Featured Ex-semi driver has questions about Tesla Semi

can't buy one anyway, so what does it matter?

 

Source: Tesla Semi Will Transport Cargo Between Fremont And Gigafactory

The four-hour trek from Fremont to Reno (~260 miles) is a monumental expense for Tesla. It’s also something that’s unavoidable since the two factories work hand-in-hand to build Tesla’s vehicles. This is especially true with regards to the Model 3, and the Gigafactory was discovered to be the site of a bulk of the “bottleneck” issues. Having a reliable and regular form of inexpensive transportation between the two sites is key.

Tesla may have planned the electric semi partly for its own benefit. However, once other companies see its successful deployment, it should increase its appeal. Musk has made comments in the past about the pain and expense of moving loads between the two factories, and when batteries are involved, we’re not talking about light loads here. Now, Tesla will be able to do it much more cheaply, and without tailpipe emissions.​

My guess is the truck will be loaded with batteries when it descends from Reno to Fremont. The return trip might lighter meaning each trip could be a net energy gain.

Bob Wilson

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I concur on the seating position, and with the screens blocking the view.
The brightness and color settings of the screens can be adjusted to prevent glare and night vision disruption. I don't think airliner pilots have such issues with the glass cockpit. That may not apply to the use of the screens as mirror replacements, though.
More cameras, and night vision ones, can always be added. But I say that while still not fully adjusted to the Camry's rear camera.
The jack knifing claim likely depends on the use of Tesla's trailer which could contain more automated systems to help with controlling it.

 

An interesting chart about the Tesla truck:

• $1.51 / $2.50 ~= 0.604 gallons per mile
  • ~1.66 miles per gallon = 1 / 0.604 gallons per mile
• $1.27 / $0.07 ~= 18.14 kWh per mile
  • 500 mi * 18.14 kWh ~= 9.07 mWh battery capacity
  • 300 mi * 18.14 kWh ~= 5.44 mWh

The second chart gives a clue for a mix fleet operating as a convey, 240,000 GVW:

• $0.85 / $0.07 ~= 12.14 kWh per mile
  • 500 mi * 12.14 kWh ~= 6.07 mWh
  • 300 mi * 12.14 kWh ~= 3.64 mWh

So one mix would be one 500 mi truck and two 300 mi trucks. The 500 mi truck can handle long distance, single loads. The 500 mi truck could also lead two 300 mi trucks when there is an an exceptionally large, coordinated delivery.

Now I'm not so sure an 80,000 lb, 40 ton, truck only gets 1.66 miles per gallon. I don't have direct experience and there are other reports of getting higher mileage: Fuel Rules | American Trucker

Bob Wilson

 

The $1.51 cost per mile is not just from fuel costs, but other costs as well, otherwise the Tesla would be about 14 cents per miles.

 

I showed my work. Where did the "14 cents per mile" come from?

Bob Wilson

 

2 kWh per mile (or .5 miles/kWh) and 7 cents per kWh

 

Caution: My reply is personal speculation with no formal basis

If solid state batteries and extreme speed charging live up to the hype that I've seen in the articles posted here, then expect something like 60-0 in three or four seconds, even going downhill, in ten years.

Note: We don't really know for sure... too early to tell.

 

Hummm, 2 kWh per mile seems a little small. I probably would have done it this way:

• ~3,000 lbs, Prime and BMW i3-REx
• ~250 Wh/mile
• 80000/3000 ~= 27 times heavier
• 27 * 250 ~= 6.75 kWh / mi - rolling drag
• 2 x area estimated cross section of BMW i3 vs semi-trailer
• 2 * 6.75 kWh ~= 13.5 kWh / mi - aero drag
• 6.75 kWh + 13.5 kWh ~= 20.25 kWh ... close to the 18.14 kWh / mi estimate

Bob Wilson

 

This article has a video on another diesel semi mechanic's thoughts on the Tesla semi. He's done his homework as the stuff he mentions was mentioned in the presentation, though he goofed up on the "Auto-pilot" system's name when talking about how it'd keep your car a certain distance away from the car in front via adaptive cruise control as part of that system.

I also like that he doesn't just dismiss the concept entirely, despite mentioning he may be out of a job in 10-15 years.

Tesla Semi Examined From A Mechanics Perspective - Video

 

There is a shell aero semi with a 16mpg stretch goal and a realistic return of 11mpg

 

2 kWh per mile (or less) was stated by Tesla

 

I missed that. Where?

The reason I ask is:

• $1.51 / mi - Tesla truck cost from Tesla charts
• $0.14 / mi ($0.07 * 2 kWh / mi) - from ??
• $1.37 / mi - all the overhead, maintenance, e.t.c.

Bob Wilson

 

The $1.51 and $1.26 costs you are working from are not fuel costs, but total operating costs. The costs like insurance, inspection, licensing, etc. are the same for either truck, so their specific numbers weren't presented.

