Cars Plugless Wireless Tesla Model S charger

Published on March 24th, 2016 | by James Ayre

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Wireless Tesla Model S Charger Close To Production (We Got A Sneak Peek)

March 24th, 2016 by  

Originally published on EV Obsession.

Tesla owners potentially interested in a wireless home EV charging system will be happy to hear that Evatran’s efforts to bring such a system to market appear to be moving forward. The company recently sent an email to EV Obsession and CleanTechnica with two “sneak peek” photos of the upcoming Plugless product.

The 7.2 kilowatt (kW) Plugless Vehicle Adapter possesses dimensions of around 16″ x 33.5″ x 1″, according to the email. The pictures are of the portion of the system installed underneath the Tesla Model S that receives the inductive charge.

Plugless Wireless Tesla Model S charger

Plugless tesla

Image Credits: Evatran/Plugless


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About the Author

's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.



  • Wayne Williamson

    I realize that I’m behind in my reading(article is 6 days old), but just have to say that the easier(read no thought) it is to refuel the more reasons to get an EV.

  • Philip W

    As some other commenters here im also not a big fan of wireless charging for home use. The efficiency loss is just not worth it.
    It takes like 10sec to plug the car in. Is that really a dealbreaker for a lot of people? Most likely not, since you already save a lot of time by not standing at a pump for minutes every few days.

    If you really want some automatic system, wait for the Tesla metal snake charger or something similar. Saves electricity and is not constrained in charging speed.

  • Philip W

    As some other commenters here im also not a big fan of wireless charging for home use. The efficiency loss is just not worth it.
    It takes like 10sec to plug the car in. Is that really a dealbreaker for a lot of people? Most likely not, since you already save a lot of time by not standing at a pump for minutes every few days.

    If you really want some automatic system, wait for the Tesla metal snake charger or something similar. Saves electricity and is not constrained in charging speed.

  • Mod Mark

    Americans are glutton concerning energy, our per capita consumption is 313 ( (Million Btu per Person) compared to Germany or France at ~166. And Germany has the autobahn! (source: EIA 2011 data).

    Germany can afford Energiewende and higher retail electric rates (~$.30Kwh) because they are very efficient with electric use. The average German electric bill is similar to the US.

    So yes, loses of 7-12% is a big deal. Many of these renewable plans depend on reducing energy consumption by 2050.

    A better approach, a warning system (Smartphone app, flashing light on your key remote) when you forget to plug in.

    • Michael B

      Our (US) average per capita energy consumption is probably highly distorted by including military consumption, which is off the charts. Also, transportation is bound to be much greater, given the size of our country. I’d love to see “normalized” values just for ordinary citizens’ ordinary mostly domestic activities.

      Do you happen to know them?

  • Joe Viocoe
  • Ed

    While I applaud this effort, you may not be able to detect my half-hearted clapping. Inductively-coupled charging systems need to be fully integrated into the vehicle to be practical, so I worry that this aftermarket system will not be a good fit. And with an inherent air gap in the magnetic core, there are significant limitations in power transfer per mass. As noted, efficiency will always take a hit.

    Most importantly, a long range car like the Tesla needs a huge amount of current to keep charging times practical at Superchargers. Here is a snapshot when I was charging after a long run in Kansas. Yes, that is 328 amps coursing into the Tesla at 359 volts! I have seen over 340 amps. Whomp! Sizing an inductive coupler for that kind of current will be extremely difficult and/or grossly impractical.

    At a trade show last year, someone selling an inductive EV charging system tried to convince me that it was the equivalent of the electric starter on ICEs: like eliminating hand-cranking an ICE to start the engine, the inductive coupler would make EV ownership practical. Nice try, but that is not a rational comparison. It takes my wife 5 seconds to plug in the Tesla.

    But, please keep trying!

    • Ronald Brakels

      Dang! 118 kilowatts! Those superchargers really are super, aren’t they? I presume it decreases somewhat as the battery gains more of a charge, but still very impressive.

      • Ed

        Yes is drops off. I usually hit the road about the time is it down to 70 amps or so. That happens when 230-240 miles of range is on board. Tesla has it figured out pretty good. If any company would have tried to make inductive coupling work, it would have been Tesla.

      • Ed

        Yes is drops off. I usually hit the road about the time is it down to 70 amps or so. That happens when 230-240 miles of range is on board. Tesla has it figured out pretty good. If any company would have tried to make inductive coupling work, it would have been Tesla.

    • Ronald Brakels

      Dang! 118 kilowatts! Those superchargers really are super, aren’t they? I presume it decreases somewhat as the battery gains more of a charge, but still very impressive.

    • Eric Zucker

      The coil dimensions are the main factor, and there can not be metallic parts nearby. Especially aluminum.

