Riddle: What’s 5 Times More Expensive, 10% Less Efficient and Half as Powerful as Today’s Level 2 Chargers?

DEC 18 2013 BY MARK KANE 39

Wireless Charging Unit

Wireless Charging Unit

Some people are saying that wireless charging is the future for electric vehicle. Well, is it really?

We’ve recently observe price drops for conductive charging to below $600 for EVSEs with power of over 7 kW, which is useful for vehicles with higher-power 6.6 kW on-board chargers. Of course, some additional costs need to be added in for installation.

On the other side, we have wireless charging with the first product introduced on the market. The cost is ~$3000 (and varies depending on vehicle – Nissan LEAF or Chevy Volt). But power is just 3.3 kW with efficiency below 90% before it even is sent into on-board charger.

The question is, who will buy a device that is 5 times more expensive with half the power (and twice the charging time) and over 10% more losses on an energy bill?

And with wireless charging, you can’t share your terminal with friends or family members who may come to visit you unless their EVs are set of for it.

Is the desire to eliminate the plug worth a few thousand extra bucks and all the related hassle?

Categories: Charging


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39 Comments on "Riddle: What’s 5 Times More Expensive, 10% Less Efficient and Half as Powerful as Today’s Level 2 Chargers?"

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I’m glad to see the author feels the same way about this as I do. It’s ridiculous. And it’s not that 10% power loss sounds like that much…. until one understands how much power we’re talking about.

What’s more convenient and time saving: wireless charging for your car, or not having to turn on your lights when you walk into your house? Because leaving your lights on in your house 24/7 will likely save you MORE time, cost less in electric bills than a wireless charger and cost you exactly zero dollars to implement TODAY!


That’s a good point about the lights.

The the thing you’re forgetting about wireless charging is that if you just drive your car into your garage the same way everyday, you’ll be charging automatically. If you forget to charge one every 100-200 days and it makes you 1 hour late for work or makes you take a cab, that alone could be worth that 10% (about $3/mo).

But yeah, $3k is a bit obscene. Gotta admit that there’s a cool gadget factor, though.


If I forget to charge, I just drive to work with what was left in the battery the previous day, then plug in there. No problem.



you obviously haven’t used an inductive charger for your phone, where you set your phone down and it didn’t start to charge and later when you need it … it is dead. The same thing will happen to your car.


As I’ve said before, I’m sure wireless charging will have its place, but it won’t be in my garage. I don’t know who will want this, but if there’s a market for it, why is it a bad thing? As EV enthusiasts, we should be encouraging every novel enhancement made possible by EVs, which were never possible with ICEVs.

Mark Hovis

That is my stance too Brian. I have no desire for it in my home, but it doesn’t mean there isn’t a place for it. The industry is young.

Sam EV

Agreed. I could see them being used in public places where vandalism is a concern. Charging cords/cables seem somewhat vulnerable.


The problem I have with wireless charging is that the time and money spent on it is not being spent on what EV owners need:

1) more DC fast chargers
2) more workplace charging, 120 V and J1772
3) more hotels with J1772 charging
4) lower cost batteries



The problem with this type of thinking is that you assume that this money would otherwise go towards those other things. Let’s take QualComm, for example. They are a highly respected company in the wireless communications industry. They are using that expertise to try to get into the EV industry with wireless charging. What makes you think their time and efforts would otherwise go into any of the things you listed instead? The way I see it, this is mostly new money spent on the EV industry to keep it interesting and advancing. I don’t see it detracting at all from infrastructure or battery research.


That is a good point, especially for companies like Qualcomm.

However, I see automakers working on slow inefficient wireless charging, and at the same time they are not installing any DC fast charge stations whatsoever, and sometimes not even offering DC fast charge on their EVs!

This is a very misplaced priority in my opinion.



Given that your EV is probably the biggest chunk of your electric bill most months, and a majority some months, 10% is a big freaking deal. I’m certain it will never be ubiquitous. Wireless keyboards are not ubiquitous in business because, well, wireless always has big downsides over physical connection. In the case of computers, there’s protocol complexity and reliability–a company would rather have wired keyboards than have their techs wasting time on problems that only occur because of wireless.

Thomas J. Thias

“[…]Given that your EV is probably the biggest chunk of your electric bill most months, and a majority some months, 10% is a big freaking deal[…]”

Yuppers, this statement is very true if you have NO Home Appliances, No Air Conditioning, live in a cardboard box……..

Good Shot Anderlan! A new reader to this outstanding Plug-In electric Car Forum would be very confused by this silly, sloppy statement of yours!

1) 74% of us drive less then 35 miles a day-

2) Baseline EV Fueling .125 cents kWh, National Average- Bout A Buck A Day!

3) Bout A Buck A Day, EV Fueling, 110V AC just fine-All EVs Charge This Way!

4) Gasoline Offset can equal at times driving for FREE! So says Wall Street Journal!

Thanks for listening!

