Tesla CEO Elon Musk has shown off an upcoming advance in the service it provides for its electric cars after demonstrating the first battery pack swap for a Model S. Two cars were serviced in the time that it took for a pre-recorded filling of a 20-plus gallon gas tank, indicating the simplicity and speed of the process.

Currently, Tesla cars can be recharged for free at a Supercharger station, but the process takes between 20-30 minutes and yields three hours of driving time. The new option is for those who are in a rush or without patience.

It is, however, not free and will cost somewhere between $60-$80. Tesla says that figure is based on the local price of a 15 gallon tank of gas — a reasonable comparison for a ‘fill up’.

That rate is based on ‘loaning’ the new battery not buying it outright. When a Tesla owner returns to the original supercharger station they get their original battery back (fully charged) and pay the refill fee again. Those that opt to keep the new battery pack must pay the difference in cost — which is worked out based on the difference in age between the new and original batteries.

Musk says that the recharging stations cost Tesla some $500,000 a pop, and they will be installed at selected charger stations, initially on the I5 corridor in California and Boston-DC route on East Coast. The swap facilities should arrive before the end of the year, most likely in the final quarter, he added.

“I think it’s important for us to address the concerns that people have. We need to address the reasons that people aren’t buying electric cars,” Musk said. “People need to feel that they have the same level of freedom as a gasoline car.”

Musk also said he will entertain the possibility of third party involvement, though he noted that vendors would be required to make their setup at least as convenient as Tesla’s.

Tesla engineers had been planning for a battery swap option since day one. The swap system is built into the ground and automatically removes the pack from the floor of the car, changes coolant and then re-bolts the new battery to the vehicle.

With this new move, Tesla’s is positing its Model S as something that is as convenient as a gas-powered car, in order to counter the argument that electric vehicles are inconvenient and bothersome.

Generally, it will be better for people to take a pit stop and wait for the free supercharge. But, by introducing the battery swap, Tesla presents a quicker option to those in a rush or unconcerned by paying what amounts to a regular gas charge to top up.

Josh Ong contributed reporting to this article.