Discuss data from the LEAF Battery app, and Comparisons

[Weatherman]

I sure wish my LEAF's battery temperatures were in the low 20s.

After about four days of typical, hot, Florida summertime weather, my LEAFs battery temperature slowly climbed up to around 35C. Not wishing to charge the battery again, yesterday evening, which always adds a couple degrees C to the temp, I took the Volt to work, today, instead. The LEAF got to spend the day, Friday, in the garage.

When I got home this evening, after being idle, and without a recharge for 24 hours, the LEAFs battery temp was back down to 30C (same as the air temp in the garage).

I won't see lower 20s until sometime in December.

 

[aminorjourney]

A week ago, I was driving my LEAF from Norwich, to Bristol in the U.K. I left at 5am and arrived back in Bristol at 2:30pm, having quick-charged five times on the journey. Total length was about 270 miles as one of the quick chargers I normally use was offline and I had to go cross-country to make the next charging point.

It was during our 'hot spell,' where outside temperatures were in the mid to high 80s (ºF). Because I had to be back in time to pick the kids up from school, I basically drove and charge, grabbing food and toilet breaks while the car charged. I don't think there was any point during the entire trip where the car wasn't either charging or driving.

By the time I got to the final quick charge -- about 50 miles from my house -- the battery pack was sitting at 115 ºF. By the time rapid charging was done, it was above 120 ºF. I've never seen it that high, and the temperature gauge was about to go into the red. Luckily, it cooled down over the next few days as the weather got a bit cooler too.

I've noticed a couple of weird things about the battery pack since installing the app on my Kindle Fire (I'm running the latest Beta)

1) The first battery temperature sensor invariably has a warmer temperature than the rest of them. Not sure why this is, but only ever seen another sensor reach a higher temperature when the car had been on a 100% overnight charge.

2) My battery pack health has been going up and down like a yoyo! Yesterday morning, my battery pack health was touching 86% (which after 41,600 miles is pretty amazing) but by the time I'd driven it to London and back yesterday (230 miles) it had dropped to 83.25%. This morning, it was back up to 85.7%. (I did three quick charges + one slow partial charge yesterday and a whole bunch of freeway driving)

Would it be worth us creating a google database using forum member's IDs detailing the reported health and capacity of packs from month to month? Easy enough to do manually, but perhaps even something we could do with an automated script?

I think it would be fascinating for us to compare our battery pack health every 1k miles, or every month, whichever is a more sensible period. We could also have a column for noting average temperatures and geographic location (perhaps lat/long to 2 significant figures?)

Nikki.

 

[LEAFer]

^^^ Interesting report.

I have seen nothing but a slow and monotonically decreasing (one tiny exception) AHr and SOH. But I must add that most of this data is post-P3227 re-program and may thus be affected by the "re-learning" the BMS is doing.

Then again, we almost never do QC and have a regular and short daily use, not a pattern of long-distance tripping like Nikki's report.

See http://www.mynissanleaf.com/viewtopic.php?f=31&t=10653&start=37" onclick="window.open(this.href);return false;

 

[TomT]

I've given up seeing battery temperatures below 80 degrees until summer is over! But it is "fun" watching the battery degradation soldier on in the meantime... So much for Nissan's claim that battery degradation would level off...

 

[LEAFfan]

The cars' BT sensors are on the passenger side here. Mine varies on which one is highest. Also, since we have high ambient temps now, the AH and SoH continually decrease. I'm hoping like hell that it will stop before I lose a bar.

 

[highend]

data from today with new version with health

could somebody tell me why CAP is now 96.55%, and just 5 days ago it was 97.31%,
is capacity decreasing so quickly? almost 1% in 5 days???????
and there was quite hot but not very hot.... also car is parked in shade
SOC was between 45-80%

or I just need to charge to 100% to balance cells and it will change again?

also btw (off topic) - I checked small 12V battery, and it needs topping up distilled water and charge - I think in very hot climates it needs really more attention

 

[surfingslovak]

there was quite hot but not very hot.... also car is parked in shade
SOC was between 45-80%

I don't know about Poland, but most of Central Europe has experienced and continues to experienced a heat wave, which could break a few records.

