EV Charging Stations

By John Donovan, Low-Power Design, for Drive for Innovation

Electric vehicles (EVs) are growing in popularity, but "range anxiety" isn't going away. Unfortunately when you're on the road, electrons are a lot harder to come by than gasoline, due to the lack of EV charging stations. Fortunately, a number of companies are rushing to fill the void, and a number of cities and states, and even the federal government are providing incentives to install them.

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We mentioned in an earlier article that there are three types of charging stations for EVs:

• Level I refers to single-phase AC using grounded receptacles. In North America this typically means a 120V/20A circuit using a NEMA 5-20R outlet. The driver uses a standard charging cord to connect the vehicle to a Level I charging station. Using a Level I charger you can recharge your Chevy Volt battery in about 10 hours.
• Level II refers to single- or three-phase AC at 208-240V at up to 80A. The Society for Automotive Engineers (SAE) J1772 specification is the standard for Level II charging in North America, where the J1772 connector and charging cord are permanently fixed to the charging station. You can install a Level II charger in your home and recharge your Volt in about 4 hours.
• Level III refers to DC charging, or “fast charging.” To achieve very short charging times, Level III chargers supply very high voltages (300-500VDC) at very high currents (100s of amperes). A Level III charger can recharge a Volt battery in anywhere from 30 minutes to 60 minutes. Unfortunately, the SAE is yet to agree on a Level II standard, which makes manufacturers reticent to invest in these chargers.

Level II–Over to You

Coulomb Technologies makes a range of Level I and II charging stations for residential and commercial use. The company’s ChargePoint station contains an on-board computer, a fluorescent display, a standards-based RFID reader, and a utility-grade meter providing precise, bi-directional energy measurement. Coulomb is building a nationwide network of charging stations that can be accessed online to find and reserve times for nearby network stations, pay for a ChargePass card, and even get turn-by-turn driving directions for smart devices. EV owners can't yet travel very far from major metropolitan areas, but if they live in or near one, they may be able to pass every gas station in sight.

GE Energy makes WattStation^TM Level II charging stations for residential and commercial customers. GE’s version of the electric gas pump is its DuraStation, a Level II gas pump look-alike that pulls 208VAC-240VAC at 40A. The company claims it takes between four hours and eight hours to fully recharge a 24 kWh battery. GE is also working to build an EV charging infrastructure in the U.S. and Canada, though it is not as robust as Coulomb’s. EV owners can search GE’s online database by state or province to locate charging stations on a planned route.

Clipper Creek boasts “the first UL listed EVSE charge station manufactured in America.” The company makes portable Level I and fixed Level II chargers for home use as well as the CS Series of UL-approved Level II commercial charging stations.

Unmanned aircraft (read: drone) maker AeroVironment offers a wide range of Level II EV chargers, including one that charges Jay Leno’s Chevy Volt.

Level III–Are We There Yet?

The lack of an SAE standard for Level III charging stations hasn’t kept forward-looking firms from designing them.

AeroVironment’s big dog is the EV250-PS, a Public Fast Charging Station that draws up to 330A at 480V three-phase AC, delivering 50-700V at up to 550A. This Level III charging station, designed for office buildings, airports, city streets, and highway rest stops, has yet to hit production or receive UL or CSA certification. Despite the lack of standards, AeroVironment claims the EV-250-PS uses the “CAN V2.OB protocol to interface with your vehicle-specific Battery Management System (BMS),” so if AES continues to delay on the standard, the responsibility for oversight falls back to automakers.

Announcing its Level III product with the headline “Get ready!,” Aker Wade is rolling out its fast charging systems, claiming they can recharge Li-Ion batteries in EVs in up to 15 minutes, or about the time it takes your kids to refill at the mini-mart attached to the electric gas station. These systems – thought not in production – could address a utility-level problem by providing a smart grid interface capability. Optional on-site battery banks would enable users to store off-peak power for later use and prevent peak loading on the utility grid.

"If You Build It, They Will Come"

Well, not if they can’t find it. The U.S. Department of Energy (DEO) provides a handy online map that helps EV owners find the nearest charging station anywhere in the U.S. Just click on your state to get a listing of area charging stations, complete with addresses and some other basic information—unfortunately no maps, so you may need a GPS. Darwin 3D, LLC, even offers a free CarStations app that allows users not only to locate stations all over the world from a smart device, but also add new charge station locations to the database.

Despite a lack of standards for Level III charging stations, expect to see them come online soon—and Level II installations to start appearing along your commute route even sooner. Coulomb’s Level II network is growing rapidly, and even with its late start, GE Energy likely will catch up quickly. The Electric Auto Association has set up a fund to help construct a national EV infrastructure, and the DOE is currently offering an Alternative Fuel Infrastructure Tax Credit of up to 30% of the cost, not to exceed $30,000, for EV fueling stations placed into service in 2011. Owners of qualified residential fueling equipment may receive a tax credit of up to $1,000.

There are a lot of moving pieces in the EV infrastructure puzzle, but they are moving quickly. The time when hybrid EVs—not to mention gas-powered cars—are eclipsed by all-electric vehicles, while not exactly near term, is growing closer.

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2 Responses to EV Charging Stations

1. Ted Marshall says:

   November 22, 2011 at 11:10 am

   Although the SAE has not agreed on a DC charging standard, there is a perfectly good standard, Chademo, from Japan. My Nissan Leaf can charge to 80% in 30 minutes with this. Chevrolet chose not to put a Chademo port on the Volt. Some in the EV community feel that the American manufacturers are pushing the SAE DC standard to slow down installation of Chademo stations to try to put Nissan and other Japanese manufacturers at a disadvantage. 
   Unfortunately, right now, there are very few Chademo stations installed in the US. I feel this is partly due to the SAE.

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2. John Donovan says:

   November 22, 2011 at 4:54 pm

   CHAdeMO fast DC chargers do indeed work well, but until recently there were few outside of Japan–in fact only 7 in the rest of the world, according to the CHAdeMO Association–surely one reason that GM didn't put such a connector on the Volt, which is primarily for domestic consumption. There is a lot of investment in the SAE standard, and dueling standards are always bad for business, so I suspect that's also part of the reason behind the slow pick up of CHAdeMO chargers; but their association has only recently started to gain momentum, and the U.S. hasn't been a major focus. Still, AeroVironment and Eaton in the U.S. are CHAdeMO licensees, and if the SAE doesn't deliver soon you're likely to see a lot more smiley face CHAdeMO logos popping up along with adaptor cables.

   Reply