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Tesla Semi truck’s battery pack and overall weight explored
The big question on everyone’s mind–at least on the minds of those who understand the freight transportation industry–is how much the Tesla Semi might weigh. If Tesla’s all-electric semi truck is to be competitive at all, it must be capable of carrying the same loads as current-use semi-trucks in the Class 8 field do.
A big point of contention from nay-sayers and those in the trucking industry who understand logistics was the lack of announcement of the Tesla Semi’s actual weight. Plenty of press was given to the much-touted “80,000-pound capacity” number bandied around by CEO Elon Musk during the truck’s unveiling late last year. That number, however, refers only to the gross vehicle weight (GVW) of the Tesla Semi and is, in fact, exactly the same number used by every Class 8 truck on the road. They’re called Class 8s, in fact, because the 8 refers to that 80,000-pound total vehicle capacity.
What wasn’t given by Tesla was the gross vehicle tare weight (GVTW) of the Semi. This is a far more important number. Where the GVW gives the total capacity of the truck in terms of how much its freight plus the truck itself can weigh, the GVTW gives just the weight of the truck, sans trailer and freight. This number tells logistics experts how much actual freight and trailer the truck can haul legally.
For example, a typical “day cab” configuration 18-wheeler with a diesel engine weighs roughly 32,000 pounds with a relatively lightweight box trailer attached and full fuel tanks. That leaves about 48,000 pounds of freight capacity for the truck. That’s important because, although the truck won’t be loaded to capacity every time, it will be expected to be capable of carrying up to about that weight. Most big rigs on the road are capable of hauling 44,000 or more pounds worth of freight, depending on configuration and trailer type.
Having experience with driving commercial trucks in the past, once hauling a refrigerated trailer that had a freight capacity of 44,500 pounds, I learned that some industries count on freight capacity as part of their logistics costs and will literally fill a truck to its maximum in order to minimize those costs.
In logistics, weight and total freight capacity are highly important metrics in the overall scheme.
What We Know
Thinking about that, then, let’s look at what we know of the Tesla Semi and its potential weight. We know that the truck uses four independent electric motors that are derived from the Model 3, that it has an energy consumption of less than 2 kWh per mile, and that it can be charged to up to 400 miles in about half an hour. We also know that Elon promised 300 to 500 miles of range in total. On that latter point, it’s pretty clear that a “lower range, cheaper option” will be offered as has been done with most of Tesla’s vehicles to-date. So we can assume a 300-mile version and a 500-mile version will be forthcoming for the Semi.
We also know that the Tesla Semi had eight ports in its charging plug array. We saw this at the unveil in some close-up photos.
It’s clear to us that even if the Tesla Semi isn’t to become a big player in the trucking industry, the idea behind it will change things forever.
What We Don’t Know
What we don’t know is whether Musk and Co have something up their sleeves for the batteries. Much of the speculation regarding the Tesla Semi has been in regards to Tesla Semi’s massive battery pack.
In actuality, having a huge battery breakthrough on a vehicle like the Tesla Semi would not necessarily be a good thing for business. If there is a huge breakthrough, then all bets are off and most of our speculation in this article is moot. That would, however, mean that the sales potential of the Semi would be far lower than it would be otherwise because one thing that logistics companies and fleet managers aren’t interested in are flashy new, breakthrough, and (most importantly) untested, unproven technologies.
To a fleet manager, those phrases mean “breaks often, expensive to fix” and the potential positives will be ignored because of that. No one who wants to keep a job as a fleet manager or logistics purchaser will gamble on something unproven. Like new battery technology for a truck whose primary cost will be in its batteries. Likewise, unless there is a clear benefit in some terms other than pure business (like marketing or potential tax breaks), no board of directors will risk shareholder wrath on new tech either.
Close-up look at Tesla Semi’s drivetrain from underneath
We can say, as a side note, that most of the orders that have been placed for the Tesla Semi thus far are from corporations and companies who are doing business in areas where the marketing bonanza and potential tax incentives for laying down those relatively low-cost deposits are immense. Most of the companies involved have already invested heavily (and very publicly) in alternative fuel options outside of Tesla over the past few years. We also note the timing of both the Tesla Semi’s announcement (and order-taking) and the before-2018 rush by potential customers to put in deposits.
