JB Straubel Discusses Tesla Semi, Says Its Like Model S Times 4

Tesla Semi


Take the Model S, double it and then double it again. End result is basically the Tesla semi.


The Tesla Model S P100D

That’s how Tesla chief technical officer JB Straubel described the Tesla semi during his keynote speech at the Midwest Renewable Energy Association’s Annual Energy Fair last weekend in Wisconsin.

Here’s Straubel’s quote

“It may not be intuitive to everyone, but the same technology that’s in the Model S can be scaled up. In fact you can just kind of double it and double it again, you can scale it to vehicles that are much much bigger.”

We already knew that the Tesla semi would make use of existing Tesla parts. In fact, Tesla CEO Elon Musk made this known not too long ago:

“No, we will manufacture that ourselves. Most of that semi is actually made out of Model 3 parts by the way. It’s actually using a bunch of Model 3 motors, without revealing too much about the future of it, so we are able to use a very high volume vehicle, and then combine several motors to have (pause) I think it’s actually going to have a very good gross margin like…not something that the other…it’s like you can’t do that with a traditional truck. So effectively (the Semi-Truck) was just a very compelling product that has low unit cost.”

It now sounds like the Tesla semi will repurpose more and more existing Tesla parts.

Take some S, add a bit of X and some 3 and the result is the Tesla semi, which will be fully revealed in September 2017.

Source: Teslarati

Categories: Tesla, Trucks

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45 Comments on "JB Straubel Discusses Tesla Semi, Says Its Like Model S Times 4"

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So, 4 charging ports?


You win the internet for today.

Joke, but maybe not…. A much larger battery pack could benefit from multiple charge ports (as long as the system is able to handle the required communication between battery modules)

I’d imagine that they wouldn’t need to do that though if there are special semi superchargers that can handle higher kWh charging speeds (350/400+?)

“…special semi superchargers that can handle higher kWh charging speeds (350/400+?)”

Or even 500 kW, like Proterra’s EV bus charger… or possibly even more.

Yeah, the idea of a BEV semi tractor charging at a standard Supercharger station, looking like a spider with something like 4-16 charging cables all plugged into a single vehicle, is a silly idea which an astounding number of people have suggested. Nobody is going to engineer a BEV semi tractor that way. And if they did, can you imagine the outrage from Model S/X drivers from a single vehicle hogging that many Supercharger cables all at once?

I’d like to suggest, in what I hope is a civil manner, that people suggesting that have not really thought the idea through.

They have to load and unload at each end, time for charging. I can think of several places where freight comes in a sea port and has to go inland to warehouses.

You don’t have superchargers and likely not even enough electric power at every random ramp in random warehouse you need to unload to. What you end up with is small niche of short range trucks for fleets. Most of the short range class 8 trucks are used long and medium range trucks that are too old and unreliable to be sent cross country, and as they are short distance, they may be drive that many miles to recoup initial investment into expensive battery and new truck.

400kWh battery?

Nobody knows outside Tesla. If Tesla’s BEV semi really is to have a 600-750 mile range, which it would need for truly long-distance trucking, then estimates range from 1200 kWh to 1800 kWh.

More modest estimates assume only short- to mid-range delivery routes, where 400 kWh or even less might suffice.

The various statements from Elon about just what kind of semi tractor Tesla will make seem rather contradictory, at least to me, so I personally am no longer trying to make any guess or prediction of what we’ll see.


All joking aside, diesel semi tractors typically have twin fuel tanks, and often use two fuel hoses to fill them simultaneously. Saves time.

On the other hand, Proterra’s 500 kW EV bus charging system uses a single blade for its charging system, not multiple contacts. Of course, using a blade rather than plugs gives it more surface area to carry the current. There’s obviously an analogy to be made between a larger surface area connecting the charger, and larger total cross-section of using two hoses at the diesel truck stop instead of just one.

Here is how they solved the charging for the BEV ferries between Sweden (Helsingborg) and Denmark (Helsingör). 5 km distance with ferries leaving every 15 minutes taking ~1200 passengers plus a number of vehicles.


