INL L2 vs DC initial capacity test results after 50k mi+

[RegGuheert]

All the anecdotal evidence today indicates, IMO, that we can now expect much longer mileage, 80k to 100k to 80% remaining capacity, and perhaps well past 100k miles to ~70% EOL) for cool climate LEAFs.

The Battery Aging Model, which has proven especially accurate in cool to mildly warm climates, predicts 73.6% capacity remaining for a Leaf in Seattle driven 20,000 miles per year for 5 years, 4 miles per kwh, not parked in the sun. I don't think these Leafs will make 80% after 5 years, but I do think it likely they will make 100,000 miles before 70% capacity loss if driven at least 20,000 miles per year.

+1

The real question is why did Nissan tell all of us that they expect us to have 80% of our battery capacity remaining after five years of use when virtually no one will?

NISSAN estimates that battery capacity will be approximately 80% of original capacity after five years, although this is only an estimate, and this percentage may vary (and could be significantly lower) depending on individual vehicle and Li-ion battery usage.

 

[edatoakrun]

More on the four test LEAFs below:

http://avt.inl.gov/pdf/prog_info/SAEHybridSymposium2014.pdf" onclick="window.open(this.href);return false;

DC FAST, WIRELESS, AND CONDUCTIVE CHARGING EVALUATION PROJECTS
Matt Shirk, Idaho National Laboratory
SAE Hybrid and Electric Vehicle Technologies Symposium
February 13, 2014
INL

Most interesting new info IMO is on m/kWh and available battery capacity when new, on page five:

Track Testing for Vehicle Performance
•Performed at Beginning of Study

Giving 45 mph constant-speed range test (averaging ~4.8 m/kWh) that confirms the results from earlier tests:

http://avt.inel.gov/pdf/fsev/fact2011nissanleaf.pdf" onclick="window.open(this.href);return false;

As discussed at:

LEAF Range and kWh use, at 45, 60 and 70 mph DOE tests

Sublime

From the battery (from the wall):
45mph = 4.85mi/kWh (3.94mi/kWh)
60mph = 3.70mi/kWh (3.04mi/kWh)
70mph = 2.92mi/kWh (2.48mi/kWh)

http://www.mynissanleaf.com/viewtopic.php?f=31&t=13265" onclick="window.open(this.href);return false;

The reports of available capacity as a percentage of total capacity on page seven (as reported previously) show the LBCs allowed the four test LEAFs to access only ~88% to ~90% of total battery capacity when new, rather than a higher and constant percentage between "100%" charge and shut-down, which many seem to accept.

The only capacity I care about is that available to the user, so all my percentages are based on that. The unavailable capacity (5% on the top, 2% on the bottom) is of no use to me.

Exactly, if the car is saying the battery is down 17% less energy to use according to the gauges, is confirmed through on-the-road driving and that is again confirmed through from-the-wall energy measurements, what else matters and why should I feel compelled to answer 99 of Ed's questions which have all been addressed by multiple people before, especially when it's off-topic?

Looking forward to the final paper, with all the details.

DC Fast Charge Study
•50k mile battery lab tests and track vehicle testing scheduled to occur in March, 2014
•Full paper will include all of the track, on-road, and laboratory data analysis.

PS-

Drees, you may want to edit the thread title for discussion of the entire 50k mile test results.

 

[edatoakrun]

I just realized that page eight, which shows Average Range per Charge Grouped by Charge Type seems to indicate that all four LEAFs have been fully discharged, from "100%" to dead, on every charge cycle, since new.

Twice a day in Phoenix...

If that is correct, this is even more of a torture test for the battery packs, and a level of use/abuse far beyond what any private owner is likely to inflict, IMO.

http://avt.inl.gov/pdf/prog_info/SAEHybridSymposium2014.pdf" onclick="window.open(this.href);return false;

 

[DaveEV]

The reports of available capacity as a percentage of total capacity on page seven (as reported previously) show the LBCs allowed the four test LEAFs to access only ~88% to ~90% of total battery capacity when new, rather than a higher and constant percentage between "100%" charge and shut-down, which many seem to accept.

