By 2015, more than 1 million EVs in 20 different models could be on U.S. roads, according to the U.S. Department of Energy. You probably know what your monthly payment will be, how much you’ll save in fuel costs and maybe even when the car will need scheduled maintenance, but do you know how you will charge the vehicle at home?
While some people simply plug the car into a regular wall outlet (as long as an outlet on a branch circuit is near the garage), many want a Level 2 charging station that’s capable of charging an electric car completely in only a few hours. Level 2 chargers supply 240 volts (V), like an electric dryer or oven uses. These chargers typically consist of a circuitry box and a dedicated cord that can improve safety by waiting until a connection is made before sending power. Level 2 also allows for a range of charging speeds, all the way up to 19.2 kilowatts (kW), or about 70 miles of range per hour of charging.
A manufacturer or dealer will recommend a certified installer, but a skilled electrician also can set up a Level 2 charging station. The project could cost $1,000 to $2,000 but most states have tax incentives, as does the federal government.
Some industry watchers consider wireless charging to be the way of the future as factory-installed systems are now coming onto the market. These systems use an induction coil to create an alternating electromagnetic field from within a mat on the floor; a second induction coil in the car takes power from the electromagnetic field and converts it back into electrical current to charge the battery.
Since you don’t have to deal with cables, and the car begins to charge as soon as you park, companies that design and market these systems promote them as a big convenience that will push EV cars into the mainstream.
Wireless systems may be more convenient in some ways than hard-wired systems, because people don’t have to handle the power plug. But UL is studying the potential dangers of exposure to electromagnetic radiation (if someone crawled under the car during charging, for example), electric shock (if someone tampers with the coil in the EV) or fire (if insulation fails to contain a short.)
As the automotive industry and other organizations continue to develop and improve the technology of wireless charging, UL is running both simulations and experiments to evaluate the magnetic fields and equipment used for wireless EV charger systems.