Google's prototype self-driving car. AP Hands-free driving isn't the only trick Google wants its autonomous cars to perform.

Google-parent company Alphabet is testing a way to wirelessly recharge the electric batteries on its self-driving cars, according to a report in IEEE Spectrum.

The technology would allow Google's pod-shaped cars to juice up their electric batteries simply by rolling over a special charging transmitter in the ground, similar to a manhole cover on the street, rather than needing to be plugged into a wall with a power cable, according to the report.

The technology uses resonant magnetic induction to basically beam power into the underside of the car. In theory the system could allow the cars to recharge themselves as they travel, rolling over a network of such special transmitters embedded in the pavement.

Google is testing the technology at its Googleplex headquarters in Mountain View, Califonia, as well as its special self-driving car testing facility in Merced, California, the report notes, citing recent FCC filings by two companies developing the wireless-charging technology. Google is testing systems made by Hevo Power and Momentum Dynamics.

Google told IEEE Spectrum that it tests many different technologies for its self-driving cars.