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Tesla Roadster Update Extends Range
mrflash818 sends word that Tesla Motors has announced an upgrade for their Roadster vehicles that boosts the range from about 240 miles to almost 400. In addition to the battery improvements made since the Roadster launched in 2008, Tesla has a kit to retrofit the body to reduce its drag coefficient from 0.36 to 0.31. They also have new tires, which improve the rolling resistance coefficient by about 20%. They say, "Combining all of these improvements we can achieve a predicted 40-50% improvement on range between the original Roadster and Roadster 3.0. There is a set of speeds and driving conditions where we can confidently drive the Roadster 3.0 over 400 miles. We will be demonstrating this in the real world during a non-stop drive from San Francisco to Los Angeles in the early weeks of 2015." Tesla stopped producing the Roadster in 2012.
I confess, I was not impressed with the practicality of the all-electric concept, and felt it would always be pretty much a rich person's toy. Common in Hollywood and maybe the Silicon Valley and around Wall Street, and maybe Redmond, for bragging rights, but you'd never see one in Omaha.
The two issues as I saw it were range and charge time. (Cost is also a factor, but cost usually goes down over time.) It looks like Tesla is making a good faith effort to tackle the range issue, and there is some effort being made to reduce the charge time. Good for them.
It also occurs to me that for self-sufficiency, all-electric vehicles may be an advantage, as electricity could be easier to make and store than methane, for instance.
Oliver's law of assumed responsibility: If you're seen fixing it, you will be blamed for breaking it.
If the car wasn't built with a supercharger in mind it might not be practical. Charging generates heat, and too much heat causes malfunctions at best and fires at worst.
>Low rolling resistance tires number one problem has been bad road comfort.
Which surprises me. I fitted low rolling resistance tyres to my bike and experienced improvements in ride comfort, traction, and significantly reduced rolling resistance (tire wear was increased though as these are technically "racing" tyres). When it is your legs powering the vehicle you can really feel all this. On bikes they achieve the improvements with suppler casing (which increases ride comfort) and softer/suppler rubber (which increases traction and ride comfort but decreases tire life).
(And why is it that people assume that low rolling resistance has anything to do with the coefficient of friction and traction?)
I was surprised by the .36. When Lexus first came out c. 1990 they advertised the LS400 heavily as having a .28 and later models got down to .24. .36 is 50% worse than a 1990's sedan and surprising since range has always been an issue.
I guess it looks cool, though (hard to argue with the company's success).
You're missing the part about where this is a roadster. Convertibles have considerably more drag than cars with roofs. Also, you're only looking at Cd. Cd is used in the drag equation to calculate total drag, and the part that isn't part of Cd is surface area. The lexus vehicles have much higher total drag because they're all much bigger cross-sectionally. The Tesla Roadster is tiny.
"No, no, no. Don't tug on that. You never know what it might be attached to."