Capacity Loss on 2011-2012 LEAFs

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Stoaty said:
edatoakrun said:
I don't understand why you have come to that conclusion, since one axis itself is months since delivery.

I wanted to see what might account for the anomalous 24,000 mile one bar loss report, and only then realized it must be the 10 month/20,000 mile report on the Wiki, right?
Right. To be honest, I don't know which is the correct comparison:

One compares the total miles driven to the time it takes to lose a bar - no correlation
The other compares the rate at which miles are accumulated to the time it takes to lose a bar - moderate correlation

The more I think about it, the more confused I have become. I welcome input from others more knowlegeable than I. :oops:

Where are the "no correlation" results graphed, for the same group of bar loss reports?
 
TonyWilliams said:
I'm not sure what you are actually saying, or trying to prove.
He's answering someone who questioned his statement that his treadmill test would consume 80% of the power that it does when driving. I also questioned that, guesstimating it would be less than 50% of normal driving power.

The problem is that his treadmill does not allow him to dial in any amount of loss and therefore match the 15KW that is seen during normal driving, so there is some concern that it may take several hours to drain the battery. We'll see when he does the test.
 
sub3marathonman said:
It is possible that Orient Express is right, since so far there is only anecdotal evidence, not proof. We need a valid representative sample of all Leafs, not just ones with capacity bar losses. So far, I don't know if it is 90% of the Leafs in Phoenix losing capacity, or only 9%. I don't know how that percentage corresponds to the people in Seattle. I don't know if this data has been compiled either, since the focus is ONLY on Leafs with capacity bar losses.

What is more important than mileage, which has shown a low correlation to capacity loss, is the temperature history of each battery, but I don't know if the car tracks that data.

"Maybe it is right" sounds like the way every religion was ever sold to me. Sure, maybe.

To determine if OrientExpress is right or wrong, you would first have to specify which of his many statements is perhaps right.


1. "So far, all of the posts on this subject are speculation, hearsay, innuendo, and opinion."

2. "In reading through all the cases, I really don't see a problem"

3. "I have to believe that if there was an issue, it would have been detected and solved by now"

4. This is just a problem with "several vocal individuals."

5. There is so much confidence, he agreed to swap his battery!!! >>> "sure, come on by, and we will put the cars up on blocks and switch them out." :)

6. There are as many cars with reduced capacity as there are with ">>excess<< capacity and they are both edge cases". I sure as heck haven't seen a mention of that excess case(s) !!!!

7. "If there is an actual issue with a customer's battery, then it will be a simple routine warranty repair."

8. This is just "battery FUD that is concentrated in some posts... Kuddos to Nissan for a job well done."

9. Hey, it's only "17 cars out of a population of 25000 is .00068.... or in layman's terms, an edge case."

10. "for the 0.00074074074074 of LEAF owners..... investigate the myriad of options other than complaining to get satisfaction for your transportation needs."

11. Still no problem; just charge more!!! "'the only complaint being that they have to be "filled-up" more often"

12. "Of the fewer than 10 posters that make up the the vast majority of the posts in the 148+ pages of this thread, I'm probably the most rationale one of the bunch."

13. It's a little battery problem because "in the larger scheme of things this is just a fart in the breeze."

14. "8 or so posters that have been the key proponents of this... with some interpretative data that they have been able to glean from some homebrew devices". Hey, Phil, when will you have my homebrew device ready?

15. And then the insults got more pronounced... "Nothing smells right when you don't have a sense of smell". And then there's: "
One of the sure signs of dementia is paranoia and being convinced that everything smells bad."


16. All of the previous statements are because "I have a deeper understanding of how failure analysis in the automotive industry works."

17. So, it might be a software problem... "What if this whole thing is just a SW bug that is not accurately reporting the capacity of the battery?" A bit later, that was upgraded to, "reputable highly-placed sources suggest that a software bug". Naturally, no data to support this, or any other claim.

