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

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DaveEV

Well-known member
Joined
Apr 23, 2010
Messages
6,253
Location
San Diego
Test details:
4 identical 2012 Nissan LEAFs
2 will be charged using only L2
2 will be charged using only DCQC
Battery packs will be tested every 10k miles for 30k miles.
2 additional battery packs will be lab tested at a constant 30C ambient - one only charged on L2, one only charged DCQC.

At 10k miles, no significant difference in capacity between L2 and DCQC - capacity is down between 5.5-6.5% approximately.

http://www4.eere.energy.gov/vehiclesandfuels/resources/merit-review/sites/default/files/vss113_francfort_2013_o.pdf" onclick="window.open(this.href);return false;

There are more interesting reports if you search the DOE Merit Review site:
http://www4.eere.energy.gov/vehiclesandfuels/resources/merit-review/" onclick="window.open(this.href);return false;
 
Really interesting report! I had lunch with a friend at Ecotality this week who was telling me about this testing, although he didn't know many of the technical details of this. It looks like the testing is being done from Oct 2012 until Oct 2013, so it must be still going on?

Sounds like they are doing testing immediately after driving AM/PM shifts, so they should get a really hot battery if DC charging during the hot time of the day, during the summer. It's very easy for me to get my battery pack up to 8 or 9 TBs using DCFC. And they'd need at least two DCFC sessions to get to about 140 miles a day.

I'm pleased at their findings so far, which seems to show very little degradation difference between an L2-charged car and a DCFC-charged car (slide 9). However, that was only at 10K miles, so they only had run from 10,000 miles / 140 miles/day (from their data) = 71 days. That would mean that run was from Oct 1, 2012 to about Dec 10th, 2012, if I'm understanding their testing correctly. This run would be to about Jan 1st, 2013 if they are doing 5 day work weeks, which I suspect.

October is in the upper 90s/low 100s max during the day, but the evenings are dropping to the 70s. Cooler yet in November and December, with December usually in the 70s during the day, 50s-60s in the night. The batteries will get a pretty low ambient temperature at night to cool off.

From the map, they have a decent mix of highway and side-street driving. The stretch of I-10 they are using will be very heavily congested in the early morning (7-9AM) and afternoon (3-7pm). If they are varying their time so that they sometimes avoid traffic, they will get times on I-10 that they are running at highway speed.

The 'third 10K' sample is the most interesting to me, as they should be doing several DCFC charges during the June-July-August timeframe and the ambient temperature stays high into the evening.
 
Wish we already had the baseline constant speed track tests for each of the four LEAFs, as promised.


Looks like the six packs all tested ~ 2 to 3 percent below spec in static capacity when "new", at the BOT?


Technical Backup Slide 1
Test
Measureable
BOT

kWh Discharged (kWh)
23.40
23.47
23.31
23.59
23.38
23.24

http://www4.eere.energy.gov/vehiclesandfuels/resources/merit-review/sites/default/files/vss113_francfort_2013_o.pdf" onclick="window.open(this.href);return false;

IMO, if you are looking for some good data on early calendar aging, you might want to find the build dates for each of these LEAFs, and watch the results from the 10k, 20k, and 30 k mile capacity and range tests.
 
I'm not the least bit surprised with this data. I've been telling and posting about QCs since I started using them in Nov., '11. I knew that QCing a few times a day wasn't going to degrade the battery pack any more than any other multiple charging. With my 2011, I had QCd hundreds of times through 10,000 miles. I knew it wasn't the reason I had lost a CB, but high ambient temps over time caused it and because I drove mine the first six months at very low speeds, it kept it from losing the second CB.
 
phxsmiley said:
...Sounds like they are doing testing immediately after driving AM/PM shifts, so they should get a really hot battery if DC charging during the hot time of the day, during the summer. It's very easy for me to get my battery pack up to 8 or 9 TBs using DCFC. And they'd need at least two DCFC sessions to get to about 140 miles a day.


...The 'third 10K' sample is the most interesting to me, as they should be doing several DCFC charges during the June-July-August timeframe and the ambient temperature stays high into the evening.


There you go.