Ps, I save over $200.00 every month in Chevy Volt EREV fuel costs driving a robust 13,000 to 14,000 miles a year! That now equals over $4,200 total NOT spent on gasoline after my $1 a day or less electric fuel costs.

So, if my home electric bill has gone up $20.00 a month since March of 2012 and with charging at work and area FREE L2s does it really matter?

Plug It Not Pump It!


Thomas J. Thias

My OnStar Stats-



10% of an EV’s electric bill should be under $4/mo for most. I don’t think anyone who is willing to pay $3k (or even $1k) for a luxury charger cares about that.

Keyboards are rarely taken away from from their computer. EVs tend to drive away from outlets 🙂

This would be kinda like having your phone charge every night without having to take it out of your pocket. It sucks waking up and realizing you forgot to charge your phone.

Doug B

For the general public, logic does not trump convenience, for municipalities and businesses the potential to make charging almost vandal proof by embedding into parking spaces, or for taxi drivers to pull into a rank line and continue to charge as they move up the line will mean these become the standard system in the future.

We can argue about the cost and efficiency of wireless, but the owner climbing out of their car with arms full of bags is not interested. You need only look at the number of cars now sold with automatic door open and closing systems, at what cost! just to not pull a handle!


Or electric windows. Look at all that electricity wasted on window motors when you could just crank it by hand. LOL


The issue is definitely one of convenience vs efficiency. And, the cost of the convenience. Personally, the amount of my time spent plugging/unplugging my EV is less than the time spent finding a gas station and filling up when I had an ICE. So, I don’t see the need for this convenience. Plus, the fact than I can “one hand” my tesla charger means that it isn’t much of an effort.

The one real argument for wireless charging is the lack of physical contact means it should last longer. It still doesn’t seem cost effective.

John Hansen
Some perspective is needed here. In the context of the cost of the charger alone, then it sounds like a lot, but let’s consider to full EV price. $35k for an EV (some are less, some are more, let’s say this is average) $1k for EVSE install (again, some less, some more) $700 or $3000 for the EVSE (plug vs wireless) Total difference in cost? $36,700 vs $39,000 People spend that much extra for leather seats. On the 3.3kw issue. For home chargers, 3.3 vs 6.6 doesn’t make much, if any, difference, since you charge at night while you’re asleep. The only case where it would be handy is if you happen to drive far enough to exhaust your battery, then you can drive home, recharge, and head straight back out. At least for me that isn’t a common scenario. Where the 6.6kw and higher chargers really make sense is for public chargers. THOSE should be 20kw minimum, and shame on auto manufacturers for not all supporting 20kw! On the 10% charging loss issue, yup, that’s too bad and the only downside in my opinion. That said, with the additional 10% charging loss an EV is still about 60% (ok,… Read more »
Thomas J. Thias


Well Said!

Thomas J. Thias



Yes, well said. And prices will continue to drop for wireless as power & efficiency will increase. Heck there’s an electric bus that chargers wirelessly at 100kW. That’s more than most DC fast chargers.


You have got to be kidding me! Wireless charging is an absolute must for my next EV. EV charging is less that 10% of my electric bill each month so I’m not concerned the loss of energy. Pluging and un-plugging my car is a real pain. Most of the time I have something in my hands which makes it even more of a pain. Even locateing and pushing the button on my Leaf to open the port is more pain than I want. I just want to drive my EV and never – ever – think about charging. It should just happen all by it’s self.

I’m sure wireless chargers will get more efficient and cheaper in the future.


“Pluging and un-plugging my car is a real pain. Even locating [sic] and pushing the button on my Leaf to open the port is more pain than I want.”

Really? If you are in that much pain, please ingest a bottle of Tylenol and wash it down with a fifth of whiskey.


John Hansen

Wow… a man states an [inoffensive] opinion and you reply by suggesting he kill himself? That escalated quickly. You should consider toning down your zealotry a little, it’s not helping the EV movement.

And I even agree with you…


Well said, John. Zealotry is a huge turnoff among EV proponents.

Alan Campbell

A 3.3kw inductive charger will be the perfect mate to the growing number of plug-in hybrids launched and being sold. With over 80% of charging done at home….at night, the owner no longer has to worry about plugging in every night, or each time they pack their car at home, because it will charge itself. 5 hours can charge a 21 mile battery pack.

Also it’s important to understand that cars equipped with inductive charging also have their plug that still works.

And if someone visits that needs a plug, they can just use an outlet.


For buses trying to run all day automatic wireless charging at each (or at least some) stops makes electric buses much more practical.

Electric Car Insider

I think these will be most popular in car share services, where you can not depend on the user to plug in after use.


