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
News
Tesla reliability rankings skyrocket significantly in latest assessment
“They definitely have their struggles, but by continuing to refine and not make huge changes in their models, they’re able to make more reliable vehicles, and they’ve moved up our rankings.”
Tesla ranked in the Top 10 of the most reliable car companies for 2026, as Consumer Reports’ latest index showed significant jumps from the past two years.
In 2022, Tesla ranked 27th out of 28 brands. Last year, it came in 17th.
🚨🚨 Tesla entered the Top 10 in Consumer Reports’ list of reliable carmakers for the first time
In the past two years, Tesla has ranked 17th in 2024 and 27th out of 28 brands in 2022.
Subaru, BMW, Porsche, Honda, and Toyota were the Top 5 OEMs in the rankings. pic.twitter.com/z216bccVoH
— TESLARATI (@Teslarati) December 4, 2025
However, 2026’s rankings were different. CR‘s rankings officially included Tesla in the Top 10, its best performance to date.
Finishing tenth, the full Top 10 is:
- Subaru
- BMW
- Porsche
- Honda
- Toyota
- Lexus
- Lincoln
- Hyundai
- Acura
- Tesla
Tesla has had steady improvements in its build quality, and its recent refinements of the Model 3 and Model Y have not gone unnoticed.
The publication’s Senior Director of Auto Testing, Jake Fisher, said about Tesla that the company’s ability to work through the rough patches has resulted in better performance (via CNBC):
“They definitely have their struggles, but by continuing to refine and not make huge changes in their models, they’re able to make more reliable vehicles, and they’ve moved up our rankings.”
He continued to say that Tesla’s vehicles have become more reliable over time, and its decision to avoid making any significant changes to its bread-and-butter vehicles has benefited its performance in these rankings.
Legacy automakers tend to go overboard with changes, sometimes keeping a model name but recognizing a change in its “generation.” This leads to constant growing pains, as the changes in design require intense adjustments on the production side of things.
Instead, Tesla’s changes mostly come from a software standpoint, which are delivered through Over-the-Air updates, which improve the vehicle’s functionality or add new features.
Only one Tesla vehicle scored below average in Consumer Reports’ rankings for 2026 was the Cybertruck. Fisher’s belief that Tesla improves its other models over time might prove to be true with Cybertruck in a few years.
He continued:
“They’re definitely improving by keeping with things and refining, but if you look at their 5- to 10-year-old models that are out there, when it comes to reliability, they’re dead last of all the brands. They’re able to improve the reliability if they don’t make major changes.”
Regarding Subaru’s gold medal placing on the podium, Fisher said:
“While Subaru models provide good performance and comfort, they also excel in areas that may not be immediately apparent during a test drive.”
Other notable brands to improve are Rivian, which bumped itself slightly from 31 to 26. Chevrolet finished 24th, GMC ended up 29th, and Ford saw itself in 18th.
Elon Musk
Tesla Full Self-Driving v14.2.1 texting and driving: we tested it
We decided to test it, and our main objective was to try to determine a more definitive label for when it would allow you to grab your phone and look at it without any nudge from the in-car driver monitoring system.
On Thursday, Tesla CEO Elon Musk said that Full Self-Driving v14.2.1 would enable texting and driving “depending on [the] context of surrounding traffic.”
Tesla CEO Elon Musk announces major update with texting and driving on FSD
We decided to test it, and our main objective was to try to determine a more definitive label for when it would allow you to grab your phone and look at it without any nudge from the in-car driver monitoring system.
I’d also like to add that, while Tesla had said back in early November that it hoped to allow this capability within one to two months, I still would not recommend you do it. Even if Tesla or Musk says it will allow you to do so, you should take into account the fact that many laws do not allow you to look at your phone. Be sure to refer to your local regulations surrounding texting and driving, and stay attentive to the road and its surroundings.
The Process
Based on Musk’s post on X, which said the ability to text and drive would be totally dependent on the “context of surrounding traffic,” I decided to try and find three levels of congestion: low, medium, and high.
I also tried as best as I could to always glance up at the road, a natural reaction, but I spent most of my time, during the spans of when it was in my hand, looking at my phone screen. I limited my time looking at the phone screen to a few seconds, five to seven at most. On local roads, I didn’t go over five seconds; once I got to the highway, I ensured the vehicle had no other cars directly in front of me.
Also, at any time I saw a pedestrian, I put my phone down and was fully attentive to the road. I also made sure there were no law enforcement officers around; I am still very aware of the law, which is why I would never do this myself if I were not testing it.
I also limited the testing to no more than one minute per attempt.
I am fully aware that this test might ruffle some feathers. I’m not one to text and drive, and I tried to keep this test as abbreviated as possible while still getting some insight on how often it would require me to look at the road once again.
