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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
News
Tesla surges Robotaxi fleet ahead of Cybercab launch event
Tesla’s unsupervised robotaxi fleet quietly grew sevenfold in three weeks just before Cybercab Day arrives.
Tesla’s unsupervised Robotaxi fleet has grown far faster than the public numbers suggested, and the timing lines up with the company’s biggest autonomy showcase yet. According to data compiled by the crowdsourced Robotaxi Tracker, Tesla now has nearly 200 vehicles operating without a safety monitor across Austin, Dallas and Houston, yielding a roughly 7X increase in about three weeks.
The jump lands four days before this week’s Tesla Cybercab launch event in Austin, where the company plans to show off its purpose-built, two-seat robotaxi with no steering wheel or pedals in a live commercial setting for the first time. Stick with us on X and Facebook for live reporting from the event.
The strategic logic is straightforward. Tesla has spent the past year scaling Robotaxi in small, deliberate steps, first widening geofences, then extending operating hours, then quietly growing fleet size, usually with little advance notice. Ashok Elluswamy told investors on the Q2 earnings call that the program had logged more than 380,000 unsupervised miles with zero notable incidents, a safety record the company has leaned on to justify moving slowly. Critics have used the flip side of that caution, a fleet that appeared stuck around two dozen vehicles for months, as evidence that Tesla’s driverless ambitions were outrunning its actual deployment.
A fleet quietly scaling to nearly 200 vehicles right before Cybercab Day undercuts that argument without Tesla having to say anything about it directly. It also sets up the event to do double duty. Rather than simply introducing new hardware, Tesla can point to an operating base of unsupervised Model Ys already running at meaningful scale, then argue the Cybercab, which uses the same underlying Full Self-Driving stack according to earlier coverage of the fleet’s software upgrades, is a natural next steps. Tesla has separately been registering the two-seat Cybercabs with Texas regulators this week, with the count climbing from seven to 45 in a matter of days.
The two ramps, one in software-driven Model Y deployment and one in physical Cybercab registrations, are happening in parallel rather than in sequence. That suggests Tesla wants Thursday’s event to land as proof that the robotaxi business is already running at scale, not just a reveal of a new vehicle shape. Whether the unsupervised numbers hold up once Cybercabs start mixing into the same fleet is the detail worth watching once the event wraps.
Tesla is lowering the monthly price of its Cybertruck Windshield Protection Plan from $35 to $25. The new rate will apply to the first payment on or after October 1, 2026. Tesla has told subscribers that all other benefits stay the same.
The plan covers unlimited repairs for chips and minor cracks on the front windshield. It also includes one full replacement every 12 months at no extra charge. Additional replacements in the same year carry a $100 deductible. Service is performed with Tesla glass and camera calibration, which matters because Autopilot and Full Self-Driving rely on those lenses behind the windshield.
Looks like Tesla is decreasing the Cybertruck windshield protection plan price from $35 to $25
Awesome https://t.co/MRlTU1XTbf pic.twitter.com/PWkMZt1H7G
— TESLARATI (@Teslarati) August 28, 2026
There is no long-term contract. Coverage applies only to the front glass and does not include collision, vandalism, or weather damage.
The Cybertruck’s large, complex windshield has been more expensive to replace than glass on Tesla’s cars, which is why the pickup started at a higher subscription price. The $10 monthly cut reduces the annual cost from $420 to $300. Tesla has not publicly explained the change. The timing coincides with a year of claims data after the plan was extended to the Cybertruck.
Tesla sells several related protection products as monthly subscriptions through the Tesla app. The Windshield Protection Plan is also offered on other models. Model 3 and Model Y currently cost $16 a month. Those passenger-car rates are unchanged in the latest Cybertruck notice.
The Wheel and Tire Protection Plan covers road-hazard damage such as potholes, nails, and debris. Repairs are unlimited. Each wheel or tire replacement appointment has a $25 deductible. Pricing varies by model and whether the vehicle is a Performance version. Tesla is raising some of those rates on the same October 1 date.