 

[highend]

there was quite hot but not very hot.... also car is parked in shade
SOC was between 45-80%

I don't know about Poland, but most of Central Europe has experienced and continues to experienced a heat wave, which could break a few records.

yes the hot wave is here too (32C today, west Poland 37C in shade even!) , but I also park Leaf under shade and even at 32C outside my batteries are around 26C which I consider to be safe? Checked today with very hot weather

 

[gbshaun]

Never having used a GID meter, I was rather surprised (disappointed) when first connecting the App to see i was down to 86.65% (57.4 AHr). Although the car is 2 years old, we're N. coast San Diego where it rarely hits even 80F, and the car only has 16,000 miles on it with mostly 80% charges and never using a L3.
I haven't noticed much reduced range. Each week i do a 54mile r/t downtown (freeway) which always put me down to ~ 2 bars
Maybe I've simply become more economical in how i drive.

Also surprising was the rate at which the remaining capacity dropped down. In just 6 weeks it went from 86.77% to 83.75% (55.5 AHr) at which point, this past Monday, I lost my 12th bar.
How can it drop 3% in 6 weeks, yet only have lost 13% in 100 prior weeks?


However,..... yesterday I had the software P3227 update.
Driving away my capacity was now up to 89.74% (59.5 AHr)
I 100% charged last night and today I was down to 89.22% (59.1 AHr). Seems like a big drop. Maybe settling in and getting more accurate?
It's still showing 11 bars

When i first checked it this morning the SOC was 92.2%, then i triggered another charge (which i believe Nissan frowns on) and it got to this 93.1%. These seem to be normal for my car. Sure would like to be able to get above that on the rare occasion I might need it.
Is this consistent with what others are seeing? Did the software update affect the battery capacity that's available? or merely change the way it's determining what's available?

Thanks,
Shaun

ps As an indication of range, a few weeks ago two of us drove 60 miles round-trip @ 65mph (74F, light A/C use), and the app said I had 3.8KWh remaining (18.4% SOC). I'd just got the LBW.
This is consistent with the LEAF range chart for a 100% capacity battery. I'm quite satisfied with that range.

 

[TickTock]

could somebody tell me why CAP is now 96.55%, and just 5 days ago it was 97.31%,
is capacity decreasing so quickly? almost 1% in 5 days???????

1% is in the noise. It will move up and down - probably will be back in a day or two. Need to watch it for a month or so before you can really look for a trend.

 

[edatoakrun]

Never having used a GID meter, I was rather surprised (disappointed) when first connecting the App to see i was down to 86.65% (57.4 AHr). Although the car is 2 years old, we're N. coast San Diego where it rarely hits even 80F, and the car only has 16,000 miles on it with mostly 80% charges and never using a L3.
I haven't noticed much reduced range. Each week i do a 54mile r/t downtown (freeway) which always put me down to ~ 2 bars
Maybe I've simply become more economical in how i drive.

Also surprising was the rate at which the remaining capacity dropped down. In just 6 weeks it went from 86.77% to 83.75% (55.5 AHr) at which point, this past Monday, I lost my 12th bar.
How can it drop 3% in 6 weeks, yet only have lost 13% in 100 prior weeks?

...ps As an indication of range, a few weeks ago two of us drove 60 miles round-trip @ 65mph (74F, light A/C use), and the app said I had 3.8KWh remaining (18.4% SOC). I'd just got the LBW.
This is consistent with the LEAF range chart for a 100% capacity battery. I'm quite satisfied with that range.

Don't be too disappointed, Shaun.

It is extremely unlikely your actual battery capacity dropped anywhere near the ~3% in six weeks that the app reported, and IMO, it is entirely possible you 2011 LEAF (and many others) still have very close to the available range they did on delivery, as does my own LEAF.

