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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
Tesla has reopened reservations for its long-delayed next-generation Roadster, asking buyers for a $50,000 deposit just days before an October 1 reveal event in Waco, Texas. The move revives a reservation process first launched in 2017 and later paused when Tesla pulled pricing from its website in 2021.
The reservation page requires an immediate $5,000 credit-card payment, described as fully refundable, followed by a $45,000 wire transfer due within 10 days, which is identical to what was expected previously. Reservations are not considered final until the wire clears.
The structure matches the 2017 terms Tesla used when it first collected deposits after unveiling a prototype. Tesla has not published a confirmed retail price or production start date on the order page.
Go buy a Roadster pic.twitter.com/n7rhouAmIS
— TESLARATI (@Teslarati) September 21, 2026
The October 1 event is scheduled in Waco, about 90 minutes north of Tesla’s Austin headquarters and near SpaceX’s McGregor rocket test site. Tesla sent invitations to existing reservation holders and posted a “Go for launch” teaser on September 12.
The Federal Aviation Administration (FAA) established a temporary flight restriction over the McGregor area from September 18 through October 2, consistent with plans for a demonstration involving SpaceX-designed cold-gas thrusters. Elon Musk has previously described the optional package as enabling extreme acceleration or brief hovering. Tesla has said the event will include pricing, specifications, and production targets.
The second-generation Roadster was first shown in November 2017 during Tesla’s Semi launch. Musk promised production in 2020, with claimed performance of 0-60 mph in 1.9 seconds, more than 250 mph top speed, and roughly 620 miles of range.
Those targets have slipped repeatedly.
Tesla later pointed to 2022, 2023, 2024, and 2025-2026 before indicating production would not begin until 2027 or 2028 at Gigafactory Texas. Design work has continued, with reports of a sharper, Cybertruck-influenced look replacing the original curvy prototype.
Original reservation holders who paid $50,000 in 2017, or $250,000 for the Founders Series, have waited nearly nine years without a production car. Some high-profile customers canceled. Tesla’s decision to reopen orders now, after previously shutting them down, tests whether new buyers will commit substantial funds before seeing a finalized production vehicle. The October 1 event is intended to answer remaining questions about what those buyers will actually receive and when.
Tesla’s Full Self-Driving (Supervised) is heading to Czechia after the Czech Ministry of Transport recognised the Dutch RDW’s provisional type approval, making the country the seventh EU member state to clear the system for public roads. Tesla Europe announced on 21 September 2026 that “FSD Supervised is now approved in Czechia” and that rollout “will begin soon.”
The decision marks a notable reversal. Earlier in 2026, Prague had declined to automatically recognise the Netherlands’ April approval, citing concerns over speed-limit compliance, traffic-sign recognition and driver-attention monitoring, and arguing that a coordinated EU approach was preferable. Officials said months of expert review, talks with Tesla and other member states, and real-world data from countries already using the system resolved those issues.
🚨 Tesla FSD heading to Czechia 🇨🇿 pic.twitter.com/mkzlM9QjrB
— TESLARATI (@Teslarati) September 21, 2026
“Safety remains the top priority,” the ministry stated.
FSD Supervised remains a Level 2 driver-assistance system: the driver must stay engaged and is legally responsible. Eligible vehicles need AI4, the company’s most up-to-date hardware version. Tesla is expected to push the feature over the air in the coming days, following the pattern seen after earlier national approvals.
Europe’s rollout began when Dutch regulator RDW issued a provisional EU type approval on 10 April 2026 after extensive testing. Mutual recognition then produced a rapid cascade: Lithuania (20 May), Estonia (29 May), Denmark (9 June), Belgium (10 June) and Slovenia (7 September). Czechia now completes that list of seven.
The approvals cover only a modest share of the EU population, but they add political weight ahead of a 6 October vote by the Technical Committee on Motor Vehicles. A qualified majority, at least 15 of 27 member states representing 65 percent of the EU population, could open the remaining markets, including large ones such as Germany, France, Italy and Spain that have so far preferred to wait for a bloc-wide decision.
For Czech Tesla owners, the immediate prize is access to the same supervised highway and city driving already available in the other six countries. For Tesla, each new market generates additional European driving data and strengthens the case that FSD Supervised can operate safely under the continent’s varied road rules. The Czech approval is therefore both a local milestone and another incremental step toward a wider European launch.
The Federal Aviation Administration (FAA) has established a Temporary Flight Restriction over SpaceX’s McGregor, Texas, rocket development and test facility, a move widely viewed as preparation for Tesla’s October 1 Roadster reveal. The restriction took effect September 18 and runs through October 2.
NOTAM FDC 6/3825 covers a 1.5-nautical-mile radius around the site near Waco and extends from the surface to 10,000 feet above ground level. The FAA cited hazards under 14 CFR 91.137(a)(3) and barred aircraft and drones from the zone. Tesla’s invitation to reservation holders already placed the event in Waco, about 20 minutes from McGregor, making the timing and location more than coincidental.
A TFR has appeared around SpaceX’s McGregor Testing Site up to 10,000ft and runs through until the 2nd of October 👀 pic.twitter.com/rcZ4p4JkLm
— Niall Anderson (@INiallAnderson) September 18, 2026
What stands out is the altitude. Typical recent TFRs at McGregor for engine static fires and component tests have used far lower ceilings, often around 2,000 feet. Raising the limit to 10,000 feet is unusually high even compared with some Starbase restrictions and signals operations that go beyond a standard ground-level engine test.
That extra airspace has fueled speculation about the long-promised SpaceX Package for the Roadster. Elon Musk has described cold-gas thrusters that could deliver sub-one-second 0-60 times and, more dramatically, brief lift-off. Reports earlier this year indicated Tesla planned a remote-controlled demonstration at McGregor in which the car would leave the ground with no one inside; spectators kept hundreds of yards away because of the noise.
The 10,000-foot envelope would give operators a large safety buffer even if the vehicle only hovers a short distance.
Tesla has not confirmed a flight demo. The company has only used the phrase “Go for launch” and posted a teaser image of the car on what looks like a launch pad. The TFR itself mentions only hazards. Still, closing airspace this high and this close to the reveal date strongly suggests the event will include more than a static display.
Whether the Roadster actually hovers on October 1 remains to be seen. What is certain is that the FAA has cleared a large vertical slice of Texas sky for whatever Tesla and SpaceX intend to show. Reservation holders heading to Waco will be among the first to find out if the car can do more than drive.
Tesla Roadster is available for order once again following brief hold
Tesla Full Self-Driving expands to another European country
