Capacity Loss on 2011-2012 LEAFs

[Stoaty]

Note that the rate of capacity bar loss seems to have slowed dramatically in the last few weeks, further indicating, IMO, that the LEAF "gauge problem" causing inaccurate Wh/gid and capacity bar loss are both strongly correlated to exposure to high ambient temperatures.

Or, it could be that the batteries are no longer getting cooked, such that the batteries aren't losing capacity and tipping over to loss of a bar. All this indicates is that heat is the source of the problem, not whether it is a gauge error or actual capacity loss (we know, in fact, that it is both).

 

[edatoakrun]

="Stoaty"

Note that the rate of capacity bar loss seems to have slowed dramatically in the last few weeks, further indicating, IMO, that the LEAF "gauge problem" causing inaccurate Wh/gid and capacity bar loss are both strongly correlated to exposure to high ambient temperatures.

Or, it could be that the batteries are no longer getting cooked, such that the batteries aren't losing capacity and tipping over to loss of a bar...

If that is the case, I think you should still see a very considerable continuing rate of bar loss over this winter, as numerous LEAFs now just short of the "tipping point" of bar loss, continue to lose capacity over the next six months.

Of course, the exaggerated rate of capacity loss now indicated by capacity bar loss should be expected to decline seasonally, in any case.

We shall see.

 

[vegastar]

My gid count is slowly improving, now that the weather is cooling:

The energy to charge 80% from a given voltage level is the same, so the gids have a high bias with cold tempeatures and a low bias with warm temperature. The question is what is the temperature sweet spot where the error is lowest.

 

[TonyWilliams]

My gid count is slowly improving, now that the weather is cooling:

The energy to charge 80% from a given voltage level is the same, so the gids have a high bias with cold tempeatures and a low bias with warm temperature. The question is what is the temperature sweet spot where the error is lowest.

I'd guess 20C.

 

[spooka]

So, just got off the phone with Adrian, the arbitration specialist in TN. She said there is nothing they can do at this time, that the car is performing to specification. Nice.

I told her that 7,500 miles a year was not acceptable for any car, and she essentially said it was a niche car, to which I responded NO, it's not, it's a car that was/is sold as being capable of everyday driving, which means average mileage of 12-15K miles. It's not a NEV or a golf cart..

Per Mark Perry the Leaf is a "Primary Use Car" that is driven 37 miles per day.

http://green.autoblog.com/2011/10/2...ge-leaf-is-driven-37-miles-per-day-more-rang/

I drive mine 89% of what a Leaf is driven per this article in a day (33 miles/day) and have abrupt, significant capacity loss. Nissan is in CYA mode and any arbitrator will see this with their eyes closed.

The Leaf is not a niche car, it is a primary use car that can be driven 13,500 miles a year and is performing well below specifications as defined by Mark Perry.

 

[DaveinOlyWA]

My gid count is slowly improving, now that the weather is cooling:

The energy to charge 80% from a given voltage level is the same, so the gids have a high bias with cold tempeatures and a low bias with warm temperature. The question is what is the temperature sweet spot where the error is lowest.

I'd guess 20C.

i would agree. 80º seems best for range and driving conditions but not best for battery.

 

[TonyWilliams]

My gid count is slowly improving, now that the weather is cooling:

The energy to charge 80% from a given voltage level is the same, so the gids have a high bias with cold tempeatures and a low bias with warm temperature. The question is what is the temperature sweet spot where the error is lowest.

I'd guess 20C.

i would agree. 80º seems best for range and driving conditions but not best for battery.

Well, 120F / 50C is best for range. 0F / -10C is best for long life.

20C / 70F is just where to two intersect.

 

[wishboneash]

Could you plot the GID count versus the ambient temperature if possible? Thanks

My gid count is slowly improving, now that the weather is cooling:

The energy to charge 80% from a given voltage level is the same, so the gids have a high bias with cold tempeatures and a low bias with warm temperature. The question is what is the temperature sweet spot where the error is lowest.

 

[nosuchthing]

LEAFfan,

5.5 plus 6.5 is exactly 12. You're getting the right range on your first 2 bars. The 73 mile-range is at 65 mph. I get more range if slower speeds are involved, and it ranges depending on how many slow speed miles are involved.

 

[GRA]

LEAFfan,

5.5 plus 6.5 is exactly 12. You're getting the right range on your first 2 bars. The 73 mile-range is at 65 mph. I get more range if slower speeds are involved, and it ranges depending on how many slow speed miles are involved.

Well, 75 miles @ 65 mph per Tony's chart. 73 miles is the range on the EPA two-cycle test, which has since been replaced by a five-cycle test (but only newer BEVs like the Tesla S have been tested on that yet).

 

[spooka]

Good article about how LEAF owners have been affected in hot environments. The only thing they get wrong is that only high mileage cars are affected. A lie that Nissan keeps repeating.

http://www.extremetech.com/extreme/...n-leafs-need-costly-battery-replacements-soon

 

[TonyWilliams]

LEAFfan,

5.5 plus 6.5 is exactly 12. You're getting the right range on your first 2 bars. The 73 mile-range is at 65 mph. I get more range if slower speeds are involved, and it ranges depending on how many slow speed miles are involved.

