Capacity Loss on 2011-2012 LEAFs

[edatoakrun]

Gerry,

I forgot to ask you, what were your ~pack temperatures during the recharge sessions?

edatoakrun wrote:

...Gerry, do you have the LBC calculations of your pack's available capacity ("SOH") to compare with the actual ~72.5%, average difference, from the four charge sessions ?

If not, did you test your old pack right after losing the ninth bar, and if not, ~about what was the time (during which month) and miles driven, that passed before you metered your old pack capacity?

In any case, looks like Gerry's LBC was over-reporting capacity loss by at least 6.5%, adding to the LBCs perfect record (AFAIK) of over-estimating capacity loss in warm and hot climates.

For this reason, if you want to estimate your own actual average available battery capacity loss over time, I suggest you do not rely on your LBC.

If you are trying to calculate the current battery capacity by metering the charge accepted, battery temperature is an important variable to normalize, just as it is when you are calculating your available discharge capacity from a range test. Expect to see overall trip efficiency to increase at higher battery temperatures, due in part to more efficient charging.

Remember though, that this efficiency loss when charging a colder battery, is not really a reflection of lower overall efficiency, since that extra energy is not wasted, when its being used to warm up a cold battery. Nissan has stated that LEAFs passive thermal management utilizes this temperature efficiency curve, to help maintain capacity in lower ambient temperatures. All those wasted Wh during low-temperature charging heat up the pack and increase your kWh accepted, which you (usually) want.

You can observe both the changes in your LEAFs nominal kWh use report error and seasonal variations in overall trip efficiency on your own LEAF, by observing the CarWings KWh use reports and dividing those nominal kWh used, by the actual kWh accepted on recharging, as shown by an external meter.

In 2011-12 LEAFs, CarWings reports the same nominal kWh use displayed on the nav screen m/kWh, and with a ~2.5% odometer under-report error, on the dash m/kWh.

While I don't believe these use reports could be completly accurate, I have never been able to find errors in these reports over a single discharge cycle, or between cycles completed over a short time period, in any range/capacity test.

So, in a 2011-12 LEAF, I believe you can depend on the nav Screen to fairly accurately report odometer miles/nominal kWh, and the dash to display ~2.5% under-report of odometer miles/nominal kWh use, at all times.

Over the longer term, however, it is obvious the large nominal efficiency increase in all my LEAFs m/kWh reports over time can only be explained by an increase in the actual Wh content per each nominal kWh reported, which of course is also showing up in my nominal overall trip efficiency, as described below.

If you want to find your own average available capacity, I suggest you should try to average over a large sample of discharge/recharge cycles, due to variations in the charge level your LBC allows, and use a consistent end charge setting, either "80%" or "100%".

At seasonally lower average battery temperatures, you would expect to observe the seasonal drop in average efficiency.

In addition to the seasonal drop in trip efficiency due to ambient temperatures, you should also see any variations in the Wh per nominal kWh use reports over time.

For example, My LEAF had a nominal overall trip efficiency average of ~77.9%, over a sample of nine ~middle of the pack cycles, starting at "80%", and ending between the LBW and the VLB, in January 2014, and ~76.8% nominal overall trip efficiency average over a sample of seven of the same charge cycles, with very similar pack temperatures, in January 2015.

So, you can see both the magnitude of the nominal kWh constant reporting error I started 2014 with, and the increase over the last year. Each of the nominal kWh from CarWings, as displayed in my dash and nav screen m/kWh readouts while I drove, clearly reflects I had far over 1,000 Wh per nominal kWh last year, and the Wh/nominal kWh continued to increase over the last year.

Unfortunately, I don't know of a good estimate of overall trip efficiency over the ~middle of the pack, which is all I use to make my usual 50-60 mile trips, but, IMO it could be significantly higher than for the entire available battery capacity, which we do have data for.

The most comprehensive report from the AVTA (AFAIK) found an average Overall Trip Efficiency E/A 82.7%, and average Wall Plug energy 21.722 AC kWh, on "100%" to stop discharge cycles.

Advanced Powertrain Research Facility
AVTA Nissan Leaf testing and analysis
October 12th 2012...

