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Tesla Semi’s EPA range rating will simply never exist…Here’s why

There's no way they averaged 66 mph. Just watch the video, very little time is spent above 60 mph, most of the time is spent from 50-55 mph.

This is actually my biggest beef with the run, it's fairly obvious that they were hypermiling it, most trucks run ~60 mph on I5 when they were doing 50-55 even when the road was wide open in front of them.

I can't see how we should expect any manufacturer to report or demonstrate economy results at illegal speeds. And I wouldn't call 55 in a 55 "hypermiling" in any sense.
a) Clearly it was a demo route that had features they wanted (hill, 500 miles, etc) as a PR move though. The PR they got and was spread everywhere is the Tesla semi goes 500 miles and the competitors go 250 miles ... even if the the demo was hand selected and many competitors are building "short haul" trucks vs "long haul" trucks.
While definitions vary regarding what exactly counts as long-haul and short-haul driving, generally routes that involve a 200-mile radius or less should be considered short-haul, whereas anything over 250 miles is considered long-haul driving.

b) More realistic speed limits are 65-70 mph as you can see from this link:

Sample from middle of the list:
FKdRAfg.jpg
 

SageBrush

REJECT Fascism
May 7, 2015
14,162
19,691
New Mexico
Many diesel Semis (by no means all) have flat terrain range considerably over 500 miles. But that is the point -- the Tesla Semi is 500 miles of NET flat terrain. The effect of intervening climbs and descents are minimal. Put a diesel on a mountain route and it does not come close to 6 mpg.

Add 1/2 hour at a Megacharger, and the Tesla Semi has 750 all terrain miles. If the Tesla Semi comes close to a diesel's carrying weight, it is a slam dunk Vs diesel due to the much cheaper fueling costs.
 
a) Clearly it was a demo route that had features they wanted (hill, 500 miles, etc) as a PR move though. The PR they got and was spread everywhere is the Tesla semi goes 500 miles and the competitors go 250 miles ... even if the the demo was hand selected and many competitors are building "short haul" trucks vs "long haul" trucks.
Of course they chose the demo to prove a point. But that doesn't invalidate the result. They did traverse 15,000 feet of climbing and they did travel 500 miles and they did so at max gross weight and at or near the speed limit. It's remarkable and there's no "beef" to be had. I imagine anyone seriously interested in applying this vehicle to other conditions is intelligent enough to anticipate the effects in general and to research for specifics. Even the EPA doesn't run its economy tests to simulate mountainous terrain or at 80mph just to please Coloradans or Idahoans respectively.
 

Dave EV

Active Member
Jun 23, 2009
2,467
3,218
Earth
I can't see how we should expect any manufacturer to report or demonstrate economy results at illegal speeds. And I wouldn't call 55 in a 55 "hypermiling" in any sense.
I have no issues with the 55 in a 55 or driving the posted speed limit in CA. But if you watch the video, you will see that once they get over the Grapevine and head east on 210 at the 1:12 mark on the YouTube video, instead of driving the posted speed limit (or higher, there were sections down I5 where they were driving high 50s and ran at 65 mph a few times), the cruising speed was lowered to 50-51 mph. (See these timestamps on the video: 1:12, 1:15, 1:17, 1:43, 1:49, 1:50)

So yeah, to me it's clear that they ate up a bit more range than expected getting into LA and then slowed down to compensate.

I would probably be a lot less annoyed by this if Elon hadn't specifically said they didn't play any tricks. Well, they did. I mean, if they had topped it off to 100% right before leaving and drained it to 0%, I would also be less annoyed - had they done that, they probably could have avoided slowing down, too.

I'm sure truckers also want to know real world range where the speed limits are higher (65 / 70 / 75 mph). Heck, even give a scenario where you double up the bathroom break with a Supercharge - you probably pick up at least a couple hundred miles range there.

Don't get me wrong, the Semi is a great product and desperately needed and I hope that Tesla sells as many as they can make.
 
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The right hand scale applies to the shaded elevation graph, not the blue line... very little elevation change.

I have driven this route many times and think it is a real test except I don't think the Semi was driving as fast as traffic, probably close to 55mph, not the 65+ most trucks do on the 5...
Speed limit for semis in California is 55 mph.
 
a) Clearly it was a demo route that had features they wanted (hill, 500 miles, etc) as a PR move though. The PR they got and was spread everywhere is the Tesla semi goes 500 miles and the competitors go 250 miles ... even if the the demo was hand selected and many competitors are building "short haul" trucks vs "long haul" trucks.


b) More realistic speed limits are 65-70 mph as you can see from this link:

Sample from middle of the list:
FKdRAfg.jpg
Posted limits mean nothing in the commercial truck industry, most company trucks are speed limited 58-65 mph for economic reasons.( insurance and fuel) and all trucks are speed limited from the factory/dealer to match the speed rating of the tires installed.
 
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While range is important, people need to consider other Tesla Semi benefits. Much quicker acceleration, regen reduces brake wear and fade on longer downhills, comfort, vision, lack of noise, lack of shifting etc benefit drivers. Each buyer will consider both EV and Diesel, depending on their predicted usage and need. Neither EV nor Diesel will get 100% of the market.
Initially long haul drivers will lean to traditional Diesel, while those making urban deliveries will be better off with electric. 20 years from now, most trucking will be Electric. Once cities ban entry by Diesels due to air pollution, noise and smell, the EVs will have their day.

As far as arguments about the route Tesla chose, it has little relevance to its EV benefits. Whether the Semi can do 450 or 550 miles will not be the deciding factor in purchases. With quick Supercharging along most highways, stopping for a 30 minute charge while driver gets a bathroom/snack break will most likely not be a big deal on an 8+ hour trip.
 
