mksE55
Posts: 176
Joined: Fri Oct 21, 2011 8:10 pm
Delivery Date: 22 Oct 2011
Leaf Number: 5086
Location: Tyler TX

Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Fri Aug 17, 2012 6:46 am

RegGuheert wrote:
mksE55 wrote:I dont know the real world percent but when I do this I will get a quick since of it by the number of bubbles it will take to keep it moving at 60mph, and the Kwh rating.
Rather than looking at the number of bubbles, please use the power from the pie chart in the ZeroEmission->Energy Usage display. You should be able to read the power used for propulsion to a resolution of about 500 W.

Thanks for doing this experiment!
Good point, I will get some of that on Video as well, but to me the real issues is will this take 1-2 hrs or like 4-5 hrs, I can quickly guesstimate with the others.
Bye Bye Exxon , Shell, Mobil
* 2011 SL
3 bar loss 23,000 mi
in less than 2 yrs
4/14 now 4 bar loss 32,000 just over 2 years

mynameisjim
Posts: 140
Joined: Fri Oct 08, 2010 2:12 pm
Delivery Date: 17 Jul 2012
Leaf Number: 23226
Location: Minneapolis, MN

Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Fri Aug 17, 2012 6:56 am

I am growing quite tired of Orient Express' denial of the evidence regarding displayed battery capacity loss.

edatoakrun
Posts: 5222
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Fri Aug 17, 2012 7:29 am

To eliminate what is almost certainly the greatest variable in early capacity bar loss, climate, I'd suggest you might try graphing only the one or two-bar loss LEAFs reported from the Phoenix area.

And also, perhaps, graph only the first-hand reports from LEAF drivers, and only those reporting who received delivery, as opposed to orphans, demos, and pre-owned LEAFs, with much less certain use/abuse histories.

If there is still a low correlation, then other factors (amount of time spent a high rate of charge, for example) might prove more significant than time and miles driven.

Manufacture date would also probably be better than delivery date, but I realize you don't have that for most of the reports.

And total kWh use (which no one seems to be reporting) would probably be a better indicator than miles driven. A leaf that has driven a given number of miles at 3 m/kWh, has done about twice the battery cycling as one that has averaged 6 m/kWh.

Stoaty wrote:Here is a scatter graph of Annual Mileage vs. Months Owned to first capacity bar lost including all available data:

Slope - -576
Intercept - 21500
Correlation coefficient - 0.13

Interpretation: while visually from the line drawn it appears there may be some relationship, the very low correlation coefficient says that there is not a correlation from the available data. As a reminder, here is how to interpret correlation coefficient:

Image

Image
no condition is permanent

Stoaty
Posts: 4486
Joined: Fri Jun 18, 2010 9:50 pm
Delivery Date: 12 Jun 2011
Leaf Number: 3871
Location: West Los Angeles

Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Fri Aug 17, 2012 8:09 am

edatoakrun wrote:To eliminate what is almost certainly the greatest variable in early capacity bar loss, climate, I'd suggest you might try graphing only the one or two-bar loss LEAFs reported from the Phoenix area.

And also, perhaps, graph only the first-hand reports from LEAF drivers, and only those reporting who received delivery, as opposed to orphans, demos, and pre-owned LEAFs, with much less certain use/abuse histories.

If there is still a low correlation, then other factors (amount of time spent a high rate of charge, for example) might prove more significant than time and miles driven.

Manufacture date would also probably be better than delivery date, but I realize you don't have that for most of the reports.

And total kWh use (which no one seems to be reporting) would probably be a better indicator than miles driven. A leaf that has driven a given number of miles at 3 m/kWh, has done about twice the battery cycling as one that has averaged 6 m/kWh.
Very good thoughts, but my time and energy (and the data) are limited. Besides, my Leaf is cooling its battery in my 70 degree parking garage where it spends most of its life, so I am not personally affected to any great degree (although the hot San Fernando Valley where the Leaf spends its time during work days is somewhat of a concern).

However, here is the latest data on one bar capacity loss in the Phoenix area. Plot is annual mileage vs. months to first capacity bar loss. There are 26 data points.

Slope = -1,274
Intercept = 29,095
Correlation coefficient = 0.51

Edit: mean annual mileage = 13,894 and standard deviation of annual mileage = 3,967 for Phoenix area.

Interpretation: There is a moderate correlation between annual mileage and number of months to first capacity bar loss. This data suggests that some of the capacity loss may indeed be due to cycling losses rather than calendar losses.

Note: when I did the graph previously in another thread, I did not plot against annual mileage,which is the correct figure. I believe the current analysis is the correct one, but comments are welcome re: whether the Y-axis should be total miles (previously plotted) or annual mileage (the current, and probably the correct choice).

Image
Last edited by Stoaty on Fri Aug 17, 2012 8:36 am, edited 1 time in total.
2011 Leaf with 62,000 miles given to Nephew
2013 Tesla Model S85 with 251 miles rated range at full charge
Leaf Spy Manual
Battery Aging Model Spreadsheet

edatoakrun
Posts: 5222
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Fri Aug 17, 2012 8:35 am

="Stoaty"...Note: when I did the graph previously in another thread, I did not plot against annual mileage,which is the correct figure. I believe the current analysis is the correct one...
I don't understand why you have come to that conclusion, since one axis itself is months since delivery.