In all probability, the battery app only allowed you to see your LEAF's "gauge error" over the time period before it showed up in the inaccurate indication of "~15%" loss of capacity as indicated by your 12th capacity bar loss. And the "gauge error" in excessive capacity loss reported by the app definitely seems to be related to recent battery temperatures, as is also shown by the near-complete absence of reports of capacity bar loss by LEAFs while exposed to seasonally lower ambient temperatures.

See my recent post below on the 20,000 mile thread:

="edatoakrun"
MY LEAF turned over 20,000 miles yesterday.

I’m very satisfied with my decisions more ~38 months ago to order, ~27 months ago to take delivery on a lease, and ~15 months ago to buy, my LEAF.

I seem to have been relatively immune to the range anxiety, battery degradation anxiety, resale price anxiety, and the multiple other anxieties that seem so common among many other MNL members.

My LEAF has very close to the same range it has always had, in my regular 50+mile commute, in my ~500 ~600 mile round trips to the Bay area, and on the regular test route from “100%” to ~VLBW I've been driving for ~22 months:

Use CW report from range test to determine battery capacity

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

My LEAF’s battery also seems to be accepting close to the same kWh from recharging that same ~VLBW to "100%" battery capacity, as it always has:

Collecting data:Off-the-wall power for turtle to 100% charge

http://www.mynissanleaf.com/viewtopic.php?f=31&t=6876&start=210" onclick="window.open(this.href);return false;

So, while I will have no precise conclusion about what the first capacity bar loss on my LEAF actually indicates when it occurs (and I’ll probably lose it very soon, as the app now shows 56.05 AHr and 84.59 CAP) I don’t expect it will be any great blow to my LEAF experience.

If that “15%” figure from the capacity bar display (and the near-identical percentage of available kWh reported on my LEAF’s dash and nav screen m/kWh, and from my CarWings kWh use reports) exceeds the actual loss of available battery capacity my LEAF has experienced from new (as I strongly suspect) then I probably will have little problem with battery capacity, or range, for many years.

On the other hand, if I actually have experienced ~"15%" battery degradation, and since I could recently drive ~110 miles with over 6,000 feet of total ascent and descent, on a hot Summer day, before the VLBW, with that almost “15%” degraded battery:

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

http://www.mynissanleaf.com/viewtopic.php?f=27&t=7022&start=590" onclick="window.open(this.href);return false;

Then the “30%” capacity warranty should kick in before my own basic maximum range requirements (which are, ~60 miles at ~35 to ~50 mph, beginning with ~2000 total ft. of descent, and ending with the same ascent, at temperatures down to ~25 F) exceed my battery capacity.

(But)
...Nissan has failed to remedy, or even explain adequately, the “gauge error” which has made accurately assessing the actual loss of battery capacity of any LEAF, and which has caused such near-hysteria (if not near-panic- Oh!...The “bloodbath”!) among those who take capacity bar loss, and declining gid counts and AHr readings, far more seriously than I do.

http://www.mynissanleaf.com/posting.php?mode=quote&f=27&p=312931" onclick="window.open(this.href);return false;

My LEAF has also shown an App-reported loss of ~3% over the last ~four months, and I now find myself annoyed by my anticipation of that twelfth capacity bar loss, every time I power up.

My LEAF's latest stats are 55.85 AHR, 84.30%, and 81.24 Hlth, and if the twelfth capacity bar is still there next time I start up, I may decide to drive down to Redding Crown motors, and plug in and charge up on their L2 for the whole day in the hot sun, just to warm up my battery enough to induce the bar loss, to get the damn thing over with...

 

[DaveEV]

Also surprising was the rate at which the remaining capacity dropped down. In just 6 weeks it went from 86.77% to 83.75% (55.5 AHr) at which point, this past Monday, I lost my 12th bar.
How can it drop 3% in 6 weeks, yet only have lost 13% in 100 prior weeks?

The Ah/GID counts are affected by long term battery temperature and trend down with higher temperatures and up with lower temperatures. So at the beginning of each summer the Ah/GID counts drop rapidly.

FWIW, just updated my sig with my latest data (56.04 Ah, 20.8k mi) . Seems my car is doing slightly better than yours despite quite a few more miles.

