Every one of the modern electric cars on the market for almost seven years requires plugging in a cord to recharge the battery using grid electricity.
Inserting the cord into the socket takes just a few seconds, and most cars today are charged overnight.
But soon there will be another option: wireless charging, in which the car is positioned over a pad on the floor or ground, with no need to plug in anything.
Inductive charging, as it's known technically, transfers power through coils in the pad and corresponding coils on the underside of the vehicle.
The two coils generate an alternating magnetic field, through which electricity is transmitted without cables or contacts
Such a system is not inexpensive, and it's always been expected on pricier luxury brands first.
Now, BMW has announced that it will offer wireless charging next year as an option on its BMW 530e iPerformance plug-in hybrid sedan.
Inductive charging substitutes for plugging in at a conventional 240-volt Level 2 charging station; most such standardized equipment today runs at up to 7.2 kilowatts.
The system to be offered by BMW operates at 3.2 kilowatts, equal to the least powerful onboard charger in a handful of base-model electric cars, including the Nissan Leaf.
BMW says the system can be used indoors or outdoors, and will charge the 530e's 9.2-kilowatt-hour battery pack in roughly three and a half hours.
The 2018 BMW 530e plug-in hybrid was unveiled last December and will go on sale in the U.S. within months; it has not yet been rated for range or efficiency by the EPA, though BMW quotes a 28-mile electric range on the gentler European cycle.
Its 2.0-liter turbocharged inline-4 is pairedwith a single electric motor integrated into the 8-speed automatic transmission. Total peak output of the powertrain is 248 horsepower and 310 pound-feet of torque.
The car's conventional plug-in charging port remains, of course, as it will on the Mercedes-Benz 550e plug-in hybrid, another German luxury sedan that will offer optional inductive charging next year.
Wireless-charging companies suggest that the convenience of not having to open the door over a port and unfurl a cable from the wall unit to plug in will be attractive to some buyers.
That convenience will increase when cars with some self-driving abilities can maneuver themselves into position in exactly the right place over the fixed charging pad.
That will eliminate the need for the driver to position the parked car carefully in the right place to allow charging.