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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.
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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.
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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 released Full Self-Driving version 14.3.7 yesterday, and after about 90 miles of testing today, it is evident there are some definite fixes from version 14.3.6, which I wrote about last week and called a regression.
Within the first 40 minutes of my drive on v14.3.7, it saved me from getting into an accident with an unaware Dodge Charger driver, and some of the things Tesla seemed to miss in v14.3.6 were definitely improved. All in all, the release so far has some really great performance, and I’m looking forward to testing it further.
For now, here’s everything I noticed with v14.3.7:
Overall Improvement
Just generally speaking from a ride perspective, this was a really great experience. A lot of the hesitancy I experienced on v14.3.6 was gone. There were no instances of brake-stabbing, wheel-jerking, or any uncertain or unconfident movements. It was void of anything that I felt made it timid with v14.3.6.
The one thing I do hope to see down the road is a smaller need to adjust Speed Profiles so often. Because Tesla calls FSD “Supervised,” I’m okay with needing to hit the scroll wheel a few times a drive.
However, I hope that things can be incrementally improved upon with speed. Sometimes it’s too fast; other times it’s too slow. It’s a difficult thing to hone in and refine, but I hope it eventually gets there.
I didn’t notice any significant left lane camping or any behaviors that were completely out of line. I am hopeful that this opinion does not change, but after driving a few days with this version and putting it in a variety of different situations, you are exposed to more behaviors, some of which are not necessarily what I’d prefer.
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The big things to notice, at least in my experience thus far, are that the major issues with previous versions — meaning the braking stabbing and wheel jerking — simply weren’t there. That’s enough to already consider this progress compared to .6.
Manual Signal Override is More Responsive
On .6, I had quite a few issues with FSD ignoring my manually input turn signals. If Tesla wants to call it “Supervised,” then the car should not ignore any input the driver gives. If I touch the accelerator on FSD, the car speeds up.
🚨 Tesla FSD v14.3.7 obeying manual turn signals https://t.co/6eqToXpQfC pic.twitter.com/vHBlFQ4PDV
— TESLARATI (@Teslarati) August 2, 2026
The car did a great job of obeying my turn signals when I wanted it to change lanes, which is welcome.
Parking Lot Performance
Before .6, I traditionally took over in nearly every parking lot my car entered, because I knew it would not park somewhere that I wanted, and usually, it was just a tad too timid in this setting.
The one bright spot of .6 was how well it handled parking lots. This continued with v14.3.7:
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I’m always really happy to see progress at all, but once parking preferences come to FSD, as long as this performance is still around, that could potentially be the biggest improvement I’ve seen in FSD in the year I’ve been using it personally on a daily basis.
Full Self-Driving Averts Disaster
A Dodge Charger changed into my lane without checking if I was there, running me off the road. FSD made the initial avoidance maneuver; I grabbed the wheel out of instinct, looked in my side mirror to ensure I had nobody following closely behind, hit the brake, and straightened the car back up to avoid a curb:
🚨 Guys this is why you all NEED to stay vigilant behind the wheel, even on Tesla Full Self-Driving
Human drivers are UNHINGED and have no idea what they’re doing anymore. This was a kid obviously younger than 20 years old with zero awareness.
First drive with v14.3.7 https://t.co/1vTbCMpCn8 pic.twitter.com/lz7KKEF6bj
— TESLARATI (@Teslarati) August 2, 2026
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There have been quite a few responses to this video stating that I should never have grabbed the wheel. To be honest, I really wish I had not done so, because I do believe FSD would have avoided any sort of collision with anything, including the car or the curb.
However, this was the first time I had ever been this close to being hit while using FSD. My natural reaction was to take over. I think if I had had something like this happen before, my reaction might have been different.
Hitting the brake avoided hitting the curb, while FSD swerved to avoid the car. My concern after the car was clear of my front end was the curb. All in all, I’m really happy with how things turned out, and I think anyone could be a critic of how I handled it. I only had a split second to really make a decision, and thankfully, any damage was avoided.
It is clear FSD managed to avoid the car coming down before I was able to. I truly credit FSD for avoiding the collision.
What Needs to Improve
Better Recognition of Potholes, Uneven Roads, Sharp Changes in Roadway/Bumps
On Friday, my Fianceè and I were in the car, and FSD was driving us. We crossed over a roadway that has a traffic light, and FSD was traveling at 40 MPH on Standard, 5 MPH over the speed limit. Everything was more than reasonable.
However, the road we were crossing at the light has a major bump both as you start and finish crossing it. Without a speed reduction, your car can go airborne. The Tesla did just this on Friday on v14.3.6; it was an uncomfortable bounce that pretty much confirmed I would not ever let FSD go over again unless we were sitting at that intersection when there is a red light.
I even tried scrolling down into Sloth quickly, but I ended up just taking over:
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This is that big bounce that I mentioned in the quoted post.
