^ Okay. Got it. Thanks.
^ Okay. Got it. Thanks.
Anyone tried to compare our calculated 65 mph numbers with the Tesla-store-big-screen-range-calculator numbers? It seems those are better than our calculations, although I wouldn't know if those numbers were obtained with parameters which would give exactly 300 miles for 55 mph.
Buying an EV is one thing, being able to drive it beyond city limits another...
Or interpolated from this data file:
For the Model S values I used the estimated range that rabar10 posted in posting #22, dividing the pack kW by estimated range.
This looks consistent with daxz's graph in posting #25.
I have not seen anything from Tesla on how they came up with the range values for the Model S battery packs. However, I find the values released, particularly the 300 mile range, suspiciously nicely rounded. As a result I believe "doing the math" of dividing battery capacity by stated range would probably yield misleading efficiency numbers.
I believe the chart, and the supporting data, represent a reasonably accurate model that approximates the result of the EPA 2-cycle (city/highway) tests. The EPA puts the 2-cycle results at 245 miles of range. The Tesla model data puts it at about 239 miles of range at 55 mph. That's within 2% of the EPA combined tests.I've heard people say "range at 55mph" but they use the same language "range at 55 mph" to describe the Roadster's range of 245 miles. That would contradict the data from the chart you referenced unless there are other factors. So I'm wondering if you are comparing data for equal parameters for each car?
If I understand the methodology used by radar10 and daxz they started with the Roadster data and applied various multipliers to the factors that effect efficiency, i.e. aerodynamic drag, tire losses, etc. For example, radar10 used a .98 multiplier for aerodynamics, meaning he feels that the net aerodynamic drag considering the coefficient of drag and the cross-sectional area, is only slightly better on the Model S over the Roadster. If I have interpreted daxz's postings correctly, his aerodynamic multiplier would be .88. Since these are ratios applied to the original Roadster data, the issue of comparing different parameters shouldn't arise.
Both of these efficiency values for the Roadster and derived for the Model S do not consider losses in the charging system. Other efficiency numbers quoted for the LEAF in the U.C.S. study do include charging losses.
Last edited by Larry Chanin; 04-21-2012 at 11:03 AM.
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