BMW, Daimler Agree to Develop Wireless Charging System

Rivals BMW AG and Daimler AG are collaborating to develop a common system to recharge their electric and plug-in hybrid vehicles wirelessly.

The inductive system transmits energy between a pad that can be placed on a garage floor or parking space and a secondary coil built into the vehicle's undertray. The system works indoors or outdoors in virtually all weather conditions.

The driver begins the charging process by pressing a button. The car's own operating system establishes a wi-fi communication link between the vehicle and charging station to help position the car above the primary coil and begin the charging process. The system also monitors the space between the coils and shuts down immediately if it detects a foreign object.

The wireless 3.6-kW system can recharge a plug-in car's battery in about three hours, according to BMW. The company says a 7-kW system may be developed for all-electric cars so their larger batteries can be fully charged overnight.

Daimler will test the system with its S 500 plug-in hybrid luxury sedan, which will go on sale in September. The car can travel 33 km (20 miles) on electric power alone. Its powertrain, which delivers 436 hp and 479 lb-ft of torque, emits only 65 grams of carbon dioxide per kilometer on the New European Driving Cycle, according to the company.

BMW aims to use the charging technology with its "I" series electric cars and future plug-in hybrid models.