Not sure exactly what you're saying here. The fact that the SOC% percentages reported by the car don't match bench-tested SOC levels in the lab isn't exactly surprising.

What the car thinks is uses as a "100%" cell voltage is very likely different from what the lab uses as "100%" is the most likely reason for the missing ~3-5%. Besides, what's important is that they measured 21 usable DC kWh - a number Tony long ago determined was a good estimate for a new LEAF.

Anyway, what's more interesting in the paper is the validation of the real-life loss of capacity and range of all 4 vehicles after 48k miles of abuse. While all vehicles were able to maintain 70+ miles of range before heading back to the depot for the first 30k miles (which spanned Oct-Jun), the next ~18k miles resulted in a steep loss of range ending in 50-55 mi range for the DCQC cars and 55-60 mi range for the L2 cars. As a result, the cars are only doing between 75-80% of the daily miles they were able to when the cars were new, a number which corresponds with the measured reduction in battery capacity over the test.

 

[RegGuheert]

I hope they keep this test running at least through this summer. So far there is only one summer's worth of data. It would be interesting to see how capacity loss through the second summer compares with the losses seen during the first summer.

 

[GRA]

I found the Evatran wireless charging results on page 11 particularly interesting, as they reported the same or better efficiency (86.1 - 88.8%) as Phil measured for the conductive charger. Or am I misunderstanding how this works, and that's the output efficiency from the wireless charger _into_ the OBC, which then imposes its own ca. 85% efficiency?

 

[RegGuheert]

I found the Evatran wireless charging results on page 11 particularly interesting, as they reported the same or better efficiency (86.1 - 88.8%) as Phil measured for the conductive charger. Or am I misunderstanding how this works, and that's the output efficiency from the wireless charger _into_ the OBC, which then imposes its own ca. 85% efficiency?

I took it as the latter, but it's not clear one way or the other. -87% just for the transformer seems about right.

Somehow I doubt this result is achieved at 60Hz. Does anyone know what frequency is used in these wireless charging approaches?

 

[edatoakrun]

50,000 mile results in.

I'm pleasantly surprised that the battery packs exceeded my expectations in the final 10 k of this battery torture test.

..It also looks to me like the L2 cars are probably headed for 70% battery capacity (EOL) at ~60k miles, and the DC LEAFs at ~50k miles, rather than at ~100k "normal" miles, as statements by Nissan indicated...

While the effect of DC charging is clear, none of the packs have reached EOL (70% initial) capacity.

Still unknown is the amount of accelerated degradation caused by (apparently) constant cycling from "100%" to dead in this test, rather than more normal pack use.

http://avt.inl.gov/pdf/energystorage/DCFC_Study_FactSheet_50k.pdf" onclick="window.open(this.href);return false;

Check out the pack temperature while charging data.

 

[Deleted member 770]

50,000 mile results in.I'm pleasantly surprised that the battery packs exceeded my expectations in the final 10 k of this battery torture test.

I'd be willing to wager that the primary reason for that is the temperatures during the test period (Oct-Mar) vs. the 30K-40K mile period (Jul-Oct).

If they continue the testing, the interesting results will be the next two periods, made during the summer months. I for one fully expect to lose another bar this summer...

 

[edatoakrun]

50,000 mile results in.I'm pleasantly surprised that the battery packs exceeded my expectations in the final 10 k of this battery torture test.

I'd be willing to wager that the primary reason for that is the temperatures during the test period (Oct-Mar) vs. the 30K-40K mile period (Jul-Oct)...

The capacity loss in the latest 10k was much less than I anticipated because it was so much less (less than half as much) as in the previous October-January period.

