Tesla Semi

[AudubonB]

1. I’ve moved a number of weather-related posts into here.

2. Winter driving conditions - slush and wind, for example - affect the fuel consumption, which is range, just as much for a truck driven by diesel or mule train as it does an EV. Until you get down into Arctic conditions, cabin heat is the only situation where a diesel rig, with all that waste energy having been converted to heat, easily can be repurposed, thus giving it the advantage over EV. The ameliorating factor here is in torrid situations, where it is the opposite: while both have to run the same reverse heat pumps, the diesel rig also has to combat the nascent engine heat, which seeps into the cab regardless of insulation.

3. In Arctic conditions, the picture is unclear. An EV needs to maintain pack temperature at a certain level - this we know. But a diesel rig also must idle 100% of the time, both to keep its diesel, crankcase oil and transmission fluid from turning to honey or worse, and to provide the cab with the necessary heat that only the engine can provide.

 

[MP3Mike]

3. In Arctic conditions, the picture is unclear. An EV needs to maintain pack temperature at a certain level - this we know. But a diesel rig also must idle 100% of the time, both to keep its diesel, crankcase oil and transmission fluid from turning to honey or worse, and to provide the cab with the necessary heat that only the engine can provide.

Don't forget that it also has to keep the DEF from freezing as well. (At least on a modern Semi.) Though some modern Semis also have APUs, Accessory Power Units, that can provide the necessary heat without idling the main engine. (Still diesel powered.)

But the overall impact isn't going to be as high as it is for a BEV car. The Semi is using ~6x the power of say a Model Y for locomotion, but it isn't going to need 6x the power to keep the cab warm. And that 6x power usage will provide more heat for the system to use for the battery/cabin/etc.

I don't know what it works out to in the end, but I expect the temperature related penalty to be significantly smaller than it is in a normal BEV car.

 

[khorton]

No challenging this, but this number seems too good to be true. Remember besides heating the cabin, there is also additional battery heating and the air resistance is higher due to denser cold air. The last one is the big factor between say 20F vs. 80F.

This probably belongs in the Semi thread.

As a point of reference, the air density at 20F is 12.5% higher than the air density at 80F, assuming the altitude is the same. So aerodynamic drag would be 12.5% higher, as would the power required to overcome that drag at a given speed.

 

[cpa]

BTW, for the return trip empty, 500 miles just requires 629 kWh of charge. So a 75% charge to return should suffice, whereas for the loaded trip you want to start with near 98% charge (just a little capacity for regen braking). This differential suggests that logistics firms will want to place more charging infrastructure and allow for more charging time near where they load trucks and less near where they unload. Of course if the loading area is at much higher elevation than the unloading areas, this could get reversed, but in that case, you're getting free energy from your load!

From my clients in the long-haul trucking industry:

Most truckers do not want to return empty. There is no money in driving an empty trailer. If the truck is for a large business (like Wal-Mart), either trailers are swapped out or reloaded with merchandise to be hauled elsewhere. If the truck is an independent company, then loads are arranged from other businesses or locations for the return trip (which may not necessarily be a straight line.) There may be a short leg where the trailer is empty or detached and the driver only has the tractor. But typically a trucker who leaves the Bay Area for Dallas will grab another load perhaps to Kansas City before getting a third load or trailer for a return trip via Denver or Salt Lake before receiving their final load destined for Sacramento. Then, he might return empty.

My son works for UPS. The feeder trucks (those are from major distribution centers) and the long-haul trucks are almost always full. Frequently the drivers meet in the middle to swap trucks and return to their point of origin so they go home at night and stay under the 11-hour mandate and keep their OT pay at a minimum.

Doubtless there are companies out there who might not return from a longish delivery loaded. But I suspect that most of them will be at least partially laden for most of the return trip.

Edited to add that I also had a client who was a truck broker. They arranged for trucking companies to haul loads to and from all sorts of businesses.

