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What is the Future of Wireless Power?

Posted by CmdrTaco on from the this-is-gonna-burn-my-crotch-isn't-it dept.

mfbatzap writes "According to Firdooze, we have seen various devices that can free ourselves from wires at CES 2008. The manufactures, Wildcharge, Powercast and Fulton Innovation, came out with two different methods of transmitting power from source to the devices. Wildcharge and Fulton banked on magnetic coupling while Powercast decided to go with RF (Radio Frequency). So which technology will eventually prevail to be the future of wireless power? Or will the technological setbacks from transferring power wirelessly make it unrealistic to accomplish a wire-free world?"

22 of 178 comments (clear)

  1. I for one hail our new glowing overlords by debatem1 · · Score: 4, Funny

    I have to wonder whether this announcement and the glowing pigs announcement are just coincidental...

  2. Wireless Everything by ShawnCplus · · Score: 5, Funny

    Well my laptop has wireless internet and a wireless mouse, why not wireless power? I'd gladly accept a benign tumor or two if I could get more than 3 hours out of my battery.

    --
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    1. Re:Wireless Everything by ByOhTek · · Score: 4, Funny

      well, I experimented with this. While the tumors were benign to me, after the third or fourth time I woke up to find one gnawing on the limb of a small child it apparantly captured/ate/killed, I decided it was time to have it removed. Apparantly three doctors were lost during the procedure.

      --
      Self proclaimed typo king, and inventor of the bear destroying coffee table (patent not pending).
  3. is there a way by JeanBaptiste · · Score: 3, Interesting

    to transfer power wirelessly without cooking whatever happens to pass inbetween the sender and receiver?

    1. Re:is there a way by Otto · · Score: 5, Interesting

      From what I understand, it depends on the frequency. For instance, a microwave oven operates at whatever frequency best excites a water molecule, which leads to cooking by making the water in everything hot. That is incorrect, but you're forgiven because it is a common misconception that's even in a few encyclopedia's and such.

      Microwaves work by producing an alternative electric field (using non-ionizing microwave radiation) that acts on molecules which have electric dipoles. Water is one of those, but so are many others, including fats and such. The process is called Dielectric Heating.

      Basically, the molecule being heated is a dipole. It has a positive charge at one end, and a negative charge at the other. In an alternating electric field, it rotates as it tries to align itself with the field. This causes motion, which translates to heat. The heat spreads as the molecules hit other molecules and transfer the energy to them. Now, this process works really good on water because water is a very strong dipole, but it does not operate solely on water, and it doesn't have anything to do with water in particular.

      See, the frequency doesn't actually have much to do with it. Normal kitchen microwaves operate at 2.4 Ghz or close to that. Industrial microwave devices tend to work at 915 Mhz. Also, if the frequency had something to do with it, then 2.4 Ghz would be the wrong one. The resonant frequency for water is somewhere in the 20 gigahertz range. The only reason 2.4 Ghz is used for microwaves is that it's a free bands of frequency (ISM frequency bands) that can be used worldwide.

      So, there you go. Now you know.
      --
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    2. Re:is there a way by Sarutobi · · Score: 3, Insightful

      As long as we're getting in the scientifically correct... Frequency does matter. If the frequency is too high, the dipole won't be able to follow and you'll see other phenomena pop up. That is, for instance, why water is blue. The frequency of the electrons around the dipole allow them to absorb a bit of red light. If you go even higher, it will stop interacting altogether. If you go too low, the energy transfer will be hindered.

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  4. Out of curiousity... by Krinsath · · Score: 5, Interesting

    Does anyone know how much power is "wasted" (if any) due to using wireless methods versus wired connections?

    Off my limited knowledge, it would seem to be akin to one of the problems with biofuels...they currently take more energy to produce than they store. So will using this technology to charge a device result in taking two or three times more energy to transmit the same amount of power to the device, or is there no discernible difference between wireless and wired?

    Just wondering is all...

    1. Re:Out of curiousity... by mblase · · Score: 5, Insightful

      Off my limited knowledge, it would seem to be akin to one of the problems with biofuels...they currently take more energy to produce than they store.

      If I remember my Second Law of Thermodynamics correctly, this is true in any case.

      (Yes, I know what you meant.)

