Progress on Wireless EV Charging Continues, But Is It Useful?

By · July 17, 2012

Evtran Wireless Charger

Is lining up your car in a certain spot better than grabbing a plug?

I suppose that every few weeks we will hear about another successful demonstration of wireless charging of electric vehicles. The latest came yesterday when Evatran, an engineering company formally known as MTC Transformers, said that it had installed wireless charging for Hertz, Duke Energy and Clemson University.

Going wireless makes some sense to me when it comes to public charging, because management of the cords in a public environment could be problematic. But frankly, I just don’t understand the advantage of wireless charging at home—where about 95 percent of EV charging takes place. Even last night when I realized at midnight that my LEAF wasn’t plugged in, and a fine mist was coming down, it took me all of 20 seconds to walk to the car and plug it in. (My car is set to automatically start charging at 2 am, to take advantage of time-of-use off-peak rates.) That did not seem like a hassle to me—and is much easier than a trip to the gas station at any time of the day.

News about wireless EV charging started to flow as early as December 2011, when Daimler started testing concepts for the new battery version of the B-Class Mercedes and Nissan started talking about it as option on the 2014 LEAF. That’s also when Evatran announced that it would sell wireless kits for the LEAF and Chevy Volt, and work toward bringing plugless power to the individual homes. In January 2012, the SAE taskforce on wireless charging of plug-in vehicles began developing wireless charging standards. In April, the US Department of Energy said it would award up to $12 million in federal funds to companies that specialize in developing wireless charging systems for electric-drive vehicles.

In May, various technology leaders, including Samsung and Qualcomm, formed an alliance “to promote global standardization of a wireless power transfer technology that offers spatial freedom” and other benefits. Spatial freedom?

I heard it argued that luxury EV owners will not consider the handling of a recharging cord to be “dignified,” and therefore luxury electric cars will need to go wireless. Haven't those same luxury vehicle owners been pumping their own foul-smelling spillable gas for years? An EV cord is clean, and compared to a wireless system, you can see with your own eyes when the plug engages. For the next couple of years at least, wireless EV charging is likely to be less reliable and more costly.

I've been wrong many times before about the value of a technology innovation. Is wireless EV charging another example? Help me out, folks. What am I missing?


· · 5 years ago

Wireless charging will be really exciting when it works while I am driving on the highway. Imagine a cross-country road trip with no stops for fuel! A couple of different groups are working on making it happen. It would certainly be expensive, but I would happily pay for it.

· Roland Steinmetz (not verified) · 5 years ago

Brad, the people driving EV's now don't worry too much about the plug. We actually like to plug and experience the EV to the max. The majority of people we try to convince to drive an EV will probably not like this hassle with cord and ID-card two times a day. Wireless charging is still in early development phase but in my opinion essential part of the client friendly solution in about 5 years from now.

· (not verified) · 5 years ago

You are missing the cost!! An inductive connection will probably require large amperage and wire sizes, meaning a "large" transformer on each side. The cost is carefully avoided here, and except for a few "loss leaders" to start the market, or perhaps a huge, juicy grant, I doubt it will be practical......... Am I wrong?

· · 5 years ago

I think what Brad is talking about, vatavan, is charging an EV while parked . . . not an electrified highway, as you are proposing. That latter scenario would be amazingly expensive to implement and, given the resistance to financing any sort of massively scaled government project these days, I can never see it happening. The money would be far better spent on high speed rail.

Sorry to be the wet blanket here, but even stationary wireless charging is less than practical. There is appreciable energy loss when compared to any sort of hard wired connector and, here again, I can't see the extra funds being allotted to public EV infrastructure projects just for the gee-whiz factor of someone being able to hold both hands in the air and say "Look, mom, no cable!"

Something like this is always going to be more expensive for the home than a simple wired EVSE, but it could live on as a cost-no-object rich boy toy.

Keep it simple. If people can't learn how to plug the connector in on their own, they probably shouldn't be driving.

· Anonymous (not verified) · 5 years ago

Wireless charging is normally inefficient due to induction losses. Unless you're lazy, why pay more for wireless electricity vs. wired electricity? Let's not turn into the people shown in "Wall-E"....

· Chris O (not verified) · 5 years ago

The use if for public charging spots. Build into the road it can't be vandalized, nobody can unplug your car for a joke or because they want to plug in their own car. It avoids having to place extra obstacles in the public space and avoids a dreary picture of many EVs tethered to charging spots like ships to the quay. If it could be used for fastcharging it avoids consumers having to handle ever heavier cables when batteries become bigger and charge times shorter.

