Everything We Know About the Tesla Semi

By Kevin Armstrong
Tesla's Semi will revolutionize the trucking industry
Tesla's Semi will revolutionize the trucking industry
Tesla

Tesla delivered its first production Semis on December 1, 2022, to its first customer PepsiCo. It was five years in the making; Elon Musk first introduced this idea to the world on December 14, 2017. With deliveries officially taking place, the Tesla Semi is on the right track to change the trucking industry and in the words of Musk: This is going to revolutionize the road, make the world a better place in a meaningful way.

The Semi Beginning

Elon Musk first mused about the Tesla Semi in his Master Plan Part Deux, which appeared on the company website on July 20, 2016. Under the header: Expand to Cover the Major Forms of Terrestrial Transport, the CEO went further than sedans and SUVs. "There are two other types of electric vehicle needed: heavy-duty trucks and high passenger-density urban transport.

Both are in the early stages of development at Tesla and should be ready for unveiling next year (2017)," wrote Musk. He also added, "we believe the Tesla Semi will deliver a substantial reduction in the cost of cargo transport while increasing safety and making it really fun to operate."

However, you could trace the Semi back even further. At the delivery event, Musk reminded everyone of the Tesla mission, “Our actual mission is to accelerate the advent of sustainable energy. So that is why we are making this wide range of cars that don’t really make sense from a brand standpoint traditionally, but makes total sense when you consider what is the mission of the company.”

The company stated there are 15 million passenger vehicles sold in the U.S. every year, but only a couple hundred thousand big rigs. But that small percentage of long haulers makes up 20 percent of U.S. vehicle emissions because they are large vehicles that are always being used. Musk also pointed out that more than one-third of articulate emissions are produced by semi-trucks.

Tri-motors and a 1,000-volt Powertrain

When Musk introduced the Tesla Semi in 2017, he compared it to current semi-trucks on the road today and to a $2 million supercar, the Bugatti Chiron. The first features the CEO talked about were performance, but not just any performance.

Instead, Tesla referred to it as BAMF Performance. I'll let you figure out the acronym. While the appearance alone will make the Semi a standout at truck stops, it's the performance that will change the trucking industry.

The Semi was initially going to have four independent motors; however, when delivered it was down to a tri-motor system, similar to the Model S Plaid. But don’t let that fool you. Senior Manager of Tesla’s Semi Engineering, Dan Priestley, explained why many people refer to the Semi as the beast.

“(It has) three times the power than any diesel truck on the road right now. So, you’ve got all the power you need to get the job done, but the other reason that it’s a beast is because it is efficient, you can go 500 miles on a single charge on one of these things. It’s the mix of those two - this is a game-changer. What’s awesome is both of those are enabled by our 1000-volt powertrain. This is the first vehicle we are doing with that.”

Tri-Motors and a Clutch

The tri-motor power train system has one motor that will carry the load the majority of the time, as it’s mainly for highway driving. That efficiency motor is approximately the size of a football. The other two are for torque and acceleration. Those motors use the system straight out of the Model S Plaid powertrain except the Semi can physically disengage two motors when they're not in use.

Tesla introduced a clutch that will automatically engage or disengage the two performance motors. According to Tesla, the clutch will automatically engage the performance motors when needed and it'll do it completely seamlessly. Instead of having the motors moving freely when not in use like the Model S Plaid, disengaging them results in even better efficiency. Priestly said, “These are clutched automatically, no driver input is needed. It is seamless.”

Semi Performance

Tesla Semi achieves 0 to 60 MPH in 5 seconds (20 seconds under a full load)
Tesla Semi achieves 0 to 60 MPH in 5 seconds (20 seconds under a full load)
Not a Tesla App

Musk commented on the Semi’s performance, “It looks crazy, it looks like an elephant moving like a cheetah.” When it was launched it was promoted as reaching 60 miles per hour in five seconds without a load. It can also reach 60 miles per hour fully loaded with the maximum 80,000 pounds gross vehicle weight in 20 seconds. As for up a hill with the full weight, current diesel trucks achieve 45 miles per hour at a 5% grade; the Tesla Semi will do 65 miles per hour at the same degree.