 

[MC3OZ]

I have had some additional speculative thoughts about what might be happening with Semi production.

1. Current production rate - It seems like Tesla is in no rush to ramp production, but the Semi is unique in that it requires some installation of MW charging to be useful.
1a. Charging a client premises - requires, solar, megapacks, MW charging to be installed - needs the components, permits, and the team to do the installs.
1b. Charing on the road needs installation of V4 Supercharging.

Without 1a or 1b the Semi can't charge anywhere at a rate which makes it overly useful, the production ramp probably can't outpace charger installation.

2. Likely Austin line.
The area at the south near the Cyberpond where the concrete has been removed seems like a possible location for an Austin Semi line, they haven't even got around to doing footers, but are probably preparing for construction.
Close to the main factory is likely, as less distance to transport parts, batteries etc.

My hunch is the Austin might start out building the 300 mile variant with 4680 cells, possibly LMFP 4680 cells.

Austin Semi production might start late 2023 or early 2024.

3. Sparks line.
This is clearly a pilot line and we will see on going changes to increase the run rate, they are trying to determine an optimal line configuration before designing the Austin line and will trail and refine some of the line equipment at Sparks.

I think 500 mile variants with 2170 cells are built at Austin for a few years, perhaps forever.

I don't know is the relative demand for 500 and 300 mile variants, perhaps the 300 mile market is higher volume,

Sparks semi production may or may not close at some time in the future.

The big challenge is ramping up the installation of solar. megapacks and MW charging at customer warehouses, solar installations for Semi customers would naturally take priority over domestic installations. Megapacks and MW charging are the priority, I can see these being done first at some sites with solar happening later.

 

[petit_bateau]

Do we know to what extent castings are involved in the Semi ? That also may make a difference in how fast they build them and when they start a new line. It may also be that there is a plan to shift to bigger / etc castings as the corresponding foundry capacity becomes available ....... and here I'm thinking of those 9000t IDRA presses.

 

[JRP3]

I don't think we've seen anything other than fairly traditional ladder frame construction on the semi and I don't expect to see castings. (Other than motor/inverter/gearbox.)

 

[mongo]

I don't think we've seen anything other than fairly traditional ladder frame construction on the semi and I don't expect to see castings. (Other than motor/inverter/gearbox.)

Agree, with the caveat that the ladder doesn't get twisted by a longitudinal engine/ transmission drivetrain.

 

[wipster]

This is too cool!

https://twitter.com/x/status/1600932546543767552

 

[Rammstein]

So that Thunderfoot YouTube channel is saying that the Tesla Semi only Carrie’s 1/4 the cargo. Any thoughts on this about how much cargo the semi can carry?

 

[MP3Mike]

So that Thunderfoot YouTube channel is saying that the Tesla Semi only Carrie’s 1/4 the cargo. Any thoughts on this about how much cargo the semi can carry?

For that to be true Tesla would have had to be making false claims, which seems highly unlikely.

i.e. Complete FUD:

https://twitter.com/x/status/1600903375444664320

 

[DarkandStormy]

So that Thunderfoot YouTube channel is saying that the Tesla Semi only Carrie’s 1/4 the cargo. Any thoughts on this about how much cargo the semi can carry?

Tesla could easily disprove if they just disclosed the weight of the Semi.

 

[MC3OZ]

So that Thunderfoot YouTube channel is saying that the Tesla Semi only Carrie’s 1/4 the cargo. Any thoughts on this about how much cargo the semi can carry?

Yes my thought is that Thunderfoot is an ignorant fool.

Tesla has already said the amount of cargo that can be carried is very similar.

 

[Electroman]

He is not ignorant. He is one of those TSLAQ scum who has made many such outlandish allegations against Tesla over the years.

 

[MC3OZ]

He is not ignorant. He is one of those TSLAQ scum who has made many such outlandish allegations against Tesla over the years.

It isn't specific to Tesla, he hates all renewable energy and new technology with a passion, he cherry-picks shallow talking points just like TSLAQ.