We reiterate that our not knowing if Tesla has some kind of big battery breakthrough announcement is a big “if” in our analysis here.
What People Smarter Than Us Have Said
Some people who know more than we do about things like math and engineering science have crunched the numbers on the Tesla Semi’s battery potentials. Over at Engineering.com, John Ewbank broke the results down into layman format. Here’s the gist.
If the Tesla Semi uses 2 kWh to travel a mile, then a 500-mile range means 1,000 kWh of power. That is not the actual size of the battery, though, as the charging requirement would preclude a huge pack.
In order to get 400 miles in thirty minutes of charging, Ewbank notes, the charger would have to be 1.6MW to achieve the 800kWh of promised charge in only 30 minutes. Charging at that rate is not possible because the result would be arching in the pack, which would surely be akin to the next Boring Company Flamethrower meme when Semi trucks begin to explode in flames during charging as a regular event. So the charging has to be split up.
Tesla Semi Megacharger port could support 1 MW of power.
The answer is simple, of course, and may explain the strange layout of the eight-port charging hub shown on the Semi at its unveil: there are four battery packs.
Instead of one big pack, four smaller packs (one for each motor, even) are used and are thus charging separately from one another, but simultaneously. Based on Tesla Semi’s Megacharger port configuration, this would likely mean that four of them are positive sides and the other four are grounds. Allowing for a single, huge wire to be plugged into each. The controls for the charging system interface may be plugged in separately (perhaps the oval-shaped black thing to the side?).
What This Adds Up To
We add up that bit of information plus what we know about the truck and get an estimated weight. Using the current weight of a Tesla Model S battery pack at 540kg per 90 kWh, we can do some simple math to estimate the Semi’s batteries would weigh about 6,000 kg. We aren’t sure about the new battery weights for the upcoming battery updates, but we can assume a 10-15 percent reduction from several factors (storage density, improvements in chemistry, packaging lightening) without being too aggressive or overly optimistic. Going with the fifteen percent reduction, that 6,000 kg drops to 5,100 kg. That’s about 11,244 pounds.
A conventional tractor, as we’ve said, has a tare weight of around 32,000 pounds when fully fueled and with a lightweight box trailer in place. Remove the trailer and the truck itself is about 22,500 pounds. It’s difficult to then go to just the weight of the powertrain components and fuel, but they’re considerably less than 11,000 pounds in all.
Tesla Semi spotted doing a tire-shredding acceleration run down in the wild
Looking at the shipping weight for a crated engine and transmission for a Class 8 truck, we can see that they weigh about 8,000 pounds on average. Add in fuel and other components and another 1,500 pounds (at most) are put on the truck. We then assume that the rest of the truck (framing, braking systems, air compressor, etc) are about the same for the Tesla Semi in order for it to meet Class 8 standards. So we call those a wash.
That means that the Semi, under our estimates, is roughly two tons heavier than would be a standard day cab big truck in the Class 8 category. This means the Semi would be that much less capable in terms of freight hauling that’s offset by its unprecedented all-electric performance. That amount, however, is probably not enough to stop the primary buyers of a day cab truck like this from balking at a purchase. The weight difference alone would be repaid in potential fuel savings, tax incentives, green marketing, and maintenance costs.
The trouble will come with cost differences. If the ROI is not there, most logistics buyers won’t write any purchase orders. But at least we can say that as far as we can tell, the weight differences of the Tesla Semi alone aren’t going to be a huge bar against entry into the trucking industry.
Investor's Corner
Tesla Robotaxi gets a massive upgrade in Nevada
Nevada regulators just approved a massive expansion of Tesla’s robotaxi fleet across the entire county.
Tesla’s robotaxi footprint in Nevada just grew by roughly 500 times in a single regulatory vote.
