Tesla Motors has made a habit out of making continued improvements to its vehicles after they leave the showroom, sometimes with software "updates" that look like recalls, and sometimes with actual improvements.
The company announced one of the latter on Friday, giving Tesla Roadster owners a "Roadster 3.0" holiday gift.
Tesla said in a statement that battery technology is so improved that the company will do a nonstop run from San Francisco to Los Angeles shortly after Jan. 1 -- demonstrating a claimed best-in-class range of more than 400 miles.
That's a substantial improvement over the current Roadster's claimed 245-mile range.
The extended mileage is also due in part to a lower drag coefficient, the company said, and to reduced rolling resistance. In layman's terms, that means improved aerodynamics and better coasting as a result of lower friction from tires and brakes.
Tesla said its new Roadster 3.0 battery is 31% more efficient than the battery it introduced in 2008.
The company stopped building the Roadster in 2012, to concentrate on its Model S and upcoming Model X models.
What Tesla won't say is when the Roadster 3.0 package will be available to current owners, or at what price -- because the retrofit is still in the prototype phase.
Tesla owners without the upgrade can still drive from San Francisco to Los Angeles with almost no stops, if they take advantage of the company's station at Harris Ranch, roughly the midway point between the two cities on the Interstate 5 corridor, or at the Atascadero supercharger, along the 101 Freeway.