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Poll: What is the efficiency of the Tesla Semi?

What is the efficiency of the Tesla Semi?


  • Total voters
    21
  • Poll closed .
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1.7 kWh per mile. Elon thinks 1.6 - 1.5 might eventually be possible.
Yeah, I was impressed when I saw that.

I'm happy I was wrong on the "guessed too high" side...


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What's the speed limit for a semi in the us?
Here it's 80km/h, and law requires that semis need to be fitted with a speed limiter that limits max speed to 90km/h. I think this applies to most of europe.
Varies by state. 75MPH is currently the highest (per my quick search). Texas was 85 a while ago.
US groups are looking into speed limiters also.
 
Huh, a 41 miles section. So a 4 minute travel time reduction versus 75...
It connects to a larger 80 mph section, combined the savings is more. But the high speed limit is mostly a gimmick to attract vehicles. 130/45 was supposed to be part of a huge boondoggle to run 8 lanes plus freight and high speed rail from the border up to Dallas. Low usage isn't helping them make their case.
 
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It depends on the trailer. The cab/trailer gap is a big contributor. Side skirts help, too, and even those funky folding things on the back. And obviously a full-height trailer has more drag than one that's not as tall. Trailer tires also matter. I can see Semi around 1.8 kWh per mile at 60 mph w/o wind and a well-chosen trailer. Those 12 mpg SuperTrucks are at or below that amount of road load.

Headwinds mostly average out, because half the trucks are going the opposite direction. Crosswinds hurt you both coming and going.
The statement that headwinds will average out is not correct.

The physics of wind resistance load is proportional to the square of velocity of the airstream. So +20 mph headwind is much more costly in terms of lost range than a -20 mph tailwind. The effect of a headwind and of a tailwind are asymmetric, in terms of energy cost and energy saved.

Example:
If Semi is moving at 60 mph. With no wind, drag load is proportional to 60x60 or 3600.
20 mph headwind makes the wind load proportional to 80x80, or 6400. 2800 units of additional drag.
with 20 mph tailwind: aerodynamic drag is proportional to 40x40, or 1600, or 2000 units of reduced drag.
 
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