Results dated 8/7/13, showing both 20k and 30k mile results.

http://avt.inel.gov/pdf/energystorage/DCFC_Study_FactSheet_30k.pdf" onclick="window.open(this.href);return false;

Too bad they don't seem to be posting the exact dates of the 10 k cycles.

The expected accelerated loss of capacity in summer, as well as additional loss of capacity from fast charging, are both showing up IMO, with ~14% capacity loss on L2, and ~17% loss on DC.

If this loss of capacity is different from what you think you are seeing in your hot climate LEAFs, remember this appears to be actual loss of total capacity from discharge tests, not the available (?) battery capacity as reported by your LEAF's LBC, as displayed in dash capacity bars or app/gid meter readouts.
 
40,000 mile capacity test results after ~ one year, as reported here:


http://avt.inl.gov/pdf/energystorage/DCFC_Study_FactSheet_40k.pdf" onclick="window.open(this.href);return false;

Looks like the L2 cars have lost ~22%, and the DC-charged LEAFs ~26%.

I repeat: I think someone in the Phoenix area really should try to get a look at these LEAFs.

Has anyone even attempted to see the capacity bars and/or check the gid/LEAF Spy reported battery capacity?

If the dash bars and gid counts show indicated losses of capacity differing significantly from these actual test results, this would be extremely valuable data, IMO.
 
edatoakrun said:
40,000 mile capacity test results after ~ one year, as reported here:


http://avt.inl.gov/pdf/energystorage/DCFC_Study_FactSheet_40k.pdf" onclick="window.open(this.href);return false;

Looks like the L2 cars have lost ~22%, and the DC-charged LEAFs ~26%.
Interesting... the Battery Aging Model for Phoenix (4 miles per kwh, Leaf never parked in sun, assuming 2 months between manufacture and delivery) predicts 25.28% loss, which is pretty close. Looks like another validation of the Battery Aging Model to me. :D
 
Stoaty said:
edatoakrun said:
40,000 mile capacity test results after ~ one year, as reported here:


http://avt.inl.gov/pdf/energystorage/DCFC_Study_FactSheet_40k.pdf" onclick="window.open(this.href);return false;

Looks like the L2 cars have lost ~22%, and the DC-charged LEAFs ~26%.
Interesting... the Battery Aging Model for Phoenix (4 miles per kwh, Leaf never parked in sun, assuming 2 months between manufacture and delivery) predicts 25.28% loss, which is pretty close. Looks like another validation of the Battery Aging Model to me. :D

Climate Arco - Idaho °C | °F
Jan Feb Mar Apr May Jun
Average high in °F: 29 35 46 58 67 77
Average low in °F: 5 10 21 29 37 43
Av. precipitation in inch: 0.83 1.06 0.87 0.75 1.34 0.91
Days with precipitation: - - - - - -
Hours of sunshine: - - - - - -
Jul Aug Sep Oct Nov Dec
Average high in °F: 85 83 74 61 42 30
Average low in °F: 48 47 38 29 18 6
Av. precipitation in inch: 0.83 0.79 0.71 0.63 0.79 0.83
Days with precipitation: - - - - - -
Hours of sunshine: - - - - - -

vs.

Climate Phoenix - Arizona °C | °F
Jan Feb Mar Apr May Jun
Average high in °F: 65 69 74 83 92 102
Average low in °F: 43 47 51 58 66 75
Av. precipitation in inch: 0.83 0.79 1.06 0.24 0.16 0.08
Days with precipitation: 4 4 3 2 1 1
Hours of sunshine: 248 244 314 346 404 404
Jul Aug Sep Oct Nov Dec
Average high in °F: 104 102 97 86 73 65
Average low in °F: 81 80 74 63 50 44
Av. precipitation in inch: 0.98 0.94 0.75 0.79 0.75 0.91
Days with precipitation: 4 5 3 3 2 4
Hours of sunshine: 377 351 334 307 267 236
 
edatoakrun said:
Looks like the L2 cars have lost ~22%, and the DC-charged LEAFs ~26%.
Looks like the QC cars are holding up very well compared to the L2 cars. At 22%+ capacity loss these cars must be down between 2-3 capacity bars. It certainly feeds the belief that one should not worry about using QC when needed as long as it isn't over-used.

edatoakrun said:
If the dash bars and gid counts show indicated losses of capacity differing significantly from these actual test results, this would be extremely valuable data, IMO.
Agreed.