Reported examples include Model 3 Performance moving from $16 to $24 and Model Y Performance from $20 to $24. Cybertruck wheel-and-tire coverage has been listed at $20 a month for the standard configuration.
A separate Luxe Package bundles four years of windshield coverage, wheel-and-tire coverage, and recommended maintenance on certain new Model S, Model X, and Cyberbeast orders, although the Model S and X are now defunct.
Tesla also offers an Extended Service Agreement after the basic vehicle warranty ends. That product covers many Tesla-manufactured parts rather than glass or tires. Together, the plans give owners a menu of targeted, cancel-anytime coverage instead of relying only on auto insurance.
UPDATE: The number has now been updated to 45 units, up from 7!
Here we go! Tesla has just added another 38 Cybercabs to its Robotaxi fleet, bringing the total up to 45, according to the Texas DMV.
Robots on robots on robots! This Thursday’s launch event is gonna be awesome🤖🤖🤖 pic.twitter.com/3HF24rHK4T
— Sawyer Merritt (@SawyerMerritt) August 31, 2026
Tesla is bolstering its Cybercab fleet with the State of Texas’s regulatory bodies ahead of the planned launch of the all-electric ride-hailing vehicle this Thursday.
Seven purpose-built Tesla Cybercabs have been added to Texas’s official automated vehicle registry, appearing in the Texas Motor Carrier Credentialing System (TxMCCS) public lookup just three days before Tesla’s invite-only Cybercab launch event in Austin on September 3.
The records, visible through TxDMV’s Motor Carrier and Automated Motor Vehicle Operator Lookup, list seven 2026 Tesla Cybercabs under Tesla Robotaxi, LLC. Their VINs begin with the 5YJA prefix, distinct from the 7SAYG Model Y robotaxis that already dominate Tesla’s Texas fleet.
Community trackers that scrape the same public database recorded the new entries on August 31, bringing Tesla’s authorized Texas robotaxi total to 276 vehicles: 269 Model Ys and the seven Cybercabs:
🚨 There are now SEVEN Tesla Cybercabs registered with the state of Texas
We are just three days from Cybercab! pic.twitter.com/ndwhuFYsep
— TESLARATI (@Teslarati) August 31, 2026
Texas Senate Bill 2807, which took effect in late May 2026, created a self-certification framework for commercial Level 4 operations. Operators file through TxMCCS, attest to SAE Level 4 capability, maintain insurance, and keep an active vehicle list.
Tesla completed that process months earlier for its existing Model Y Robotaxi service, which has carried paying passengers in Austin, Dallas, Houston and other markets. Adding the Cybercabs to the same authorization means the new two-seat, steering-wheel-free vehicles are now legally recognized for commercial use on Texas roads.
The timing is deliberate as Tesla scheduled the September 3 event at its Austin campus after sending invitations to selected Robotaxi riders and other guests. The company has described the evening as a chance to “experience the future of full autonomy” and plans to livestream it.
Production Cybercabs, which lack pedals and a steering wheel, have been rolling off the Giga Texas line for months; some earlier examples still carried temporary driver controls for data collection. Registering a small fleet of the finished design immediately before the public event signals that Tesla intends to move the purpose-built vehicle from factory and test tracks into the same Robotaxi app already used by Model Y passengers.
The seven units remain a tiny fraction of Tesla’s overall Texas authorization and far smaller than competing fleets. Registration does not automatically equal unsupervised public rides; it is the legal prerequisite.
Still, the sudden appearance of Cybercab VINs in the state’s lookup system, after a year of Model Y-only listings, is the clearest official confirmation yet that Tesla’s dedicated robotaxi hardware is entering the regulatory pipeline at the same moment the company is preparing to show it to invited guests and a global livestream audience.
Whether those seven vehicles appear at the September 3 event or begin carrying passengers shortly afterward, their presence in TxMCCS marks a concrete regulatory step that has been anticipated since the Cybercab concept was first revealed.
Tesla surges Robotaxi fleet ahead of Cybercab launch event
Tesla Cybertruck windshield protection just got cheaper