18. Some very specific and detailed data from most detailed person on the forum is juat tossed aside with... "your methodology does not support your conclusions" from somebody that really hasn't provided ANY data.

19. Another "theory" with no data to support it (nor was any offered), "only those cars that have been driven in a severe and high-mileage mode trigger the condition."

20. The best for last, as this post is an all time classic!!! "very vocal and seemingly hysterical schizophrenic ADD owners ... they don't represent the vast majority of LEAF owners.... for whatever reason are unable to deal with the situation and would rather freak out. Speculation is rampant, and facts are few... fan the flames of discontent in a very trollish manner... for many that is not good enough and demand immediate satisfaction... Other than assigning wet nurses to the most vocal and impatient of those that are dissatisfied, it is hard to say what more than can be done."



My observation is that whatever OE suggests is without serious scrutiny of all the data that suggests heat on the cells that have no protection from heat is the problem (unlike Tesla and Volt, both of which have a Temperature Management System, and with no "Phoenix" problem).

Long before OE owned, or reserved a LEAF, an article titled "Is the Nissan LEAF Battery Pack under Engineered?" suggested that there were serious shortcomings with Nissan's non-temperature protected battery. The comments that were made to this article from 2009 (many that appear to be from "the industry" of people in the know) almost one year before a single LEAF was produced, also suggest Nissan made a serious mistake selling the car in hot environments like Phoenix and Texas. They used those words.

Tesla CEO Elon Musk, also in 2009, well before LEAF was released for sale "ripped" on Nissan's battery technology, and said it's "primitive" without a temperature management system. PLease read the comments on this article, also. Very well thought predictions that this would not end well for Nissan and (my biggest fear) the greater electric vehicle community.

Naturally, the Nissan legal department made clear that the battery capacity is without warrantee, but as we know, consumers have been sold a car in hot places like Phoenix that the manufacturer knew would NOT survive the heat and did NOT tell the consumer of these shortcomings.

Anybody who suggests the "non-problem" is anything EXCEPT a heat related issue to a poorly designed product is strictly a denier in my mind; not much different than climate change deniers. If anybody wants the BEST look into the future of Mark Perry, and Nissan's "answer" to this, carefully follow OE's posts.

The reason Seattle, San Francisco, and San Diego LEAF's do so well, in comparison to Phoenix and Texas, is heat.
 
3 weeks to my wife's Leaf one year of ownership, we were 'rewarded' with a 2nd capacity bar loss.

First bar loss reported back in June @ 13500 miles.

The 2nd bar loss happened on Aug 16 @ 16890 miles.

I noticed other Phoenicians also lost their 2nd bar, after about 3000 miles or two months after the first bar loss.

For the last 4 weeks, we shifted charging from 9PM at night to 3AM in the morning, but I guess that doesn't really matter as at 3AM, our garage is still in the mid to high 90s. We still only charge to 80% all the time (at most two or three 100% charge in the last 2 months). This morning we charge it to 100%, and the available range shown is 67 miles.
 
johndoe74 said:
3 weeks to my wife's Leaf one year of ownership, we were 'rewarded' with a 2nd capacity bar loss..
To report battery capacity loss to Nissan: 877-NO-GAS-EV (1-877-664-2738).
 
johndoe74 said:
3 weeks to my wife's Leaf one year of ownership, we were 'rewarded' with a 2nd capacity bar loss.

It just makes me sick to keep hearing these reports. Sorry for your loss(es), and I hope it doesn't make your daily use too difficult now. Best wishes with both your interactions with Nissan, and the final disposition of this issue.

I hope nobody goes "postal" when they stroll into a dealership with 3, 4, or more capacity bars missing, only to be met with an "all is normal".

If you don't know, it's an ABSOLUTE WASTE OF YOUR TIME to go to the dealer. They have nothing they can or will do, except give you "5 stars".

Here is my summary of the issues to date:

http://www.mynissanleaf.com/viewtopic.php?p=220120#p220120" onclick="window.open(this.href);return false;
 
Great post, Tony!