The Results
Low Congestion Area
I picked a local road close to where I live at a time when I knew there would be very little traffic. I grabbed my phone and looked at it for no more than five seconds before I would glance up at the road to ensure everything was okay:
In full: the Low Congestion Area pic.twitter.com/6DqlBnekPn
— TESLARATI (@Teslarati) December 4, 2025
Looking up at the road was still regular in frequency; I would glance up at the road after hitting that five-second threshold. Then I would look back down.
I had no nudges during this portion of the test. Traffic was far from even a light volume, and other vehicles around were very infrequently seen.
Medium Congestion Area
This area had significantly more traffic and included a stop at a traffic light. I still kept the consecutive time of looking at my phone to about five seconds.
I would quickly glance at the road to ensure everything was okay, then look back down at my phone, spending enough time looking at a post on Instagram, X, or Facebook to determine what it was about, before then peeking at the road again.
There was once again no alert to look at the road, and I started to question whether I was even looking at my phone long enough to get an alert:
In full: the Medium Congestion Area pic.twitter.com/gnhIfBVe6Q
— TESLARATI (@Teslarati) December 4, 2025
Based on past versions of Full Self-Driving, especially dating back to v13, even looking out the window for too long would get me a nudge, and it was about the same amount of time, sometimes more, sometimes less, I would look out of a window to look at a house or a view.
High Congestion Area
I decided to use the highway as a High Congestion Area, and it finally gave me an alert to look at the road.
As strange as it is, I felt more comfortable looking down at my phone for a longer amount of time on the highway, especially considering there is a lower chance of a sudden stop or a dangerous maneuver by another car, especially as I was traveling just 5 MPH over in the left lane.
This is where I finally got an alert from the driver monitoring system, and I immediately put my phone down and returned to looking at the road:
In full: the High Congestion Area pic.twitter.com/K9rIn4ROvm
— TESLARATI (@Teslarati) December 4, 2025
Once I was able to trigger an alert, I considered the testing over with. I think in the future I’d like to try this again with someone else in the car to keep their eyes on the road, but I’m more than aware that we can’t always have company while driving.
My True Thoughts
Although this is apparently enabled based on what was said, I still do not feel totally comfortable with it. I would not ever consider shooting a text or responding to messages because Full Self-Driving is enabled, and there are two reasons for that.
The first is the fact that if an accident were to happen, it would be my fault. Although it would be my fault, people would take it as Tesla’s fault, just based on what media headlines usually are with accidents involving these cars.
Secondly, I am still well aware that it’s against the law to use your phone while driving. In Pennsylvania, we have the Paul Miller Law, which prohibits people from even holding their phones, even at stop lights.
I’d feel much more comfortable using my phone if liability were taken off of me in case of an accident. I trust FSD, but I am still erring on the side of caution, especially considering Tesla’s website still indicates vehicle operators have to remain attentive while using either FSD or Autopilot.
Check out our full test below:
Elon Musk
Tesla CEO Elon Musk announces major update with texting and driving on FSD
“Depending on context of surrounding traffic, yes,” Musk said in regards to FSD v14.2.1 allowing texting and driving.
Tesla CEO Elon Musk has announced a major update with texting and driving capabilities on Full Self-Driving v14.2.1, the company’s latest version of the FSD suite.
Tesla Full Self-Driving, even in its most mature and capable versions, is still a Level 2 autonomous driving suite, meaning it requires attention from the vehicle operator.
You cannot sleep, and you should not take attention away from driving; ultimately, you are still solely responsible for what happens with the car.
The vehicles utilize a cabin-facing camera to enable attention monitoring, and if you take your eyes off the road for too long, you will be admonished and advised to pay attention. After five strikes, FSD and Autopilot will be disabled.
However, Musk announced at the Annual Shareholder Meeting in early November that the company would look at the statistics, but it aimed to allow people to text and drive “within the next month or two.”
He said:
“I am confident that, within the next month or two, we’re gonna look at the safety statistics, but we will allow you to text and drive.”
“I am confident that, within the next month or two, we’re gonna look at the safety statistics, but we will allow you to text and drive.”
Does anyone think v14.3 will enable this? pic.twitter.com/N2yn0SK70M
— TESLARATI (@Teslarati) November 23, 2025
Today, Musk confirmed that the current version of Full Self-Driving, which is FSD v14.2.1, does allow for texting and driving “depending on context of surrounding traffic.”
Depending on context of surrounding traffic, yes
— Elon Musk (@elonmusk) December 4, 2025
There are some legitimate questions with this capability, especially as laws in all 50 U.S. states specifically prohibit texting and driving. It will be interesting to see the legality of it, because if a police officer sees you texting, they won’t know that you’re on Full Self-Driving, and you’ll likely be pulled over.
Some states prohibit drivers from even holding a phone when the car is in motion.
It is certainly a move toward unsupervised Full Self-Driving operation, but it is worth noting that Musk’s words state it will only allow the vehicle operator to do it depending on the context of surrounding traffic.
He did not outline any specific conditions that FSD would allow a driver to text and drive.
Tesla reliability rankings skyrocket significantly in latest assessment
Tesla Full Self-Driving v14.2.1 texting and driving: we tested it