However,..... yesterday I had the software P3227 update.
Driving away my capacity was now up to 89.74% (59.5 AHr)
I 100% charged last night and today I was down to 89.22% (59.1 AHr). Seems like a big drop. Maybe settling in and getting more accurate?

My car also jumped up to 61.01 Ah from 57.63 Ah after the update first thing in July, but quickly trended down to the pre-update number. After a week it was back down to 57.94 Ah and now it's well below the before-update readings.

ps As an indication of range, a few weeks ago two of us drove 60 miles round-trip @ 65mph (74F, light A/C use), and the app said I had 3.8KWh remaining (18.4% SOC). I'd just got the LBW.
This is consistent with the LEAF range chart for a 100% capacity battery. I'm quite satisfied with that range.

Assuming that you have about 13 miles of range left at 65 mph from LBW for a total of 73 miles before turtle, that's actually down about 10 miles from new which is right around 15% capacity loss as one might expect having lost 1 bar.

 

[highend]

could somebody tell me why CAP is now 96.55%, and just 5 days ago it was 97.31%,
is capacity decreasing so quickly? almost 1% in 5 days???????

1% is in the noise. It will move up and down - probably will be back in a day or two. Need to watch it for a month or so before you can really look for a trend.

you sure? now it's 96.30%...... so lost 1% within 2 weeks. And yes - it's quite hot here, 90F now and I park always in shade...
there was hot wave, then three days colder - but now it's hot again.

 

[opencar]

Also surprising was the rate at which the remaining capacity dropped down. In just 6 weeks it went from 86.77% to 83.75% (55.5 AHr) at which point, this past Monday, I lost my 12th bar.
How can it drop 3% in 6 weeks, yet only have lost 13% in 100 prior weeks?

The Ah/GID counts are affected by long term battery temperature and trend down with higher temperatures and up with lower temperatures. So at the beginning of each summer the Ah/GID counts drop rapidly.

FWIW, just updated my sig with my latest data (56.04 Ah, 20.8k mi) . Seems my car is doing slightly better than yours despite quite a few more miles.

However,..... yesterday I had the software P3227 update.
Driving away my capacity was now up to 89.74% (59.5 AHr)
I 100% charged last night and today I was down to 89.22% (59.1 AHr). Seems like a big drop. Maybe settling in and getting more accurate?

My car also jumped up to 61.01 Ah from 57.63 Ah after the update first thing in July, but quickly trended down to the pre-update number. After a week it was back down to 57.94 Ah and now it's well below the before-update readings.

ps As an indication of range, a few weeks ago two of us drove 60 miles round-trip @ 65mph (74F, light A/C use), and the app said I had 3.8KWh remaining (18.4% SOC). I'd just got the LBW.
This is consistent with the LEAF range chart for a 100% capacity battery. I'm quite satisfied with that range.

Assuming that you have about 13 miles of range left at 65 mph from LBW for a total of 73 miles before turtle, that's actually down about 10 miles from new which is right around 15% capacity loss as one might expect having lost 1 bar.

GBShaun, Drees, wanted to corroborate similar status of battery for me since we have similar history cars:
56.9 Ah, GIDs 200 @ 80% and 22K mi, Jun 2011 delivery in N. Coast San Diego (my sig is a little dated)

 

[TomT]

I wish that was true in my case, but the range I now have very closely tracks the reported (deteriorated) capacity displayed by both my meters...

It is extremely unlikely your actual battery capacity dropped anywhere near the ~3% in six weeks that the app reported, and IMO, it is entirely possible you 2011 LEAF (and many others) still have very close to the available range they did on delivery, as does my own LEAF.

 

[edatoakrun]

...

ps As an indication of range, a few weeks ago two of us drove 60 miles round-trip @ 65mph (74F, light A/C use), and the app said I had 3.8KWh remaining (18.4% SOC). I'd just got the LBW.
This is consistent with the LEAF range chart for a 100% capacity battery. I'm quite satisfied with that range.

Assuming that you have about 13 miles of range left at 65 mph from LBW for a total of 73 miles before turtle, that's actually down about 10 miles from new which is right around 15% capacity loss as one might expect having lost 1 bar.