Occasionally he is right, because not all new technology ends up being commercially viable and some make product claims that are overhyped.

He isn't right often enough to be worth watching,

 

[mongo]

So that Thunderfoot YouTube channel is saying that the Tesla Semi only Carrie’s 1/4 the cargo. Any thoughts on this about how much cargo the semi can carry?

Claim is physically impossible.
Semi tractor trailer axel weight limits:
12k steering
34k drive tandem
34k steering tandem
+2k somewhere for an ev

Trailer is 10k

Absolute (and physically impossible) worst case:
Tractor is maxed out at 46k pounds
Trailer's 10k dead weight is all over its axle (to prevent overloading tractor axles).
Trailers remaining payload = 24k pounds (34 -10)
If that is 1/4 of ICE, an ICE can haul 96k pounds
Which it can't.

 

[wipster]

For all the Semi battery discussion, this is a superb tweet by @TeslaLarry (Larry Goldberg) refuting even more FUD.

https://twitter.com/x/status/1601576369728933888

 

[MC3OZ]

You can see from this video that Tesla is making the glass windscreen for the Tesla semi in house:-

We know that Tesla glass has good sound proofing and insulation.

We know that like the Cybertruck glass, the Semi windscreen is resistant to cracking and shattering.

What we don't know is:-

• Cost
• Weight

IMO the weight aspect of the Semi windscreen could be important, that is because I have a hunch that in spite of being bigger than a regular truck cab, the semi cab is lighter.

I expect some kind of lightweight skin over a cast aluminium frame, I'm not sure what the skin is, if it is a metal or if it could be another substance like fibreglass.

So ideally in spite of it's large size the Semi windscreen is surprisingly light. If it was too heavy, I think it would be smaller.
The footage of it being move on a kind of forklift suggests it is heavy, but there is no reason why Tesla would want humans carrying the windscreens around.

 

[mongo]

Ok, so my news feed sent me to this article which is casting shade on the 500 mile test. So I got ornery...

Shipped objects:
Only traceable clue: Grade GSN17-2

Which matches to Carbon Anode that arrives at Oakland USA Import data of Carbon Anode | Zauba

31 pallets per shipping container, container gross weight 23,055 kg = 50,721 - 8,159 lbs tare = 42,562 / 31 = 1,373 lb or 624kg per pallet which matches the 600kg net weight.

Trailer loading:
53 ft trailer, side post are 16 inch or 24 inch on center, depending on position. Dry Van Specifications - Utility Trailer
So pallets are about 48 inches which means 13 fit front to back if they pack them tightly.
Big question, how deep is the double stack at the front?

Visible pattern (from rear).
2,2,1,2,1,2, from the sidewalls, there is room for two more rows and one is a double, let's assume the other is a single (only 1.4k either way):
1,2
That results in 8 single stack rows with 13 pallets (3 voids), leaving 5 rows of 2 wide double stack = 20.
Grand total: 33 pallets, two more than an inbound shipping container and 45.3k pounds of cargo.
2,2,1,2,1,2,1,2,4,4,4,4,4
Add 10k for trailer, 55.3k
Subtract that from the 81k gross and the tractor is 25.7k pounds.
If the hidden row has 2, then tractor is 24.3k give or take.

They may have had a ~3k imbalance in the trailer vs drive axle loadings. I used 8k/2k for trailer tare.

 

[MC3OZ]

Add 10k for trailer, 55.3k

Wonder about this.

Specifically if Tesla is making the trailer, and has managed to shave 1-2K off the trailer weight.

So it might not be able to tow exactly the same weight using other trailers.

This might be one reason why the specs are not published, others will try to get a trailer to teardown and will copy the design.

I can see it being difficult to get hold of semis and trailers for teardowns, there may be a "gentleman's agreement" that buyers don't on sell them for a few years. By that time battery energy density improvements will close the hypothetical weight gap.