Tesla Semi

[MP3Mike]

Or does the Semi use any standard trailer without any specific Tesla feedback?

It has to be able to work with any standard trailer. So there will be a hookup for lights, and hookup for air controlled brakes.

 

[Big Earl]

Is there any specific Tesla communications between the Semi and the Trailer?
- At least, to have a rear view camera but also to activate the trailer bakes?

Or does the Semi use any standard trailer without any specific Tesla feedback?

Trailer brakes are controlled by pneumatics (air pressure) from the tractor. Lights are controlled by electronic connections. Semi conforms with these standards.

 

[mongo]

Does thoses elongated trucks have also the same 80k Lbs weight limitation?

Weight limits are mostly per axel set, 12k steering, 34k tandem. Doubles/ triples have higher totals.

 

[mongo]

I'd rather see a "Tesla trailer" with a motor on at least one axle with the ability to regen brake, manage traction, and designed to feed the tractor's battery.

Trailer braking only comes into play if requested deceleration is higher than max tractor regen or needed for trailer control.
Its limited usage needs to compensate for continuous mass, drag, and cost penalties.

 

[2daMoon]

Trailer braking only comes into play if requested deceleration is higher than max tractor regen or needed for trailer control.
Its limited usage needs to compensate for continuous mass, drag, and cost penalties.

Here's what I had added to that original post after you quoted it. (thanks btw for moving it here)

This could be built as a "skateboard" and sold to trailer manufacturers.​

​

Add solar roof and a battery for reefers to power the Tesla heat pump based cooling unit. Fully integrated into the charging/regen circuit.​

The safety aspect of the motor for managing the trailer traction for a variety of situations might be worth the load loss of a couple of hundred pounds of added mass. Or, Tesla could design the skateboard to weigh the same as existing designs.

 

[mongo]

Here's what I had added to that original post after you quoted it. (thanks btw for moving it here)

This could be built as a "skateboard" and sold to trailer manufacturers.​

​

Add solar roof and a battery for reefers to power the Tesla heat pump based cooling unit. Fully integrated into the charging/regen circuit.​

The safety aspect of the motor for managing the trailer traction for a variety of situations might be worth the load loss of a couple of hundred pounds of added mass. Or, Tesla could design the skateboard to weigh the same as existing designs.

I've seen hydraulic accumulator trailer assist systems that seem good for urban use on ICE tractors.
In general, energy capture is more efficient and cist effective on fixed structures where they can have optimal placement and high utilization. Unless there is a need to squeeze out every last miles of range (or self sufficient climate control), trailer add ons seem sub-optimal.

Unless the trailer axles need to accelerate (which seems an odd situation to be in), ABS via brake manipulation can do a bunch.

 

[wipster]

Here's what I had added to that original post after you quoted it. (thanks btw for moving it here)

This could be built as a "skateboard" and sold to trailer manufacturers.​

​

Add solar roof and a battery for reefers to power the Tesla heat pump based cooling unit. Fully integrated into the charging/regen circuit.​

The safety aspect of the motor for managing the trailer traction for a variety of situations might be worth the load loss of a couple of hundred pounds for additional mass. Or, Tesla could design the skateboard to weigh the same as existing designs.

FYI, there are at least two manufacturers of battery powered trailers in Europe right now. I linked to them in this thread early on. Worth a look! I'll see if I can find them and repost.

 

[wipster]

FYI, there are at least two manufacturers of battery powered trailers in Europe right now. I linked to them in this thread early on. Worth a look! I'll see if I can find them and repost.

Proof of concept:

Einride Trailer Comes With 350kWh Battery To Add 400 Miles Of Range

The Swedish freight technology company plans to have Einride Trailer production for initial piloting ready in 2023.

insideevs.com

DB Schenker Pre-Orders 2000 E-Trailers - CleanTechnica

DB Schenker has ordered 2000 e-trailers from Trailer Dynamics and Krone to help reduce fuel cost and emissions from its freight operations.

cleantechnica.com

 

[MC3OZ]

In relation to storing energy from regen while going down a steep grade:-

1. The battery should have a buffer and that buffer can be kept at the strategically right SOC, after factoring in the route.
2. The route planner should recommend when to charge keeping an optimal SOC for the scheduled trip.
3. The driver can use his experience to manage charge levels.

This list is about getting the battery and reserve charge level at the right number before beginning the downhill decent,

In addition they need to factor in the loss of 1-2 motors, the front motor is as powerful as a regular diesel engine, so it should be able to match normal engine braking.

The next step is having good brakes, keeping them cold as long as possible or using them in short bursts.

The the battery level is high, the system could alternate between a mixture or regen and normal braking while always giving the regular brakes a sufficient rest to allow them to cool down.

Excess energy from regen may be able to apply cooling to the brakes via a heat pump, or blow air over the wheels to cool the brakes.

I'm not sure if this list fully covers the problem in every situation, but the next step beyond this is probably upgrading the brakes or carrying an extra battery / super capacitator

 

[mongo]

If a conventional semi can survive the loss of a driveshaft, transmission, or clutch then Tesla Semi can survive the loss of all three motors (or amy similar subsystem).