Draft terms Math Value
Charger efficiency C/B N/A
Charger & EVSECompare EVSE equipment efficiency C/A 85.3%
Overall Trip Efficiency E/A 82.7%
Battery efficiency E/C 96.9%
Pack Utilization E/D 74.8%

Analysis Note:
Values are based on
13 level 2 battery
charge events from
completely depleted
to fully charged

Measurement point Average value
A) Wall Plug energy 21.722 AC kWh
C) DC energy to pack 18.529 DC kWh
E) DC Test energy * 17.957 DC kWh

quote from P 21:

http://www.transportation.anl.gov/D3/data/2012_nissan_leaf/AVTALeaftestinganalysis_Major%20summary101212.pdf" onclick="window.open(this.href);return false;

Those are average efficiencies, likely covering a large temperature range, and after at least 13 charge cycles, the pack could not have been new.

I don't know of good data on how much Overall Trip Efficiency varies with temperature, but I think I'm seeing roughly ~2% to ~3% reduction in Overall Trip Efficiency, when comparing ~middle of the pack charge cycles, with pack temperatures during recharge averaging ~85 F in mid-Summer, and averaging ~45 F in mid-Winter.

 

[mwalsh]

Battery pack killing weather has come early to SoCal this year...it was 89 degrees in my 'hood today.

 

[dgpcolorado]

Battery pack killing weather has come early to SoCal this year...it was 89 degrees in my 'hood today.

And here as well. February should have a "frozen" Amp•hour reading but several weeks of temperatures in the 40s and 50s have started the decline in battery capacity several months earlier than I would have hoped. Winter pretty much didn't happen here except for a week or two around Christmas and New Year's Day. Local mountain snowpack is 60% of the 30 year average. And falling. I wish Boston hadn't taken all the snow...

 

[RegGuheert]

Hey, send some of that warmth our way!

Forecast lows for the next ten nights: 11F, 16F, 6F, 4F, 17F, 27F, 7F, 11F, 17F and 27F. We're paying for the electricity right now, so I guess we'll be buying more than I want to (which is NONE).

 

[WetEV]

Local mountain snowpack is 60% of the 30 year average. And falling.

Olympic mountains are at 6% of average snowpack water content. Yes, no missing "0". 6% North Cascades are doing better, at 56%, and goes down to 18% in the South Cascades.

Looks grim to me, unless we get some late snow.

 

[Valdemar]

Battery pack killing weather has come early to SoCal this year...it was 89 degrees in my 'hood today.

My regen is back, yay!

 

[RegGuheert]

My regen is back, yay!

Regen?

Can you kindly remind me what that is?

 

[dgpcolorado]

Local mountain snowpack is 60% of the 30 year average. And falling.

Olympic mountains are at 6% of average snowpack water content. Yes, no missing "0". 6% North Cascades are doing better, at 56%, and goes down to 18% in the South Cascades.

Looks grim to me, unless we get some late snow.

My family in Oregon were saying much the same about their mountains a couple of days ago. Hard for me to imagine the super wet Olympics at 6%. A dry Hoh rain forest? You could have an "interesting" fire season this summer.

One concern here in Colorado is that our mountains are the snowpack reservoir for a lot of river systems, notably the Colorado River (used by Arizona, California, and Nevada), the Rio Grande (that basin has been way below average snowpack for many years now, currently it is at 61%), the Arkansas River (90%), and the South and North Platte Rivers (tributaries of the Missouri River — they are doing pretty well on snowpack this year).

 

[edatoakrun]

Local mountain snowpack is 60% of the 30 year average. And falling.

Olympic mountains are at 6% of average snowpack water content. Yes, no missing "0". 6% North Cascades are doing better, at 56%, and goes down to 18% in the South Cascades.

Looks grim to me, unless we get some late snow.

My family in Oregon were saying much the same about their mountains a couple of days ago. Hard for me to imagine the super wet Olympics at 6%. A dry Hoh rain forest? You could have an "interesting" fire season this summer.

One concern here in Colorado is that our mountains are the snowpack reservoir for a lot of river systems, notably the Colorado River (used by Arizona, California, and Nevada), the Rio Grande (that basin has been way below average snowpack for many years now, currently it is at 61%), the Arkansas River (90%), and the South and North Platte Rivers (tributaries of the Missouri River — they are doing pretty well on snowpack this year).

On-topic thread below.

It could be a lot worse.

And unfortunately, it probably soon will be.

A ‘megadrought’ will grip U.S. in the coming decades, NASA researchers say

The long and severe drought in the U.S. Southwest pales in comparison with what’s coming: a “megadrought” that will grip that region and the central Plains later this century and probably stay there for decades, a new study says...

