, so not even a 110 volt opportunity to be had! So, if replacing the weak cells can give me another 15 to 20 km range it is huge for me. I will have to track the data more at low SOC to get a better idea of the impact of them. Also I want to run it down and charge back fully a few more times to see if they improve.

One reason I posted it is because a poster on another forum saw that he also had cells 1 and 48 showing up weak. I wonder if it is a design issue? These packs or on either end of the rear module pack. So, maybe a connection issue, or an ambient temp, or an internal air circulation issue.
 
JonO said:
...As it is, I can reach the Level 2 on a good day, but arrive with 1 or 0 bars, at maybe 40 to 20 gid. On the return trip the last 30 km are bush, so not even a 110 volt opportunity to be had! So, if replacing the weak cells can give me another 15 to 20 km range it is huge for me. ...
Boy that sure is pushing the range.
Any truck stops or RV parks with 240V outlets where you can use portable L2 EVSE?
With 30 km of not even 120V, I think I would be carrying small Honda generator as a back up.

I can see where a few "bad" cells has much more impact and risk for you than most people.
Will be interesting to see if Nissan will replace them.
Two of my "bad" cells are 1 and 48 too.

You have a really low km 2011 LEAF.
How did you find one with only 1,800 km in Dec. 2013?
Was it a demonstrator that was still unsold?
 
I do feel your pain. It is understandable that range loss due to weak cells has a real world impact on some. Everyone has their own specific situation. It does sound like you really are pushing the bounds of what the LEAF can do as a daily commuter. I bet you must be looking forward to longer range batteries, eh?! ;)
 
Leaf Spy may just be right but it does not pass the Nissan smell test. No reverse engineered unit will count at Nissan service. They have their own procedures that a bad battery must show up on.
 
RegGuheert said:
I do believe cell-pair #37 is a bit weaker than the rest, but that didn't stop me from driving over 69 miles last Friday and arriving home with 34% charge remaining. So while the car's instrumentation is reporting a loss of 16% of the original capacity and a "Health" of only 70%, I'm achieving best-ever (by quite a bit) trip performance out of the vehicle. (And, yes, I understand there are many other factors involved!)

Coincidence or not?

I saw a weak cell flagged by LEAFSpyPro and it was cell pair #37.

Here's the screen shot

https://photos.app.goo.gl/LG8qisJ2DtimBDvY6

Lots of cell pairs shunting. Lit up like an xmas tree :)

The day this occurred I drove from a fully charged battery (topped off at work using a L1 EVSE) down to 1 mile past LBW, 68 miles in total. I lost about 15 GID's in the time I'd normally use 7 or 8 GIDs on the final approach home (it takes 8 GID's from McDonalds to my house, that day it was double). I have only driven the new Lizard pack down to LBW maybe twice since getting it 18 months and 22,000 miles ago. I rarely go below 40% SOC. Charge to 80% overnight and add 10% directly prior to leaving the house.

Is it known if a 2011 LEAF with Lizard pack re-balances with a single charge like the 2013 packs or is the BMS the same as in the original?

I'm going to assume this was just pack imbalance and not a faulty cell. But if the same cell pair comes up repeatedly I will ask the dealer to test the pack for faults. I have 34,000 miles warranty left on the new pack.
 
JPWhite said:
RegGuheert said:
I do believe cell-pair #37 is a bit weaker than the rest, but that didn't stop me from driving over 69 miles last Friday and arriving home with 34% charge remaining. So while the car's instrumentation is reporting a loss of 16% of the original capacity and a "Health" of only 70%, I'm achieving best-ever (by quite a bit) trip performance out of the vehicle. (And, yes, I understand there are many other factors involved!)

Coincidence or not?

I saw a weak cell flagged by LEAFSpyPro and it was cell pair #37.

Here's the screen shot

https://photos.app.goo.gl/LG8qisJ2DtimBDvY6

Lots of cell pairs shunting. Lit up like an xmas tree :)

The day this occurred I drove from a fully charged battery (topped off at work using a L1 EVSE) down to 1 mile past LBW, 68 miles in total. I lost about 15 GID's in the time I'd normally use 7 or 8 GIDs on the final approach home (it takes 8 GID's from McDonalds to my house, that day it was double). I have only driven the new Lizard pack down to LBW maybe twice since getting it 18 months and 22,000 miles ago. I rarely go below 40% SOC. Charge to 80% overnight and add 10% directly prior to leaving the house.