When it comes to the typical American consumer, convenience will win out over energy efficiency any day – just look at the number of electronic devices that use remote controls, just to save people from taking a few steps. How many BEV owners have garage door openers? While the relatively small % of dedicated greens don’t mind plugging in and will moan about the loss of efficiency, the mass won’t care, and as others have pointed out there are real operational and security advantages to wireless. Their prices will come down, charge rates will go up and efficiencies will improve, just the same as has happened with conductive charging. This is definitely a case where the ‘best’ (in energy efficiency) is the enemy of the ‘good enough’ (wireless being superior in other areas).


I agree! I did not buy an EV to be green. I bought it for the convience of not going to a gas station and because I’m an engineer and I liked the technology and its cheaper to run. We have got to get over this idea that people by EVs because they are green – most people are not tree huggers. Not that it isn’t a nice plus that EVs are green but it is no where near the top reason for buying an EV for most people.

Someone indicated – well thats the reason the goverment is giving you incentives to buy one – so what? Its not my reason….


Garage door openers are a great analogy. I wonder if the vampire draw from a garage door opener is greater than the 10% efficiency loss of a wireless EV charger.


A bad new opener will use 9W standby. A good one 1W (I’ve seen that for a belt driven system). Unfortunately a lot don’t have standby in their specifications. I’m going to have to take a Kill-a-Watt round to a showroom and see if I can plug it in.

For the extra 5/cents, I’ll skip unplugging and plugging my car back in every day. If you live in the snowy/cold parts of this country, it’s not fun to spend more time messing with storing a charge cord or opening a charge port (which can freeze shut). Also the cables get dirt on them which then gets on your clothes/hands. And my hands are always full, so the charge port is just one more annoyance. Wireless also solves vandalism, and could let you pay for charging via the car’s touchscreen. No more kiosk, or getting your card out. It helps in preventing you from forgetting to plug in, or forgetting to unplug, or forgetting to close your charge port and having to step back out into the heavy rain to do so. Efficiency #’s are improving, not that 90% isn’t bad. Power rates are also increasing. On top of all this, the wireless standard has already been developed, so no SAE vs Chademo scenario. Further into the future think of charging on the fly. Stop lights, drive-throughs, car washes, lots of possibilities. Everyone likes to say “I’m not lazy! I can plug my car in”, but how many people use… Read more »

Some people still think wireless charging will be a fade after all these comments ? I for one am handicap and i walk with 2 canes and pluging in my Volt is difficult if i have to get to the handle, pull it to the car (that wire is heavy). Wireless gets rid of all that and in a world where average population age is rising fast, plugs are on the way out. Is it not the Nissan Leaf next gen to come with wireless.

Dr. Kenneth Noisewater

Heavier and more cumbersome than a gas hose and nozzle?

Frankly, I’d rather see wireless charging standardized at a much higher power level by SAE or ISO, embedded in roadbeds, and used to power vehicles underway. Embed induction coils ever dozen yards and have sensors power them up when a charger-equipped vehicle passes over top.

Tony Williams

Wireless won’t take over completely, but I’ll bet the majority newly installed low power (under 20kW) AC charging is wireless in ten years.

I don’t need maximum efficiency for it to be good enough, and convenient enough, for me. I’m sure all you efficiency experts are in perfect physical shape for maximum food efficiency.

Marc Lausier

Wireless charging will be a great option for people who will drive autonomous EV’s in the near future. Lots & garages with wireless inductive EVSE’s in the pavement/floor will be a place to park autonomous vehicles that will top off their batteries than move to other spots to allow the next vehicle in the queue to charge. Also when you are out and about especially at night, you will be able to call your car and have it drive to your location…that can’t happen if the car is using conductive charging. Inductive charging will also be embedded in highways so you can charge/power the car while driving certain routes. etc.

There is third way between the standard plug and on the ground wireless, it is on the ground (a half cylinder actually) secured contacts. No one else then a major SETI person actually did this kind of charger. He used high weight contacts that are switched on by the presence of the front wheels as base security and a guidance system but that one can actually be missed by relying on large contacts on the top of the half cylinder with just enough place to fit a flexure mounted contact between it and the bottom of the car. Additionally a synthetic brush all around the contacts isolate it further from pets that would try to though it while charging. When the car is absent the heavy weight contact switches (off which both must be closed) prevent any current from flowing to the contacts. The contacts themselves get friction cleaned by the car scratching up and off of it and are made of a corrosion resistant material. Best of all, you can take it away with you on vacation and just plug it in on your destination in a standard socket. Cost should be less then 300 $, yield is the… Read more »

My wife, who forgot to plug in her LEAF last night because she was distracted when she arrived home and therefore had to drive the Prius to work this morning, would disagree with this opinion that wireless EV charging is not needed.


It’s like any other option. Some will think it’s worth the extra cost, some won’t. No big deal either way.


You should check out HEVO Power (www.hevopower.com). HEVO’s wireless EV charging system has a 10kW charge rate and works with any vehicle equipped with a HEVO Power Network Receiver. Rolling out in NYC in early 2014. Also, there are a variety of benefits of wireless power, such as eliminating tripping hazards and avoiding damage or theft of charging kiosks.