Tesla stated 2 kWh per mile, and typical overland trucks get 6 to 9 mpg.
The pack size is around 1000kWh in capacity.
Tesla’s Game Changing Class 8 All-Electric Semi Reveal | CleanMPG

 

Actually I was interested in a Tesla sourced press release: Press Kit | Tesla

The biggest immediate cost-advantage comes from savings in energy costs: fully loaded, the Tesla Semi consumes less than two kilowatt-hours of energy per mile . . . (more below)​

The Model 3 is now listed: Compare Side-by-Side

• 0.27 kWh / mi (27 kWh / 100 mi) Model 3 Long Range
• 2.0 kWh / mi Tesla semi press release power required
• 7.4 ~= 2.0 / 0.27 kWh Tesla semi energy per mile vs Model 3
• 
  
• 3814 lbs (Model 3 Long Range) source: Press Kit | Tesla
• ~21.0 times heavier ~= 80000 / 3814
• 
  
• 82.2" * 56.8" ~= 32.4 ft{2} - Model 3 cross section, rough
• 101" x 96.5" ~= 67.7 ft{2} - reefer truck size, rough: http://www.freightmatchers.com/assets/files/General%20Dry%20Van%20Trailer%20Specifications.pdf
• 2.1 time area ~= 67.7 / 32.4 - relative profile area

Or perhaps someone made a mistake in a press release. Going back to the original Tesla press release:

The biggest immediate cost-advantage comes from savings in energy costs: fully loaded, the Tesla Semi consumes less than two kilowatt-hours of energy per mile and is capable of 500 miles of range at GVW and highway speed, accommodating a wide range of shipping applications given that nearly 80% of freight in the U.S. is moved less than 250 miles. Coupled with the low and stable nature of electricity prices – which average $0.12/kWh in the U.S. and can be significantly less for commercial and industrial users, falling to almost nothing when combined with local solar generation and storage – owners can expect to gain $200,000 or more in savings over a million miles based on fuel costs alone.​

Now if that "two kilowatt-hours" is the overhead, given a typical 90% efficiency, we come back around to ~18 kWh for the motive power previously calculated from the Tesla presentation charts. Also curious the press release uses "$0.12/kWh" versus the "$0.07/kWh" of the Tesla charts that assumes a solar source.

Ok, let's go over the hypothesis:

• physics break through reversing ~200 years of classical physics
• $1.37 / mi overhead that is NOT used to move truck
• someone made a typo error in a press release

Since I'm not in the market for a Model 3 or a Tesla Semi, I'm just an ordinary engineer doing the maths. But if I were, I'd like to have a Model 3 and 3/4 (*) that is a Tesla Semi shrunk to the size of a Model 3.

Bob Wilson

* - A "3 and 3/4" as in:

 

Well sometimes it is easy to forget the original question: what is the battery capacity of the Tesla Semi. So let's start from the press release for the Tesla Semi and for fun, parallel to the Model 3 Long Range (LR):

	Tesla Semi	Model 3 LR	Comments
1	2 kWh/mi (1)	27 kWh/100 mi (2)	power consumption per distance
2	500 mi (1)	310 mi (2)	total range
3	1000 kWh	83.7 kWh	usable battery capacity
4
5	$0.12/kWh (1)	$0.12/kWh (1)	Tesla reported electricity cost
6	$0.24 / mi	$0.032	calculated electrical cost per mile

1. Press Kit | Tesla for Tesla Semi
2. http://www.fueleconomy.gov for Model 3 Long Range

If we use a different source, the PowerPoint presentations at the roll-out, we get different numbers because "operational cost per mile" apparently involves some undefined, per mile cost in addition to electricity. Sad to say, those costs and assumptions are not defined in the presentation. It also has an uncommonly low, but not impossible, $0.07/kWh. There are industrial electrical rates in this range per US Energy Administration.

The remarkable thought is an 80000 lbs truck, 20 times weight, with twice the frontal area of the ~4000 lbs Model 3 Long Range costs only 7.5 times more per mile in electrical cost. It stretches credibility but I'm not likely to be a future customer. As for the PowerPoint presentation, well pick your poison.

Bob Wilson

 

I stumbled across this interesting YouTube:

Fixed, I also made a rookie mistake by mixing units in a table:

* * * *

Well sometimes it is easy to forget the original question: what is the battery capacity of the Tesla Semi. So let's start from the press release for the Tesla Semi and for fun, parallel to the Model 3 Long Range (LR):

	Tesla Semi	Model 3 LR	Comments
1	200 kWh/100 mi (1)	27 kWh/100 mi (2)	power consumption per distance
2	500 mi (1)	310 mi (2)	total range
3	1000 kWh	83.7 kWh	usable battery capacity
4
5	$0.12/kWh (1)	$0.12/kWh (1)	Tesla reported electricity cost
6	$0.24 / mi	$0.032	calculated electrical cost per mile

1. Press Kit | Tesla for Tesla Semi
2. http://www.fueleconomy.gov for Model 3 Long Range

If we use a different source, the PowerPoint presentations at the roll-out, we get different numbers because "operational cost per mile" apparently involves some undefined, per mile cost in addition to electricity. Sad to say, those costs and assumptions are not defined in the presentation. It also has an uncommonly low, but not impossible, $0.07/kWh. There are industrial electrical rates in this range per US Energy Administration.

The remarkable thought is an 80000 lbs truck, 20 times weight, with twice the frontal area of the ~4000 lbs Model 3 Long Range costs only 7.4 times more per mile in electrical cost. It stretches credibility but I'm not likely to be a future customer. As for the PowerPoint presentation, well pick your poison.

Bob Wilson

 

Well Toyota has Hydogen trucks in the works and is currently running two in the LA basin to move cargo from Toyota ships to other facilities. So hydrogen is going to be a strong contender in this race against Tesla. Also Toyota already has manufacturing of trucks through their Hino brand of trucks.

 

Can we PLEASE put real world money on this "race?" I'll even give you really good odds.