When Elon Musk stepped on stage at Tesla’s product-launch event earlier this month, he knew the market’s confidence in Tesla’s brand had sunk to an all-time low since he took over the company a decade ago. So, he resorted to a tactic that should be familiar to anybody who has been following the company: Shock and awe.

While the event was ostensibly scheduled to introduce Tesla’s new semi-truck – a model that won’t make it’s market debut for another two years, assuming Tesla sticks to its product-rollout deadline – Musk had a surprise in store: A new model of the Tesla Roadster that, he bragged, would be the fastest production car ever sold.

Musk made similarly lofty claims about the battery life and performance of both vehicles. The Tesla semi-trucks, he said, would be able to travel for 500 miles on a single charge. The roadster could clock a staggering 620 – more than double the closest challenger.

There was just one problem, as Tesla fans would later find out, courtesy of Bloomberg: None of it was true.

In fact, many of the promises defy the capabilities of modern battery technology.

Elon Musk knows how to make promises. Even by his own standards, the promises made last week while introducing two new Tesla vehicles—the heavy-duty Semi Truck and the speedy Roadster—are monuments of envelope pushing.

To deliver, according to close observers of battery technology, Tesla would have to far exceed what is currently thought possible.

Take the Tesla Semi: Musk vowed it would haul an unprecedented 80,000 pounds for 500 miles on a single charge, then recharge 400 miles of range in 30 minutes. That would require, based on Bloomberg estimates, a charging system that’s 10 times more powerful than one of the fastest battery-charging networks on the road today—Tesla’s own Superchargers.

The diminutive Tesla Roadster is promised to be the quickest production car ever built. But that achievement would mean squeezing into its tiny frame a battery twice as powerful as the largest battery currently available in an electric car.

These claims are so far beyond current industry standards for electric vehicles that they would require either advances in battery technology or a new understanding of how batteries are put to use, said Sam Jaffe, battery analyst for Cairn Energy Research in Boulder, Colorado. In some cases, experts suspect Tesla might be banking on technological improvements between now and the time when new vehicles are actually ready for delivery.

“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.”