Stoaty said:
Interesting... the Battery Aging Model for Phoenix (4 miles per kwh, Leaf never parked in sun, assuming 2 months between manufacture and delivery) predicts 25.28% loss, which is pretty close. Looks like another validation of the Battery Aging Model to me. :D
Yeah, not bad.

I find it interesting how little capacity was lost between 10-20k miles. Were those miles purely put on during the winter months? The miles between 20-40k were a LOT harder on the batteries than the miles between 0-20k. At the 20k mark all cars were down about 2kWh, but at the 40k mark, cars are down 5-6 kWh - 2-3 times more capacity loss!

The L2 cars are losing about 1.31 kWh every 10k miles while the QC cars are losing about 1.47 kWh every 10 miles, or about 12% faster. After 40k miles, the QC cars hold about 0.7 kWh less energy than the L2 cars.
 
GRA said:
Climate Arco - Idaho °C | °F
Jan Feb Mar Apr May Jun
Average high in °F: 29 35 46 58 67 77
Average low in °F: 5 10 21 29 37 43

vs.

Climate Phoenix - Arizona °C | °F
Jan Feb Mar Apr May Jun
Average high in °F: 65 69 74 83 92 102
Average low in °F: 43 47 51 58 66 75
Not sure why you are bringing this up. The road testing was done in Phoenix. See page 16:

http://www4.eere.energy.gov/vehiclesandfuels/resources/merit-review/sites/default/files/vss113_francfort_2013_o.pdf" onclick="window.open(this.href);return false;
 
drees said:
I find it interesting how little capacity was lost between 10-20k miles. Were those miles purely put on during the winter months? The miles between 20-40k were a LOT harder on the batteries than the miles between 0-20k. At the 20k mark all cars were down about 2kWh, but at the 40k mark, cars are down 5-6 kWh - 2-3 times more capacity loss!
Testing started in October, so the second 10,000 miles would be January-March (test was to run for one year, so presumably the 40,000 mile mark corresponded to one year of calendar aging and cycling the battery through all the seasons).

The L2 cars are losing about 1.31 kWh every 10k miles while the QC cars are losing about 1.47 kWh every 10 miles, or about 12% faster. After 40k miles, the QC cars hold about 0.7 kWh less energy than the L2 cars.
Yes, it suggests that periodic QC--rather than continual QC in the test cars--would have very little effect on battery life... unless you do multiple QC in a day and push the battery pack temp really high. :eek:
 
Back to the 40k mile report:

http://avt.inl.gov/pdf/energystorage/DCFC_Study_FactSheet_40k.pdf" onclick="window.open(this.href);return false;

And the original study description:

http://www4.eere.energy.gov/vehiclesandfuels/resources/merit-review/sites/default/files/vss113_francfort_2013_o.pdf" onclick="window.open(this.href);return false;

First notice that this study is not designed to determine LEAF capacity loss in typical use.

It is intended to measure the variable loss increase induced by DC charging in a atypical driving pattern, most unusually the (140-150 miles per driving day?) necessary to rack up 40,000 miles in 12 to 13 months.

Even the L2 cars, since they are spending such a large time heating their batteries by repeated charge/discharge cycles, are introducing an additional factor in capacity loss that does not exist for Phoenix LEAF drivers with more typical miles driven per day or year.

So we can't see the extent to which the beneficial effects (from cooler batteries) by driving "normal" miles per day/year, and the detrimental effects longer-term calendar capacity loss, may offset each other, from these reports.

All four lost over 20% by sometime in the late summer, somewhere between 30,000 and 40,000 miles.

I would say the additional capacity loss from DC is very significant in these four LEAFs, but that does not necessarily imply the same results using DC in more "normal" conditions of use, where temperature effects on capacity loss could be expected be far less.

Both pairs of LEAFs, of course, will have far less than the 80% remaining capacity "approximately 5 years of normal (12 k miles driven per year, or 60 k total miles ?) operation" in the LEAF sales disclaimer.

