In a post on the company blog, Tesla Motors outlined the areas addressed with an upcoming a Roadster 3.0 upgrade, based on learnings from the Model S. Tesla also said no new Model S battery pack or major range upgrade is expected in the near term. The prototype Roadster 3.0 package consists of three main improvement areas:
Batteries. Tesla said it has identified a new LI-ion cell that has 31% more energy than the original Roadster cell. Using this new cell, they have created a battery pack that delivers roughly 70 kWh in the same package as the original battery.
Aerodynamics. The original Roadster had a drag coefficient (Cd) of 0.36. Using modern computational methods, Tesla expects to make a 15% improvement, dropping the total Cd down to 0.31 with a retrofit aero kit.
Rolling Resistance. The original Roadster tires have a rolling resistance coefficient (Crr) of 11.0 kg/ton. New tires on the Roadster 3.0 have a Crr of roughly 8.9 kg/ton, about a 20% improvement. Tesla is also making improvements in the wheel bearings and residual brake drag that further reduce overall rolling resistance of the car.
Tesla expects the combination of the three to deliver a 40-50% improvement on range between the original Roadster and Roadster 3.0. There is a set of speeds and driving conditions under which Tesla says it can confidently drive the Roadster 3.0 more than 400 miles. Tesla will demonstrate this in the real world during a non-stop drive from San Francisco to Los Angeles in the early weeks of 2015.