Elon Musk says that Tesla Motors will offer an upgrade to the Roadster, which is no longer in production, that will increase the range from around 240 miles (~385 km) to nearly 400 miles (~640 km) – Elon Musk on Twitter:

Roadster upgrade will enable non-stop travel from LA to SF — almost 400 mile range. Details tmrw. Merry Christmas!”

That’s close to the max range of most gasoline powered cars. There is still the big challenge to lower the very high cost of the battery packs but Tesla is clearly making good progress in EV technology.

Earlier in the week, Tesla also demonstrated a fast battery swap system for the Model S:

Update: Elon added this to his tweet above – Elon Musk on Twitter:

Should mention that a battery pack upgrade is not coming soon for the Model S, but it obviously *will* happen long-term.

Update 2: Here are the details : Roadster 3.0 – Blog/Tesla Motors –

Battery technology has continued a steady improvement in recent years, as has our experience in optimizing total vehicle efficiency through Model S development. We have long been excited to apply our learning back to our first vehicle, and are thrilled to do just that with the prototype Roadster 3.0 package. It consists of three main improvement areas.

1. Batteries
The original Roadster battery was the very first lithium ion battery put into production in any vehicle. It was state of the art in 2008, but cell technology has improved substantially since then. We have identified a new cell that has 31% more energy than the original Roadster cell. Using this new cell we have created a battery pack that delivers roughly 70kWh in the same package as the original battery.

2. Aerodynamics
The original Roadster had a drag coefficient (Cd) of 0.36. Using modern computational methods we expect to make a 15% improvement, dropping the total Cd down to 0.31 with a retrofit aero kit.

3. Rolling Resistance
The original Roadster tires have a rolling resistance coefficient (Crr) of 11.0 kg/ton. New tires that we will use on the Roadster 3.0 have a Crr of roughly 8.9 kg/ton, about a 20% improvement. We are also making improvements in the wheel bearings and residual brake drag that further reduce overall rolling resistance of the car.

Summary
Combining all of these improvements we can achieve a predicted 40-50% improvement on range between the original Roadster and Roadster 3.0. There is a set of speeds and driving conditions where we can confidently drive the Roadster 3.0 over 400 miles. We will be demonstrating this in the real world during a non-stop drive from San Francisco to Los Angeles in the early weeks of 2015.

Appointments for upgrading Roadsters will be taken this spring once the new battery pack finishes safety validation. We are confident that this will not be the last update the Roadster will receive in the many years to come.