Semi Range and Efficiency

While the speed and acceleration are undoubtedly impressive and a considerable improvement over the current diesel trucks on the road, the range is the industry's most important factor. Tesla states that its Semis have a 500-mile range at maximum gross vehicle weight and highway speeds. This number is significant because 80% of trucking routes are 250 miles or less. "You can deliver a load out to the middle of nowhere and come back," said Musk.

It seems that this claim was the most in dispute. Bill Gates openly doubted the range in a blog post dated August 24, 2020. The Gates Notes stated: Even with big breakthroughs in battery technology, electric vehicles will probably never be a practical solution for things like 18-wheelers, cargo ships, and passenger jets. Electricity works when you need to cover short distances, but we need a different solution for heavy, long-haul vehicles.

Tesla set out to prove him wrong. They recorded an entire, unedited video of the Tesla Semi traveling 500 miles on a single charge. Luckily, they speed up the eight-hour video to a few seconds for the presentation, but it did show a long haul, with 82,000 pounds, going from Fremont to San Diego.

There are several advanced technologies at work to make this happen. The Semi's current efficiency is about 1.7kWh per mile, but Musk sees a way to make it even more efficient.

"We designed the Tesla truck to be like a bullet, whereas normal diesel trucks are designed more like a barn wall; this is a bullet," said the Tesla CEO. The Semi can generate the performance and the range due to the design. The drag coefficient or wind resistance of the regular diesel trucks is a .65 to .70. The Tesla Semi scores a 0.36, cutting the regular diesel truck drag in half and even beating the Bugatti Chiron score of .38.

The sleek nose and flat bottom are accompanied by side flaps that adjust to the trailer. These features help cut the drag and increase the range.

Charging the Semi

The Semi will be capable of charging much faster than ordinary EVs
The Semi will be capable of charging much faster than ordinary EVs
Tesla

Tesla nearly upstaged the Semi delivery by announcing what will be charging it. The new V4 Superchargers are capable of producing 1 MW DC. Musk explained, “to charge a truck like this quickly you need a high-powered charger. It’s our next-generation immersive cooling. It’s liquid-cooled, so you don’t need like a gigantic elephant truck of a cable, you can actually have a small cable, and that cable delivers a megawatt… We’ve 3x-ed the current density.”

Priestley, went further into detail, “This is pretty cool stuff. You’re actually immersing the conductor in the coolant. This water-based coolant that we have, we are doing some really neat isolation monitoring on the back end to ensure that it is safe and delivering what it needs to. But it means that we can really shove a lot of current in a very, very small place. So, for those who have charged their cars at a V3 Supercharger and the cable’s nice and maneuverable, it’s the same thing here, but now we’re just shoving a megawatt through it instead.”

Tesla wants the Semi to go from empty to 70 percent in 30 minutes. That time is vital to note because, in most jurisdictions, drivers must stop every six hours for a 30-minute break. The company says that the Semi will have added 400 miles in half an hour, which can last another six hours. Additionally, these chargers will be at destinations that would allow owners to charge the Semi while it is being loaded or unloaded.

Tesla Semi Unveiling

Displays and Software

The Semi's interior is most similar to the Model 3 or Model Y.

The Semi lacks an instrument cluster but features two horizontal displays, one to either side of the driver.

The right display appears to contain the traditional launcher we have in today's Teslas with access to music, phone, cabin temperature and more, while the left display contains truck-specific features at the bottom, such as tire PSI, trailer air supply and parking brake functions.

Although the software can be changed at any point, the best way to describe the vehicle's current software is to compare it to a Model 3/Y.

The Semi essentially takes the display of the Model 3 or Model Y, and splits it down the middle then puts those items on two separate displays.