· Chris C. (not verified) · 5 years ago

Brad, I think you've bent the facts to fit your position here. It could not have possibly taken 20 seconds, round trip, for you to correct your oversight on plugging in your car. More like 3 minutes, minimum -- go time it, starting from when the idea pops into your head, sitting on your couch (or worse, lying in bed). Now make it 5 minutes for Amurcans with McMansions.

I think the benefit of wireless charging applies best to home, not public, exactly the opposite of your position. "Lining up" at home is something each of instinctively knows how to do every day in our own garages. At a public station, with the regular public? Forget it, unless the technology has huge positioning margins, which means complexity and/or efficiency costs.

Further, your mention of the "mist" makes the point that it can be a real pain to go out at night if you forget. The whole idea here is that you can't forget to plug in! You drive up, you hit the target while parking the car ("lining up"? come on), and you're done. There are valid criticisms of wireless charging, including the real-world cost issue raised by Phil above me, but owner effort is not one of them.

I generally enjoy (and agree with) just about everything else you write, but I think you struck out on this one, at least the way you chose to illustrate it.

Still smarting from when I forgot to plug my Chevy Volt in last week, and the text message alert from OnStar didn't work ...

(Oh, and highway-speed charging? THAT is worth an eye roll. I've got some fuel cell technology to sell you ...)

· StephsFuelCell (not verified) · 5 years ago

I don't know how far away the wireless charger can be from a plug, but this is really important for off-peak charging for people who can't plug in to a garage -- people in older homes (my garage doesn't have a plug, believe it or not), apartment residents, people with "projects" filling their garages, too many drivers per residence, etc. Friends in San Francisco don't even have a garage & have to park their car in a lot several blocks away...

· Christopher (not verified) · 5 years ago

Yeah, I don't want wireless charging. To me, the inefficiency (loss of energy) that comes with wireless charging kills any minor benefit of needing to remember to plug-in.

· · 5 years ago

You know, StephsFuelCell, I hadn't thought of that before. One of the ongoing problems of wider EV adoption is how apartment dwellers - especially ones in densely populated urban areas, where things like adjoining carports and dedicated spaces inside parking garages - don't exist. Wireless charging like this could come into it's own is in such situations. Hmmm . . .

· Spec (not verified) · 5 years ago

Oh, it is useful. As long as you park in the same spot, it will charge up automatically.

But is it worth the extra money and the efficiency loss? I doubt that.

· · 5 years ago

Opinion looks divided. @ChrisC - I just replicated by charging task from last night and timed it. From bedside to carport to plug and back: One-minute and 10 seconds. That's when I forget to plug in after pulling into the driveway. If I do that, it's about 10 seconds.

· · 5 years ago

I agree that it could be useful for apartment/condo dwellers. Limited range EVs are well suited to higher density city use (shorter average daily mileage), except for charging. Inductive makes city charging more secure. Would I put one in my garage? Doubtful, as I'm well used to plugging and don't want the efficiency hit. But if it helps a newbie fence-sitter to take the plunge and go electric, then great!

· · 5 years ago

I think a lot of us with EV's now don't see a personal need for wireless charging. But if wireless charging broadens the market for EV's then I'm all for it. Also, the wireless breakthroughs likely to be achieved could have wider, much more valuable applications, too.

· · 5 years ago

Haven't those same luxury vehicle owners been pumping their own foul-smelling spillable gas for years?

No, they have lackeys to do that for them.

Said lackeys are totally incapable of doing the same thing with a wire, doncha know. :-)

· David Martin (not verified) · 5 years ago

Hi Brad.
By focussing first on charging in the home you have missed the advantages of inductive charging, which are all about making it easier outside.
In European and Asian cities there simply is not the room to have the clutter of chargers lined up along the pavement, which is where many cars are parked and where charging access has to be provided if battery cars are ever to be a universal solution:
Here is the street furniture compared:

Even in the US the problem of vandalism and so on remain.
You don't get any of that with chargers buried beneath the road.

All this is aside from the potential to provide on the go charging at stop lights, for buses and so on.

Those who are critiquing this as very inefficient don''t seem to have seen the figures, and the cost of providing the charger in the car can come down a heck of a lot, so critiquing it on the basis of the tiny volumes we now do is not appropriate.

So if we want battery cars to serve the 50% who do not have garages inductive charging is an enabling strategy.

· · 5 years ago

This makes me thing about radio waves LW, MW and FM. Everybody was indicating the advantages and disadvantages of each type of radio waves. LW was available everywhere but low quality, FM was high quality but only local. MW was somewhere in between. In the end the 3 types of radio waves where integrated in car radio receivers (until later RDS and satellite changed the game).
With EV charging we also have 3 possibilities, charging by using a plug, and two types or “Park & Forget” systems, wireless charging or conductive charging.