If you look at battery temperature data:

http://avt.inl.gov/pdf/energystorage/DCFC_Study_FactSheet_50k.pdf" onclick="window.open(this.href);return false;

It is apparent that the higher battery temperatures and rapid capacity loss earlier in the study were due not only to high ambient temperatures, but also due in part to the very high miles driven daily earlier in the test.

"ahagge"...If they continue the testing, the interesting results will be the next two periods, made during the summer months... I for one fully expect to lose another bar this summer...

Well, I expect to lose my second bar this Spring or Summer, but fortunately, we now have data showing how inaccurate bar or gid loss is as indicative of actual capacity loss.

I expect all four of these test LEAFs probably lost at least four capacity bars (and at least ~34% of gids) well before they had accumulated 40k miles, even though they had only lost ~22% to ~26% of actual battery capacity by that time.

The battery temperature data also from this study seems to explain why my own LEAF has probably only lost from one third to one half as much of its original capacity as its LBC (~19.5% at ~26 k miles) indicates.

My average battery temperatures over the past three Summers were probably not much higher than during the two coolest 10k mile study segments, when these LEAFs only lost two to four percent capacity over 10 k miles, even with the abusive 100%-to-Dead-twice-daily discharge cycle.

In My leaf, due in part to efficiency increases, capacity loss is not measurable yet in a slow-speed range test, and 100 miles is still as easy as it was when my LEAF was new, as I posted here:

100 Mile Club & 200 km Club & NEW 300 km Club !!!!

http://www.mynissanleaf.com/viewtopic.php?f=27&t=7022&start=700" onclick="window.open(this.href);return false;

At you miles, ahagge, you could probably get a fairly good indication of your actual available capacity loss in a constant-speed range test.

I'd suggest anyone who is anxious about capacity loss in their own LEAF do the same.

 

[DaveEV]

Well, I expect to lose my second bar this Spring or Summer, but fortunately, we now have data showing how inaccurate bar or gid loss is as indicative of actual capacity loss.

I really don't know why you continue to think this when energy used from the wall to recharge matches up with GID/Ah readings.

My car's GID/Ah reading is currently ~53.9Ah / 225 GID at 100%. How much energy from the wall do you think it takes to recharge from Turtle (or VLBW and LBW) to 100% and how much capacity do you think I've really lost?

 

[edatoakrun]

Well, I expect to lose my second bar this Spring or Summer, but fortunately, we now have data showing how inaccurate bar or gid loss is as indicative of actual capacity loss.

I really don't know why you continue to think this...

Maybe you should re-read this thread and compare the actual capacity loss reports to the gid and capacity bar loss reports from the LEAFs in the Phoenix range test:

http://electricvehiclewiki.com/Battery_Capacity_Loss" onclick="window.open(this.href);return false;

After you replace the incorrect (very unfortunate that the wiki still has not been corrected) efficiency assumption (4.0 m/kWh) used in the wiki, with the ~ correct m/kWh for new LEAFs at the Phoenix test speeds and temperatures as shown by the AVTA studies (~3.6 m/kWh at ~62 mph) you must add the same ~10% to each test LEAF's calculated "percentage of new car capacity" to see just how far off the gid/bars were in predicting range loss.

Of course, in any range test, you have to also take both variable vehicle efficiency and variable LBC access to battery capacity into account (both of which the wiki ignores) while in recharge tests you need to consider both variable LBC operation and variable recharge efficiency.

="drees".....when energy used from the wall to recharge matches up with GID/Ah readings...

Sounds like interesting data.

Where is it?

="drees"...My car's GID/Ah reading is currently ~53.9Ah / 225 GID at 100%. How much energy from the wall do you think it takes to recharge from Turtle (or VLBW and LBW) to 100% and how much capacity do you think I've really lost?

Again, if you actually believe your LEAF's LBC reports are accurate, why don't you post or link to the data?

Remember, neither a range capacity test or a recharge capacity test can determine your batteries total capacity, since the percentage of capacity allowed by the LBC between "100%" and any low SOC point is not a constant, as shown by this thread's study and other publications.