Is it known if a 2011 LEAF with Lizard pack re-balances with a single charge like the 2013 packs or is the BMS the same as in the original?

I'm going to assume this was just pack imbalance and not a faulty cell. But if the same cell pair comes up repeatedly I will ask the dealer to test the pack for faults. I have 34,000 miles warranty left on the new pack.

There is no easy way to do this but get your LEAF around 70% SOC give or take. start car, let it simmer a bit, take note of #37's position relative to the other cells in the pack. Then find a place where you can do at least 2-3 circles of acceleration for 5-10 seconds continuously. Check the relationship of #37 then.

On your screenshot a delta of 100mV is quite the norm at low SOC's. I have a screen shot (with SOC at 4% ) with a 300+mV delta. Several in the 200's but on my "Turtle" run on my 2018, I went to 1.7% SOC with a delta of 93 mV. In none of these cases did I see a bad cell warning.
 
Marktm said:
This just showed up on LeafSpy. Is there a point at which "weak cells" turn into bad cells and Nissan will honor a defective battery warranty - has anyone had this happen?

I posted something similar on June 13th.

I'm monitoring to see if the the same cell weakens repeatedly or not. If it does I'll have Nissan check the battery out. I see your SOC was pretty low, so imbalances can occur at low SOC.. Just keep your eye on it.
 
Marktm said:
This just showed up on LeafSpy. Is there a point at which "weak cells" turn into bad cells and Nissan will honor a defective battery warranty - has anyone had this happen?


Looks like you are a ways from a warranty claim. When you see turtle pop up at 30% SOC, then you got a claim. Seeing weak cells at a low SOC is hardly desirable but its also not unheard of. What does it look like when you are at 30% SOC?
 
If I am reading the numbers correctly, about 10% of range is lost due to the weak cells.
I have no idea what performance criteria Nissan uses before they agree that a battery is defective, and I am uncertain (but doubt) whether a weak cell will reduce the calculated Ahr capacity, and by extension, the battery capacity bar graph that Nissan uses for its degradation warranty.
 
SageBrush said:
and by extension, the battery capacity bar graph that Nissan uses for its degradation warranty.

Bad cells (by Nissan's definition, whatever that is) is covered by the standard materials and workmanship warranty, not by the degradation warranty.
 
DaveinOlyWA said:
Marktm said:
This just showed up on LeafSpy. Is there a point at which "weak cells" turn into bad cells and Nissan will honor a defective battery warranty - has anyone had this happen?


Looks like you are a ways from a warranty claim. When you see turtle pop up at 30% SOC, then you got a claim. Seeing weak cells at a low SOC is hardly desirable but its also not unheard of. What does it look like when you are at 30% SOC?
Yep.

Marktm may want to Google for site:mynissanleaf.com cvli and look at http://www.mynissanleaf.com/viewtopic.php?f=9&t=21700.
 
JPWhite said:
SageBrush said:
and by extension, the battery capacity bar graph that Nissan uses for its degradation warranty.

Bad cells (by Nissan's definition, whatever that is) is covered by the standard materials and workmanship warranty, not by the degradation warranty.
[/quote][/quote]
Unless the bad cells lead to a "degradation" threshold. I tend to think they do not, at least at the level Mark showed.
 
cwerdna said:
Marktm may want to Google for site:mynissanleaf.com cvli and look at http://www.mynissanleaf.com/viewtopic.php?f=9&t=21700.


Interesting series of posts.

Has anyone talked with a highly knowledgeable Nissan tech guy that understands the parameters used (and the calculations based on those parameters) that determine when a battery is "defective"? NOT degraded, but defective? Having a casual understanding of FLA batteries installed in series (and experience with the resulting problems - mostly associated with no BMS), it would be interesting to understand the designers perspective - that can have a serious monetary effect to the corporation! LeafSpy has likely allowed us users to have much more information than these designers expected!
 
I also found the link Cwerdna posted to be very informative. I still don't know how he keeps track or remembers but he is a fantastic resource.

"It seems to me that with one module (two cell-pairs) replaced, the battery will have an EASIER time passing the CVLI test since a cell-pair would have to drop below the mean voltage by 1.5X the amount that those new cell-pairs exceed the average voltage. In other words, you will have to have quite a bit weaker cell in order to fail that test."

That would be the defective cell test:
Average - Min > (max - average) * 1.5
 
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