The left display contains the speedometer, gear selector, battery indicators and the vehicle's visualization.

The Semi's interior features two horizontal displays
The Semi's interior features two horizontal displays
Tesla

The right portion of the display on a Model 3 which includes information such as maps and apps is displayed on the Semi's right display.

However, Tesla isn't taking up the entire display with these features. About one-third of each display appears to be reserved for always-on blind spot camera monitors.

Battery

Although Tesla hasn't released the exact size of the batteries in the Tesla Semi, they have released enough information for us to accurately assess its size.

Tesla has said that the Semi will achieve an efficiency of less than 2 kWh per mile (1.24 kWh per km). Tesla has also said that the Semi will have a range of approximately 300 or 500 miles.

With these two bits of information, we can speculate that the Semi will be available in two versions. A "Long Range" model that will have approximately a 1,000 kWh, or 1 MWh battery, and a "Standard" version with about a 600 kWh battery.

For comparison, a 2022 Model S contains a 100 kWh battery, so the Tesla Semi will have a significantly larger battery at 6x to 10x the size of its smaller cousin.

Having a larger battery will allow the Semi to charge faster than Tesla's current models since the current can be spread across more batteries.

The first Tesla Semi trucks will use the 2170 battery cell; the same one that is used in the Tesla Model 3 and the Model Y. However, it's expected the Tesla will eventually switch over to use their 4680 batteries once production improves.

Safety

The Semi comes with the same safety features as Tesla's existing vehicles, the same kind of standards that have earned Tesla countless accolades. The Semi has Enhanced Autopilot, Automatic Emergency Braking, Automatic Lane Keeping and Forward Collision Warning.

The company also believes that moving the driver seat to the middle of the vehicle makes the Semi safer if it is involved in a crash. It has a low center of gravity due to the battery pack's location at the bottom and middle of the vehicle. That is the same as current Teslas, reducing the vehicle's chance of rolling over. "Jackknifing is impossible," declared Musk. He said that due to the independent motors, the Semi would detect a jackknifing situation and adjust the torque to the wheels needed to keep the vehicle from skidding out of control. "Your worst nightmare is gone with this truck. Gone. You never have to worry about it."

Driver Experience

When it comes to the experience of driving a Tesla Semi, Musk summed it up best, "it's like driving a Model S or X or 3. It's just big." Today, big trucks on the roads can have anywhere from 10 to 18 gears . That's a lot of shifting. Operators of the Tesla Semi need to simply shift into drive. It's a lot less fatiguing and lets truckers focus more on the road.

The driver's seat is in the center of the expansive cockpit that is also tall enough that someone can stand in it. The videos and pictures have failed to show the sleeper cab portion of the vehicle. However, there is a significant amount of room behind the cockpit to house a sleeping area.

Reliability

At the unveiling, Musk made a shocking promise; he guaranteed that the Semi will not break down for a million miles. He was confident in that number because of the independent drivetrains. If one motor stops working, the others can pick up the slack. Musk said if just two of the motors were active, the Semi would still beat a diesel truck in performance.

Trucks put brakes to the test because they haul so much weight. But, again, like other Teslas, the brakes will be used as generators and put back energy into the battery. "Brake pads literally last forever," said Musk. Removing the internal combustion engine also means no transmission to maintain, emissions scrubber or differentials.

The Semi has thermonuclear explosion glass. Musk quipped, "it survives a nuclear explosion, or you get a full refund." He pointed out that, on average, semi-trucks' windshields crack at least once a year. Trucks are not legally allowed to drive with a cracked windshield in several areas worldwide. That means a single crack could park a trucker for an undetermined amount of time waiting to get fixed. The Tesla armored glass takes away that risk.

Just like other Teslas, the app will be available for the Semi. That feature includes remote diagnostics, predictive maintenance, location tracking, and connection to Tesla Mobile Service.

