Capacity Loss on 2011-2012 LEAFs

[cwerdna]

^^^^
Umm, we do have a thread for "lizard" pack stats/capacity loss at http://www.mynissanleaf.com/viewtopic.php?f=30&t=24532.

You no longer have the crappy battery that came w/Leafs built before 4/2013.

Also, can you update your location info via your user name in the upper right > User Control Panel > Profile tab? That way, we don't need to ask in future posts/threads or do sleuthing to deduce it. I have no idea where you are.

[cwerdna]

The battery is losing SOH a little faster than the Battery Aging Model for Boston, but then again I'm 40 minutes in from the coast and there's no shade at my office. My car is baking on the blacktop and today is 93F with a heat index of 101F. The car was manufactured 6 years 8 months ago and the Battery Aging Model estimates 70% SOH at 7.8 years.

An amazing battery aging report by the "early adopters". When was this last updated? I may have missed it, but the statement about "recent" and "2013" indicates that not too much information on the "Lizard" has been included?

I was not involved in authoring the "aging model" but it originally covered the only known battery revision at the time: whatever was in '11 and '12 Leafs during the whole Phoenix/hot climate capacity loss fiasco: http://www.mynissanleaf.com/viewtopic.php?t=9694. Turbo3 (he lives a few miles from me) and I did loan some equipment to Surfingslovak for him to bring w/him to Phoenix to conduct Tony's range test (results at https://web.archive.org/web/20160113132 ... p?p=228326).

https://web.archive.org/web/20140714232 ... acity_Loss (July 14, 2014) seems to be as far back as the history goes of that page, at least at archive.org. Not sure if it was hosted elsewhere before and if earlier copies exist.

It is not clear to me whether the model covers the better batteries found in Leafs built 4/2013 thru model year '14. Probably not. We didn't know those were better until probably ~2 years after 4/2013. And, 4/2013 is a good educated guess as to when the switch happened. It seems Nissan quietly made a switch as it was never announced and AFAIK, never acknowledged either.

The copy of that page from July 14, 2014 most definitely couldn't cover the "lizard" packs which we'd just learned of on June 27, 2014: http://www.mynissanleaf.com/viewtopic.php?f=4&t=17168. It generally takes at least 2 hot summers for us to tell how a pack is holding up. BBrockman alluded to a "hot battery" (as some have termed it) being in testing in Aug 2013: http://www.mynissanleaf.com/viewtopic.p ... 54#p320754. Presumably, that became the "lizard" battery.

BTW, Leftiebiker coined a bunch of nicknames for some of the pack revisions: http://www.mynissanleaf.com/viewtopic.p ... 20#p533420. I'm not sure if we ever got confirmation that the newly developed cell at https://www.nec.com/en/global/techrep/j ... 120112.pdf became either the "wolf pack" or the "lizard pack". One would guess that lessons learned from that were incorporated into some packs that went out to customers.

[Marktm]

Appreciate the detailed response - and the reminder about my location - Thought I had taken care of that some time ago.

I am on my second summer of the "Lizard" replacement pack - I'll post the updated curve later this summer on the Lizard thread - however it does appear that the rather large uptick in ahrs during early summer is heading back down.

[SageBrush]

The latest battery report on my replacement "Lizard" battery. It does seem the range is taking a nosedive recently - I'm going to have to watch closely.

Compared to my 5 year old battery, yours is quite unbalanced, to say nothing about cell pair 75/76.
Isn't there a Nissan set limit for a weak cell pair that invokes the battery warranty (not degradation) ?

[Marktm]

The latest battery report on my replacement "Lizard" battery. It does seem the range is taking a nosedive recently - I'm going to have to watch closely.

Compared to my 5 year old battery, yours is quite unbalanced, to say nothing about cell pair 75/76.
Isn't there a Nissan set limit for a weak cell pair that invokes the battery warranty (not degradation) ?

This topic covers weak cells and testing to determine a warranty based fix http://www.mynissanleaf.com/viewtopic.php?f=9&t=17676. Be sure to read Regs posts on cell replacements - makes some good points. There is a forum member that had such weak cells that seems to have significantly reduced range.

So far, no DTC's have been registered.

[SageBrush]

CVLI test
http://www.mynissanleaf.com/download/fi ... &mode=view

Discharge battery to two capacity bars

A = pack voltage
B = maximum cell voltage in mv

Test value = (2.5*A - 0.144*B) / 96

---------
I suspect that LeafSpy is flagging the cells that fail this test.
The manual (albeit from 2011) says that the test identifies modules that have to be replaced in the absence of a DTC.

[Marktm]

Has anyone had success with cell replacements based on LeafSpy's identification?

[SageBrush]

Has anyone had success with cell replacements based on LeafSpy's identification?

Almost assuredly not.

The point here would be for a customer to have the confidence to authorize a CVLI test at the dealership. My understanding is that a battery found eligible for a warranty claim transfers the diagnostic charges to Nissan.

[RegGuheert]

Has anyone had success with cell replacements based on LeafSpy's identification?

Almost assuredly not.

The point here would be for a customer to have the confidence to authorize a CVLI test at the dealership. My understanding is that a battery found eligible for a warranty claim transfers the diagnostic charges to Nissan.

I seriously doubt that Marktm can qualify for (or needs) cell replacement. The reason is that the CVLI test calculation should be done when the average cell voltage is 3.712 V (about 356 V for the pack) and Marktm's pack is way below that point in the picture he posted. It should be expected that ANY pack will get unbalanced at 5% SOC, even one that it is still well-balanced at 20% SOC.

FWIW, in the wintertime my pack capacity is always limited by cell-pair #37, but I see no such behavior during the rest of the year. It's a bit frustrating to me since the wintertime is when the capacity is already lower and this cell-pair further reduces the range of our car. But clearly the behavior tells the story that the capacity is roughly the same as the other cell-pairs but that the resistance is worse.

[SageBrush]

I seriously doubt that Marktm can qualify for (or needs) cell replacement. The reason is that the CVLI test calculation should be done when the average cell voltage is 3.712 V (about 356 V for the pack) and Marktm's pack is way below that point in the picture he posted.

As I noted, the test should be performed at ~ 2 bars capacity remaining per the Nissan instructions.

I make no predictions about Marktm's pack. My post was to clarify two points:
A bad cell pair may be covered until the Nissan battery warranty unrelated to overall degradation
LeafSpy lets us test in the same way that Nissan will test with their "CVLI" test