Well, 75 miles @ 65 mph per Tony's chart. 73 miles is the range on the EPA two-cycle test, which has since been replaced by a five-cycle test (but only newer BEVs like the Tesla S have been tested on that yet).

There's no connection between steady 65 mph and the EPA testing for 73 mile range!!! Completely different.

 

[leafkabob]

Today was my day to meet the Nissan Engineer at ABC Nissan in Phoenix. I have 13,285 miles on my 2011 Leaf and have lost two capacity bars.

The meeting got off to a bad start when I arrived on time but he wasn't there and the dealership knew nothing of the meeting. I called the Cust. Service line and the rep there took the blame (despite me calling this same rep twice within the four hours before the meeting asking him to verify that everything was all arranged. Both times he assured me everything was a "go.")

I ended up waiting 45 minutes for the engineer (actually he is the Field Rep for 42 Nissan dealerships in AZ, New Mexico and Nevada. His office is in the Casa Grande test facility). It wasn't his fault that he was late so I didn't take it out on him. He was actually a very nice guy and I felt he was fairly candid with me.

He explained that his job was to collect data, which he would be forwarding to the Nissan Arbitration Specialist at the Dispute Resolution Team, who would then get in touch with me within a week. When I expressed my frustration with Nissan's approach to resolving issues "on an individual basis," and that I was expecting to be told that everything is normal, he told me "they will do something for you." He said he didn't know what it would be, but they would do something for me. Anyway, it was interesting that he was so adamant about that.

I asked if I could look over his shoulder during the testing and he said that would be up to ABC Nissan. I promised to keep my hands in my pockets and ABC said okie dokie. The first thing they had to do was give me the "recall" update from last spring that I never had done (the door chime and whatever else). After they did that they did a "min/max" test of the cell voltages. He said that he was going to print the screen that would show the difference in voltage of the lowest cell versus the highest cell. He said he could print the numbers for all 96 cells (exact quote) but he was only interested in seeing what the spread was. He said it should be between 20 and 40 millivolts. At 40 mV, he said he would expect to find a bad cell. Mine turned out to be a 27 mV difference. (We were all watching the computer screen to see what the spread was and the numbers appeared to be constantly changing, like numbers that never "settle." I don't know if that was the case or not, because the numbers I saw at one point showed a difference of 29, but the printout he gave me a copy of shows 27. (So perhaps the numbers hadn't settled or perhaps the screen took a shot when the numbers fluctuated a bit. (Clearly this part is not something I understand. )

So they gave me copies of all of the screen shots (the others showed the updates they did, plus one of the 5 star battery reports for good measure) and said then next needed to charge the car to 100% and take a photo of the dash. Since my dash showed it was going to take 2.5 hours to charge to 100%, the Field Rep gave me a ride back to work (it was on his way to Avondale Nissan) and my wife picked up the car later. When she picked up the car, it showed a 100% charge and the GOM showed 64 miles in Eco. They had not driven the car, and I did my normal granny impersonation driving to the dealership (flat as a pancake the entire drive), so I don't think it was reflecting extreme driving.

Sorry for this being so long, but I wanted to add a couple of statements the Field Rep made that surprised me:
1. He related a story of when he worked in Smyrna and a co-worker put 29000 miles on his leaf, charging to 100% twice per day in one year. He said that guy finally lost his first bar after that first year (implied at around 13-14 months). He then said, "The heat in Phoenix is the difference." I took that to mean that under the same circumstances here in Phoenix that owner would have lost several bars. At any rate, I didn't expect him to be that honest.
2. While the diagnostics were being run on my car, I asked him what the magic amount of time was that you should not exceed when your battery is at 100%. He seemed perplexed by my question and said that it really doesn't matter, because the only problem with charging to 100% is the amount of heat that is generated between 80% and 100%. The ABC Nissan leaf tech that was helping with this was nodding his head in agreement at this remark. I was quite surprised to hear that. Shocked actually.

One other interesting remark was in reply to my statement that Nissan's communication is sorely lacking. He said that Nissan did not anticipate this problem. He told me they tested the Leaf in Phoenix for two years before it was for sale. I pressed him on whether the cars spent two summers in Phoenix and he wasn't sure. I then asked him how many bars they lost and at this moment I can't remember his reply. Seems like he said he didn't know.

Finally, I also found it interesting that when I tried to explain to him that I believed that part of the problem for leaf sales in Arizona is a disclosure problem, he seemed a bit defensive and defended the "disclosure" that everyone (except me) had to sign at sale closure. I'm not trying to start that particular discussion up again but it stood out to me that he (and apparently Nissan) believe that disclosure is not a problem.

Here are the numbers from the Min/Max Voltage test:
HV Battery - Maximum Cell Voltage - 3997 mV
HV Battery - Minimum Cell Voltage - 3971 mV
HV Battery - Total Battery Voltage - 383.53 V

That's my report.

 

[DaveinOlyWA]

Thanks for the great detail in your report.