      My company has a prototype which demonstrated 120 kW inductive transfer with 94.6 % efficiency from AC in to DC out. 20 cm air gap.
      Parts on the vehicle weigh about 50 kg.

      Wired charging is not 100% efficient either. There needs to be a rectifier, control circuits, all these heat up too. Even cables have resistance.

      The interest is not just convenience, it’s reduced maintenance and wireless charging gives autopilot complete energy autonomy.

    • Eric Zucker

      The coil dimensions are the main factor, and there can not be metallic parts nearby. Especially aluminum.

      My company has a prototype which demonstrated 120 kW inductive transfer with 94.6 % efficiency from AC in to DC out. 20 cm air gap.
      Parts on the vehicle weigh about 50 kg.

      Wired charging is not 100% efficient either. There needs to be a rectifier, control circuits, all these heat up too. Even cables have resistance.

      The interest is not just convenience, it’s reduced maintenance and wireless charging gives autopilot complete energy autonomy.

  • Darcy Toombs

    Could this lead to charging while driving, if a power source is built into the road?

    • Joe Viocoe

      Could? Yes. Will? No.

      We have solid interest in flying cars for 60 years now. But they are called helicopters and are impractical for many reasons.

      In road charging will equally be impractical.

      • Michael B

        I agree, except for the “solid interest” in flying cars part.

      • Michael B

        I agree, except for the “solid interest” in flying cars part.

  • Null66

    Wonderfully fitting!
    Tesla
    Inductive!

  • DecksUpMySleeve

    Wireless charging is less efficient. On anything over a kWh I largely oppose it.
    Adding 10-20% power use to every charge is unecological as all get out.
    Regardless of market appeal it’s a horrid trend to start.

    • Null66

      Uhm, Kinda like complaining about paying for a winning lottery ticket…

      So instead off 100% better (on current grid) its only 93% better, but with wider faster adoption and massively simplify charging away from home…

      • DecksUpMySleeve

        How do you get 93%? There are more than 7% losses.
        Furthermore, this basically renders the car less efficient, 12% in a 50-90kWh vehicles is 6-10.8 kWh nothing short of wasted.
        That’s a lot of power, anyone choosing this over a plug in the name of convience can hardly even call themselves green.
        An electric bicycle could ride 369-664 miles on the power wasted(1.3kWh GreyP G12, 80 mile range).

        • Null66

          Uh, it doesn’t reduce what the car stores. It just has to draw more from the grid.

          So it ‘wastes’ maybe $20.00 a year in grid electricity.

          Who cares what people call themselves? A radical reduction in emissions is still a radical reduction in emissions.

          And who cares what you “oppose”?

          How do you get around?

          • Bob_Wallace

            My understanding is that batteries heat up both while being charged and while being discharged. If that’s correct then there some loss (waste heat) on both ends of the process.

          • Null66

            Yes, nothing in this world is perfect and nothing is loss-less.

            The loss storing energy in a battery is completely independent upon how you couple the car to the grid. Which is the topic.

            If you hate loss, well, then the most efficient transportation is the bicycle as measured by energy in to distance traveled.

            Electric cars are the most efficient automotive transport.

          • DecksUpMySleeve

            More like ~$80 if you drive 20K miles a year.
            Though grid electricity isn’t calculated in $ but instead pounds of Carbon Dioxide, Mercury, and Methane.

          • Most EV drivers have clean electricity. You can’t blame them for the emissions of staunch coal lovers.

          • DecksUpMySleeve

            Electricity wasted is electricity which could be fed elsewhere. Until the whole generation pool is clean all those on the grid are weighed by coal/peak which they inversely use.

          • Null66

            You must be so incensed by gasoline car transport that you require sedation if you’re worried about the losses from induction charging.

          • DecksUpMySleeve

            Nope, just seeking maximum efficiency and not excusing >10% more pollution as a byproduct of expedience and laziness.

          • DecksUpMySleeve

            Nope, just seeking maximum efficiency and not excusing >10% more pollution as a byproduct of expedience and laziness.

          • DecksUpMySleeve

            More like ~$80 if you drive 20K miles a year.
            Though grid electricity isn’t calculated in $ but instead pounds of Carbon Dioxide, Mercury, and Methane.

          • Frank

            I’m assuming you have no tolerance for incandescent bulbs either.

  • Even though I don’t own and don’t plan on owning a car, I’m looking forward to robotic chargers becoming the norm. Anything that shuts up EV nay-sayers is good technology, and this is in that category. The 7% loss over level-1 corded and 12% loss over level-2 chargers isn’t a big deal. There are far greater losses just in transmission of electricity or over production. Hell, there’s greater losses just from dirty fuel injectors and improperly tuned engines. If a charging station is solar powered and over produces, 7% is ¯_(ツ)_/¯.

