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Tesla Semi and Roadster could be relying on a “battery breakthrough”

Published

8 years ago

December 9, 2017

Evannex

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.

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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.

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“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.

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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

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Evannex

EVANNEX carries aftermarket accessories, parts, and gear for Tesla owners. Its blog is updated daily with Tesla news.

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Tesla analyst sees Full Self-Driving adoption rates skyrocketing: here’s why

“You’ll see increased adoption as people are exposed to it. I’ve been behind the wheel of several of these and the different iterations of FSD, and it is getting better and better. It’s something when people experience it, they will be much more comfortable utilizing FSD and paying for it.”

Published

38 minutes ago

November 18, 2025

Joey Klender

tesla interior operating on full self driving

Credit: TESLARATI

Tesla analyst Stephen Gengaro of Stifel sees Full Self-Driving adoption rates skyrocketing, and he believes more and more people will commit to paying for the full suite or the subscription service after they try it.

Full Self-Driving is Tesla’s Level 2 advanced driver assistance suite (ADAS), and is one of the most robust on the market. Over time, the suite gets better as the company accumulates data from every mile driven by its fleet of vehicles, which has swelled to over five million cars sold.

The suite features a variety of advanced driving techniques that many others cannot do. It is not your typical Traffic-Aware Cruise Control (TACC) and Lane Keeping ADAS system. Instead, it can handle nearly every possible driving scenario out there.

It still requires the driver to pay attention and ultimately assume responsibility for the vehicle, but their hands are not required to be on the steering wheel.

It is overwhelmingly impressive, and as a personal user of the FSD suite on a daily basis, I have my complaints, but overall, there are very few things it does incorrectly.

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Tesla Full Self-Driving (Supervised) v14.1.7 real-world drive and review

Gengaro, who increased his Tesla price target to $508 yesterday, said in an interview with CNBC that adoption rates of FSD will increase over the coming years as more people try it for themselves.

At first, it is tough to feel comfortable with your car literally driving you around. Then, it becomes second nature.

Gengaro said:

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Tesla Full Self-Driving take rates also have to increase as part of CEO Elon Musk’s recently approved compensation package, as one tranche requires ten million active subscriptions in order to win that portion of the package.

The company also said in the Q3 2025 Earnings Call in October that only 12 percent of the current ownership fleet are paid customers of Full Self-Driving, something the company wants to increase considerably moving forward.

News

Tesla scores major court win as judge rejects race bias class action

The ruling means the 2017 lawsuit cannot proceed as a class action because plaintiff attorneys were unable to secure testimony commitments from at least 200 workers.

Published

5 hours ago

November 18, 2025

Simon Alvarez

Credit: Tesla

Tesla scored a significant legal victory in California after a state judge reversed a class certification in a high-profile race harassment case involving 6,000 Black workers at its Fremont plant. The ruling means the 2017 lawsuit cannot proceed as a class action because plaintiff attorneys were unable to secure testimony commitments from at least 200 workers ahead of a 2026 trial, a threshold the judge viewed as necessary to reliably represent the full group.

No class action

In a late-Friday order, California Superior Court Judge Peter Borkon concluded that the suit could not remain a class action, stating he could not confidently apply the experiences of a much smaller group of testifying workers to thousands of potential class members. His ruling reverses a 2024 decision by a different judge who had certified the case under the belief that a trial of that size would be manageable, as noted in a Reuters report.

The lawsuit was originally filed by former assembly-line worker Marcus Vaughn, who alleged that Black employees at Tesla’s Fremont factory were exposed to various forms of racially hostile conduct, including slurs, graffiti, and instances of disturbing objects appearing in work areas. Tesla has previously said it does not tolerate harassment and has removed employees found responsible for misconduct. Neither Tesla nor the plaintiffs’ legal team immediately commented on the latest ruling.

Tesla’s legal challenges

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While the decertification narrows the scope of this particular case, Tesla still faces additional litigation over similar allegations. A separate trial involving related claims brought by a California state civil rights agency is scheduled just two months after the now-vacated class trial date. The company is also contending with federal race discrimination claims filed by the U.S. Equal Employment Opportunity Commission, alongside several individual lawsuits it has already resolved.