The Nevada Transportation Authority approved Tesla’s full Autonomous Vehicle Network Company permit on Thursday, clearing the way for the company to deploy up to 5,000 driverless vehicles across Clark County over the next 12 months. The decision came during a four hour general session meeting that Tesla investor Sawyer Merritt watched live and reported on X, noting the vote replaces the interim order that had limited Tesla to just 10 robotaxis on a narrow stretch of the Las Vegas Strip.
EXCLUSIVE: Tesla has just officially received approval for its full Autonomous Vehicle Network Company permit in Nevada, clearing the way for Tesla to launch a paid public Robotaxi service in Las Vegas.
This officially allows @Tesla to deploy up to 5,000 robotaxis over the next… pic.twitter.com/DPs5UtUlrE
— Sawyer Merritt (@SawyerMerritt) August 20, 2026
That earlier cap, covered here after it surfaced on August 13, came with restrictions that looked stricter than what Tesla runs in Austin: a 45 mph speed ceiling, no airport pickups, and a geofence confined to the Strip corridor. The new approval extends Tesla’s operating authority to all of Clark County, with room to request an even wider geofence across the state.
Tesla representatives at the meeting said they have no intention of putting 5,000 cars on the road right away. Commercial rides are expected to start within 30 days, pending vehicle inspections, insurance filings, and fare approval, the standard steps every robotaxi operator in Nevada has had to clear.
Tesla’s own Robotaxi account replied to the news with a short line, The golden future is upon us.
The timing lines up with Tesla’s broader robotaxi push this month. The company is preparing to open Cybercab rides to the public in Austin as soon as this month, and it opened a sweepstakes for riders to win a seat at the launch event. Tesla filed its original application for a 5,000 vehicle Nevada fleet back in June, a request regulators trimmed to 10 vehicles when they issued the interim order in July. Thursday’s vote effectively grants the number Tesla asked for from the start.
Zoox, the Amazon owned robotaxi operator, has run in Nevada since 2025 and was capped at 100 vehicles before Thursday’s decision. Tesla’s new ceiling puts it well ahead of that comparison on paper, though the company has said its actual fleet size will depend on how quickly FSD v15 rolls out, the software update executives have called the gateway to scaling unsupervised robotaxi operations nationwide.
Tesla welcomed JPMorgan analysts to one of its factories earlier this month, with the Wall Street firm highlighting its findings in a new note to investors. One of the more pertinent pieces of information is that Tesla admitted to slowly integrating Model Y vehicles into its Robotaxi fleet, but it has a good reason.
JPMorgan analysts recently toured Tesla’s Fremont Factory and met with the company’s investor relations team, emerging with a clearer picture of the automaker’s Robotaxi strategy. According to the bank’s note, Tesla is intentionally limiting the addition of Model Y vehicles to its existing Robotaxi fleet.
The firm’s analysts said:
“Tesla indicated it is intentionally holding back on adding Model Y units to the robotaxi fleet, expressing confidence in its ability to scale Cybercab in the near-term. On FSD V15, Tesla views this release as a step-change in performance, comparable to the leap from V13 to V14. The V15 upgrade encompasses seven core technologies, with ~40% of those currently being tested in the robotaxi fleet, where initial feedback has been encouraging.”
JPMorgan after meeting with Tesla recently in Fremont:
“Tesla indicated it is intentionally holding back on adding Model Y units to the robotaxi fleet, expressing confidence in its ability to scale Cybercab in the near-term. On FSD V15, Tesla views this release as a step-change… pic.twitter.com/W9yGCWRT3C
— Sawyer Merritt (@SawyerMerritt) August 20, 2026
Far from signaling delays or doubts about autonomy, the move reflects strong management confidence in the near-term scalability of the purpose-built Cybercab.
Tesla has operated its Robotaxi service primarily with modified Model Ys since launching in Austin and expanding to other markets. Yet the company is now deliberately holding back further Model Y conversions. The rationale is straightforward: leadership believes the Cybercab, a two-seat, steering-wheel- and pedal-free vehicle optimized for high utilization, can ramp production and deployment more efficiently in the coming months.
This dedicated form factor promises better unit economics for the majority of rides, which typically involve one or two passengers, while freeing consumer Model Y inventory for retail sales.