If you really believe that the range of a "new" LEAF at 65 mph is 83 miles, from "100%" to turtle, then you will, of course, also convince yourself that you are suffering significantly reduced battery capacity when your LEAF does not meet that imaginary range.

The DOE testing posted at the link below shows the measured kW use for a LEAF allowing accurate m/kWh calculations, rather than the erroneous m/kWh results compiled from the dash/CarWings, in which many still maintain faith.

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

With more details on the test conditions and links to other LEAF Battery test data here:

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

Can anyone provide an Executive Summary for Dummies? Avg. m/kWh at 45, 60 & 70 mph maybe?

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;

So, under the test conditions documented above, it would take ~ 22.4 kWh for a LEAF to travel 83 miles at 60 mph, and ~28.4 kWh at 70.

So it would certainly require well over 25 kWh to cover the same 83 miles at 65 mph under the same (battery and ambient temperature, altitude, altitude variation, etc.) test conditions, and IMO, a completely implausible available kWh capacity for a "new" LEAF battery.

Of course, for Shaun or anyone else to accurately calculate there own dash/nav screen/Carwings m/KWh "gauge error" (which in my LEAF seems to be extremely close to, and quite possibly identical to the App's capacity loss report error) they would have to replicate the same conditions of one of the three DOE constant-speed tests.

 

[surfingslovak]

It's worth noting that the PDF document from the Idaho National Laboratory linked by Ed above is one set of results measured by one lab using their instrumentation and methodology. While the document outlines how the tests were performed, it does not include much detail on the instruments used and the test setup itself. That said, the second page includes range projections the lab has calculated from their own numbers. It's worth noting that both the both the UDDS and the US06 rage figures are significantly lower than one would expect and what was reported from other sources. The calculated UDDS range of 90.2 miles is particularly suspect, since Nissan's advertised design goal was 100 miles on the LA4 cycle, which has been widely reported. Based on this figure alone, it would appear that the lab is overstating energy consumption of the vehicle by about 10% or understating the usable battery capacity by the same amout. It's difficult to say why, and how this type of error could be introduced, since they don't share all the details.

 

[edatoakrun]

It's worth noting that the PDF document from the Idaho National Laboratory linked by Ed above is one set of results measured by one lab using their instrumentation and methodology. While the document outlines how the tests were performed, it does not include much detail on the instruments used and the test setup itself. That said, the second page includes range projections the lab has calculated from their own numbers. It's worth noting that both the both the UDDS and the US06 rage figures are significantly lower than one would expect and what was reported from other sources. The calculated UDDS range of 90.2 miles is particularly suspect, since Nissan's advertised design goal was 100 miles on the LA4 cycle, which has been widely reported. Based on this figure alone, it would appear that the lab is overstating energy consumption of the vehicle by about 10%. It's difficult to say why, and how this type of error could be introduced, since they don't share all the details...

Please read the DOE test reports and the comments posted on the thread linked.

You do not seem to understand that this was a test on a less-than-new "Phoenix" LEAF, with a documented less-than-new available battery capacity, which (for example) accepted only 18.4 kWh in the subsequent recharge after the 60 mph test.

In other words, these tests were on a LEAF with (probably) ~10% less-than-"new" available battery capacity.


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

Since you bring up the LA4 test cycle results in particular, you may want to consider my prior comments on what the LA4 cycle results suggest for the actual range of a LEAF with a "new" battery at constant speed, keeping in mind that the LEAF's 100 mile L4 range was not determined, IIRC, not from the same actual test procedure as was done by the DOE on LEAF #0356:

...Let us look at it differently - how exactly would I use this new info from the lab ?

IMO, the first thing we can conclude, is that it is even more foolish now to try to establish a single “new” available kWh capacity value for a LEAF, than was the case before these results were available.

We already had a lot of evidence that capacity varies with recharge temperature, and the results from the three constant speed tests seem to indicate that even where the recharge temperatures are closely controlled, the recharge capacity the test LEAF’s LBC allowed appeared to have varied by at least ~3%.