--------------------------

Update to the "11 people I know" sample (I remembered another guy who bought a Leaf and asked him if he had lost any capacity)...

1. 3 bars (dh)
2. 3 bars (rr)
3. 2 bars (mc)
4.   2 bars (mm)
5. 1 bar (tc)
6. 1 bar (rs)
7. 1 bar (pg)
8. 1 bar (cs)
9.    1 bar (sn)
10. on the cusp of losing 1 bar (js)
11. No known capacity loss. 80% charges, owned 1 year, only 5000 miles driven (em)

So...

82% already lost 1 to 3 bars
9% just about lost 1 bar
9% no known loss w/ 80% charges in 1 year and 5,000 miles

Background: There are 11 people (including my wife) I knew before they purchased Leafs (or met immediately after they purchased their Leafs). I did not meet any of these people *because* they began complaining of capacity/range issues. I simply met them before or immediately after they purchased Leafs. And now, let's check in on those 11 cars (all here in Phoenix) and see whether they have lost any capacity...
 
johndoe74 said:
3 weeks to my wife's Leaf one year of ownership, we were 'rewarded' with a 2nd capacity bar loss.
Added to Wiki. We don't have a case number for your report to Nissan or the date of the report. Other info missing from the Wiki is the date of manufacture (month & year), which I believe is on the frame where drivers door closes.

Latest stats:

The geographic breakdown of these cases is: Arizona - 36, Texas - 13, California - 6. The breakdown by number of capacity bars lost is: one bar - 29, two bars - 22, three bars - 4.
 
Avondale Nissan checked out LEAF today. As assumed, “Battery tested good at this time, but is not an indication of future failure.” All computer diagnostics checked out OK. Was informed there’s no ‘cooling fan’ for the batteries, but I do have the battery heater in this vehicle.
Received update on Casa Grande testing…Nissan looking at specific cells measuring highest charge cells vs. lowest charge cells to determine reason for variation. Also, they ARE able to replace out individual modules. In addition, Nissan was able to say LEAFs have approximately 5% more capacity, than what is listed via Li-ion battery capacity level gauge… Good to know.
They did state this is one of the lowest mileage LEAFs they encountered with the battery degradation problem…other owners had at least 20-30k on their vehicles.
Nissan will keep me posted with their conclusions, but nothing as of yet…as expected.
Lastly, received contact back from Executive Relations spokesman for Mark Perry and he said as assumed, no information yet, but Nissan diligently testing. I suggested Nissan offer good faith replacements for these batteries and when /if they have updated versions in 2013 to replace again. Some owners use this vehicle for work, and if they can’t get the range need, it will impact them negatively.
Will keep forum posted…
 
dsh said:
In addition, Nissan was able to say LEAFs have approximately 5% more capacity, that what is listed via Li-ion battery capacity level gauge… Good to know.

That's actually about 7% total; 5% at the top of the battery capacity, and 2% at the bottom. It's NOT good; manufacturers like GM with the Volt have about 40% "more capacity", which adds to the life of the battery. Volt is warranteed for capacity loss, in accordance with EPA emission rules for Volt's gas engine (will burn more gas if battery degrades).


…other owners had at least 20-30k on their vehicles.


I don't believe this. We have detailed data right here that suggests very average mileage.
 
EdmondLeaf said:
leiko49 said:
I observed two days ago, while I was driving, during my first mile on my journey to work, I lost a bar (first one), was down to 11 bars, and then it returned about a mile later, and I currently have 12 bars.

Is this common?

I have 9K miles on my Leaf.
This happened to RickS from Phoenix he got back 12 battery capacity bar for short time, but after few weeks bar gone for good. Can you provide more details where you located and where car is parked day and night. Thank you

Interesting. I wonder how the capacity gauge makes its calculations?
  • It seems to be based on readings from some set of sensors which may not be consistently calibrated--one of the Leafs taken for testing in Arizona was re-calibrated and bars came back.
  • Possibly can be reset although reports of such may just be due to calibration corrections.
  • Bars can come and go as reported above. So it is not based on some aging algorithm that decays but rather live analysis.

