Manhole Covers May Charge New Yorkers’ Next Electric Vehicles

by Clifford Atiyeh
October 22nd 2013

Whenever we drive in cities, dodging manhole covers becomes something of a game. In places like Detroit and New York, they’re often recessed under layers of crumbling pavement, creating a camouflaged trap for delicate rims and low-profile tires. But one NYC startup wants to direct drivers toward manhole covers—so they can wirelessly recharge an electric vehicle while grabbing a coffee.Hevo Power, a seven-man startup armed with another dozen NYU professors and grad students, isn’t trying to mess with the city’s sewer system.

By early next year, as first reported by Wired, the group will install two magnetic resonance charging pads made from a fiberglass composite that resemble manhole covers—and perhaps most important, fit flush to the pavement.
The test cars, a pair of Smart ForTwo Electric Drive models equipped with the company’s 10-pound wireless receivers and an AC-to-DC converter, will juice up curbside at NYU’s Washington Square campus without any cords.Unlike inductive charging bases used for electric toothbrushes or the interior mats Chrysler, GM, andToyota offer to replenish smartphones, Hevo relies on magnetic resonance. Like induction, magnetic resonance transfers electrical energy with magnetic fields generated by coils, but adds capacitors that resonate at a matched frequency between the car and the charging pad. The result is a more forgiving field that doesn’t need to be lined up perfectly to work and can even wrap around interfering objects. Hevo’s electronics optimize the frequency to the car’s ride height (greater distances can reduce the power) and then relay information to a smartphone. After that, the manhole bases charge nearly as quickly as a wired Level 2 station, although Hevo’s three-phase 60-amp service is about 10-percent less efficient.“When it comes to charging, we don’t think public stations are tenable,” says Hevo Power chief operating officer Steven Monks. “They crowd the walkways, the cords are a tripping hazard.”But just as automakers are still trying to agree on a fast-charging standard, how wireless charging should work is similarly up in the air.

The Society of Automotive Engineers has tried to formulate a new standard for the past two years. Other wireless charging startups like WiTricity of Watertown, Massachusetts, have partnered with Mitsubishi, Audi, and Toyota to develop similar magnetic resonance systems, while Nissan says it would use inductive charging “once that technology is ready.”In the meantime, Monks says that the commercial sector will be an easier target than public streets. By the second quarter of 2014, Hevo plans to partner with several electric-truck manufacturers including Smith Electric, used in limited capacity by Frito-Lay and FedEx, and the new Via Motors co-founded by Bob Lutz.If automakers and municipalities catch on, we’re sure EV drivers would be happy not to “plug and play” ever again.