It seems from your and Stoaty's previous comments, you may have missed that point:

More on the four test LEAFs below:

http://avt.inl.gov/pdf/prog_info/SAEHybridSymposium2014.pdf" onclick="window.open(this.href);return false;

...Most interesting new info IMO is on m/kWh and available battery capacity when new, on page five:

Track Testing for Vehicle Performance
•Performed at Beginning of Study

Giving 45 mph constant-speed range test (averaging ~4.8 m/kWh) that confirms the results from earlier tests:

http://avt.inel.gov/pdf/fsev/fact2011nissanleaf.pdf" onclick="window.open(this.href);return false;

As discussed at:

LEAF Range and kWh use, at 45, 60 and 70 mph DOE tests

Sublime

From the battery (from the wall):
45mph = 4.85mi/kWh (3.94mi/kWh)
60mph = 3.70mi/kWh (3.04mi/kWh)
70mph = 2.92mi/kWh (2.48mi/kWh)

http://www.mynissanleaf.com/viewtopic.php?f=31&t=13265" onclick="window.open(this.href);return false;

The reports of available capacity as a percentage of total capacity on page seven (as reported previously) show the LBCs allowed the four test LEAFs to access only ~88% to ~90% of total battery capacity when new, rather than a higher and constant percentage between "100%" charge and shut-down, which many seem to accept.

The only capacity I care about is that available to the user, so all my percentages are based on that. The unavailable capacity (5% on the top, 2% on the bottom) is of no use to me.

Exactly...

...

There are also indications that the percentage of available battery capacity may decrease from the new percentage, ~88% to ~90%, following exposure to higher temperatures. Hopefully, well see more data on this question when the full study is published.

If you throw this additional error of ~5% or more of "capacity loss" into your analysis, I can see how it would be much easier to convince yourself (as it sounds like you have) that your LEAF's battery is degrading at a higher rate/energy throughput than the four LEAFs in this study, which suffered much higher battery temperatures and much more demanding ("100%" to dead, twice a day) charge cycling, than your LEAF has experienced in San Diego.

 

[TonyWilliams]

Maybe you should re-read this thread and compare the actual capacity loss reports to the gid and capacity bar loss reports from the LEAFs in the Phoenix range test:

http://electricvehiclewiki.com/Battery_Capacity_Loss" onclick="window.open(this.href);return false;

After you replace the incorrect (very unfortunate that the wiki still has not been corrected) efficiency assumption (4.0 m/kWh) used in the wiki, with the ~ correct m/kWh for new LEAFs at the Phoenix test speeds and temperatures as shown by the AVTA studies (~3.6 m/kWh at ~62 mph) you must add the same ~10% to each test LEAF's calculated "percentage of new car capacity" to see just how far off the gid/bars were in predicting range loss.

Of course, in any range test, you have to also take both variable vehicle efficiency and variable LBC access to battery capacity into account (both of which the wiki ignores)...

First, for whoever reading this doesn't know our esteemed "Ed", let's just say that his "information" isn't widely regarded here. But, I'll play along a bit for what I predict will quickly turn into another Ed hatefest.

Ed was an early "range loss denier", and then a frequent heckler of anything I posted. So, having briefed the troops, Ed, why don't you tell us first how a new battery that was measured at a government test at 21.3kWh is wrong.

To get 84-89 miles that a LEAF can do at 62mph ground speed on level roadways at 70F or above air and battery temperature (Ed likely will deny this is possible), then you must have 4 miles per kWh from the battery.

