Alongside the development of self-driving electric cars, technology giant Google is looking into wireless charging systems.

Google’s parent company Alphabet has filed documents with the U.S. Federal Communication Commission (FCC) that reveal that company has been testing two different wireless charging systems.

The first was installed at Google’s California HQ in February, 2015 by Hevo Power while the second unit was installed in July by Momentum Dynamics. The address for Momentum’s installation corresponds to secret ‘X division’ self-driving car testing locations.

Hevo’s charger is said to be able to deliver 1.5 kilowatts of power from a charger which is “embedded like a manhole cover” in pavement. Momentum Dynamics claims its chargers can send up to 200 kW, although the filings didn’t confirm this.

Google’s vision of the self-driving car future includes wireless charging pads where the cars can park for short periods of time between trips and recharge. Ultimately, infrastructure that constantly recharges these cars as they drive is the goal.

SEE ALSO: Dear Elon Musk: Your Wireless Charging Solution is Here

The CEO of Momentum Dynamics, Andy Daga, says that his company can already recharge electric bus batteries in a matter of minutes, allowing them to operate for up to 24 hours at a time.

Wireless charging is available currently through aftermarket companies, though next year the Society of Automobile Engineers will issue final standards for wireless charging systems, likely making them more common.

This article originally appeared at