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.

But of course, these LEAFs may have also been subjected to most (and in the case of the two DC LEAFs, all?) factors known to accelerate capacity loss.

We do not know how much longer (or shorter) in time/miles/charge cycles the batteries in other hot climate LEAFs with more typical driving patterns will last, nor how much longer cool climate LEAF batteries will last, since we do not have any accurate test data for these LEAFs, only the dash bars and LBC data intercepts.

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.

So we don't know if LEAF batteries will meet (or fall short or exceed) Nissan’s battery life projections in “normal” use, though It doesn’t look to me like the results are likely be way off.

I won’t speculate why Nissan did not emphasize the large factor the variable of battery temperature would have on capacity life, which has led to the near-hysteria, including the repeated cries of a “bloodbath”, on this forum.

I will restate that, IMO, Nissan’s present policies RE LEAF buybacks and the battery capacity warrantee, may indicate that Nissan is more concerned with concealing the actual rate of LEAF battery capacity loss in all climates and due to other use variables, rather than in quantifying the effects of the various factors.

My own best guess at this time, is that my own warm climate LEAF will probably come pretty close to the “normal” rates of capacity loss Nissan stated when I bought it.

But if I lose four bars on my dash by 5 years or 60 k miles, even if that corresponds to anything less than ~30% of actual capacity loss, I expect to take Nissan up on its warranty offer to put one or more bars back on my dash.

I hope Nissan will actually take action to increase my real available battery capacity, and not just light up a few of my LEAFs dash bars...
 
edatoakrun said:
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.
If you are referring to Pacific Northwest LEAFs (which I believe to be the benchmark for "cool climate" here in the USA), I think that they will be well under 80% by 100k since TaylorSFGuy is currently around 77% at 100k miles. Since calendar life degradation is still the major component of capacity loss, I expect even Seattle cars to be under 70% capacity by 10 years and 100k miles. If you drive 20k miles/year, you should be slightly over 70% at 5 years 100k miles. And if you drive 33k miles/year, you should be just under 75% at 3 years.

edatoakrun said:
My own best guess at this time, is that my own warm climate LEAF will probably come pretty close to the “normal” rates of capacity loss Nissan stated when I bought it.
I very highly doubt it. I expect your car to be in the low 70% by the time 5 years 60k miles rolls around (assuming your climate is similar to Sacramento). Even if it's slightly cooler, you might be at 75% which is significantly less than the estimated 80% Nissan has been telling us to expect after 5 years of typical driving.
 
Drees, so that I will not have to reply in alternate, would you please state what you are trying to express with these percentages?

Do you mean percentages of actual total battery capacity?

Which is what the INL is measuring, and I am referring to in all my comments (on the test results) of this thread.

Or do you mean LBC data/dash capacity bar displays?

And if referring to the latter:

Do you believe the LBC data/dash capacity bar displays are percentages of total battery capacity, or just the lesser available (stop to "100%" charge) capacity?

Why do you accept the LBC data/dash capacity bar displays as accurate, when all evidence (that I am aware of) indicates that they are not?

drees said:
edatoakrun said:
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.
If you are referring to Pacific Northwest LEAFs (which I believe to be the benchmark for "cool climate" here in the USA), I think that they will be well under 80% by 100k since TaylorSFGuy is currently around 77% at 100k miles. Since calendar life degradation is still the major component of capacity loss, I expect even Seattle cars to be under 70% capacity by 10 years and 100k miles. If you drive 20k miles/year, you should be slightly over 70% at 5 years 100k miles. And if you drive 33k miles/year, you should be just under 75% at 3 years.

edatoakrun said:
My own best guess at this time, is that my own warm climate LEAF will probably come pretty close to the “normal” rates of capacity loss Nissan stated when I bought it.
I very highly doubt it. I expect your car to be in the low 70% by the time 5 years 60k miles rolls around (assuming your climate is similar to Sacramento). Even if it's slightly cooler, you might be at 75% which is significantly less than the estimated 80% Nissan has been telling us to expect after 5 years of typical driving.
 
