Investigating the Use of Vehicle-Mounted Wind Turbines to Partially Recharge EV Batteries and Extend EV Range

Drivers of electric vehicles (EVs) are currently limited to 200 - 350 miles of range on a single charge. In this study, we investigate the capacity for vehicle-mounted wind turbines to extend EV range. As a function of (simulated) vehicle speed, v, i.e., encountered wind speed, we measured the rotation rates, drag forces, F_D, and corresponding drag power losses, P_D, experienced by several wind turbine models. For top performing turbines (high RPMs and low drag), we then measured the power generated, P_T, as a function of v, as selected turbines turned the axis of a generator. Our power data is well described by a power law: P_T = Av^k. The power loss due to drag is also well characterized by a power law: P_D = F_Dv = Dvⁿ. We discuss the turbine geometries and velocity ranges for which P_T exceeds P_D in our laboratory experiments. In scheduled, future experiments, we will test power production vs. drag losses for a prototype system in a wind tunnel.