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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
Elon Musk
Tesla made napping in a Robotaxi easier with its latest update
Tesla’s quiet mode reaches Model Y Robotaxis, blacking out the screen for riders wanting rest.
Tesla’s quiet mode, the setting that blacks out the screen for riders who want to rest, has moved beyond the Cybercab. A video posted Thursday by Spencer (@scotsrule08) shows the feature running in a Model Y Robotaxi on a night ride that appears to be in Dallas.
New quiet mode now on @Robotaxi https://t.co/2cM2eM9NeN — Spencer (@scotsrule08) October 29, 2026
The rider taps a small crescent moon icon in the bottom right corner of the map screen. The map, media player, app shortcuts and Grok prompt disappear, leaving a dark display with “Arriving soon,” the destination and a line reading “Tap display to exit quiet mode.” Controls a passenger may still need, including Pull Over, cabin temperature, volume and Support, stay visible. One tap anywhere brings the full map back.
Quiet mode first showed up in the Cybercab last week, which Teslarati reported alongside a new rear camera view. Tesla has been trimming cabin noise in other ways too. On October 25, Spencer reported that Robotaxi turn signals now chime for the first four blinks and then go silent. Tesla has not published release notes for either change.
Elon Musk has been pitching this use for more than a decade. In October 2014, he said that “maybe five or six years from now I think we’ll be able to achieve true autonomous driving where you could literally get in the car, go to sleep and wake up at your destination,”
By 2017 he was setting a higher bar. Speaking at TED, Musk said the hard part was not making self-driving work 99.9 percent of the time, “because, like, if a car crashes one in a thousand times, then you’re probably still not going to be comfortable falling asleep. You shouldn’t be, certainly.”
Owners asked for something similar in their own cars. In December 2019, a Tesla owner requested a Nap Mode that would keep the climate running and wake the occupant with an alarm, and Musk answered “Ok,” as Teslarati covered at the time.
The line returned when the Cybercab was unveiled at the We, Robot event in October 2024. “We’ll move from supervised Full Self-Driving to unsupervised Full Self-Driving, where you can fall asleep and wake up at your destination,” Musk said. On Tesla’s first quarter earnings call in April 2025, he called it the deciding measure: “The acid test is, can you go to sleep in your car and wake up in your destination and I’m confident that will be available in many cities in the US by the end of this year,”
Tesla has run driverless Model Y rides in Dallas and Houston since April, so a passenger dozing off on the way home is now a realistic use of the button. Tesla is also offering new riders a free first trip in both cities, according to an in-app screen shared by tracker Ethan McKanna, and said on its third quarter call that Cybercab rides would launch in Dallas next month.
News
FCC green lights SpaceX’s move to a showdown with Verizon and AT&T
The FCC advanced plans opening 482 MHz to satellite phone service, boosting SpaceX’s Starlink Mobile.
The Federal Communications Commission voted Thursday to move forward with a proposal that would open an additional 482 MHz of spectrum to satellite service beamed directly to ordinary phones, a step that could widen the road for SpaceX’s Starlink Mobile to compete with the country’s largest wireless carriers.
The commission adopted the notice of proposed rulemaking at its October open meeting in Washington, Reuters reported. The proposal would raise the number of bands eligible for Supplemental Coverage from Space from five to 13, according to the FCC fact sheet. Commissioners also advanced a companion item proposing an auction of 25 MHz in the 1675 to 1695 MHz and 2020 to 2025 MHz bands, which could be used for terrestrial service, direct to device service or both.
Thursday’s vote does not hand any spectrum to SpaceX. It opens a public comment period, and final rules will come later. Under the draft, comments would be due 60 days after the notice is published in the Federal Register. The FCC had not released the adopted text at the time of writing, so it is not yet clear whether any bands were changed before the vote.
That question is where the fight now moves. AT&T, Verizon and T-Mobile, through industry group CTIA, asked the FCC to drop the 2.5 GHz and 3.45 GHz bands, which make up 290 MHz of the 482 MHz on the table, as Teslarati reported ahead of the vote. T-Mobile argued satellite interference could wipe out up to 96% of a cell site’s uplink coverage area. SpaceX asked the commission to go the other way and add the 902 to 928 MHz band.
