Canadian researchers say they've developed a safe, efficient technology to wirelessly charge electric vehicles using "remote magnetic gears."

"Wireless charging has been a much sought-after technical solution for everything from cellphones to electric cars," University of British Columbia physics Professor Lorne Whitehead says.

"A significant concern for charging cars wirelessly has been the high power and high frequency electromagnetic fields and their unknown, potential health effects on humans."

A system invented by Whitehead and his research team operates at a frequency 100 times lower and with negligible exposed electric fields, a UBC release reported Monday.

Their system uses "remote magnetic gears" -- a rotating base magnet driven by electricity from the grid, and a second located within the car -- to eliminate the use of radio waves.

The base gear remotely spins the in-car gear, which in turns generates power to charge the battery.

Four wireless charging stations have been installed in a campus parking lot and university service vehicles have been retrofitted with the new technology.

Tests show the system is more than 90 percent efficient compared to a cable charge, giving a full charge in 4 hours that enables the vehicles to run for an eight-hour shift, the researchers said.

"Since we began testing the system, the feedback from drivers has been overwhelmingly positive -- all they have to do is park the car and the charging begins automatically," said David Woodson, managing director of UBC Building Operations.