Cost of Ownership

The Semi can be charged while the vehicle is loaded or unloaded
The Semi can be charged while the vehicle is loaded or unloaded
Tesla

Trucking is a unique business. The costs are difficult to predict mainly due to the fluctuations in the cost of diesel and maintenance. When the Semi was unveiled in 2017, the diesel fuel price per gallon was $2.50; Five years later, it has more than doubled.

Tesla estimates that operators will save approximately $200,000 over three years because electricity is 2.5 times cheaper per mile. There will also be considerable savings by not having to leave the truck in the shop for routine maintenance and less time off the road for cracked windshields.

Aerodynamics and Drag Coefficient

The Tesla Semi has a drastically lower drag coefficient compared to other trucks
The Tesla Semi has a drastically lower drag coefficient compared to other trucks
Tesla

The Semi's aerodynamics produce even bigger cost savings if they operate in convoy. It's estimated a three-truck convoy averaging 60 miles per hour would cost $0.85 per mile. That price not only beats diesel trucks but also trains.

The Tesla Semi has a drag coefficient of just 0.36. This helps reduce wind noise and improve efficiency. A traditional diesel semi truck has a drag coefficient range between 0.65 and 0.70, while a Buggatti Chiron has a coefficient of 0.38. For comparison the Tesla Model 3, one of the most aerodynamics vehicles ever created, has a coefficient of 0.23.

Buyers

Big name companies were some of the first to put down a deposit. Walmart ordered 130 Semis, UPS purchased 125, Pepsi is waiting for 100, Anheuser Busch asked for 40, and FedEx has reserved 20.

Other names reported to have bought the Semi include Sysco, DHL, Ryder and Loblaws. It's believed that several independent truckers have also secured the Semi. Obviously, Tesla is using its Semi. The attention-grabbing technological breakthrough has been spotted delivering Tesla products to dealerships in California.

A Megacharger has been installed at the Pepsi facility in California as well. Expect more companies to jump on board as these impressive beasts start to be spotted on highways worldwide.

While Tesla has closed reservations, buyers in the United States may be lining up to get in once Tesla starts retaking orders. The Inflation Reduction Act announced in July could net Tesla Semi buyers upwards of $40,000 in incentives.

Tesla Holiday Update Wishlist - Charging & Safety Edition

By Karan Singh
Not a Tesla App

As December approaches, Tesla’s highly anticipated Holiday update draws closer. Each year, this eagerly awaited software release transforms Tesla vehicles with new features and festive flair. If you’re not familiar with Tesla’s holiday updates, take a look at what Tesla has launched in the Holiday update the past few years.

While leaked features like Blind Spot Monitoring While Parked hint at thoughtful improvements, the real magic lies in the unexpected. From potential features such as the Apple Watch app to a smart assistant, the possibilities are endless.

For this chapter in our series, we’re dreaming up ways Tesla could improve the charging experience and even add some additional safety features. So let’s take a look.

Destination State of Charge

Today, navigating to a destination is pretty straightforward on your Tesla. Your vehicle will automatically let you know when and where to charge, as well as for how long. However, you’ll likely arrive at your destination at a low state of charge.

Being able to set your destination state of charge would be an absolute game-changer for ease of road-tripping. After all, the best EV to road trip in is a Tesla due to the Supercharger network. It looks like Tesla may be listening. Last week, Tesla updated their app and hinted at such a feature coming to the Tesla app. A Christmas present, maybe?

Battery Precondition Options

While Tesla automatically preconditions your battery when needed for fast charging, there are various situations where manually preconditioning the battery would be beneficial.

Currently, there is no way to precondition for third-party chargers unless you “navigate” to a nearby Supercharger. If you need to navigate to a Supercharger that’s close by, the short distance between your location and the Supercharger will also not allow enough time to warm up the battery, causing slower charging times.

In Europe, you can navigate to and precondition for Qualified Third Party Chargers, but not for unlabelled ones.

