Tesla system will swap a Model S battery in 90 seconds

"This is the title fight," said Elon Musk, in typical brashness. "This is battery-powered versus gasoline."

The Tesla CEO preached this to a crowd of Tesla owners and supporters while formally confirming the company's worst-kept secret: the fact that the Model S sedan's batteries were designed from the beginning to be swapped out. The system Tesla envisioned has plenty of ambitious, techno-wizardry automation, with a focus on as much convenience as possible: The Model S will drive over a pit containing machinery which automatically changes the battery from underneath in approximately 90 seconds -- and the driver doesn't even have to get out of the car.

Remember, this is the same company that built a network to charge cars for free. Next door, they're building rockets. As impressive as Tesla's Supercharger network is -- available from here to Folsom, Boston to DC, and points between coming soon -- it still takes 20 minutes at best to charge up a Model S. Some people just don't have time for that. That's why the swappable battery pack was designed into the Model S from its inception.

Future Tesla models will all use the same form factor, even if internal changes will wring out even more energy and range -- making the next generation of Tesla cars backwards-compatible. Each battery pack will carry a warranty of eight years.

The first Tesla stations with automated battery-swapping pits will launch by the end of this year on California's Interstate 5. Once a Model S drives onto a pit at such a station, robotized nut drivers are programmed to find the bolts holding the underslung battery pack in place. Because the battery is liquid-cooled, the pit uses automatic liquid disconnects to prevent spilling. Arms lower the old battery, jettison it underneath, then descend underground to grab a fresh new battery. When it is installed onto the Model S, the nut drivers will torque the bolts precisely to factory spec.

To demonstrate, a red Tesla Model S drove onstage above one such pit, while a timer counted down alongside video of a Tesla employee filling up an Audi A8 at a local gas station. (Musk estimated the gas tank to be approximately 20 gallons, which -- at an official listing of 23.8 gallons -- was on the mark.) Machines whirred, the car was raised, and mechanical arms scurried underneath, and after exactly 1:33.4 minutes the red Model S drove offstage. The poor Tesla employee was still filling up the tank. So another Model S drove up. This one took 1:36.6 minutes. It too drove off to wild applause.

If all of this sounds familiar, then it is -- Better Place had the same idea, but famously imploded after bleeding money for three straight years. Said Musk, "it's worth noting that Shai Agassi got the idea from a visit to Tesla. We talked about battery swaps for a long time. This isn't a revelation. They were better at marketing than they were at engineering."

How much will all this cost? The Supercharger will still and always be free, Musk assured us. But for a fresh battery pack, Tesla aims for a cost that's the same as a full tank of gas. Yet the costs are a little more involved than that: the original battery can be reinstalled on the way back or the new battery can be kept as well, with the old battery delivered to owners for a "transport fee." Billing will be electronically charged to the customer. No word on whether Paypal or Bitcoin are an acceptable means of payment.

Building and installing the pits won't be cheap either -- Musk estimates half a million dollars per station, to say nothing of infrastructure, upkeep, and energy usage charging batteries day in and day out. But he's not worried. "The expense is on Tesla," he said. "I suppose we'll be less profitable. But we'll just deal with it."

Blake Z. Rong
Elon Musk fields questions from journalists and silently hides his contempt.

Musk envisions a network of Tesla stations, not just Superchargers, blanketing the highways and byways of America. Each station will have a pit for automatic swapping, and as many as 50 spare battery packs, all recharging directly from the station. That would imply that a lot of Model S cars will be on the road -- not so farfetched, Musk claimed, since Model S sales are only production-limited at the moment.

By Blake Z. Rong