Western USA drought worst in modern era

http://www.mynissanleaf.com/viewtopic.php?f=13&t=15592&p=412047#p412047" onclick="window.open(this.href);return false;

 

[electricfuture]

Nissan refuses to do anything untill it reads less than 9 battery bars - been sitting at 9 since June. I have 54,000 miles on it. I really like my car but can not drive it due to distance I need to drive. Dealer kept it for a month and said they couldn't find anything wrong!!!! Any help or suggestions would be greatly appreciated

Hi Imapa,

I had a similar issue as related earlier in this tread. I have 2 suggestions: On the week end put extra weight in your car and drive to a quick charge station re-charging when you are down to 1 bar. I believe NRG has some in Texas - usually at the dealership. With your current low range you could probably re-charge the battery several times in a day. This should accelerate the battery's degradation. This will reduce the hassle time you are now experiencing even though it will cost you $6-7 per quick charge.

Second, find another dealership. There is no way they should have kept your car a month. They only run the test and send the results to Nissan who tells them what to do. The tests take a few minutes. Also be absolutely sure you request the detailed battery report for each test that is made. The tests results can vary from minute to minute so multiple tests would be required to identify a problem.

However, I don't think you have a cell problem. You will probably loose the 4th bar soon, sooner if you take the first suggestion.

 

[Valdemar]

With temps rising somehow lost 0.4AHr in just 2 days and now down to 9 bars, the 10th didn't last as long as the 11th, more frequent QC is likely the culprit. Sucks but the car should work for my needs until the next EV generation is out if it is for real.

 

[dhanson865]

Anybody in or near TX want a cheap leaf?

originally in Grand Prairie, TX, then second owned in Arlington, TX as a Nissan CPO
05/25/2011 to 02/05/2015 gets us to 41,070 miles and a 4 bar loser.

2011 Nissan Leaf SL
VIN 5164
asking $9,900 at Auto Merchants of Plano, TX

you could buy it and get a free battery from Nissan and have a pretty nice car for $10,000 and the hassle of dealing with a dealer for a week or two.

Amazing to me that the CPO owner didn't get the battery replaced when it dropped the 4th bar.

 

[vegastar]

Just lost my 11th bar. 51.7Ah, 87000km (54375 miles) and 3 years and 5 months since delivery. No replacement battery for me...

 

[highend]

vegastar - you still have 1,5 year left to make battery claim.
just don't go over 100.000km (60.000 miles)

only 2 bars to go you can loose them by the end of next year.

 

[TimLee]

^But vegastar is pretty close on miles.
Will have to do a lot of no or very low miles usage to lose two capacity bars in that few miles.

 

[kolmstead]

Leaf 257 joined the 3BL crowd this morning. 33,460 miles, fifty months of use. 46.01 Ahr, 49.36% Hx. Need to lose three or four more Amp-hours in ten months, which shouldn't be a problem with summer coming on. Ridgecrest, CA daytime summer temps are routinely 107 F, with occasional excursions to 117 F.

The second bar disappeared back in July of 2013, nineteen months ago. I was pretty well convinced that the P3227 update was preventing the update of capacity bar display, especially since the battery has been under 47 Ahr, the normal threshold for loss of bar 3, since last October. I'm still wondering if Nissan hasn't revised the capacity thresholds downward by an Amp-hour or so. They promised that they wouldn't do that... but that was a couple of years and one or two changes in management ago, when the battery capacity warranty was announced. One thing for sure, battery capacity bars are very "sticky" when the battery is cold. Nissan doesn't want bars disappearing in the winter and reappearing the following summer when the battery warms back up.

-Karl

 

[edatoakrun]

... I was pretty well convinced that the P3227 update was preventing the update of capacity bar display, especially since the battery has been under 47 Ahr, the normal threshold for loss of bar 3, since last October. I'm still wondering if Nissan hasn't revised the capacity thresholds downward by an Amp-hour or so. They promised that they wouldn't do that... but that was a couple of years and one or two changes in management ago, when the battery capacity warranty was announced. One thing for sure, battery capacity bars are very "sticky" when the battery is cold...

Congratulations!

The "sticky" bar phenomenon was very noticeable from the beginning ~two years ago, when bar loss reports virtually halted during the winter of 2012-13, so I doubt P3227 had much (if any) effect of bar loss in relationship to the LBC AHr report, though it did of course, drastically increase the LBC AHr reports, temporarily (and maybe, to a lesser extent, permanently).