There has been speculation that bars may come back when the weather cools in a month or two. However, the capacity meter seems to offset for cold temperatures otherwise some of us would have seen temporary drops in winter. So I don't think the meter measures absolute, instantaneous capacity. Perhaps then it projects capacity in ideal conditions, which means it is making some estimates. (A Leaf gauge that makes estimates? How shocking!) If that is true then likely we will not see any bars come back when the weather cools.
 
Here is the same data from the Phoenix area one bar losers presented in a slightly different way that drives home the point that racking up miles more quickly leads to quicker loss of battery capacity. I have plotted Miles Driven Per Month vs. Percent capacity loss per month. Linear regression shows:

slope - 831
intercept - 168
correlation coefficient is 0.51 (moderate correlation)

Since miles driven per month means more cycling of the pack per month, it appears that both heat and cycling of the pack are factors in capacity loss:

capacitylosspermonth.jpg
 
Stoaty said:
Here is the same data from the Phoenix area one bar losers presented in a slightly different way that drives home the point that racking up miles more quickly leads to quicker loss of battery capacity. I have plotted Miles Driven Per Month vs. Percent capacity loss per month. Linear regression shows:

slope - 831
intercept - 168
correlation coefficient is 0.51 (moderate correlation)

Since miles driven per month means more cycling of the pack per month, it appears that both heat and cycling of the pack are factors in capacity loss:

capacitylosspermonth.jpg

This data is very interesting. It would be nice to see the data from the Leafs that lost two bars, plotted for the interval between the loss of the first and second bar. My limited data shows a 3%/month capacity loss and I believe I am about to lose my 2nd bar.
 
DaveinOlyWA said:
there is a lot of hysteria on the board right now and some balance is needed and i dont think that OE's comments are farther out than comments made on the other side. both are rife with speculation and the problem we have is really limited information and no parameters to go by.

so the only thing we can do is continue to gather what information we can, continue to crunch it various ways and see what results.

speculating on how badly Nissan is doing is becoming counterproductive to this forum. i am not saying that the affected should not be unhappy or should not voice their concerns to Nissan but that issue ALONE has made it difficult to sift thru the real value of pertinent information posted here.
Your right that there is a lot of hysteria on the board and why not?
First, the people who live in cool weather climates seem to be the ones who are not effected and posting comments that enrage the ones who have had losses and are being stonewalled by Nissan. Maybe they should self sensor their comments or perhaps say to themselves "what would Jesus say online". I'm not saying they shouldn't have an opinion but, hysteria like all things, don't exsist in a vacuum! There were plenty of Pinto owners who loved and defended their cars and were perfectly fine as long as they didn't get rear-ended.
Second, as far as being counterproductive, if Nissan is not going to admit they have a problem publicly, any advice that could be vetted here (oh yes I did say vetted in an election year) will be appreciated by those of us who do have real problems and might lead to a short term remedy. Also, when Nissan comes out with their "secret warranty" (http://www.autosafety.org/secret-warranties" onclick="window.open(this.href);return false;) to those people in the Phoenix area, it will be nice for those of us who live in CA and TX to find out about it here first.
 
High miles per month would also be generally indicative of those battery packs that tend to be cycled from very high to very low states of charge, and/or are heated, by frequent mid-day recharging, above those temperatures caused by ambient conditions.

So I think that the correlation of loss of capacity and cycling that you point out, could actually be, in part or in all, only coincidental.

Stoaty said:
Here is the same data from the Phoenix area one bar losers presented in a slightly different way that drives home the point that racking up miles more quickly leads to quicker loss of battery capacity. I have plotted Miles Driven Per Month vs. Percent capacity loss per month. Linear regression shows:

slope - 831
intercept - 168
correlation coefficient is 0.51 (moderate correlation)

Since miles driven per month means more cycling of the pack per month, it appears that both heat and cycling of the pack are factors in capacity loss:

capacitylosspermonth.jpg
 
edatoakrun said:
High miles per month would also be generally indicative of those battery packs that tend to be cycled from very high to very low states of charge, and/or are heated, by frequent mid-day recharging, above those temperatures caused by ambient conditions.