Not that it is super relevant, just that it is cool with huge BEV vehicles of all kinds. 😉 And that I like robots 😛

Wow, they use a giant, complex and obviously expensive robot arm — like the ones in Tesla’s auto assembly plant — just to plug in the oversized charging cable?

I think Proterra has a much better design, with a simple (and obviously much less expensive) mechanical arm which extends over the charging port.

I realize that on a ferry, the arm has to deal with motion in more dimensions, but still, that seems like absurdly expensive overkill in using something complex and expensive for a mechanically simple task.

WOW …peterbilt, Mack, Volvo and all other diesel manufacturers are on notice Tesla is coming to take your lunch LOL and make our planet a cleaner place. I can’t wait to see Tesla semis on the road and not put up with a dirty cloud of toxic diesel exhaust.

Go Tesla Go!

I could be wrong but how I read this is, if the semi-truck used a 100kwh battery pack like on the Model S but it could just take multiple packs. And if each pack could take it’s own supercharger connection then having 4 or even 8 of these packs (and as many supercharger connections as packs) then it would just work.

I’m not sure how they’d hook up multiple SC connections to a semi-truck but maybe they’ve solved this problem? How about having some extension cable that can take supercharger connections and then that plugs into the semi-truck? Semi truck wouldn’t need to be directly outside the stalls.

The Semi would likely charge at a truck stop or warehouse, not a general purpose SC stall.

So they can pack as many plugs as they want in that application.

One would have to ask why they wouldn’t use PowerPacks for this application with a custom high current plug.

“One would have to ask why they wouldn’t use PowerPacks for this application…”

Because PowerPacks are not intended for use in EVS, are not engineered for the high power output needed for a heavy truck, and almost certainly use a different cell chemistry than is used in Tesla’s cars.

Using multiple Model 3 packs in a semi would make much, much more sense.

Agree with that Mister G

So, 8 drive motors and a 400kWh battery? It certainly would have enough torque/power, but what about range? I vaguely remember an estimate of 0.5 miles/kWh, so that would only be 200 miles of cruising range. Certainly not enough for long-haul trucking, but I bet there are tons of applications for a 200-mile Semi.

I was coming here to ask the exact same thing ( 8 wheel drive, 400 kWh?).

The one area of Tesla expertise that could change the driving range is aerodynamics. Once at speed on the highway, this is the dominating power requirement. If you could cut the CdA in half, the higheay range could surprise some. The current Teslas are all better at highway range than city range.

Full self driving capability is also the long term value proposition.

“The one area of Tesla expertise that could change the driving range is aerodynamics. Once at speed on the highway, this is the dominating power requirement.”

Unfortunately a commercial semi has to be able to haul a standard trailer, and you can’t do much with the aerodynamics of that. Well, you can install “skirts” and a “boat-tail” to reduce drag, but that means a lot more time require to hook up a trailer and drop it off, plus a requirement to only do so where there is a stockpile of skirts and boat-tails.

Now, if Tesla can use its own specially designed trailers, then things get interesting in the efficiency department. But that would severely limit the market for such BEV semi tractors.

“Once at speed on the highway, this is the dominating power requirement.”

Not exactly. In general, that is true. But in a low air drag car that happens to be very heavy, the so called 50/50 split where rolling resistance and aerodynamic drag cross over point is about 55mph.

A semi might have a large FA but it can have much lower Cd since its length helps.

That is why most trains and airplanes have far lower Cd than most passenger vehicles.

I don’t see why they’d need 8 drive motors. 4 should be plenty.

Only 4 M3 motors to push an 80,000 lb. truck up a mountain at highway speed?

In previous comments, Elon Musk said they’d use 2, 4, or 6 Model 3 motors for the BEV semi tractor. I haven’t done the math, but my gut feeling is that 4 motors would not be sufficient to accelerate an 80,000 lb. fully loaded semi truck up a mountain grade at highway speed. 6 motors sounds more reasonable. Only 2 motors sounds more like a mid-sized truck, not a semi… unless it’s just a “yard mule” semi tractor intended only for low-speed work on flat ground.

If Model 3 motors are capable of at least 300HP, then 4 of them are 1,200 HP. Even if they are only 200HP each, 4 of them are 800HP which is more than comparable to the current diesel semi we have on the market.