I wanted to see what might account for the anomalous 24,000 mile one bar loss report, and only then realized it must be the 10 month/20,000 mile report on the Wiki, right?
Stoaty wrote:... here is the latest data on one bar capacity loss in the Phoenix area. Plot is annual mileage vs. months to first capacity bar loss. There are 26 data points.

Slope = -1,274
Intercept = 29,095
Correlation coefficient = 0.51

Interpretation: There is a moderate correlation between annual mileage and number of months to first capacity bar loss. This data suggests that some of the capacity loss may indeed be due to cycling losses rather than calendar losses.

Note: when I did the graph previously in another thread, I did not plot against annual mileage,which is the correct figure. I believe the current analysis is the correct one.

Image
no condition is permanent

Stoaty
Posts: 4486
Joined: Fri Jun 18, 2010 9:50 pm
Delivery Date: 12 Jun 2011
Leaf Number: 3871
Location: West Los Angeles

Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Fri Aug 17, 2012 8:48 am

edatoakrun wrote:I don't understand why you have come to that conclusion, since one axis itself is months since delivery.

I wanted to see what might account for the anomalous 24,000 mile one bar loss report, and only then realized it must be the 10 month/20,000 mile report on the Wiki, right?
Right. To be honest, I don't know which is the correct comparison:

One compares the total miles driven to the time it takes to lose a bar - no correlation
The other compares the rate at which miles are accumulated to the time it takes to lose a bar - moderate correlation

The more I think about it, the more confused I have become. I welcome input from others more knowlegeable than I. :oops:
2011 Leaf with 62,000 miles given to Nephew
2013 Tesla Model S85 with 251 miles rated range at full charge
Leaf Spy Manual
Battery Aging Model Spreadsheet

DaveinOlyWA
Posts: 14101
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Feb 2018
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Fri Aug 17, 2012 8:53 am

taking miles driven is one thing but i think a weighted number is better similar to car evaluations on mileage where they take a set figure (currently 15,000 a year) and then deduct points for miles over that or add points for miles under that.

there are basically 2 #s. the 15,000 used to value used cars and the 12,000 used as standard warranty fair (3 yrs OR 36,000 miles, etc.)

so that is the real metric that we should be looking at since both time and distance play a part along with temps
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 15,000 miles, 478 GIDs, 37.0 kwh 109.81 Ahr , SOH 94.61, Hx 120.15
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

sub3marathonman
Posts: 309
Joined: Wed Nov 03, 2010 11:57 am
Delivery Date: 31 Mar 2012
Location: Bartow, FL

Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Fri Aug 17, 2012 8:59 am

mynameisjim wrote:I am growing quite tired of Orient Express' denial of the evidence regarding displayed battery capacity loss.
It is possible that Orient Express is right, since so far there is only anecdotal evidence, not proof. We need a valid representative sample of all Leafs, not just ones with capacity bar losses. So far, I don't know if it is 90% of the Leafs in Phoenix losing capacity, or only 9%. I don't know how that percentage corresponds to the people in Seattle. I don't know if this data has been compiled either, since the focus is ONLY on Leafs with capacity bar losses.

What is more important than mileage, which has shown a low correlation to capacity loss, is the temperature history of each battery, but I don't know if the car tracks that data.

User avatar
TonyWilliams
Posts: 10090
Joined: Sat Feb 19, 2011 1:48 am
Location: San Diego
Contact: Website

Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Fri Aug 17, 2012 9:08 am

mksE55 wrote: since of it by the number of bubbles it will take to keep it moving at 60mph, and the Kwh rating. If it crazy high like 6-7 I will probably bail on the experiment, but if its in the 4-5 range I may wait it out. Guess thats why they call it an experiment. Many unknowns. ;)
I'm not sure what you are actually saying, or trying to prove. The LEAF takes about 250 wattHours per mile at 60mph on level, sea level elevation, 70F, no wind, on dry hard surfaced roads. That's 15kW of power (20 horsepower).

DaveinOlyWA
Posts: 14101
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Feb 2018
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Early Capacity Losses-Was(Lost a bar...down to 11)

Fri Aug 17, 2012 9:09 am

sub3marathonman wrote:
mynameisjim wrote:I am growing quite tired of Orient Express' denial of the evidence regarding displayed battery capacity loss.
It is possible that Orient Express is right, since so far there is only anecdotal evidence, not proof. We need a valid representative sample of all Leafs, not just ones with capacity bar losses. So far, I don't know if it is 90% of the Leafs in Phoenix losing capacity, or only 9%. I don't know how that percentage corresponds to the people in Seattle. I don't know if this data has been compiled either, since the focus is ONLY on Leafs with capacity bar losses.

What is more important than mileage, which has shown a low correlation to capacity loss, is the temperature history of each battery, but I don't know if the car tracks that data.
there is a lot of hysteria on the board right now and some balance is needed and i dont think that OE's comments are farther out than comments made on the other side. both are rife with speculation and the problem we have is really limited information and no parameters to go by.

so the only thing we can do is continue to gather what information we can, continue to crunch it various ways and see what results.

speculating on how badly Nissan is doing is becoming counterproductive to this forum. i am not saying that the affected should not be unhappy or should not voice their concerns to Nissan but that issue ALONE has made it difficult to sift thru the real value of pertinent information posted here.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 15,000 miles, 478 GIDs, 37.0 kwh 109.81 Ahr , SOH 94.61, Hx 120.15
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

Return to “Problems / Troubleshooting”