Stoaty said:
GRA said:
Climate Arco - Idaho °C | °F
Jan Feb Mar Apr May Jun
Average high in °F: 29 35 46 58 67 77
Average low in °F: 5 10 21 29 37 43

vs.

Climate Phoenix - Arizona °C | °F
Jan Feb Mar Apr May Jun
Average high in °F: 65 69 74 83 92 102
Average low in °F: 43 47 51 58 66 75
Not sure why you are bringing this up. The road testing was done in Phoenix. See page 16:

http://www4.eere.energy.gov/vehiclesandfuels/resources/merit-review/sites/default/files/vss113_francfort_2013_o.pdf" onclick="window.open(this.href);return false;
Ah, missed that. Thanks.
 
edatoakrun said:
Why do you accept the LBC data/dash capacity bar displays as accurate, when all evidence (that I am aware of) indicates that they are not?
I think we're all in agreement that post P3227 update the data provided by the car is largely accurate and matches data used from the wall to recharge the battery which is the best way for the average person to verify capacity loss outside of the using the gauges. You are the only person who claims otherwise. Or are you claiming to have pulled the pack and measured the capacity of the pack the same way that INL is? If you want anecdotal data, in 2.5 years I am now able to only travel about 82-83% as far on a 80% charge to LBW (43 mi vs 52 miles at 4.3 mi/kWh). That very closely matches capacity loss as reported by the car as well as matching energy drawn from the wall.
 
edatoakrun said:
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.

So we don't know if LEAF batteries will meet (or fall short or exceed) Nissan’s battery life projections in “normal” use, though It doesn’t look to me like the results are likely be way off.
Well, I have driven my Leaf extremely conservatively, and after 2.5 years and 23,000 miles I have lost about 17% of capacity (based on the capacity in Ah from the LeafDD and the percent loss of Gids at an 80% charge). I have lost 19% at full charge, but that may be due to inadequate balancing of the battery or temporarily from colder battery pack temps. So I will be approaching by 3 years the 5 year estimate of Nissan to 80% capacity--only two years short of their prediction, but that also means that they predicted a time that was 66% greater than my actual time.

I won’t speculate why Nissan did not emphasize the large factor the variable of battery temperature would have on capacity life, which has led to the near-hysteria, including the repeated cries of a “bloodbath”, on this forum.

I will restate that, IMO, Nissan’s present policies RE LEAF buybacks and the battery capacity warranty, may indicate that Nissan is more concerned with concealing the actual rate of LEAF battery capacity loss in all climates and due to other use variables, rather than in quantifying the effects of the various factors.
Well, there you have it in your own words--they didn't emphasize the large effect of battery temperature on capacity life because the wanted to conceal it (and still do, except for Phoenix).
 
Stoaty,

Drees was unable or unwilling to answer my questions below earlier.

Maybe you want to give it a try?

You do seem to state below that your model is designed to predict the loss of capacity, as reported by the LBC.

Before I restate my position on why this is, IMO, unreasonable, could you answer one further question?

You posted capacity percentages below, but I have never seen you explicitly state whether your model is intended to predict percentages of total battery capacity, the lesser available (stop to "100%" charge) capacity, or perhaps, some other definition of capacity?

Stoaty said:
...I have driven my Leaf extremely conservatively, and after 2.5 years and 23,000 miles I have lost about 17% of capacity (based on the capacity in Ah from the LeafDD and the percent loss of Gids at an 80% charge)...

edatoakrun:

Drees, so that I will not have to reply in alternate, would you please state what you are trying to express with these percentages?

Do you mean percentages of actual total battery capacity?

Which is what the INL is measuring, and I am referring to in all my comments (on the test results) of this thread.

Or do you mean LBC data/dash capacity bar displays?

And if referring to the latter:

Do you believe the LBC data/dash capacity bar displays are percentages of total battery capacity, or just the lesser available (stop to "100%" charge) capacity?...
 
edatoakrun said:
You posted capacity percentages below, but I have never seen you explicitly state whether your model is intended to predict percentages of total battery capacity, the lesser available (stop to "100%" charge) capacity, or perhaps, some other definition of capacity?
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.
 
Stoaty said:
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?
 
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