So I think that the correlation of loss of capacity and cycling that you point out, could actually be, in part or in all, only coincidental.
Agreed. It could be higher depth of discharge, being left at high SOC for longer periods of time in order to do a longer commute, heating from mid-day recharging, etc. The main thing is that this is the first time I have found a correlation that suggests that calendar loss from high heat is not the only factor; something about the battery cycling seems to be involved also.
 
I am curious as well why our gauges are 5% off, respecitively ~5% lower for each and every car. This could be the "software" bug that has been floating around on this thread. Regardless, that still doesn't address the accelerated loss occuring (it may not be as extreme but it is still significant). I am extremely afraid Nissan is counting the ~7% of our battery that cannot be accessed. To me, its very misleading to include that total since we would never be allowed to use it! But thats only speculation, and we can't verify that at all.

I do know that since I have owned the car, I am experiencing ~15-20 miles reduced capacity from new. That is with improved driving habits (finally hit 4 mi/kWh last month for lifetime average!), a very mild north Texas summer, and more chances to pre-cool/heat to extend my range. If I had retained the same level, I would be getting more range now. If I had lost only a few %, I think I would be having the same range with better "oustide" factors.

An interesting idea that occured that could relate to quicker degredation is "topping off" I am not aluding to plugging in the car to charge if 80% or greater capacity remains (something the manual advises to mimimize), but the use of the heating and cooling, especially on a 100% charged car. Everyone here knows that instead of creating a dedicated circuit to handle power from the outside source to run the A/C or heater, the LEAF uses the default set-up and pulls energy from the battery itself while the outside line recharges the battery. I recognize this when I precool my car in the morning for about 25 minutes with a the Level 1 (my wife uses the Level 2 for the volt). I am actually down some power (my time to charge will range from 10-40 minutes via Level 2 on the dash), once I was even down an addition fuel bar when I leave. If "topping off" is not ideal, why have this setup with easy access to climate control your car and encourage it to extend range!

It could be a compounded problem as the heat + the topping off occuring from using the CC together causes extra degradation? Its only a guess. If this was a greater factor than the heat (I doubt it) a proof of concept would be vehicles in extreme cold climates seeing battery loss from this next winter (cars would be a year+ by then too). If the idea does not hold clout then they will all drive happily to and from work!
 
Stoaty said:
edatoakrun said:
High miles per month would also be generally indicative of those battery packs that tend to be cycled from very high to very low states of charge, and/or are heated, by frequent mid-day recharging, above those temperatures caused by ambient conditions.

So I think that the correlation of loss of capacity and cycling that you point out, could actually be, in part or in all, only coincidental.
Agreed. It could be higher depth of discharge, being left at high SOC for longer periods of time in order to do a longer commute, heating from mid-day recharging, etc. The main thing is that this is the first time I have found a correlation that suggests that calendar loss from high heat is not the only factor; something about the battery cycling seems to be involved also.
Of course heat is not the only factor. But it must be the biggest factor.

I assume that the 20% loss over 5 years as predicted by Nissan is mainly cycling loss. Anything more than this is probably due to other factors, but heat is the biggest factor.
 
Pipcecil said:
I am curious as well why our gauges are 5% off, respecitively ~5% lower for each and every car. This could be the "software" bug that has been floating around on this thread.

Where do you get this? What gauge are you referring to? The capacity gauge can be set to any value Nissan intends; that's not "off". The current misleading values are 15% reduction for the first bar, which fairly well correlates to the observed Gid count, then either 6 or 7% for the remaining bars. The two values, Gid wattHours, and battery capacity, are measured and calculated differently (so the magic software problem would have to affect both).

Again, Nissan is going to say virtually ANYTHING except their cells can't handle the heat.
 
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