Electric vehicles are the future of personal transportation – but hooking your car up to a cable every time you stop can be a drag. Several automakers are working on wireless inductive technology that can recharge electric vehicles without cables – and BMW just announced that it’s testing the technology with its i3 and i8 electric vehicles.

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The biggest advantage of inductive charging over conventional charging stations is the cable-free connection between the supply point and the vehicle’s high-voltage battery. Drivers can simply position their electric vehicle over a system embedded in the floor of their garage to charge it. BMW and Daimler have signed an agreement for the joint development and implementation of a standardized technology for inductive charging electric cars and plug-in hybrid vehicles. The system consists of two components: A base plate with a primary coil is located on the ground underneath the car, and a secondary coil is located in the vehicle’s floor.

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Electrical energy is transmitted via an alternating magnetic field generated between the coils, contact-free, without charging cables and at a charging rate of 3.6 kW, with an efficiency factor of over 90 percent. BMW estimates that the i8’s battery can be recharged in about two hours, and engineers are currently working on doubling the charging rate to fully recharge the i3 overnight.