Electric car manufacturer Tesla recently announced the charging speed and capacity of two new vehicle models that some experts claim far exceed what is possible using current technology.

Bloomberg reports that Tesla’s current estimates for both charging speed and capacity of the vehicles far exceed the capabilities of the fastest charging stations on the markets today, the Tesla supercharger. The company claims that their semi truck would transport approximately 80,000 pounds as far as 500 miles on just one charge and would be capable of recharging 400 miles of range in 30 minutes, a figure that would require a charging system ten times more powerful than Tesla’s own superchargers.

Tesla’s Roadster, which plans to be the quickest production car ever made, would have to hold a battery twice as powerful as the largest battery currently available for any electric car inside the vehicle’s notably smaller frame. Tesla’s promises so far go against all industry standards for electric vehicles and would require massive advances in battery technology or an entire rewriting of how batteries work for the company to deliver on these promises according to Sam Jaffe, battery analyst for Cairn Energy Research in Boulder, Colorado.

“I don’t think they’re lying,” Jaffe said. “I just think they left something out of the public reveal that would have explained how these numbers work.” Salim Morsy, an electric vehicle analyst at Bloomberg New Energy Finance, commented on Tesla’s claim that they can charge their new semi truck to a 400-mile charge capacity in just 30 minutes, saying, “I don’t understand how that works, I really don’t.”

Tesla also claims that their fastest car so far, the Roadster, will have a battery range of 620 miles on one charge, a longer charge than any battery-powered vehicle available today. According to Morsy, one of the only ways this could possibly be achievable would be to stack batteries on top of each other under the car’s flooring, but still, these batteries would not fit in the Roadster based oits’s current compact design. “I really don’t think the car you saw last week had the full 200 kilowatt hours in it,” Morsy said. “I don’t think it’s physically possible to do that right now.”

Battery density may be key to Tesla’s claims, and given the battery density has been increasing at a rate of 7.5 percent a year, by the time Tesla’s new vehicles are in production they may have better capabilties.

“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.”