It’s just a tad too drastic to take at the speed FSD wants to go over it. You can see me quickly swipe down into Sloth, but I intervened. https://t.co/K20PK9ysBg pic.twitter.com/81Oc82ZJcZ
— TESLARATI (@Teslarati) August 2, 2026
A few people have said it remains related to the vision-based approach and its difficulty comprehending 3D. This is a huge issue because this can cause serious damage at certain speeds.
Navigation
Nothing new here. I still turn off “Online Routing” quite frequently to get the car to take logical routes from time to time.
Auto Wipers
Auto Wipers are just plain bad. I really hope Tesla just uses a rain sensor. I thought they had improved at one point, but I still get dry wipes, Speed 4 on a drizzle, and Speed 2 on a steady rain. In reality, these should be switched.
You can watch our full review of Tesla Full Self-Driving v14.3.7 below:
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🚨 Tesla Full Self-Driving v14.3.7 saved me from an accident! FULL REVIEW: https://t.co/1vTbCMpCn8 pic.twitter.com/9mHmKVoMVA
— TESLARATI (@Teslarati) August 2, 2026
SpaceX will report second quarter results after the market closes on Tuesday, August 4, marking the first time the company has opened its books to the public since its record IPO in June. Management will host a live audio only webcast at 4:30 p.m. ET, streamed on X, with no dial in option.
The debut carries more weight than a typical first quarter as a public company. Two trading days after the release, on August 6, the first tranche of SpaceX’s lockup expires, freeing roughly 911.5 million insider and employee shares, worth well over $100 billion at current prices and the largest such release in Wall Street history. A second, larger tranche tied to the stock trading 30 percent above its $135 IPO price never triggered, since shares have spent most of July trading below that price.
Wall Street’s models point to revenue near $6.9 billion for the quarter, up sharply from the $4.69 billion SpaceX reported in the first quarter, with a narrower per share loss than the $1.27 posted three months earlier, according to estimates compiled by Motley Fool. Those numbers will be the first look at how SpaceX’s three segments, Starlink, launch and AI, are performing independently.
SpaceX scores another massive Pentagon deal to support military satellites
Investors heading into the call have a specific list of questions. How many net new Starlink subscribers did SpaceX add after ending March with 10.3 million, and is average revenue per user holding up as the service expands into lower income markets. How much of the AI segment’s revenue reflects contract signings with Anthropic, Google and Reflection AI this year, deals that combined could annualize to nearly $28 billion if fully ramped. Whether capital expenditures, which nearly doubled in the AI segment alone between 2024 and 2025, are still accelerating or starting to plateau. And whether management offers any forward guidance at all, something SpaceX has never done publicly.
The report will also land days after Elon Musk publicly denied a Wall Street Journal report describing internal planning to separate Tesla’s China business ahead of a potential Tesla-SpaceX merger. Whether Musk or SpaceX executives address that speculation on the call, even indirectly, maybe something investors will be listening for on Tuesday.
As Teslarati reported after Musk’s own warning to short sellers last week, the CEO has made clear he expects skeptics to be proven wrong over time. Tuesday will be the first chance for the numbers themselves to make that case.
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Elon Musk
SpaceX’s Starship just got filmed by its own cargo
SpaceX released new footage of Starship in space captured by the Starlink satellites it deployed.
SpaceX released a new video Friday evening showing Starship from an angle showcased by its own Starlink satellites, watching the rocket drift away in orbit.
The 65 second clip, posted on X, stitches together footage from four cameras mounted on a single Starlink V3 satellite. It opens with a close view of Starship’s 171 foot upper stage, still catching sunlight, then pulls back as the two spacecraft separate.
The footage comes from Starship’s 13th flight test, which launched July 24 from Starbase after a scrubbed attempt and an abort caused by an engine issue the week before. When Flight 13 finally flew, it carried the first batch of functional Starlink V3 satellites Starship has ever deployed, twenty of them, with six equipped with cameras meant to scan the ship’s heat shield during reentry.
View of Starship in space from a Starlink V3 satellite on Flight 13.
This composite is made of imagery from four separate cameras on a single satellite. Six of the satellites were equipped with cameras to scan Starship’s heat shield and transmit imagery down to operators to… pic.twitter.com/sNTHHz5vLr
— SpaceX (@SpaceX) July 31, 2026
Flight 13 checked most of its boxes. Starship deployed all 20 satellites, relit a Raptor engine in space, and splashed down softly in the Indian Ocean off Western Australia. Musk’s longer term plan calls for a Starlink V3 constellation of 100,000 satellites, according to a recent FCC filing, with Starship as the only vehicle capable of launching them at the volume that requires. Each Starship flight is designed to carry up to 60 V3 satellites once the vehicle reaches routine service, well beyond what Falcon 9 can carry in a single mission.
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Starship is next expected to fly with an attempt at catching the ship itself with the launch tower’s mechanical arms, a maneuver SpaceX has so far reserved for the Super Heavy booster.
Tesla Full Self-Driving v14.3.7 early review: FSD saved me from an accident
SpaceX’s biggest test yet arrives this week and it’s not a rocket launch
