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Raven "Rated" Watts Per Mile and Real World Experience

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I actually have a question about this... (because I truly want to know more about this).

I understand in the winter you need to use your heater so therefore efficiency goes down, but in the summer I find myself using my AC more and preconditioning the car more before getting in and I'm seeing my efficiency as significantly worse than during the spring/fall. I know not every climate is the same and San Diego is pretty forgiving in terms of temperatures, but having the AC running when it's hot seems like it wouldn't make the the most efficient time, right?

Yeah, my usual experience is that the late spring and early fall are the most efficient times. Still, his point that the winter efficiency will drag the numbers up somewhat is quite valid.

How much remains to be seen - and I'm quite certain that my Ludicrous Raven is doing somewhat better than my prior X75D in the same conditions.
 
Rolling resistance - Wikipedia
Excerpts:
Sidewall deflection is not a direct measurement of rolling friction. A high quality tire with a high quality (and supple) casing will allow for more flex per energy loss than a cheap tire with a stiff sidewall.[citation needed] Again, on a bicycle, a quality tire with a supple casing will still roll easier than a cheap tire with a stiff casing. Similarly, as noted by Goodyear truck tires, a tire with a "fuel saving" casing will benefit the fuel economy through many tread lives (i.e. retreading), while a tire with a "fuel saving" tread design will only benefit until the tread wears down.

Temperature: with both solid and pneumatic tires, rolling resistance has been found to decrease as temperature increases (within a range of temperatures: i.e. there is an upper limit to this effect)[50][51] For a rise in temperature from 30 °C to 70 °C the rolling resistance decreased by 20-25%

The introduction at the top of that wiki page is probably worth reading too. It goes into the impact of Silica vs Carbon Black and so forth.


If you just make the tread compound softer/more adhesive then yes your rolling resistance will go up.

If you keep the tread the same and use a more compliant sidewall, then you will reduce rolling resistance as the energy required by the sidewall deflecting to create the contact patch goes down.

In summary if you soften the tire in the right ways it becomes easier to roll, as it takes less energy to deform to create the contact patch. Running winter specific tires allows you take advantage of low temperature compounds that deform more easily under their intended conditions and as such use less energy than a tire operating at the very low end/below it's temperature range.
 
Thanks for that- I learned a lot. There are no references for the claim, though, so I am left hungry for knowledge!
Rolling resistance - Wikipedia
Temperature: with both solid and pneumatic tires, rolling resistance has been found to decrease as temperature increases (within a range of temperatures: i.e. there is an upper limit to this effect)[50][51] For a rise in temperature from 30 °C to 70 °C the rolling resistance decreased by 20-25%

 
http://onlinepubs.trb.org/onlinepubs/sr/sr286.pdf
Page 42 FACTORS CAUSING AND INFLUENCING ROLLING RESISTANCE

The bottom of page 45 is probably particularly interesting.

"Higher ambient temperatures are associated with reduced rolling resistance because the amount of energy dissipated when the rubber is subjected to repeated deformation declines moderately as temperature rises, which is a commonly observed behavior of viscoelastic materials. Accordingly, the length of time a tire has been running since the last cool-off affects rolling resistance, which declines until the passenger tire has been rolling for about 30 minutes."


I didn't find references to condition specific tires in that PDF, but it stands to reason if a tire compound is designed for a temperature range that it will be more compliant in the middle of that range than a tire operating at the low end or below it's temperature range. As with many very deep detail topics it is hard to find information unless you work for Good Year etc. My experience has shown winter tires to be superior in range to all season tires in cool weather. My guesstimate is that it gains about 20 degrees F of efficiency, as in a winter tire will give similar efficiency to an all season tire that is 20 degrees warmer. At 50 my winter tires seemed to give range in line with All Seasons at 70.
 
If you keep the tread the same and use a more compliant sidewall, then you will reduce rolling resistance as the energy required by the sidewall deflecting to create the contact patch goes down.
Yes, sort of. The issue with this statement, although true, is that in a radial tire the carcass cords and sidewall offer very little resistance to start with. This can be shown by removing the belts and tread from the tire and then pressing down with your hands to feel how very little resistance there is. (Of course the equipment to do this is not easy to come by). Most of the rolling resistance comes from the belts and tread compound bending while going into and out of the contact patch.
 
True enough, but if you toss that carcass in the freezer it will get noticeably harder to do that same amount of deflection.

In general these cars are quite efficient so deforming rubber is a substantial amount of energy. Imagine compressing that carcass with your hand thousands of times per second.
 
True enough, but if you toss that carcass in the freezer it will get noticeably harder to do that same amount of deflection.
Certainly, but that wasn't my point. Just that spending a lot on reducing the energy used in carcass flexing doesn't bring the best bang for the buck. And of course, warmer is typically better for rolling resistance--and not just because of tires, but fluids (including wheel bearing grease) add a lot of rolling resistance (just not to the tires). And certainly winter tires are better in winter than summer tires would be. Depending upon the tire, many turn to wood when the temperature gets cold.
 
Interesting how many of us P85D folks are here in this thread. Here's my P85D (ludicrous upgrade) lifetime, just before trading it in on the Raven Performance (new rules, so Ludicrous included). I'm having a similar experience over my "familiar" drives -- it seems easy to get as-good or better mileage. But... summer, etc. One thing I'm anxious to try is preconditioning the battery with Ludicrous+ in the winter, that's where I get clobbered up here in Wisconsin. And oh, that new suspension. Lovin' that.

P85d lifetime mileage.jpg
 
To find the Wh per rated mile, I look at where the projected range on the energy screen crosses the rated range in the cluster. For my Ludicrous Raven X, that happens when the average consumption hits 324 Wh per mile.

My prior 2016 X75D crossed at 308 Wh per mile.

Despite that, the Performance Raven consumes less power as long as I keep the pedal under control - often ~10% less than I would have expected from prior experience.

Odd my P85DL is 310 / wh mile rated and my lifetime actual is 306. You'd think the P100D with the magnet motor on the front would be way more efficient.
 
in wk057's tear down of the p100d battery, he states that the pack has 98.4kwh usable.

100D: 98400 / 370 = 266 wh / mile
P100D: 98400 / 345 = 285 wh / mile

These are average values for the epa loop which is supposedly done in range mode.