Researchers at North Carolina State University have developed a 50-kw fast charger that they say costs half as much as conventional DC fast chargers, is more efficient, and only 1/16th the size.
Instead of being mounted on concrete slabs, sometimes in two locations, with a transformer behind a fence and a charge station box by a parking space, the new 50-kw fast charger can be mounted on a pole like a Level 2 charger. The charger will cost about $35,000, versus $75,000 for today's fast chargers including installation costs and is only 10 percent as big, about 4 cubic-feet, versus 150 cubic-feet.
The NC State charger can connect directly to medium-voltage transmission lines, says professor Srdjan Srdic, who developed the technology. It uses multiple modules with their inputs connected in series to gradually step down the voltage from high-power transmission lines, while their DC outputs to the car are connected in parallel to get maximum power.
At full power, it is 97.6 percent efficient, up from 94 percent for today's fast chargers.
Although the prototype charger is only 50 kw, Srdic says his next step is to build a higher-powered version. Since the technology is modular, he says, it can be scaled up to handle the latest cars being developed, including 800-volt ultra-fast charging for the Porsche Taycan, the Audi e-tron GT, and the Aston Martin Rapide E.
NC State says the charger can handle four times as much power and four times as many cars as a conventional charger in the same footprint.
A fast charger that can charge more cars at half the equipment outlay may be just what's needed to expand access to high-speed charging—and get more electric cars on the road.