The most important new information, IMO, is that I think we can now find the available capacity for the LEAF’s 100 mile EPA rating, and relate it to the constant speed and recharge capacity tests, which I think is very useful.

Since the UDDS (LA4) methodology was replicated in the baseline dynamometer test, resulting in 90.2 miles of range, and this testing criteria Is designed to be constant for available battery capacity, I believe we should be able to use the same ratio to determine ranges from the (close to) constant average kW use from the constant speed tests.

And since the 60 mph constant speed test (for example) resulted in 65.3 miles range, I believe we may tentatively conclude that a “new” 2011 (as defined by one allowing the same available battery capacity shown by the EPA 100 mile rating) should get ~72.4 miles, (+/_ at least ~3%, due to variable LBC operation) of range, if you are able to accurately replicate all the test conditions.

That 72.4 mile range, BTW, looks to be well within the range that Nissan says it should be, if your trip computer actually accurately displayed the ~3.7 m/kWh that the 60 mph test did show.

http://mynissanleaf.com/wiki/index.php?title=File:NTB11-076a.jpg" onclick="window.open(this.href);return false;

And corresponds quite closely to the highway range performance Nissan promises, both on their website and in the sale/lease battery disclosure:

Highway driving in the summer: 112km (70 miles)
Speed: Average 88km/h (55 mph)
Temperature: 35 degrees Celsius (95 degrees Fahrenheit)
Climate control: On

Though we do not know exactly how much the lower speed and higher ambient and battery temperatures should increase the range, as opposed to the range decrease due to the AC use in this example.

http://www.nissan.ca/vehicles/ms/leaf/en/range-fundamentals.aspx#/range-fundamentals" onclick="window.open(this.href);return false;


So you could try to run your own constant speed range test, at any of the three test speeds, to assess your own battery capacity compared with 100 mile LA4.

Remember however, that neither a range test or a recharge test will determine your batteries level of “degradation”. They can only show you the level of battery capacity your LEAF is allowing you to access, out of the total capacity, as compared to that capacity level allowed the LEAFs the EPA used in it’s testing to get the 100 mile L4 rating.

And you may find attempting a constant-speed range test may not be the best use of your time and energy.

We have numerous examples on MNL of amateur attempts to get accurate constant-speed range test/capacity results, but failing, due to their inability to understand and adequately control all relevant test variables. If you want to give it a try, at least you now have an accurate reference test for comparison, and a 29 page checklist of methodology you can attempt to replicate, to the best of your ability. Good luck!

I believe you may find that you actually may be able to get more accurate (or at least less inaccurate) capacity results with your own L2 timed recharge tests, compared to the results published from LEAF 0356.

And probably more accurate than either, would be establishing your dash or nav screen m/kWh error rate, by using Carwings and replicating one of the m/kWh test conditions from 0356 over a practical test distance, to find the common error in your m/kWh displays and CarWings kWh use data, and so find the actual kWh use and available battery capacity of your LEAF.

...The total stats for the day from Carwings are 80.8 miles driven, 20.9 kWh net consumption, 3.9 miles/kWh.
A brand new car with zero degradation is supposed to have 21 kWh usable...

You might want to go to the thread links I posted on Friday on page 3 for more suggestions on using your CW kWh use data.

edit link:

http://www.mynissanleaf.com/viewtopic.php?f=31&t=13265&start=30" onclick="window.open(this.href);return false;

 

[surfingslovak]

I see, thanks for the clarification. Where is this LEAF located, would you know? I could not find that information anywhere on their website. Although they list the maintenance records going back to 2011, it's not clear why they would perform initial battery capacity tests and range tests when the vehicle was one year old and had over 6,000 miles on the odometer. The vehicle apparently needed two module replacements earlier this year, which might be indicative of a hotter climate.