4 * 21 = 84 miles
4 * 21.3 = 85.2 miles



Here's the wiki post you presumably cite as "wrong":

In an effort to determine how much range was affected for those with lost battery capacity bars, a group of owners led by Tony Williams did a range test of 12 cars in Tempe, Arizona on September 15, 2012. A largely level course was driven at 100 km/h as measured by the LEAF’s onboard GPS (62 mph ground speed, 64 mph indicated speed as displayed on the LEAF’s speedometer) with the cruise control engaged. It was estimated that this speed would yield a target energy usage rate of 4 miles (6.437 km) per kWh without climate control. Based on Nissan’s published official range data below (from Nissan Technical Bulletin Media:NTB11-076a.pdf), it was determined that a new car would travel 84 miles (135 km) until “turtle” mode (a reduced power mode to safely get the vehicle off the road before the battery disengages power altogether). In addition to the extensive testing by Tony Williams that showed this to be the range of a new Leaf, there is another test that shows range of at least 84 miles. Further confirmation of the range of a new Leaf comes from a teardown of a Leaf by the NREL which revealed usable energy of a new Leaf at 21.381 kwh, which would result in a range of 85.5 miles at 4 miles/kwh:

 

[Stoaty]

For those who don't want to wade through the details, let me paraphrase Ed's hypothesis:

"You have way more actual battery capacity than the capacity bars state. Don't believe Nissan's statement that the capacity readings are 0 to minus 4% with the updated firmware. The fact that your car won't drive as far as it used to until you get to Turtle has no bearing on the actual battery capacity. Nissan is developing the Hot Battery to solve a problem that doesn't actually exist."

 

[edatoakrun]

Another presentation on the AVT Phoenix battery torture test posted by IAL.

The test has been extended to 70,000 miles, so we will eventually see data on an EOL (at and below 70% of new capacity) LEAF battery pack.

Most interesting new data is the divergence in test results of range and capacity between the four test LEAFs, shown on pages 18-19. Unexplained is why the DC charged LEAFs are only losing capacity slightly faster than the L2 Charged LEAFs, but have much larger losses in the 45 mile constant-speed range test.

In any case, IMO the test results show why it is extremely naïve to assume vehicle efficiency and that the percentage of battery capacity the LBC allows you to access from "100%" to shutdown are constants.

DC Fast Charger Use, Fees, Battery
Impacts and Temperature Impacts
on Charge Rates - EV Roadmap

http://avt.inl.gov/pdf/prog_info/DCFCEVRoadmap7PortlandOregonJuly2014.pdf" onclick="window.open(this.href);return false;

DC Fast Charging Impact Study on 2012 Leafs
• Percentage Range and Capacity at 50,000 miles compared to testing
when new

L2 Average DCFC Average
Range 79.0% 69.3%
Capacity 75.2% 72.6%

Increasing efficiency offsetting capacity loss is what I have seen in my own range tests, as I posted on the 100+ mile thread a few days ago.

In my LEAF's case, when driving an even slower average speed and with my batteries never having experienced the hell of Phoenix Summers, No perceptible loss of range has occurred at all.

Four more 100+ mile trips since my last posting last Spring on p 71.

That makes 22 total 100+ mile-on-an-"100%"-charge trips on my LEAF (not including the multiple 100+ mile trips utilizing net descent) the last eight made after losing capacity bar 12 last August.

To sum it up, still no perceptible loss of range on this mountainous and low-speed route, since I started range/capacity test back in the Summer of 2011, as the increase in vehicle efficiency has continued to very closely offset the loss in available battery capacity....

http://www.mynissanleaf.com/viewtopic.php?f=31&t=9064" onclick="window.open(this.href);return false;

5/25/14:
104.4 odometer miles to ~VLBW, 15.1 kWh.

6/15/14:
102.0 odometer miles to ~VLBW, 15.0 kWh.

Those two were (fairly closely) time and temperature matched range tests to gauge changes in efficiency and changes in both nominal (dash, nav screen and CarWings reported) and actual.

...The last two were maximum range tests. Driving speeds were much slower, and ambient (and the battery pack) temperatures were much hotter than my present test standard.

For the first time since delivery, I took my pack below ~VLBW....
6/30/14:
109.3 miles to VLBW, 14.9 KWH (at~200 ft higher altitude than start point)
121.0 odometer miles to 10 gids, 16.2 kWh.

