News
Tesla Semi and Roadster could be relying on a “battery breakthrough”
Elon Musk and Tesla have made some bold claims for the new Tesla Semi and Roadster. Those who understand batteries have been scratching their heads trying to figure out how the company can deliver the specs it’s promising – and concluding that the only possible way is some as-yet-unannounced advancement in battery technology.
Musk says the Tesla Semi will be able to haul 80,000 pounds for 500 miles, and recharge to 400 miles in 30 minutes, which would revolutionize the trucking industry. As for the Roadster, its promised 0-60 acceleration of 1.9 seconds effectively shuts down every one of the world’s baddest supercars, and its touted 620-mile range would be double that of any EV produced to date.
However, industry experts are questioning Tesla CEO Elon Musk’s touted range and charging capabilities, saying the specifications defy current physics and battery economics.
According to Bloomberg, analysts at Bloomberg New Energy Finance point out that Tesla Semi’s announced specs would require a battery capacity of between 600 and 1,000 kilowatt hours (6-10 times the size of the largest Model S battery). Using current technology, an 800 kWh battery pack would weigh over 10,000 pounds and cost more than $100,000. That’s just for the battery – Tesla has said its entire truck will start at $150,000. It seems plain that Tesla is counting on falling battery prices to square the circle. “The first Tesla Semis won’t hit the road until late 2019,” Bloomberg points out. “Even then, production would probably start slowly. Most fleet operators will want to test the trucks before considering going all-in. By the time Tesla gets large orders, batteries should cost considerably less.”
It isn’t just the capacity of the battery that’s causing analysts to wear out their calculators – Musk’s claim that the Tesla Semi will be able to add 400 miles of charge in 30 minutes would require a charging system 10 times more powerful than Tesla’s current Supercharger – which is already by far the most powerful in the industry.
Tesla Semi Megacharger port could support 1 MW of power.
“I don’t understand how that works,” said Bloomberg New Energy Finance EV Analyst Salim Morsy. “I really don’t.” Tesla’s current generation of Superchargers have a power output of 120 kilowatts and can add about 180 miles of range to a Model S battery in 30 minutes. To meet Tesla’s charging claim for the Semi would require the promised Megacharger to deliver an output of at least 1,200 kW.
Perhaps Tesla’s biggest bombshell is the promise that it will guarantee truckers electricity rates of 7 cents per kilowatt hour, which Bloomberg estimates could translate to fuel savings of up to $30,000 a year. Musk says that adding solar panels and battery packs at the charging stations will account for at least part of the cost reduction. However, BNEF’s Salim Morsy insists that Tesla will have to heavily subsidize those electricity rates – he estimates that Tesla will pay a minimum of 40 cents per kWh. “There’s no way you can reconcile 7 cents a kilowatt hour with anything on the grid that puts a megawatt hour of energy into a battery,” Morsy said. “That simply does not exist.”
Of course, that’s no different from what Tesla does for its current Supercharger network, offering free electricity to many customers, while paying almost $1 per kWh to produce it, according to Morsy’s estimate.
And how about that Roadster? To deliver its promised range of 620 miles, it will need a 200 kWh battery pack, twice the size of Tesla’s largest currently available pack. Mr. Morsy predicts that Tesla will stack two battery packs, one on top of the other, beneath the Roadster’s floor.
Even with a double-decker pack however, it’s hard to escape the conclusion that Tesla is counting on improving battery tech to make the Roadster, like the Semi, feasible. Battery density has been improving at a rate of about 7.5 percent a year, and that’s without any major breakthrough in battery chemistry.
“The trend in battery density is, I think, central to any claim Tesla made about both the Roadster and the Semi,” Morsy said. “That’s totally fair. The assumptions on a pack in 2020 shouldn’t be the same ones you use today.”
A massive battery pack not only enables greater range – it’s also a key element in the Roadster’s world-beating 0-60 acceleration. Jalopnik’s David Tracy spoke with battery expert Venkat Viswanathan, a Mechanical Engineering Assistant Professor at Carnegie Mellon, who says that the 1.9-second figure actually seems reasonable.
Viswanathan explains that the power output of a motor is limited by the power draw from each battery cell. Because the Roadster’s pack is double the size, the power draw may not be that much more than that of a Ludicrous Model S.