I've also been hoping to lose a capacity bar (eleven) since late October, but at 50.66 AHr (LBC-reported) it's still there.

I remain (slightly) hopeful that I can still lose bar number ten by this Fall, and make a dash for magic number nine by May of '16.

 

[TLeaf]

Leaf #225 lost it's first bar after 50 months and 35,300 miles of travel. I think I'm still on track to have a 40 mile range (my commute distance) by the time I retire in another 16 years or so...

 

[dhanson865]

Am I the only one that finds it morally troubling that Nissan is shipping LEAFs with badly degraded battery packs east, and now it has been sold to an unsuspecting buyer in Bristol, TN for nearly $20,000?

The for sale listing had pictures of the dash with missing capacity bars still even after going from AZ to MI to TN.

Note it isn't clear that Nissan Corporate shipped it around, it could have been individual dealer transactions. Also note that the car fax report shows the leaf as a one owner vehicle even though it has been moved from state to state to state and we know that the original owner sold it/traded it in/ returned it to Nissan because he posted it here on this thread and other threads under the user name NOC8H18.

2011 NISSAN LEAF SV/SL
VIN: JN1AZ0CPXBT008887

http://www.autotrader.com/cars-for-sale/vehicledetails.xhtml?listingId=348174844" onclick="window.open(this.href);return false;

08/27/2011 NICB Vehicle manufactured and shipped to Arizona
09/27/2011 Pinnacle Nissan Scottsdale, AZ Vehicle offered for sale
09/30/2011 5 Pinnacle Nissan & Infiniti Pre-delivery inspection completed
10/14/2011 10 Pinnacle Nissan & Infiniti Vehicle sold
10/24/2011 Arizona Motor Vehicle Dept. Title #033H011297074 Registration issued or renewed
First owner reported Titled or registered as personal vehicle Loan or lien reported
10/31/2011 194 Pinnacle Nissan & Infiniti Scottsdale, AZ Window tint installed
02/16/2012 5,941 Pinnacle Nissan & Infiniti Scottsdale, AZ Maintenance inspection completed
03/27/2012 Pinnacle Nissan & Infiniti Scottsdale, AZ Vehicle serviced
05/03/2012 9,677 Pinnacle Nissan & Infiniti Scottsdale, AZ Maintenance inspection completed
07/12/2012 12,934 Pinnacle Nissan & Infiniti Scottsdale, AZ Vehicle serviced
10/12/2012 17,314 Pinnacle Nissan & Infiniti Scottsdale, AZ Brake fluid flushed/changed
Paint sealant applied/reapplied
Cabin air filter replaced/cleaned
04/18/2013 22,725 Michigan Motor Vehicle Dept. Saginaw, MI Title #279B1080140 Title or registration issued to manufacturer
05/20/2013 22,727 Auto Auction Tennessee Listed as a manufacturer vehicle Sold at auction
05/22/2013 Bill Gatton Honda Bristol, TN Vehicle offered for sale
05/29/2013 22,731 Bill Gatton Honda Bristol, TN Pre-delivery inspection completed
Maintenance inspection completed
Tires rotated and balanced
Tire condition and pressure checked

Looks like Nissan did it to me but I'm not an expert on car titling processes maybe a dealer can do that without the corporation being involved?

The pics on the autotrader listing clearly show 2 bars lost, if they refurbished the battery it would have more bars even if only temporarily.

Given it was used in AZ how long do you think it'd take for the 3rd bar to go away if someone buys it?

OK, ironically I'm looking at this car again as I search for a Leaf to buy in the next month or so.

It is now for sale in NC for $9,894 and dropping but they list the free carfax report and this time the 2nd owner had it in an accident. Apparently someone rear ended the Leaf. It's been repaired to look like new and sold/traded from dealer to dealer several times (unless all these dealers are owned by the same person/corporation).


To add to the laugh factor it has this boilerplate notice:

Seller Comments
We have performed the following as an added value of $243.90 to this vehicle: Completed the North Carolina Safety/Emissions Inspection, New oil and filter, New windshield wiper blades and New air filter.

Oh, well, tons of Leafs in the used market I don't suppose I'll have to settle for an Arizona leaf with rear end damage/repairs.

 

[DougWantsALeaf]

My 13 leaf dropped 5 gids overnight. Do cells occationally go bad. Hadn't lost a GID for about a year, so I guess I was due.