Wireless Charging for Electric Vehicles Explained

Since the early days of the 20th century, the internal combustion engine and electricity progressively became two of the most important comfort features aiding life as we know it today. By the time the first mass-produced hybrid vehicle arrived in the form of the Toyota Prius back in 1997, both the internal combustion engine and electricity became inseparable in the automotive world.
Nissan Lead wireless charging via the Plugless L2 system 7 photos
Nikola Tesla demonstrating wireless energy transmission in 1891Inductive charging systemEnergizer wireless phone chargerToyota RAV4 EVFloor charging pad sends energy to the vehicle mounted receiverNissan Leaf wireless charging via the Plugless L2 system
The next big step in electric vehicle research and development is represented by wireless charging solutions. After smartphone manufacturers started experimenting with conductive recharging solutions, automakers that offer at least one electric model in their lineup begged the Top Gear-esque question: "How hard can it be?"

Roughly 15 years have passed since small teams of engineers and a handful of car manufacturers started to tinker with this bold idea. However, the road to plug-free charging is still long and exceptionally winding. Even though this type of technology is still in its experimental phase, fast advancements and encouraging results might offer EV owners the opportunity to get rid of the traditional power cable sooner than expected.

When did the wireless energy transmission craze start?

Ever since the Oregon Railroad and Navigation Company's Columbia steamship adopted Thomas Edison's incandescent light bulb in 1880, commercial appliances powered by electrical energy spread throughout the Western world like wildfire.

Cordless charging dates back since 1891, when Nikola Tesla demonstrated wireless transmission of power and high frequency energy at the Columbia College in New York. After continued research, the Hungarian scientist came up with the fundamentals of radio technology two years later. Even though wireless power transmission is slightly different from wireless telecommunications, the scientific world credits Tesla for giving us the ABCs of inductive charging.

How does inductive charging work?

Induction chargers typically use an induction coil to create an alternating electromagnetic field from within a charging base station, while a second induction coil in the portable device takes power from the electromagnetic field and converts it back into electrical current to charge the battery.

Smartphone users that are intent on living a cordless life already have a couple of options to charge their mobile devices. Proximity power charging typically implies a charging pad with a magnetic coil fitted inside and another coil retrofitted to the device, allowing it to charge while sitting on the pad.

Consumers that want to avoid inserting a micro USB adapter into the ports of their phones will have to pay as little as $24.99 for a wireless charging pad. If your phone doesn't support wireless charging, you'll need to pay a few extra bucks ($12.99 to $39.99) for a Qi-standard wireless charger receiver. It looks like an ordinary phone cover and you fit it to the back of your Samsung Galaxy S4 or iPhone 5S terminal, for example.

This type of charging has a 72 to 90 percent efficiency rate. To put it simply, it means that 28 to 10 percent of the power used to charge the device is lost. But is this a feasible option in charging more complicated appliances such as EVs?

Can electric vehicles actually be charged this way?

Of course! One of the first electric vehicle inductive charging systems is the Magne Charge. Developed by General Motors and Delco Electronics in the late 1990s, it provided zap for the first generation Toyota RAV4 EV, Chevy S10 EV and other electric vehicles.

Even so, the first proper plug-free charging system intended for EVs came in the form of the Plugless L2. Manufactured by Evatran, this is the first wireless electric vehicle charging system to carry the prestigious ETL certification mark.

Currently available for both the Chevrolet Volt (known as the Opel/Vauxhall Ampera in Europe) and the Nissan Leaf, this system is comparable in terms of power output with a Level 2 (240V) traditional charging station. Specifically, the Chevrolet Volt needs just three hours to recharge its battery pack from zero to 100 percent.

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But the best thing about it is the simplicity of it all. Like its smartphone counterparts we've mentioned a few paragraphs earlier, the Plugless L2 utilizes a vehicle adapter thingy, which is physically attached to the rear subframe of the car. By occupying as little space as your run-of-the-mill skid plate, this component doesn't affect the ground clearance of the vehicle.

The second piece of the Plugless L2 ensemble is a parking pad which lies on the ground and looks like a robot vacuum cleaner. For charging the car's battery pack, the driver only needs to park exactly above it, with the parking pad and the rear subframe adapter directly facing each other for seamless energy transfer.

Further enhancing the experience of wireless charging is a Control Panel device, which can be mounted on the wall opposite to the garage door or on a pedestal mount. For a hassle-free experience, the Control Panel senses your arrival and displays directional arrows for guiding the driver exactly above the charging pad for maximum charging efficiency.

Evatran first showcased its Plugless L2 at this year's Las Vegas Consumer Electronics Show in January. Excluding installation costs, the whole system retails for $2,970 for both the Chevrolet Volt and Nissan Leaf.

Is wireless charging a threat to your health?

Most people are worried about the effects of the electromagnetic radiation flowing through the air when using a wireless electric vehicle charging (WEVC) system. In the case of the Plugless L2, you don't have to worry about potential health and safety hazards or electromagnetic interferences with devices nearby. It was tested to UL 2594, and CSA C22.2 No. 280-13 Standard for Safety for Electric Vehicle Supply Equipment, allowing it to carry the cETLus mark for the USA and Canada.

Conclusions and future perspectives

Due to the ever-decreasing fossil fuel resources, as well as the restrictive fuel economy and emission standards for greenhouse gases (such as the NHTSA's CAFE), hybrids and EVs are slowly but steadily taking the automotive industry's R&D spotlight.

When it comes to wireless electric vehicle charging, this technology still hasn't reached its prime of life. Think of it as what the tablet PC was back in 2002, when Bill Gates showcased the first functional color tablet PC. Just as Microsoft's tablet from 2002, WEVC technology is still underdeveloped and hasn't got an identity of its own.

What this technology needs in the following years to really take off is the right face and the right manufacturer, similar to what Steve Jobs did for the tablet in 2010 with the introduction of the iPad.
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About the author: Mircea Panait
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After a 1:43 scale model of a Ferrari 250 GTO sparked Mircea's interest for cars when he was a kid, an early internship at Top Gear sealed his career path. He's most interested in muscle cars and American trucks, but he takes a passing interest in quirky kei cars as well.
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