Supporting this pivot is Full Self-Driving (FSD) software version 15, which Tesla describes as a genuine step-change in performance, comparable to the leap from V13 to V14. The update incorporates seven core technologies; roughly 40 percent are already undergoing real-world testing in the current Robotaxi fleet, with early feedback described as encouraging.
Tesla is carefully managing software development to minimize regressions in core driving functions as new capabilities are added. Management positions V15 as the primary gateway to scaling unsupervised FSD. Importantly, the existing AI and Hardware 4 stack is already capable of running V15 and supporting unsupervised operation.
Cybercab itself is only the first vehicle on the platform. Tesla reiterated that additional form factors will follow, pointing to concepts such as the earlier “Robovan” demonstration as examples of how the architecture can evolve.
Tesla’s mysterious Robovan makes a sneak peek with Optimus in Terafab video
Parallel progress continues on the Optimus humanoid robot, which remains on track for start of production in the coming months, with commercial sales possible as early as the second half of 2027. Generation 3 details will be revealed closer to production to preserve competitive advantages, while Generation 4 scope will draw on real-world Gen 3 experience.
JPMorgan left the meeting with a deeper appreciation for Tesla’s manufacturing automation and maintained its $475 price target. The decision to slow Model Y Robotaxi integration is therefore not a setback but a calculated prioritization of a more efficient, purpose-built solution that management believes is ready to scale.
SpaceX CEO Elon Musk announced today that the company will likely attempt to catch the Starship upper stage with its launch tower arms “in a few months.”
In a post on X, Musk wrote, “Looks like we will probably catch the ship with the tower in a few months. If there had been a tower out to sea where we practiced landing the ship, it would have been caught.” He added that the first reflight of a Starship vehicle is expected by the end of 2026 or early 2027, describing it as “a fork in the road of history for consciousness reaching the stars.”
Looks like we will probably catch the ship with the tower in a few months. If there had been a tower out to sea where we practiced landing the ship, it would have been caught.
First reflight of the ship will be either end of this year or early next. That will be a fork in the… https://t.co/O5g9pqrzyo
— Elon Musk (@elonmusk) August 20, 2026
Musk’s prediction comes amid ongoing progress toward full reusability of the Starship system, a two-stage rocket designed for rapid turnaround and dramatically lower launch costs. Catching the upper stage, known simply as “ship,” with the Mechazilla tower’s mechanical arms would mark a major milestone. It would allow both stages to return directly to the launch site for quick refurbishment and reuse, eliminating the need for ocean recovery.
Musk has previously signaled plans for a ship catch. In July, shortly after SpaceX’s wildly successful Starship 13 mission, he stated that the company would attempt to catch the ship with the tower on the next flight unless problems emerged in the mission data review. Earlier comments also outline conditions such as successful soft ocean landings before attempting a land recovery to minimize risk.
SpaceX has solved Starship’s biggest challenge, Elon Musk says
The latest update from Musk adjusts this timeline to a few months, reflecting the iterative nature of the test campaign.
SpaceX has already demonstrated the tower catch technique successfully with the Super Heavy booster on a couple of occasions. The first successful booster catch occurred during Flight 5 in October 2024, when the massive first stage returned to the Starbase pad in Texas and was plucked from the air by the tower arms.
Additional catches followed on later flights, including Flight 7, proving the concept for the booster and building confidence in the system as a whole.
Achieving a similar catch for the upper stage would represent a significant step forward. The ship returns from much higher speeds and greater heat loads after orbital or near-orbital flight. Success would advance SpaceX’s goal of full and rapid reusability, potentially reducing the cost of access to orbit by a factor of 100 or more and supporting ambitions for frequent satellite deployments, lunar missions, and eventual Mars flights.
Musk has long emphasized that true reusability, refueling rather than discarding hardware, is essential for making humanity a multi-planetary species.
As SpaceX continues refining Starship through successive test flights, the coming months will test whether the ambitious catch timeline can be met. The combination of prior booster successes and improving ship landing precision suggests the company is steadily closing in on this historic capability.
Tesla Robotaxi gets a massive upgrade in Nevada
Tesla admits to slow Model Y Robotaxi integration, but for a good reason