For now, the reversal removes the large-scale exposure Tesla would have faced in a unified class trial, shifting the dispute back to individual claims rather than a single mass action. The case is Vaughn v. Tesla, filed in Alameda County Superior Court.

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Tesla Holiday Update is incoming, and the wishlist is Merry and Bright

There are a handful of big wishes, and we’ve seen a lot of different requests out there based on what owners are saying on social media. Nevertheless, what Tesla should bring and what Tesla will bring are two different things.

Published

23 hours ago

November 17, 2025

Joey Klender

Tesla’s Holiday Update is going to be on its way soon, and although we have no idea what the company is planning to implement into vehicles with the 2025 iteration.

However, the wishlist is extensive, and owners are hoping to get a vast array of new features, both useful and artificial. That’s the fun thing about owning a Tesla — not everything is necessary, and it’s okay for your car to be fun.

🚨 All I Want for Christmas (in the Tesla Holiday Update) is:

1. More streaming platforms
2. Summon for Cybertruck
3. Easier Navigation adjustment for a preferred route instead of the optimal choice

What else? pic.twitter.com/qapS1jXAuB

— TESLARATI (@Teslarati) November 16, 2025

In past years, Tesla has brought both useful things and fun things with the Holiday Update. The Custom Lock Sound, new Light Shows, and even High Fidelity Park Assist have all come in past updates, among many other things. But for 2025, people want even more, and here’s what we have seen most frequently thus far:

More Streaming Platforms

This is a personal request of ours, and it’s something that we feel is long overdue.

Sure, Netflix, Disney+, and Hulu are all great — but there’s a lot of meat left on that bone. HBOMax, Paramount+, and even YouTube TV would be a great option for those of us who have subscriptions and want to watch Live Events while Supercharging or eating in our cars.

The fact that Tesla has not added more platforms to its in-car Theater in a few years has been, dare I say, disappointing?

Full Self-Driving for Europe

This is something not even Santa can help with. Although his Elves are known for their high productivity, we’re not even sure they could convince European regulators to open the door for FSD’s entrance into the market.

Tesla deploys Unsupervised FSD in Europe for the first time—with a twist

FSD is definitely capable of handling European driving conditions, but regulators are truly dragging their feet through the mud with the approval process. Tesla has tested FSD in several countries in Europe, but nothing has been set in stone yet.

Deeper Grok Integration

Many owners have said something about how Grok is truly not super in-tune with the vehicles. This is something any owner will experience.

It seems Grok should be capable of handling all in-car requests; everything from changing the A/C to a specific temperature to adding a stop within the Navigation should be handled by Grok.

Instead, Grok cannot handle those things currently. You have to speak to the car itself using the microphone button on the steering wheel.

Interestingly, some vehicles already have the Grok logo replacing the microphone. It is likely the most realistic request of all.

‘Learn’ Mode for Full Self-Driving Arrival Options

Although it is great for public destinations, FSD still does not allow you to choose a set parking spot at your residence. It also does not allow you to choose preferences for parking in large parking lots.

Renters, and even those who live in purchased townhomes, often have assigned parking spots. Full Self-Driving v14 has done a great job of doing half the work, but there have been too many times when I’ve arrived home, the car pulls me into a spot, and I’m forced to manually back out and park in my assigned space.

Many people also do not like to park toward the entrance of a store, me included. Parking away from the front of a store eliminates parking congestion and usually is a safer bet for your vehicle to keep from being dinged by careless drivers who swing their doors open.

Navigation Adjustments

Sometimes you don’t want to turn left on the street the navigation chooses. Maybe you want to go a block down and check out that new Portuguese restaurant that just opened on the way to your next destination.

This is only possible currently by inputting a waypoint that would take you that way. Instead, the center screen could be opened, and the driver should be able to select an alternative route by simply touching a street they’d rather travel on.