    • Joe Viocoe

      The average transmission loss in the U.S…. is 6.5%

      I am waiting for the snake charger…. 0% loss, even at 135 KW of full power 🙂

      • Bob_Wallace

        According to the EIA that’s transmission and distribution losses combined. The majority loss is during transmission.

        Edit – sorry I got that backwards. Largest losses are during distribution. That will decrease as grids are upgraded.

    • Michael B

      What Joe and Bob said. 🙂

    • Michael B

      What Joe and Bob said. 🙂

  • stephan011

    wireless is nice as a feature, but if 10-20% of the power is wasted it may make it a bad idea both economically and environmentally

    • Bob_Wallace

      If wireless charging gets more people into EVs simply because they are adverse to plugging in it could be better for the environment, overall. Losing 7% (Plugless 3.3 kWh system) would mean that it takes longer to shut down coal and gas plants but it could also mean taking gas cars off the road sooner.

      Economically, that would be a personal choice. 35 miles at 0.3 kWh with 9c/kWh electricity = 95 cents a day. Use an extra 7% and the daily drive goes up to $1.01. I suspect a lot of people would be find with spending an extra 6 cents a day to avoid dealing with a charge cord.

      • Carl Raymond S

        But is it really just 7% loss? Independent data needed before this is allowed on the market.

        • Bob_Wallace

          “Our current 3.3kWh system is roughly 7% less efficient than a corded level 1 charger and ~12% less efficient than a corded level 2 charger (this is based on extensive 3rd-party testing by Idaho National Labs).”

          • Joe Viocoe

            It is about the same as what was already known.

          • Bob_Wallace

            The issue here was independent lab testing.

          • Bob_Wallace

            The issue here was independent lab testing.

          • Joe Viocoe

            It is about the same as what was already known.

      • Ronald Brakels

        Let’s see, in Australia the average car is driven an average of a little over 40 kilometers a day. At six kilometers per kilowatt-hour that comes to 7 kilowatt-hours with a marginal cost of about $1.50 US for grid electricity and 7% of that is about 11 US cents. There are definitely plenty of people who do not care about 11 cents.

        However, people earning the minimum wage of about $12.50 US will come out ahead by spending time plugging in, assuming plugging in and out totals 30 seconds. They will effectively be making more money in that time than they would at work. And if they can do it in half that time then they are laughing all the way to the bank. A very very small bank, but a bank none the less.

        So minimum wage earning Tesla owners should choose wisely.

        But, does inductive charging work backwards? In Australia it’s a case of got batteries, can trade power. With the right set up that is. But modern electric cars are so fancy all they probably need is the right software. And a car manufacturer that is okay with it, as hopefully Nissan is, since it is one of their EV selling points in Japan. So here at least, the opportunity for electricity arbitrage can be a consideration.

      • Dragon

        Tons of people are buying these wireless chargers who already bought an EV. Those people already made a choice to go EV and just want the convenience, ignoring the loss of up to 12%. I guarantee that’s slowing down the renewable energy transition more than the super rare person that cares so much about “inconvenient” plugging that that’s the one and only factor stopping them from buying an EV.

        If you can install a solar system large enough to cover the losses of the wireless system, great. Otherwise, people who go wireless are just slowing down the renewable transition significantly due to their own laziness.

      • Dragon

        Tons of people are buying these wireless chargers who already bought an EV. Those people already made a choice to go EV and just want the convenience, ignoring the loss of up to 12%. I guarantee that’s slowing down the renewable energy transition more than the super rare person that cares so much about “inconvenient” plugging that that’s the one and only factor stopping them from buying an EV.

        If you can install a solar system large enough to cover the losses of the wireless system, great. Otherwise, people who go wireless are just slowing down the renewable transition significantly due to their own laziness.

  • stephan011

    Wireless will be lossy, I think it would be better to forgo wireless and focus on some sort of plug that can be automatic.

    • Harry Johnson

      That’s my understanding too with wireless charging for an EV. Can it ever equal of the speed and efficiency of a plug? For some people it won’t matter along with the price tag. But you won’t see these lining street parking curbs anytime soon.

    • Bob_Wallace

      Tesla has already built a prototype. The “snake”. They’re now talking about a simplified version.

      Some years back some company built robotic gas pumps that could identify the model car, remove the gas cap, fill the tank, and replace the gas cap. With today’s electronics and the simpler task of just plugging in auto-chargers should not be a problem.

      But wireless has an advantage. It can be used in areas where vandalism of plug-in chargers might be an issue. Embedded in the pavement along curbside parking lanes would be a largely tamper proof system.

      • stephan011

        I would think the ideal setup would be probes that attach on the bottom of the car for charging, you drive the car over and park and something attaches on the bottom. Same deal for electric buses, drive normally and every so often park for 10 minutes and automatically recharge.