The rule change that matters most to SpaceX may be a structural one. Today, a satellite operator must lease spectrum from every carrier holding co-channel licenses across an entire region such as the contiguous United States. The proposal would replace that with a certification that the operator has coexistence agreements covering only the areas it plans to serve, or that it holds the terrestrial licenses itself.
SpaceX has spent this year building that second path. It bought EchoStar’s AWS-4 and H-block licenses in a deal worth roughly $17 billion, and earlier this month agreed to acquire Grain Management’s nationwide 800 MHz portfolio, which the company said would pave the way for Starlink to become a major US mobile carrier. The FCC approved SpaceX’s purchase of three unused AWS-3 licenses from Tristar on October 21, and cleared its plan for 15,000 next generation direct to cell satellites on October 6.
The regulator has not always sided with SpaceX. In April, the FCC dismissed a SpaceX petition seeking access to Mobile Satellite Service spectrum held by incumbents, and it rejected 2.5 GHz for satellite coverage when it first adopted the framework in 2024.
The carriers are also building their own defenses. In May, the three companies agreed in principle to form a joint venture pooling spectrum for satellite service, and T-Mobile remains SpaceX’s US launch partner for Starlink Mobile even as it leads the push to keep satellites out of 2.5 GHz. SpaceX President Gwynne Shotwell has said service on SpaceX’s own airwaves is targeted for early 2028.
Elon Musk
Tesla’s Roadster appearance at SpaceX has merger watchers talking
Tesla’s next generation Roadster was spotted at SpaceX’s Hawthorne headquarters, two weeks after its unveiling.
Tesla’s next generation Roadster turned up at SpaceX’s headquarters in Hawthorne, California on Wednesday, less than two weeks after the car flew off a ramp at its unveiling in Texas.
Photos shared on X by SpaceX Engineer (@DeannaRiceSPCX) show the new Roadster parked outdoors beside the famed Falcon 9 that stands outside company headquarters at the corner of Crenshaw Boulevard and Jack Northrop Avenue. Rocket B1019 was the first orbital-class booster ever to land after a launch on December 21, 2015 after it sent 11 Orbcomm satellites to orbit and then flew back to Landing Zone 1 at Cape Canaveral, which would be the first landing in what became SpaceX’s reusable rocket program. SpaceX chose not to fly it again. After a test fire in Florida, the booster was shipped to Hawthorne and raised upright as a permanent monument in August 2016, as Teslarati reported at the time. Putting the Roadster, which flies on SpaceX cold gas thrusters, next to the rocket that started SpaceX’s landings is symbolic in itself.
Small car, big rocket ambitions 🚀🚗 #roadster #falcon9 #spacex #tesla https://t.co/H32xUSXoCl
— Deanna Rice (@DeannaRiceSPCX) October 29, 2026
The Thrust and Rocket versions of the Roadster use cold gas thrusters fed by composite overwrapped pressure vessels, the same type of tank SpaceX flies on Falcon 9, and Elon Musk described the car as the work of Tesla and SpaceX engineers working together. Tesla lists 0 to 60 mph in under 0.9 seconds for Thrust and under 0.59 seconds for Rocket, while the base Performance model relies on a fan and ground sealing system for grip, as Teslarati detailed in its breakdown of the three Roadster configurations.
Tesla has kept the car in the spotlight since the October 15 event near Waco. Last week, the company posted a video of the Roadster’s fighter jet inspired cockpit, including a Track Mode screen with a “Thruster · 5,500 PSI” readout, which we covered in our look at the Roadster’s center display. Musk also said owners will be able to ask the car to perform the stunts autonomously, and promised a looping track at Tesla’s Texas headquarters.
The visit comes as special committees at Tesla and SpaceX weigh a possible merger, a step Musk confirmed on SpaceX’s third quarter earnings call. The Roadster, built on SpaceX hardware, has become one of the clearest examples of the two companies already building products together.
Musk said at the unveiling that Roadster production will begin in 2028. Reservations are open with a $50,000 payment, Thrust is listed as a limited release and Rocket is invite only. Tesla says the car is not approved for public road use.
Tesla made napping in a Robotaxi easier with its latest update
FCC green lights SpaceX’s move to a showdown with Verizon and AT&T
