he automotive industry continues to develop new powertrain and vehicle technologies with battery electric or hybrid electric drives. An important aspect for customer acceptance of battery electric vehicles is the expected driving range with one battery charge. Due to weight and cost of the battery cells, it is desirable to increase range by improving driveline- and overall vehicle efficiency without sacrifices in vehicle comfort and performance. This presentation will initially showcase key drivetrain components, how their efficiency and performance can be evaluated via state-of-the-art simulation and testing methods. In addition to component level testing- and simulation methods, vehicle level testing for range determination will be described. Details of vehicle measurements for range certification and in-vehicle evaluation such as drive cycles, temperatures and vehicle conditioning will be highlighted. Operating temperatures during vehicle operation and thermal management optimization can have a significant impact on vehicle range. Examples from testing and simulation of state-of-the-art battery electric vehicles will be utilized to describe efficiencies in various portions of the drivetrain, as well as full vehicle systems.