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

Posted: Thu Aug 16, 2012 10:27 pm
by Volusiano
Stoaty wrote:
OrientExpress wrote:As I thought, the mean is 14~15K, so that shows that most are high mileage. Now combine that with the severe duty environment, and it appears that there is correlation.
Actually, assuming a normal distribution 68% of the cars would fall in the range 10,344 - 18,178. Note that 14,100 is also the median, which means there are just as many cars below that value as there are above that value. There isn't any data showing that "most are high mileage". See statistics from DOT:

http://www.fhwa.dot.gov/ohim/onh00/bar8.htm" onclick="window.open(this.href);return false;

Average is 13,476 across all age groups and both sexes... very close to the 14,000 miles per year driven by the average one capacity bar loser.
Nice response, Stoaty!

And what severe duty environment is OrientExpress talking about? Is there anything else other than heat? We've already established that heat is the primary cause of capacity reduction. Calling it any other name to make it appear like owners are abusing their cars is a bunch of BS. If Nissan considers the heat in AZ severe duty to be avoided, then why sell in AZ in the first place?

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

Posted: Thu Aug 16, 2012 11:26 pm
by TonyWilliams
Volusiano wrote:
Stoaty wrote:
OrientExpress wrote:As I thought, the mean is 14~15K, so that shows that most are high mileage. Now combine that with the severe duty environment, and it appears that there is correlation.
Actually, assuming a normal distribution 68% of the cars would fall in the range 10,344 - 18,178. Note that 14,100 is also the median, which means there are just as many cars below that value as there are above that value.... See statistics from DOT:
Average is 13,476 across all age groups and both sexes... very close to the 14,000 miles per year driven by the average one capacity bar loser.
And what severe duty environment is OrientExpress talking about? Is there anything else other than heat? We've already established that heat is the primary cause of capacity reduction. Calling it any other name to make it appear like owners are abusing their cars is a bunch of BS. If Nissan considers the heat in AZ severe duty to be avoided, then why sell in AZ in the first place?
Honestly, I don't quite understand why what seems so apparent to so many, is so different to some.

12,000 to 15,000 miles is so common and average, those are the two most sold mileages for leases.

I agree that Phoenix is abusive to vehicles; what's different is that every new gasoline vehicle handles it fine (and if it didn't, the warranty would fix it). Even data from several years of Tesla Roadsters seem to be doing fine. Edit: Chevy Volt is doing fine, too.

Plus, if the problem is a software issue, as you notably informed us recently, why would mileage matter?

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

Posted: Fri Aug 17, 2012 12:05 am
by planet4ever
mksE55 wrote:It would take alot of force to get it rolling but not as much to keep it going. It still requires energy to maintain the drum at a set speed but probably 80% or real world energy.
Really? Why so much? I assumed at freeway speeds on level ground nearly all of the car's energy would be going to air resistance. Once that drum is spinning it can't slow down at all without transferring energy somewhere, probably to heat. If there is no artificial friction, what is going to be getting hot? Bearings? I would think tires would be the biggest heat generator, and they don't generate that much, do they?

Ray

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

Posted: Fri Aug 17, 2012 12:11 am
by shrink
aqn wrote:
shrink wrote:However, it does bring to mind another column for the wiki - model year. I think we all assumed the reports were from 2011's. That's not the case anymore.
What's wrong with going by the VIN? That's more fine grained than model year, no? A LEAF with higher VIN number is younger than one with a lower VIN number (excepting the few (?) that may be in the wrong chronological order due to SNAFUs resulting from the earthquake/tsunami), while "2011 LEAF" encompasses a comparatively much larger time period.
I don't know how Nissan does it, but some manufacturers restart the serial number at 1 each model year. Also, since there are typically technical differences among model years, it's just a quick way to get a sense if what is being tracked, in this case loss of battery capacity, might have something to do with the unique features of a model year.

I think most of us assumed the capacity losses were all 2011's. It's just informative to know the 2012's are being affected as well. You don't get that sense from just looking at a VIN number.

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

Posted: Fri Aug 17, 2012 12:45 am
by shrink
TonyWilliams wrote:
Honestly, I don't quite understand why what seems so apparent to so many, is so different to some[...]

Plus, if the problem is a software issue, as you notably informed us recently, why would mileage matter?
Well said, Tony. The "some" in this case went from declaring "all" the cars were high mileage; to only the mean being high mileage (despite data cited indicating the mileages were indeed average); to saying there was a correlation without actually performing a correlation. Those who actually did the calculation found no correlation.

Previously, this "some" also denied repeatedly any problem existed, then insisted the solution to the non-problem was simply to "charge more," then declared a software error (in software that checked out at the factory and subsequently gave no error messages to Nissan or the user during subsequent battery inspections) was the most rational explanation to the non-problem. Now, it's a non-correlation to mileage.

Back on topic, several in the Casa Grande study were told 85% capacity remained. Although that number seems debatable, assuming it is accurate, is that acceptable after 12-16 months of ownership when 80% after 5 years is what is advertised? I suppose it is, since capacity is not under warranty, but how many cars would have been sold if buyers knew 15% loss after a little over a year would be considered normal?

We just sit and wait for some sort of announcement about the conclusions of the Casa Grande study. I'm expecting corporate spin, but I'm hoping for a real solution. I believe there were some good ideas being discussed in part 2 of this monster thread.

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

Posted: Fri Aug 17, 2012 5:42 am
by OrientExpress
TonyWilliams wrote: Plus, if the problem is a software issue, as you notably informed us recently, why would mileage matter?
That is a great question, and should be part of the investigative mix.

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

Posted: Fri Aug 17, 2012 5:49 am
by Pipcecil
The average to me @ 14,000k+ a year is actually low. To me, the best case on how many miles should be on the vehicle (for average use) is the service manual. If follow Nissan's recommened service, it happens every 6 months OR 7,500 miles. The best case scenario is that those two numbers are in sync. This would lead to a yearly mileage of 15,000, so less than that is actuall less wear than normal.

For myself, I know I put more miles than many on mine (I average about 1,700+ per month), but there are many countercases of Washington and Oregon LEAFs with extreme high mileage and almost no capacity loss (only a few percentage points) - those cases have been discussed in this thread...somewhere.

Add to the fact that it appears the second bar was loss from almost all the vehicles at an average of 2 months, and mine was lost one day shy of 2 months really affirms that my high mileage didn't factor in when lower mileage cars were losing their second bar in the same amount of time.

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

Posted: Fri Aug 17, 2012 5:54 am
by mksE55
planet4ever wrote:
mksE55 wrote:It would take alot of force to get it rolling but not as much to keep it going. It still requires energy to maintain the drum at a set speed but probably 80% or real world energy.
Really? Why so much? I assumed at freeway speeds on level ground nearly all of the car's energy would be going to air resistance. Once that drum is spinning it can't slow down at all without transferring energy somewhere, probably to heat. If there is no artificial friction, what is going to be getting hot? Bearings? I would think tires would be the biggest heat generator, and they don't generate that much, do they?

Ray

I am no physics major but here are some. friction of bearings. air resistance on drum from other side, gravity, tire friction. 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. 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. ;)

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

Posted: Fri Aug 17, 2012 6:23 am
by RegGuheert
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!

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

Posted: Fri Aug 17, 2012 6:44 am
by Stoaty
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:

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