Live Activities

While we already mentioned Live Activities in the Tesla app wishlist, they’d be especially useful while Supercharging. Live Activities are useful for short-term information you want to monitor, especially if it changes often — which makes them perfect for Supercharging, especially if you want to avoid idle fees.

Vehicle-to-Load / Vehicle-to-Home Functionality

The Cybertruck introduced Tesla Power Share, Tesla’s name for Vehicle-to-Home functionality (V2H). V2H allows an EV to supply power directly to a home. By leveraging the vehicle’s battery, V2H can provide backup power during outages and reduce energy costs by using stored energy during peak rates.

Tesla Power Share integrates seamlessly with Tesla Energy products and the Tesla app. We’d love to see this functionality across the entire Tesla lineup. Recently a third party demonstrated that bidirectional charging does work on current Tesla vehicles – namely on a 2022 Model Y.

Adaptive Headlights for North America

While Europe and China have had access to the Adaptive Headlights since earlier this year, North America is still waiting. The good news is that Lars Moravy, VP of Vehicle Engineering, said that these are on their way soon.

Blind Spot Indication with Ambient Lighting

Both the 2024 Highland Model 3 Refresh and the Cybertruck already have ambient lighting features, but they don’t currently offer a practical purpose besides some eye candy. So why not integrate that ambient lighting into the Blindspot Warning system so that the left or right side of the vehicle lights up when there’s a vehicle in your blind spot? Currently, only a simple red dot lights up in the front speaker grill, and the on-screen camera will also appear with a red border when signaling.

Having the ambient lighting change colors when a vehicle is in your blind spot would be a cool use of the technology, especially since the Model Y Juniper Refresh and Models S and X are supposed to get ambient lighting as well.

Tesla’s Holiday update is expected to arrive with update 2024.44.25 in just a few short weeks. We’ll have extensive coverage of its features when it finally arrives, but in the meantime, be sure to check out our other wishlist articles:

How Tesla’s “Universal Translator” Will Streamline FSD for Any Platform

By Karan Singh
Not a Tesla App

It’s time for another dive into how Tesla intends to implement FSD. Once again, a shout out to SETI Park over on X for their excellent coverage of Tesla’s patents.

This time, it's about how Tesla is building a “universal translator” for AI, allowing its FSD or other neural networks to adapt seamlessly to different hardware platforms.

That translating layer can allow a complex neural net—like FSD—to run on pretty much any platform that meets its minimum requirements. This will drastically help reduce training time, adapt to platform-specific constraints, decide faster, and learn faster.

We’ll break down the key points of the patents and make them as understandable as possible. This new patent is likely how Tesla will implement FSD on non-Tesla vehicles, Optimus, and other devices.

Decision Making

Imagine a neural network as a decision-making machine. But building one also requires making a series of decisions about its structure and data processing methods. Think of it like choosing the right ingredients and cooking techniques for a complex recipe. These choices, called "decision points," play a crucial role in how well the neural network performs on a given hardware platform.

To make these decisions automatically, Tesla has developed a system that acts like a "run-while-training" neural net. This ingenious system analyzes the hardware's capabilities and adapts the neural network on the fly, ensuring optimal performance regardless of the platform.

Constraints

Every hardware platform has its limitations – processing power, memory capacity, supported instructions, and so on. These limitations act as "constraints" that dictate how the neural network can be configured. Think of it like trying to bake a cake in a kitchen with a small oven and limited counter space. You need to adjust your recipe and techniques to fit the constraints of your kitchen or tools.

Tesla's system automatically identifies these constraints, ensuring the neural network can operate within the boundaries of the hardware. This means FSD could potentially be transferred from one vehicle to another and adapt quickly to the new environment.

Let’s break down some of the key decision points and constraints involved:

  • Data Layout: Neural networks process vast amounts of data. How this data is organized in memory (the "data layout") significantly impacts performance. Different hardware platforms may favor different layouts. For example, some might be more efficient with data organized in the NCHW format (batch, channels, height, width), while others might prefer NHWC (batch, height, width, channels). Tesla's system automatically selects the optimal layout for the target hardware.