I have no issues with the 55 in a 55 or driving the posted speed limit in CA. But if you watch the video, you will see that once they get over the Grapevine and head east on 210 at the 1:12 mark on the YouTube video, instead of driving the posted speed limit (or higher, there were sections down I5 where they were driving high 50s and ran at 65 mph a few times), the cruising speed was lowered to 50-51 mph. (See these timestamps on the video: 1:12, 1:15, 1:17, 1:43, 1:49, 1:50)

...
If/when they really put up the full video I'll check to see how pervasive it was and whether or not I'd consider it justified or cheaty. Given the 4pct arrival I can see the possibility or even likelihood that some Tesla engineers were coaching him over the air, or maybe he was already well-versed in extending the range. It was kind of a Moon Shot after all. My tolerance of economy tactics may be higher than most, having driven a 24kWH LEAF for over a decade. :)
 
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Is this just a corner case or if you start around sea level and gyrate up and down and end up at roughly sea level won't your ups and downs be the same?😉
Haha, that is true. However, depending on the grade, you will use significantly more energy going "up hill" than you gain with regen going "down hill." ;)
For example, if you live in Denver, you could take a Sunday drive from and back to your house. If you go 100 miles West *OR* going 100 miles East you will arrive home with different SOC :)

I thought it would be find to play in ABRP and the below was using my 2017 X profile.
TBH, I thought it would be more dramatic since you only regain ~70% with regen.

West
O5UccLI.jpg


East
XLJnocM.jpg
 
Last edited:

aerodyne

MS LR = Last Car?
Nov 19, 2018
5,246
8,423
Los Angeles
Is this just a corner case or if you start around sea level and gyrate up and down and end up at roughly sea level won't your ups and downs be the same?😉

First, I have no doubt that Tesla optimized the pack in the test semi and did a lot of prior testing and tweaking to make sure they would meet the goal.

Per historical WX data on the test day, they had a slight headwind from the south. It would not take much coaching to know to slow down a bit in a head wind.

Second, let's say the elevation gain and drop was even throughout the trip. 30 feet up and down every mile would have near zero effect on efficiency, since Regen would not come into play at all, and the increase in resistance due to extra power required to climb would be negligible.

Going up the grapevine about 4k feet in 10 miles would certainly have losses, and going into Castaic you would be doing substantial Regen, which is only 85% effecient.

However, these losses would be minor compared to the effect of a 5 mph head or tail wind over 500 miles.

Source: many trips in MS 85D in mountainous terrain over 10k+ miles recorded on Teslafi. Less than 310 wh/mi, vs EPA rated 290 wh/mi.

Edit:. Just saw above post by @scottf200

I have data going through Denver both ways.

Suffice to say, west bound trip was higher consumption because of prevailing winds from the west.
 
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aerodyne

MS LR = Last Car?
Nov 19, 2018
5,246
8,423
Los Angeles
I have no issues with the 55 in a 55 or driving the posted speed limit in CA. But if you watch the video, you will see that once they get over the Grapevine and head east on 210 at the 1:12 mark on the YouTube video, instead of driving the posted speed limit (or higher, there were sections down I5 where they were driving high 50s and ran at 65 mph a few times), the cruising speed was lowered to 50-51 mph. (See these timestamps on the video: 1:12, 1:15, 1:17, 1:43, 1:49, 1:50)

So yeah, to me it's clear that they ate up a bit more range than expected getting into LA and then slowed down to compensate.

I would probably be a lot less annoyed by this if Elon hadn't specifically said they didn't play any tricks. Well, they did. I mean, if they had topped it off to 100% right before leaving and drained it to 0%, I would also be less annoyed - had they done that, they probably could have avoided slowing down, too.

I'm sure truckers also want to know real world range where the speed limits are higher (65 / 70 / 75 mph). Heck, even give a scenario where you double up the bathroom break with a Supercharge - you probably pick up at least a couple hundred miles range there.

Don't get me wrong, the Semi is a great product and desperately needed and I hope that Tesla sells as many as they can make.

The eastbound 210 from the 5 to the 134 is a real mess with narrow K walls and sharp lane lane shifts, esp in the truck lanes. I won't even exceed 50 in places.
 
Haha, that is true. However, depending on the grade, you will use significantly more energy going "up hill" than you gain with regen going "down hill." ;)
For example, if you live in Denver, you could take a Sunday drive from and back to your house. If you go 100 miles West *OR* going 100 miles East you will arrive home with different SOC :)

I thought it would be find to play in ABRP and the below was using my 2017 X profile.
TBH, I thought it would be more dramatic since you only regain ~70% with regen.

West
O5UccLI.jpg


East
XLJnocM.jpg
Your example is a good one and I probably zeroed in on sea lever to sea level being the same up and down while you pointed out the difference in gradient and its effects on range.
 
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Bouba

Active Member
Sep 23, 2021
1,455
1,374
France
I’m not that sure that coasting is more efficient than regen.
In the real world a vehicle going downhill accelerates until it’s going either faster than the speed limit or faster than the driver feels that they are still in control (often downhill includes sharp bends)…so the vehicle has to be mechanically slowed…this leaves the engine compression (in an ice vehicle) and the transmission and brakes taking up all the strain…and that energy is either lost through heat or damage to the moving parts all the while the engine is still burning fuel (although not a lot)…if ev regen captures any part of this then it is more efficient.
A laboratory experiment of an object rolling downhill will obey the laws of physics…a vehicle rolling downhill obeys the traffic laws
 

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