I don't have time to review all the data in detail right now, but IMHO the fact that their UDDS range figure deviates significantly from published results from other sources, indicates that either the battery has lost capacity or that the lab setup they use yields different results. The measured charger efficiency looks suspect, as I recall Phil seeing an efficiency of about 91%. The battery roundtrip efficiency is about where I would expect it to be, although it's worth noting that internal resistance will go up on a used pack, which will decrease efficiency. This should not be a significant factor on a one-year old vehicle and their numbers seem to reflect that.

Another thing I've noticed: the energy economy listed in the report was calculated from their lab instruments, yet you made a reference to NTB11-076a assuming that the dash gauge will show the same figure. We know that most of the gauges have a systemic bias or error, and it's likely that Nissan has considered that. For example, the speedometer reads about 2% higher at 65 mph and the real speed is closer to 62.5 mph (100 km/h) per GPS. Likewise for the odometer. The energy economy gauge has demonstrably delivered a wide range of results and although it seemed accurate on my vehicle, I would not trust that gauge very much.

The only test easily available to owners I could get behind is a range test at 65 mph (dash) on flat terrain or on a loop, and a measured recharge test from turtle to 100%. It's important to get the kWh from the wall and be sure to use approximately the same line voltage and ambient temperature when doing a recharge test. It would be good to perform these tests when the vehicle is new to have a valid point of reference.

As to the number from the ETA/INL: I found the battery discharge report particularly useful, but I think more data or context is needed. I would also caution against taking their reports as 100% authoritative. The stated maximum voltage of 4.20V for LMO cells would be a good examples of assumptions being made, which are not necessarily true. The battery discharge test from the Idaho Lab does not fully agree with the results from Oak Ridge National Laboratory, which drees published earlier. Both of these labs are part of the same program and are supposed to deliver complementary results.

Electric Transportation Applications and Idaho National Laboratory

ETA and INL collaborate on a fleet vehicle testing program in which fleet vehicles
undergo normal driving and maintenance schedules. The study of components from
these vehicles provides information related to the reliability and operation long-term
susceptibility of the designs.

Oak Ridge National Laboratory, Materials Science & Technology Division

Provides detailed material analysis of components such as magnets and power
electronics packages

Argonne National Laboratory

ANL provides vehicle level data obtained during extensive drive cycle testing which
enables the observation of common operation conditions and trends observed on a
system-wide basis. Converter, inverter, and motor characteristics such as efficiency
and performance are supplied to ANL for use in system-wide vehicle modeling.

National Renewable Energy Laboratory

NREL utilizes temperature measurements observed during performance and
efficiency tests to assess the characteristics of the thermal management system.
NREL provides feedback and suggestions in regards to the measurements (such as
thermocouple placement) useful to thermal management system assessments.

 

[surfingslovak]

Ah, here we go. Since the test LEAF was located in Phoenix, it would be interesting to know how it was garaged and operated and if it was purchased there new. Additional details should be made available by the lab to help explain some of the discrepancies in their published data. Anyone care to contact them?

Electric Transportation Applications
401 South 2nd Avenue
Phoenix, AZ 85003

After completion of the initial Baseline Performance Testing, vehicles are placed in
Accelerated Reliability Testing using fleets in the Phoenix, Arizona metropolitan area. Two
vehicles of a model type are typically tested for up to 160,000 miles of combined city and
highway driving. At the end of Accelerated Reliability Testing (typically 160,000 miles), each
vehicle is again subjected to fuel economy testing, as well as battery capacity and power
testing.

An objective of AVTA testing is to determine the degree of HEV traction battery degradation
over the vehicle life. To date, only one traction battery pack has failed in the AVTA’s hybrid
electric test vehicles (1.35 million total test miles). A Honda Insight with 72,000 miles had both
the battery control module and traction battery pack fail. Both were replaced by the dealer
under warranty. The cause of the pack failure is not known.

However, it is speculated that the battery pack failure was caused by the battery control module
failure. To obtain a more precise measure of battery degradation, and its impact on vehicle
performance, HEVs completing Accelerated Reliability Testing receive end-of-life Baseline
Performance fuel economy testing and battery testing including capacity testing and hybrid pulse
power characterization testing in accordance with the FreedomCar Hybrid Battery Test Manual.