Two major automakers are literally pulling the plugs on their EVs by testing inductive charging setups that charge cars without the need for wires. That increase in convenience, however, brings a loss in charging efficiency.
Daimler and Conductix-Wampfler are working on a plugless charging setup for the Mercedes B Class E-Cell concept, and Nissan has demonstrated a wireless charger we may see on the Nissan Leaf or a forthcoming EV from Infiniti.
The systems use the same technology as those wireless iPhone chargers you can buy at Brookstone, only on a larger scale. Both the car battery and power supply are connected to charging coils that, when magnetically tuned to each other, complete a circuit and charge the car. Simply drive an EV equipped with induction charging technology over a charging pad and wait for the batteries to replenish.
That convenience comes with a efficiency penalty, though.
According to Conductix-Wampfler, the Mercedes setup isn’t quite as efficient as plugging in. It’s only 90 percent as effective as a cable-based system, and there are additional challenges making sure that drivers get within an inch or so of the optimal parking position. The company estimates that parking aides may make it easier for drivers to properly align their vehicles.
Likewise, Autoblog Green reports that Nissan’s tests of wireless chargers have shown 80 to 90 percent charging effectiveness when compared to plugging in. That technology could debut on the 2014 Leaf and may also be available on an EV from Infiniti, Nissan’s luxury marque.
Aside from these latest announcements, inductive charging tests and applications have been underway for years. Conductix-Wampfler already designed a wireless charger that’s used to fill the batteries of electric buses in Genoa, Italy, and the late GM EV1 had an inductive paddle charger — albeit one connected to a cord.
More recently, the fantastic Rolls-Royce 102 EX Phantom concept is fitted with a wireless charger from HaloIPT, and Evatran announced they’re retrofitting several corporate EV fleets with their Plugless Power setups (shown above). Google installed such a setup at their Mountain View headquarters earlier this year.
While inductive charging currently offers EV owners convenience over plugging in, engineers hope that advances in technology will allow drivers of electric vehicles to someday charge their cars while driving. Drayson Racing is testing race cars that can take an inductive charge during a pit stop, and HaloIPT has already developed chargers that they estimate could be installed beneath roadways by 2020.