7/13/14:
109.2 miles to VLBW, 15.0 KWH (at~200 ft higher altitude than start point).
126.1 miles to turtle (5 gids ), 17.0 kWh.

All miles above are as reported by odometer. Due to tire wear, the odometer was reporting ~0.002 high on these last four tests. I replaced my OE tires last week, at ~28,700 miles, so I'll expect new results for odometer accuracy, and, due to the (noticeable!) increase in rolling resistance a loss of range-for the first time since I got my LEAF, on my next range test.

KWH use is as reported by dash M/kWh, nav screen M/kWh and Carwings, trip (ERS) and daily.

I believe I now have a pretty good estimate of both the actual Wh per reported kWh at this time, and also the actual loss of capacity my pack has experienced since delivery, which I'll post on-topic on another thread

.

http://www.mynissanleaf.com/viewtopic.php?f=27&t=7022&start=740" onclick="window.open(this.href);return false;

 

[GRA]

Thanks for following this and posting the updates.

 

[edatoakrun]

The most obvious conclusion-from p 17:

Largest decreases in
capacity from test before,
occurred during high heat
charging operation

• Phoenix heat likely
accelerates all results

Hard to see much evidence supporting the "bloodbath" hysteria on MNL fed by reliance on gid reports in place of actual range/capacity results.

Isn't it amazing how those INL guys can get all this done without reference to a single gid report from the four LBCs?

But, I still wonder how many capacity bars these LEAFs have left on the dash.

Have any of you Phoenix folks even tried to take a look?

What you think-maybe about four bars down for the L2 LEAFs, and five down for the DC charged, at 50k miles?

I believe that, based on Nissan's initial range and capacity loss factors disclosure we all signed on purchase, if someone had suggested to me ~three years ago that Phoenix LEAFS could retain the range the two L2-charge-only LEAFs have, and still average ~82 miles of range at 45 constant mph after covering 50 k miles (albeit, including only one full summer of use) after a charge/discharge cycle consisting of twice daily "100%"-to-dead charge cycles, I think I would probably have advised them they might be somewhat over-optimistic.

 

[TomT]

We may need to coin a new term: Ediot...

First, for whoever reading this doesn't know our esteemed "Ed", let's just say that his "information" isn't widely regarded here.

 

[edatoakrun]

="TomT" We may need to coin a new term: Ediot...

Sorry to see you can't make any more substantive argument for a losing proposition than the several previous posters could.

Coincidentally though, I actually did edit the term "gidiot" out of my previous post...

 

[JeremyW]

Unexplained is why the DC charged LEAFs are only losing capacity slightly faster than the L2 Charged LEAFs, but have much larger losses in the 45 mile constant-speed range test.

It's clear to me that the DC packs have increased internal impedance compared to the L2 packs. This agrees with testing of my own leaf, which is quick charged heavily. I have two GID meters, both with which I can measure impedance of my pack independent of the car's systems. Over the last two months I have noticed a sharp uptick in impedance from about 80 mOhm to 100 mOhm at 30 C. I have also noted that driving on the freeway at higher speeds seems to "cost" me more than just what air resistance alone would account for.

I have 28k miles on the car, 53.2 Ah, 64.3 Hx and 81% SOH. 100% Gid count is around 210-215. I've noted my Hx number is is quite a bit lower than others with the same capacity loss.

My usage is 75% city driving with hard acceleration. I quick charge several times a month, often at elevated temperatures. I don't do crazy adventures much these days but I have quick charged 6 times in a row in one day, twice, each time bringing me to 8 TB and around 46 C pack temperature. I also moved in February to an apartment with an underground parking garage that seems to stay around 30 C all the time... :?

I know what I'm doing is detrimental to the pack. As far as I can tell it's manifesting itself as elevated internal impedance. It'll be interesting what will happen when "winter" (so. cal, lol) comes and my pack temperatures go down. I may see something close to 200 mOhm impedance. I know when my pack is in the high 20's C I see close to 120 mOhm already.