 

[JusRelax]

Here's some nice Semi cold weather testing

 

[wipster]

From a TMC member's recent road trip...

 

[MC3OZ]

Emmet mentions the following Semi production targets:-

• 2023 - 10,000
• 2024 - 50,000

Emmet also expressed some doubt about hitting the 2023 target.

Cells might be one issue, one way or another Semi production is dependent on the 4680 ramp:-

• If the Semi uses 4860s, it is dependent.
• If the Semi uses 2170s, then alternative cells/pack need to be available for Model 3/Y.

10,000 per year is only an average of 28-30 per day, perhaps ramping to a peak rate of 50 per day .
Assuming 2 x 8 hour shifts, Just over 3 semis per hour or around 20 mins per semi.

Seems to me the Nevada line may be able to chase down the 2023 target.

And if there is a new line being built at Austin perhaps 2024 is the target for the start of production.

 

[FielderJones]

Here's some nice Semi cold weather testing

I wish he had some details about range. Fremont to San Diego was impressive, but what about Duluth to Chicago — in January?

 

[petit_bateau]

Emmet mentions the following Semi production targets:-

• 2023 - 10,000
• 2024 - 50,000

Emmet also expressed some doubt about hitting the 2023 target.

Cells might be one issue, one way or another Semi production is dependent on the 4680 ramp:-

• If the Semi uses 4860s, it is dependent.
• If the Semi uses 2170s, then alternative cells/pack need to be available for Model 3/Y.

10,000 per year is only an average of 28-30 per day, perhaps ramping to a peak rate of 50 per day .
Assuming 2 x 8 hour shifts, Just over 3 semis per hour or around 20 mins per semi.

Seems to me the Nevada line may be able to chase down the 2023 target.

And if there is a new line being built at Austin perhaps 2024 is the target for the start of production.

Those targets are more optimistic than I had pencilled in, and which I was beginning too think were also out of reach. However if the Sparks LRIP* prototype line is indeed sized for 10/week then that is only 0.5k in 2023 (see twtr below). So either there is a disconnect in those Tesla production targets that Emmet cites; or the LRIP line is more capable than suggested; or Tesla aim to have the client feedback and line-testing done PDQ and be into a much more automated facility (in Austin) by at least mid 2023. My guess is the target will get missed ... if only because of cell/etc supply constraints means it is better to take the slower and more cautious pathway:

* Low Rate Initial Production

https://twitter.com/x/status/1599189946086326272

 

[mongo]

Those targets are more optimistic than I had pencilled in, and which I was beginning too think were also out of reach. However if the Sparks LRIP* prototype line is indeed sized for 10/week then that is only 0.5k in 2023 (see twtr below). So either there is a disconnect in those Tesla production targets that Emmet cites; or the LRIP line is more capable than suggested; or Tesla aim to have the client feedback and line-testing done PDQ and be into a much more automated facility (in Austin) by at least mid 2023. My guess is the target will get missed ... if only because of cell/etc supply constraints means it is better to take the slower and more cautious pathway:

View attachment 881622

* Low Rate Initial Production

https://twitter.com/x/status/1599189946086326272

Or they copy paste the line(s?) they have in Sparks and add shifts.
If one line running one 5 day shift is 500/yr, ten lines with two shifts 5 day shifts is 10k.
3 shifts 7 days a week with 5 lines is also 10k.
And that is without efficiency improvements.

 

[JRP3]

If a conventional semi can survive the loss of a driveshaft, transmission, or clutch then Tesla Semi can survive the loss of all three motors (or amy similar subsystem).

Yet runaway semis happen, presumably when a clutch or driveshaft fails and the brakes can't handle the task.

 

[mongo]

Yet runaway semis happen, presumably when a clutch or driveshaft fails and the brakes can't handle the task.

My point being the standard to which Tesla Semi is held. Current tractors are not runaway proof.

That said, the brakes should be sufficient to stop a loaded semi at least once on a grade if cold and fully applied.
82k lbs at 60 MPH is less than 4kWh of energy.
49 CFR § 571.121 - Standard No. 121; Air brake systems.

 

[ecarfan]

Amazing specs on the Semi. It uses about 2kWh/m and goes 500 miles on a charge (fully loaded!) so the battery pack must be about 1,000kWh.

So I got that wrong. As @jhm noted, Elon has updated what was shown during the Semi launch presentation to say 1.7kWh/mile, meaning the pack is around 900kWh. I wonder why the 2kWh/m figure was used during the presentation?

Musk is clear that they are getting 1.7 kWh/mile.

One thing that has always been confusing about this discussion is the distinction between fully loaded efficiency and avg efficiency. A huge portion of driven miles is an unloaded return trip. So average efficiency is an average of loaded and unloaded trips.

When Musk says 1.7 kWh/mile, I suspect he is just talking about fully loaded. If so, the average efficiency could still be in range of 1.2 to 1.5.

I would assume the same; 1.7 is fully loaded. Which is impressive!

 

[Electroman]

I wish he had some details about range. Fremont to San Diego was impressive, but what about Duluth to Chicago — in January?

Just take a 40% hit in those cold, snowy, windy conditions.