Viswanathan told Jalopnik that the most modern battery cells offer specific energy of about 240 watt-hours per kilogram. Using that assumption, the Roadster’s 200 kWh battery pack should weigh roughly 1,800 pounds, a huge advance over the previous-generation Roadster. With clever use of lightweight materials, the Roadster could still come out under the nearly two-ton curb weight of the Nissan GT-R, an acceleration benchmark among sports cars.
Viswanathan concludes that a 0-60 time of 1.9 seconds and a range of 620 miles are quite feasible, although there are several other factors that will come into play – much depends on the vehicle’s tires and aerodynamics.
Meanwhile, at least one analyst thinks Tesla’s latest revelations (or claims, or fantasies, depending on your point of view) have implications that go far beyond the Semi and the Roadster. Michael Kramer, a Fund Manager with Mott Capital Management, told Marketwatch that he suspects improved battery capacities and charging times could make their way into all future Tesla vehicles.
“I’d have to imagine that Tesla has figured out how to put this technology on all of their cars, which means every car could get a full charge in under 30 minutes,” Kramer wrote. Once the Model S “is equipped with the 200 kWh battery pack in the new Roadster, which I can’t imagine is too far down the road, the range issue for the Tesla is officially dead.” (Elon Musk has said that Models S and X will not get physically larger packs, but improved energy density could increase capacity while keeping the size of the pack the same.) Someday soon, Kramer says, “The Model S would likely be able to drive further on one charge than a car on a full tank of gasoline.”
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Note: Article originally published on evannex.com, by Charles Morris
Tesla is updating Cybertruck owners on its timeline of a massive feature that has yet to ship: Powershare with Powerwall.
Powershare is a bidirectional charging feature exclusive to Cybertruck, which allows the vehicle’s battery to act as a portable power source for homes, appliances, tools, other EVs, and more. It was announced in late 2023 as part of Tesla’s push into vehicle-to-everything energy sharing, and acting as a giant portable charger is the main advantage, as it can provide backup power during outages.
Cybertruck’s Powershare system supports both vehicle-to-load (V2L) and vehicle-to-home (V2H), making it flexible and well-rounded for a variety of applications.
However, even though the feature was promised with Cybertruck, it has yet to be shipped to vehicles. Tesla communicated with owners through email recently regarding Powershare with Powerwall, which essentially has the pickup act as an extended battery.
Powerwall discharge would be prioritized before tapping into the truck’s larger pack.
However, Tesla is still working on getting the feature out to owners, an email said:
“We’re writing to let you know that the Powershare with Powerwall feature is still in development and is now scheduled for release in mid-2026.
This new release date gives us additional time to design and test this feature, ensuring its ability to communicate and optimize energy sharing between your vehicle and many configurations and generations of Powerwall. We are also using this time to develop additional Powershare features that will help us continue to accelerate the world’s transition to sustainable energy.”
Owners have expressed some real disappointment in Tesla’s continuous delays in releasing the feature, as it was expected to be released by late 2024, but now has been pushed back several times to mid-2026, according to the email.
Foundation Series Cybertruck buyers paid extra, expecting the feature to be rolled out with their vehicle upon pickup.
Cybertruck’s Lead Engineer, Wes Morrill, even commented on the holdup:
As a Cybertruck owner who also has Powerwall, I empathize with the disappointed comments.
To their credit, the team has delivered powershare functionality to Cybertruck customers who otherwise have no backup with development of the powershare gateway. As well as those with solar…
— Wes (@wmorrill3) December 12, 2025
He said that “it turned out to be much harder than anticipated to make powershare work seamlessly with existing Powerwalls through existing wall connectors. Two grid-forming devices need to negotiate who will form and who will follow, depending on the state of charge of each, and they need to do this without a network and through multiple generations of hardware, and test and validate this process through rigorous certifications to ensure grid safety.”
It’s nice to see the transparency, but it is justified for some Cybertruck owners to feel like they’ve been bait-and-switched.
Tesla has opened its northernmost Supercharger in Fairbanks, Alaska, with eight V4 stalls located in one of the most frigid cities in the U.S.
Located just 196 miles from the Arctic Circle, Fairbanks’s average temperature for the week was around -12 degrees Fahrenheit. However, there are plenty of Tesla owners in Alaska who have been waiting for more charging options out in public.
There are only 36 total Supercharger stalls in Alaska, despite being the largest state in the U.S.