The plug is simple cheap and straight forward but you need to think about it all the time and it takes some getting used to it. It is however problematic for apartment dwellers.
The wireless charging is the most expensive system and also the only one that does not have a 100% yield. It also generates some concern about the electromagnetic pollution that the induction can produce. However it is a true P&F system that could even allows charging at traffic lights.
The conductive system is simple, cheap and has a 100% yield, but it needs to have large contacts on a bumper and high weight switches to cut the current when wheels are not present or another electronic security system to control the current flow in a safe way. It can have some wearing but is the most simple and straight forward P&F system that can be imagined at the lowest cost both to install and to operate.

Again the 3 types have their advantages and disadvantages, but in the end the 3 types will likely become present on most vehicles.

· · 5 years ago

On the topic of charging at traffic lights - you do realize that this is essentially an "L2" level charge, right? At best, you can get a mile's worth of range in 2-5 minutes. How long does one actually sit at a light? Well, it may seem like forever, but in reality, it's typically less than a minute. That gives you 1/5-1/2 a mile (1000 - 2500 feet). Worth it? Not at all.

I agree that if it enables more people to adopt EVs, it can be a good thing, but for me and many others, I would never put this in my garage. It's more expensive, less efficient, and you have to align the car within inches to get a good connection. Meanwhile, my 3-year-old helps me plug in the "car juice". It really isn't a hassle!

· · 5 years ago

Ive been living for years with Ethernet cables, then I got wi-fi. That was progress, and I don't want to go back to the cables.

Same will happen with EVs, but I worry about energy losses.

· · 5 years ago

I'd take $5k of battery capacity over $5k of wireless charging any day.

· · 5 years ago

Here's a better comparison -
For years, I have plugged my phone in to charge. Now I can buy a wireless charging dock that I just have to set my phone on to charge. Well, I still plug it in because 1) it's more efficient, 2) I have to put my phone in a specific location anyway (i.e. on top of the wireless charger - which is a significant difference from your example of wifi) and 3) the wireless charger is more expensive

Sure, I know people who own and use wireless phone chargers, but more because of the technology factor than any real gained convenience.

· Jim McL (not verified) · 5 years ago

KeiJidosha hit the nail on the head. It is not worth the cost.

Does anyone remember SAE J1773? No? Why? Because the inductive charging in the EV1 generation was too expensive. That is why we now use conductive charging, J1772. It is cheaper and more efficient.

What does everyone claim is the biggest obstacle to EV adoption? Cost! Parking over an inductive charging pad is going to be more expensive than the old charging paddle from J1773, and less efficient.

This is a solution in search of a problem.

Now do you want to talk about busses charging at stops? Sure, but better get the power transfer rates up to the 200 kW range and prove that the stray fields do not cook the passengers. And again, what is the advantage compared to the existing overhead stationary buss bars with roof mounted pantograph?

This is like fuel cells. The best possible outcome is worse than present technology, as Elon Musk said comparing fuel cells to batteries.

· Objective (not verified) · 5 years ago

An approach that would be more convenient than manually plugging in, less expensive than purely inductive (wireless) charging, and without the losses of wireless compared to plugin, would be to add a bit of robotics to the charger that plugs the charger into the car. While any idea could lead to many design concepts, picture a charge port that operates like an automatic sprinkler by popping up from being flush to the pavement. If it were pretty much centered in the parking spot, and the car's matching receptor were underneath, then this would make it more inconvenient for a malicious passerby to disconnect somebody, and even more so to take advantage of it by charging their own car, because they would still need to park in that space. I think that this is technically feasible. I'm not even going to begin to explore financial feasibility, because I don't intend to pursue it. I'm just offering it up.

· · 5 years ago

I don't really agree with the majority here, but I mean no offense in saying it.

I'm all for wireless charging, I don't see any downside and lots of convenience. At least the version that Google is testing is 90% efficient, the cost of an installed charger is just slightly higher than wired and then it's all convenience forever, which is how long I plan on having my Plug ins.

Nearly everyone here has said they've forgotten to plug in before, and that's the kind of thing that's a big downside. I believe in the Volt/Priuc-c/Ford Cmax PHEV EV with generator style of plug-in. On that path of plug-in technology it's even more important because it's so easy to ignore plugging in and just running the car on it's generator.

Only pennies of downside which to me is completely offset by the convenience of wireless.

· · 5 years ago

I'm curious where you got information about a 90% efficient inductive charger. The old magnecharger paddle chargers weren't that efficient then their induction coils were practically touching.
I also have trouble imagining a UL approved floor mounted device that has to tolerate being driven over being cheaper than a glorified electrical outlet hung on the wall.

I have no problem with the concept and actually liked the magnecharger but in this case, call me a skeptic

· · 5 years ago

We're never going to solve the EV infrastructure problem if we let the industry get away with changing the standard every three years, or ever, for that matter.

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