The only problem is heat. At those peak operating power level, the electric motor will over heat. So, unless they can cool them, it will be very difficult to operate at those power level. By having more motors, it will reduce heat dissipated at each motor which making cooling design much easier.

An electric motor can easily operate at higher power level if the heat can be removed.

“Even if they are only 200HP each, 4 of them are 800HP which is more than comparable to the current diesel semi we have on the market.”

My error. Thanks for doing the math!

Actually, the HP favors the electric motors even more than the HP rating indicates, since electric motors are rated for continuous power, and ICEngines are rated at maximum power.

“Take some S, add a bit of X and some 3 and the result is the Tesla semi”

I want my semi with falcon wing doors and a 0-60 under 3 seconds…fully loaded!

I swear, the packages looked like this when they loaded the truck too.

I really like the way Tesla repurposes things like this. Also: multi purpose controller boards, using charging modules in car and in superchargers, powerwall and powerpack modules. There probably a lot more.

It’s because they are software guys designing hardware systems.

Write one piece of code that works really well, copy -> paste. (Create new instances is the more accurate analogy in OOP now)

This mindset is the real difference between Tesla/SpaceX and the existing competitors.

And the battery pack times twelve?

400 kWh would be lousy, a local delivery truck. Well, it is nice if they offer different battery pack configurations, maybe even the possibility to change the pack depending on current needs.

But largest battery pack needs to be in the ~1200 kWh proximity.

At worst I presume 0.66miles/kWh. That’s 800 mile range. No one should drive that long without a break.

There are cases where a single driver will drive a diesel semi for 800 miles in a single day; that’s the maximum, and anything over ~750 miles is pretty rare. But it doesn’t matter much that they get to stop for lunch and (I think) a couple of breaks during the shift, unless they time the stop(s) to coincide with the location of BEV truck stops for fast-charging or battery swapping.

It is not about what you should do. It is about what you can do.

Tesla will have to show the way by making vehicles that excites and breaks the limits of EVs.

Then if everyone wants the 400 or 800 kWh pack and 1200 is too much then fine. But show them that you can.

Be on the lookout for semi trucks in California with camouflage paint jobs or parked at Tesla Superchargers with a car cover on, with a lot of extension cords.


Sounds like Kindergarten explanation.
Double and double, and then what? 200 mile roundtrip truck that can’t extend range as nobody doubled electric grid and charging speed?

Well, assuming 4X a model S would be around 400 kwh. If they charged at a typical supercharger (which has basically proven itself fairly reliable by now), it should take only a little over 4 hours to get a new full charge, in moderate weather at least, since the SC can go at 115-120 kw. A small “charger optimiser’ could be standard in the semi to charge at a constant high rate, rather like passenger cars do today at 7 kw.

I’d assume Tesla would basically sell the trucking company a few supercharger bays so they can charge up a few trucks at the depot.

Anyone thought about posibility that Tesla designes not only tractor with motors and battery pack, but also a trailer with some kind of battery pack?
I think this solution could compensate increased energy consumption while towing a trailer, and maybe in this way you could have kinda unlimited distance when towing such trailers.

Yes, we have considered it and thrown the idea away.

The probem with this approach is you need to build loads of different kinds of trailers, test them, certify them etc…

Containers, refrigerated, car transporter, dry goods, tanker, flatbed, animal transport.

Trucks just come in a lot of different shapes and sizes, but most of them use pretty similar tractor units, better to build something as flexible as possible so as to capture as much potential market as possible with the one design.

JorgosZ asked:

“Anyone thought about posibility that Tesla designes not only tractor with motors and battery pack, but also a trailer with some kind of battery pack?”

Suggested many times, but never by someone with knowledge of the semi trucking industry.

The one authoritative post I’ve seen posted to InsideEVs on the subject said that trucking companies typically keep IIRC about 5-6 trailers around for every tractor. That alone kills the cost/benefit equation.

More generally, trailers are meant to be cheap and interchangeable. Putting an expensive battery pack in trailers is a non-starter.

So a 68″ screen? 😀

I can see autonomous Tesla semis putting many long haul obese diabetic drivers out of work LOL

Tesla’s Battery as Service (BAS) will take a big chunk of semi-truck market share in US …