jlsoaz
Well-known member
I thought this was helpful, but it was early days and there didn't seem to be anything (AFAIK) for the Model S and for later Leafs, in terms of study papers or data that shows climate impact in a clear way. I've emailed to them, not requesting necessarily they issue more study papers, but that they see if maybe they can add a feature to their charts pages that will show data as pertains to climate.
https://survey.pluginamerica.org/leaf/Leaf-Battery-Survey.pdf
Plug In America’s LEAF Battery Survey
by Tom Saxton
Updated: December 27, 2012
https://survey.pluginamerica.org/tesla-roadster/PIA-Roadster-Battery-Study.pdf
Plug In America’s
Tesla Roadster Battery Study
by Tom Saxton, Chief Science Officer
Released: July 13, 2013
https://survey.pluginamerica.org/leaf/Leaf-Battery-Survey.pdf
Plug In America’s LEAF Battery Survey
by Tom Saxton
Updated: December 27, 2012
Conclusions
Of 240 LEAFs reported in the survey, with a median of 11,600 miles driven, 90.8% are still showing all 12
capacity bars, meaning they are within 15% of nominal full capacity. Subjectively, 76.3% of owners
believe they have lost no more than a few miles of range.
Of the data collected and analyzed thus far in the Plug In America LEAF Battery Survey, by far the
strongest indicator of premature battery capacity loss is the owner’s local climate conditions, specifically
cars that have lost enough capacity to be visible on the car’s dashboard capacity display are nearly all in
hot-weather climates.
Not every car in a hot climate is seeing battery capacity degradation, and this study does not yet have
enough information to determine what fraction of cars are affected. Data collected on the MNL forums
suggest that at least 11.8% of the LEAFs in Arizona are affected5
. Perhaps most hot-climate cars are losing
capacity at a higher rate than cars in more moderate climates, or perhaps only a small portion of the cars are
susceptible to hot weather-related capacity loss. If it’s the later case, it could be differences in driver habits
or conditions, or it could be a manufacturing issue. The root cause cannot be determined without more data,
either from more owners participating in the survey and using aftermarket state-of-charge meters, or from
Nissan providing more data to the user community.
The high mileage vehicles in the survey thus far show that the Nissan LEAF is capable of considerable
driving before losing enough capacity to drop the first capacity bar. This would seem to bode well for
LEAFs that are not having the problems seen in some hot-climate vehicles.
The Battery Information Sheet that LEAF owners are supposed to receive when they have their annual
service done has potentially significant educational potential. If presented and explained by a
knowledgeable technician, this report can serve as a method to educate owners on best practices for
maintaining the health and capacity of their battery pack. Although the effect of doing well on the report is
apparently too small to be measured by this survey, Plug In America recommends that LEAF owners be
aware of the issues and follow them as much as is convenient in their use of the vehicle by avoiding habits
that have little benefit to the owner and potentially contribute to battery pack degradation.
https://survey.pluginamerica.org/tesla-roadster/PIA-Roadster-Battery-Study.pdf
Plug In America’s
Tesla Roadster Battery Study
by Tom Saxton, Chief Science Officer
Released: July 13, 2013
Conclusions
The projections from the various data sets studied suggest that Roadster batteries will be
at 80% to 85% capacity after 100,000 miles, on average. Stated another way, the study
shows an average loss of about 3.7 ideal miles of range (1.6%) per 10,000 miles driven.
As there is considerable variation among vehicles with similar mileage, an individual
owner’s experience may vary significantly from the average.
The survey found no significant correlation between climate and battery pack longevity.
Individual experience may vary. The survey data for high-mileage vehicles is sparse with
little variation in climate among those vehicles, so it’s possible an effect from climate
will emerge as more data is collected.
The survey found no significant correlation between vehicle age and battery pack
longevity, although the study has no data on the first year of use, nor use beyond 4.5
years.
The calculated amp-hour capacity is the most reliable measure of battery pack capacity. It
would be a benefit if this value were readily visible to Roadster owners.
It’s curious that Tesla does not offer any sort of warranty on battery pack capacity, not
previously as part of a new Roadster purchase, not as part of the extended warranty they
are now offering Roadster owners as their warranties expire, and not even to Model S
owners despite the purported improvement in battery chemistry and corresponding
increase in both time and miles on the Model S battery warranty.