I have to dispute his "100%" statement because the info warning against prolonged periods at full charge are pretty consistent across the industry

 

[leafkabob]

Thanks for the great detail in your report.

I have to dispute his "100%" statement because the info warning against prolonged periods at full charge are pretty consistent across the industry

The only explanation I can think of is that he did not understand my question. I asked if it was OK to leave it at 100% for two days and before he could answer the leaf tech directed our attention to the voltage min/max results coming up, so he never answered.

 

[Stoaty]

Thanks for the great detail in your report.

I have to dispute his "100%" statement because the info warning against prolonged periods at full charge are pretty consistent across the industry

Agreed--not too much detail at all. Appreciate hearing about it.

There is a study from NREL that clearly makes the point that max SOC of 100% has a great effect on battery capacity fade rate, UNLESS you charge to 100% just in time to drive:

"The just-in-time charging scenario, however, shows little sensitivity to SOCmax as that scenario keeps the average SOC low regardless of SOCmax limit. The result points to a tangible benefit to battery life by delaying the beginning of charge until several hours before the next driving trip."

http://www.nrel.gov/vehiclesandfuels/energystorage/pdfs/53817.pdf" onclick="window.open(this.href);return false;

 

[Boomer23]

Good article about how LEAF owners have been affected in hot environments. The only thing they get wrong is that only high mileage cars are affected. A lie that Nissan keeps repeating.

http://www.extremetech.com/extreme/...n-leafs-need-costly-battery-replacements-soon

On page 2, this report says that the new 2013 LEAF "air cools its batteries". Have I missed a blockbuster announcement, or is the reporter off base?

 

[TonyWilliams]

Good article about how LEAF owners have been affected in hot environments. The only thing they get wrong is that only high mileage cars are affected. A lie that Nissan keeps repeating.

http://www.extremetech.com/extreme/...n-leafs-need-costly-battery-replacements-soon

On page 2, this report says that the new 2013 LEAF "air cools its batteries". Have I missed a blockbuster announcement, or is the reporter off base?

I posted a response addressing that, amongst other sundry items.

 

[spooka]

While the diagnostics were being run on my car, I asked him what the magic amount of time was that you should not exceed when your battery is at 100%. He seemed perplexed by my question and said that it really doesn't matter

The exact reaction I received from the Leaf specialist at Peoria Nissan when we were discussing 100% charges. They are being very consistent on this point especially since the CA lawsuit came out. I also asked EV support about 4 weeks ago how long you could leave you car charged to 100% before driving and he said it didn't matter.

because the only problem with charging to 100% is the amount of heat that is generated between 80% and 100%. The ABC Nissan leaf tech that was helping with this was nodding his head in agreement at this remark.

I was told this also by a Blink/Ecotality tech that I met a the 101/17 QC station at Bell Ford about a month ago. He said this was especially an issue with QCing. I am thinking that the best way to combat the heat issue when charging beyond 80% is to L-1 charge to keep the heat as low as possible.

Finally, I also found it interesting that when I tried to explain to him that I believed that part of the problem for leaf sales in Arizona is a disclosure problem, he seemed a bit defensive and defended the "disclosure" that everyone (except me) had to sign at sale closure. I'm not trying to start that particular discussion up again but it stood out to me that he (and apparently Nissan) believe that disclosure is not a problem.

The issue with this is reasonable consumer expectations vs published manufacturer data. Nissan published estimates of 20% loss in 5 years and 30% loss in 10 years. An estimate is more than a guess but less than a guarantee. With actual results being 20% loss in just over a year and 30% loss projected to be around 3 years, there is no way they came close to their estimate. That would be the same as a tire manufacturer saying you will get 50,000 miles on a tire but you only end up getting 10,000. Whose going to cover the costs for the remaining 40,000 miles? Even though tire wear is not covered, you would certainly have a case for premature wear due to manufacturer defect. What the cause of the wear was, short of driver abuse, is unimportant. The buyer was harmed by the manufacturer no matter what was signed. If they don't believe this, they are about to receive a rude awakening.

I have been told by a Blink technician and a LEAF specialist at a Phoenix Nissan dealership that heat was killing the batteries here in Phoenix. What a surprise to hear.

Thanks for a great report leafkabob! Any chance they tested for capacity? I wish I knew I could have been there for my test. I would have asked. I would suggest anyone else that is getting tested to go to ABC Nissan if convenient, since they will let you watch the process.

 

[vegastar]

Here are the numbers from the Min/Max Voltage test:
HV Battery - Maximum Cell Voltage - 3997 mV
HV Battery - Minimum Cell Voltage - 3971 mV
HV Battery - Total Battery Voltage - 383.53 V

Great report!

Making a cell voltage difference at 383.53V total pack voltage is not effective. 383.53V/96 = 3.995, very close to the maximum, so the minimum cell voltage is an outlier and the maximum cell voltage is the norm. 24mV difference from the average cell voltage is equivalent to 381.22 total pack voltage if all the cells were like the weakest one. This 2.31V difference is around 1 kW.h of energy, so around 5% total pack capacity. I think the cell voltage difference must be done in 100% charge to check for imbalances, and around the knee of the voltage (3.71V) to check for damaged cells.