Will wireless EV charging be the answer?

by Ernie Hernandez on February 8, 2012

Wireless EVSE illustration

Wireless EVSE

Is there an advantage to wireless charging?

Battery powered devices – be they cell phones, laptops, or electric cars – need to be recharged. The most common way to recharge depleted batteries is to plug a charger into the wall outlet, plug the other end of the cord into the device, and let the electrons flow. An alternative, especially attractive to multiple device users, is inductive (wireless) charging.

Let’s establish a definition right up front. Inductive charging systems still have wires attached. It’s just that they don’t plug directly into the device being charged. The device is placed on an inductive charging pad of some sort, which itself is plugged into an AC power source. The device must be equipped with an adapter to accept the charge from the inductive pad. This adapter is either plugged into the charge port, or in the case of an electric vehicle (EV), wired into the charging circuitry.

If one owns many small battery powered devices (ie: cell phone, personal digital assistant, portable navigation system), it may make sense to equip them all with adapters and just toss them on the inductive pad at the end of the day. And when travelling, it could be easier to pack up one inductive pad  rather than a bunch of individual chargers for each device. But when it comes to charging an EV, we don’t really see the allure. In fact, there may be some down sides.

With the standard wired charging system, one pulls into the garage at the end of the day, plugs in and in the morning your car is fully charged. Unplug your car, stow your cable, and away you go. With the inductive pad, the thick cable that is plugged into the car with the wired charging system is permanently attached to your floor where it runs from the wall system to the inductive pad under the vehicle. This could prove to be a tripping hazard or perhaps just an inconvenience.

Then there is the matter of price. One manufacturer has a target of “under $3,000” for the equipment. This is significantly more expensive than available wired Level 2 charge solutions currently available. In addition, there is additional loss of efficiency due to the technology, which in turn causes the use of more electricity. Time to charge remains unimpacted – it just takes more energy to perform the same work.

While there may be some small added convenience of not having to plug in at the end of the day, we do not see that convenience outweighing the additional upfront and ongoing increased cost of operation.

{ 3 comments… read them below or add one }

Sasparilla February 9, 2012 at 8:41 am

I totally agree Ernie, great analysis. This is a solution in search of a problem (that doesn’t exist) – much like the better place battery changeout strategy.

Overall, besides looking kind of cool, it just costs you more money and makes your EV less efficient. Give me the plug.

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Woof! February 9, 2012 at 12:55 pm

I disagree. Once multiple EVs are in my garage, cable management will be a chore. Some sort of hidden automatic charging solution will be needed. If that’s inductive, it’ll be built into the floor like radiant heating is today. Nothing to trip over.

Cables running to the wall is not the endall of charging. Consider what houses looked like when they first became electrified..wires running across the room, through the air willy nilly. Once wiring started being built in, it became hidden as it is today. EV charging is in its infancy with visible wires to step over and drag to the car every time, just like the early days of electric lighting. The next logical step is contactless with hidden wiring. It might be inductive, might be something else, but it most likely will be invisible and automatic.

–Woof!

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Ernie Hernandez (LEAFguy) February 9, 2012 at 4:11 pm

Woof! – Welcome to Living LEAF. In the relatively distant future, your scenario may actually be the case, but for now, inductive charge systems are not built into residences, they are added on. Ultimately, forward looking residential community developers may offer such systems as options but we do not see that potentiality occurring near term. Interestingly, we just stumbled upon a wireless highway article that we will write about next.

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