  • Algorithm Selection: Many algorithms can be used for operations within a neural network, such as convolution, which is essential for image processing. Some algorithms, like the Winograd convolution, are faster but may require specific hardware support. Others, like Fast Fourier Transform (FFT) convolution, are more versatile but might be slower. Tesla's system intelligently chooses the best algorithm based on the hardware's capabilities.

  • Hardware Acceleration: Modern hardware often includes specialized processors designed to accelerate neural network operations. These include Graphics Processing Units (GPUs) and Tensor Processing Units (TPUs). Tesla's system identifies and utilizes these accelerators, maximizing performance on the given platform.

Satisfiability

To find the best configuration for a given platform, Tesla employs a "satisfiability solver." This powerful tool, specifically a Satisfiability Modulo Theories (SMT) solver, acts like a sophisticated puzzle-solving engine. It takes the neural network's requirements and the hardware's limitations, expressed as logical formulas, and searches for a solution that satisfies all constraints. Try thinking of it as putting the puzzle pieces together after the borders (constraints) have been established.

Here's how it works, step-by-step:

  1. Define the Problem: The system translates the neural network's needs and the hardware's constraints into a set of logical statements. For example, "the data layout must be NHWC" or "the convolution algorithm must be supported by the GPU."

  2. Search for Solutions: The SMT solver explores the vast space of possible configurations, using logical deduction to eliminate invalid options. It systematically tries different combinations of settings, like adjusting the data layout, selecting algorithms, and enabling hardware acceleration.

  3. Find Valid Configurations: The solver identifies configurations that satisfy all the constraints. These are potential solutions to the "puzzle" of running the neural network efficiently on the given hardware.

Optimization

Finding a working configuration is one thing, but finding the best configuration is the real challenge. This involves optimizing for various performance metrics, such as:

  • Inference Speed: How quickly the network processes data and makes decisions. This is crucial for real-time applications like FSD.

  • Power Consumption: The amount of energy used by the network. Optimizing power consumption is essential for extending battery life in electric vehicles and robots.

  • Memory Usage: The amount of memory required to store the network and its data. Minimizing memory usage is especially important for resource-constrained devices.

  • Accuracy: Ensuring the network maintains or improves its accuracy on the new platform is paramount for safety and reliability.

Tesla's system evaluates candidate configurations based on these metrics, selecting the one that delivers the best overall performance.

Translation Layer vs Satisfiability Solver

It's important to distinguish between the "translation layer" and the satisfiability solver. The translation layer is the overarching system that manages the entire adaptation process. It includes components that analyze the hardware, define the constraints, and invoke the SMT solver. The solver is a specific tool used by the translation layer to find valid configurations. Think of the translation layer as the conductor of an orchestra and the SMT solver as one of the instruments playing a crucial role in the symphony of AI adaptation.

Simple Terms

Imagine you have a complex recipe (the neural network) and want to cook it in different kitchens (hardware platforms). Some kitchens have a gas stove, others electric; some have a large oven, others a small one. Tesla's system acts like a master chef, adjusting the recipe and techniques to work best in each kitchen, ensuring a delicious meal (efficient AI) no matter the cooking environment.

What Does This Mean?

Now, let’s wrap this all up and put it into context—what does it mean for Tesla? There’s quite a lot, in fact. It means that Tesla is building a translation layer that will be able to adapt FSD for any platform, as long as it meets the minimum constraints.

That means Tesla will be able to rapidly accelerate the deployment of FSD on new platforms while also finding the ideal configurations to maximize both decision-making speed and power efficiency across that range of platforms. 

Putting it all together, Tesla is preparing to license FSD, Which is an exciting future. And not just on vehicles - remember that Tesla’s humanoid robot - Optimus - also runs on FSD. FSD itself may be an extremely adaptable vision-based AI.

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