Eight Superchargers were added to Fairbanks, which will eventually be a 48-stall station. Tesla announced its activation today:
North America’s northernmost Supercharger Fairbanks, AK (8 stalls) opened to public. https://t.co/M4l04DZ6B5 pic.twitter.com/zyL6bDuA93
— Tesla Charging (@TeslaCharging) December 12, 2025
The base price per kWh is $0.43 at the Fairbanks Supercharger. Thanks to its V4 capabilities, it can charge at speeds up to 325 kW.
Despite being the northernmost Supercharger in North America, it is not even in the Top 5 northernmost Superchargers globally, because Alaska is south of Norway. The northernmost Supercharger is in Honningsvåg, Norway. All of the Top 5 are in the Scandanavian country.
Tesla’s Supercharger expansion in 2025 has been impressive, and although it experienced some early-quarter slowdowns due to V3-to-V4 hardware transitions, it has been the company’s strongest year for deployments.
🚨🚨 Tesla Supercharging had a HUGE year, and they deserve to be recognized.
🍔 Opened Tesla Diner, a drive-in movie theater with awesome, Chef-curated cuisine
🔌 Gave access to Superchargers to several EV makers, including Hyundai, Genesis, Mercedes-Benz, Kia, Lucid, Toyota,… pic.twitter.com/yYT2QEbqoW
— TESLARATI (@Teslarati) December 10, 2025
Through the three quarters of 2025, the company has added 7,753 stations and 73,817 stalls across the world, a 16 percent increase in stations and an 18 percent increase in stalls compared to last year.
Tesla is on track to add over 12,000 stalls for the full year, achieving an average of one new stall every hour, an impressive statistic.
Recently, the company wrapped up construction at its Supercharger Oasis in Lost Hills, California, a 168-stall Supercharger that Tesla Solar Panels completely power. It is the largest Supercharger in the world.
News
Tesla shocks with latest Robotaxi testing move
Why Tesla has chosen to use a couple of Model S units must have a reason; the company is calculated in its engineering and data collection efforts, so this is definitely more than “we just felt like giving our drivers a change of scenery.”
Tesla Model S vehicles were spotted performing validation testing with LiDAR rigs in California today, a pretty big switch-up compared to what we are used to seeing on the roads.
Tesla utilizes the Model Y crossover for its Robotaxi fleet. It is adequately sized, the most popular vehicle in its lineup, and is suitable for a wide variety of applications. It provides enough luxury for a single rider, but enough room for several passengers, if needed.
However, the testing has seemingly expanded to one of Tesla’s premium flagship offerings, as the Model S was spotted with the validation equipment that is seen entirely with Model Y vehicles. We have written several articles on Robotaxi testing mules being spotted across the United States, but this is a first:
🚨 Tesla is using Model S vehicles fitted with LiDAR rigs to validate FSD and Robotaxi, differing from the Model Ys that it uses typically
Those Model Y vehicles have been on the East Coast for some time. These Model S cars were spotted in California https://t.co/CN9Bw5Wma8 pic.twitter.com/UE55hx5mdd
— TESLARATI (@Teslarati) December 11, 2025
Why Tesla has chosen to use a couple of Model S units must have a reason; the company is calculated in its engineering and data collection efforts, so this is definitely more than “we just felt like giving our drivers a change of scenery.”
It seems to hint that Tesla could add a premium, more luxury offering to its Robotaxi platform eventually. Think about it: Uber has Uber Black, Lyft has Lyft Black. These vehicles and services are associated with a more premium cost as they combine luxury models with more catered transportation options.
Tesla could be testing the waters here, and it could be thinking of adding the Model S to its fleet of ride-hailing vehicles.
Reluctant to remove the Model S from its production plans completely despite its low volume contributions to the overall mission of transitioning the world to sustainable energy, the flagship sedan has always meant something. CEO Elon Musk referred to it, along with its sibling Model X, as continuing on production lines due to “sentimental reasons.”
However, its purpose might have been expanded to justify keeping it around, and why not? It is a cozy, premium offering, and it would be great for those who want a little more luxury and are willing to pay a few extra dollars.
Of course, none of this is even close to confirmed. However, it is reasonable to speculate that the Model S could be a potential addition to the Robotaxi fleet. It’s capable of all the same things the Model Y is, but with more luxuriousness, and it could be the perfect addition to the futuristic fleet.
Tesla updates Cybertruck owners about key Powershare feature
Tesla’s northernmost Supercharger in North America opens