        • Bob_Wallace

          I see dirt and snow plow issues.

          • Carl Raymond S

            I can see it working in garages.

      • Matt

        The pavement embedded system could become important for deployment in cities.

      • Jamset

        What do you think of battery swapping in motorcycles or scooters?

        A company in Taiwan is working on that concept.

        Having a heavy battery in a car is ok but will probably have a lot of negatives in motorcycles.

        • Bob_Wallace

          I can see a market niche of people who live in apartments or other situations where they have no place to plug in. They could carry the battery in when they arrive home and carry a charged battery out in the morning.

          The model I’ve seen being talked about makes less sense to me. One drives to an exchange store and pays to swap for a charged battery. With this model you’ve got extra batteries, site costs, equipment costs, labor, and someone making a profit.

          • neroden

            The Zero motorcycle is small enough that riders apparently simply carry the entire motorcycle indoors (the way you would with a bicycle). Which is pretty cool.

          • neroden

            The Zero motorcycle is small enough that riders apparently simply carry the entire motorcycle indoors (the way you would with a bicycle). Which is pretty cool.

          • Jamset

            There are similarities with the water purification market. Some purify at home, some buy bottled water.

            Some offices get water delivered in 20L plastic containers, which is a waste.

            In some nations, the commercial buildings/factories get much cheaper electricity than the residential areas.

            Maybe it would be cheaper to recharge/swap at a university campus than to do so at home.

          • Jamset

            There are similarities with the water purification market. Some purify at home, some buy bottled water.

            Some offices get water delivered in 20L plastic containers, which is a waste.

            In some nations, the commercial buildings/factories get much cheaper electricity than the residential areas.

            Maybe it would be cheaper to recharge/swap at a university campus than to do so at home.

          • Mod Mark

            Base on what many universities charge for parking, they may add a markup on the electric sold.

          • Radical Ignorant

            Niche? In plenty of places that’s norm, not niche :p
            However I see the future with plugs on street lamps and in public garages. And those plugs are talking to connected car and charging it like e.g. You don’t care paying for every call from your pre paid phone.

        • Bob_Wallace

          I can see a market niche of people who live in apartments or other situations where they have no place to plug in. They could carry the battery in when they arrive home and carry a charged battery out in the morning.

          The model I’ve seen being talked about makes less sense to me. One drives to an exchange store and pays to swap for a charged battery. With this model you’ve got extra batteries, site costs, equipment costs, labor, and someone making a profit.

      • Jamset

        What do you think of battery swapping in motorcycles or scooters?

        A company in Taiwan is working on that concept.

        Having a heavy battery in a car is ok but will probably have a lot of negatives in motorcycles.

    • Disclosure, I work for Plugless. We are looking forward to competition in the hand-free charging space to see how others solve for equipment costs, costs to supply the electrical, vehicle and parking space integration and wear and tear. Ramping up the power for inductive power transfer is not an issue, but integration with the EV and supplying and managing higher power levels presents different engineering challenges, nothing insurmountable. We are a product company, so we look hard at balancing costs with use cases. As for speed, the 7.2kWh Plugless system for Tesla S is a true 7.2kWh charger (it charges at the same rate as any corded 7.2kWh charger – or at least 20mph of charging). Our current 3.3kWh system is roughly 7% less efficient than a corded level 1 charger and ~12% less efficient than a corded level 2 charger (this is based on extensive 3rd-party testing by Idaho National Labs). Our 7.2kWh should be about the same. Our understanding, from public statements, is that the snake is a Supercharger solution first, and first as a limited test, then maybe for home use down the road. Again, looking forward to see where the price would come in on that and its wear and tear solutions. Charge Onward.

      • Bob_Wallace

        Thanks for the numbers.

      • Those loss levels are quite acceptable for the added convenience and simplicity of wireless charging. Is there an opportunity for losses to be diminished further over time?

      • Thanks for the info.

        But if you work for a charger company, shouldn’t you know the difference between kW and kWh? 🙂

    • James

      I agree. It would be much easier to build a charge pad with charge arms that connect to undercarriage charge leads The mechanics of this could be very simple and look just like a wireless charging pad when not in use.

    • James

      I agree. It would be much easier to build a charge pad with charge arms that connect to undercarriage charge leads The mechanics of this could be very simple and look just like a wireless charging pad when not in use.

  • Shiggity

    I strongly believe that future battery packs will do both. You can either plug it in and charge or if you have a wireless pad, you can use that.

    It will initially carry a price premium, but it will become a standard feature as EV’s become more common.

    Wireless charging is the perfect compliment to autonomous driving and Uber / Taxi style driving.

    I hope they offer this as an option on the Model 3.

    • Michael B

      I compliment you on your comment, except for one misspelled/misused word. 😉

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