    2. Re:Out of curiousity... by tjstork · · Score: 4, Informative

      All fuels take more energy to produce... in a sense, our present fossil fuel predicament is because we are using stored energy from the sun over millions of years. That we can even think about creating biofuels or really, any sort of fuel, efficiently, says a lot for how far the technology has come. But we'll never be able to just "create" a fuel, and the world's going to have to accept that.

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    3. Re:Out of curiousity... by MBCook · · Score: 3, Informative

      I'd think you'd have problems with RF, it'd be easy to waste power that way. The magnetic people mentioned in the article say they've hit 98.5%, which is great.

      --
      Comment forecast: Bits of genius surrounded by a sea of mediocrity.
    4. Re:Out of curiousity... by Abeydoun · · Score: 4, Interesting
      Here's the Wiki I found on general wireless energy transmission.

      From the wiki article

      "WiPower [1] technology is a very recent example of inductive charging technology. The charging pad allow users to charge multiple electronic devices that are placed on its surface. It is insensitive to the position or orientation of the devices under charge. Unlike most inductive charging systems, the WiPower system uses air-core technology which allows the system to be integrated into very small electronic devices. The efficiency of the system actually exceeds many corded chargers which have a median efficiency of 57%."

      --
      The only consistency in life is the lack thereof
    5. Re:Out of curiousity... by snowraver1 · · Score: 3, Interesting

      200 years ago people would never fly.
      150 years ago it was impossible to talk to someone in another town
      125 years ago it was impossible to own a car
      50 years ago it was impossible to own a computer (except for banks, schools, and gov't)

      You never know what the future might hold. Cold Fusion might prove to be possible. Zero point energy might be proved and harnessed. Maybe someone will figure out a way to take the heat out of the atmosphere and make electricity from that.

      My point is, and I do have one, that nothing is impossible. There is more that we don't know then we know... Chew on that.

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  5. Re:Woah by somersault · · Score: 5, Insightful

    For the types of application this is meant for, I think the old option would be a power cable. Unless you want to run your TV and computers from a few truck sized batteries. Seriously, when they brought out laptops did you say "JUST USE A DESKTOP!"? When they invented the telephone would you have said "JUST GO FOR A VISIT!". When people are walking into hospital do you should "JUST DIE ALREADY!"?

    --
    which is totally what she said
  6. I say neither, you say neither by Ancient_Hacker · · Score: 5, Insightful
    Wireless power is not going to happen.

    Shooting photons across a room to deliver significant power just ain't gonna be practical. If you use an omnidirectional antenna, the losses will be huge. If you instead have like a parabolic dish that tracks the receiver, the losses will be lower, but what happens to kitty or your eyeballs if they get in the way? Cooking your eyeballs to a nice firm egg-white consistency is not going to fly.

    Magnetic fields are dipole fields, that means the little wavy lines leaving the North pole want to curl back as quicly as possible to the South pole. Which means they have very little extent in space. The strength drops off as the CUBE of the distance, so any significant distance is a no-go.

    1. Re:I say neither, you say neither by Jeff+DeMaagd · · Score: 5, Funny

      For the reasons you state, I'd put the people demanding wireless power among the people demanding pony-sized unicorns, at least for the forseeable future. I think pony-sized unicorns is more likely given how genetic engineering is going, but then the people that say they want them are going to say they won't pay more than $1500 for those.

    2. Re:I say neither, you say neither by MBCook · · Score: 3, Insightful

      That's not wireless (RF) like he's talking about, that's inductive. It works on the same principal as a transformer. It only works under VERY short distances. If you lift your toothbrush out of it's charger by a 1/2", it probably won't work anymore.

      An RF system would let you use the toothbrush without having it charged in a station. You could hang it from the ceiling with a piece of twine, turn it on, and let it run until something physically wears out.

      I agree with the GPP, it's impractical. Inductive coupling (which I think is the same as magnetic being discussed) makes far more sense.

      --
      Comment forecast: Bits of genius surrounded by a sea of mediocrity.
    3. Re:I say neither, you say neither by Lumpy · · Score: 3, Informative

      you dont need to shoot it across the room, just charge the device when set on a table. Make ALL your tables charging stations and now you attain the "wireless power" illusion.

      I did this way back in the 90's for one of my EE projects. I created a charge mat and charge adapters to make devices charge from the mat. worked great, erased tapes , credit cards, and discs though... All you did was set the device down and it started charging. worked great and could supply 100ma of charge current to 3 devices.

      --
      Do not look at laser with remaining good eye.
  7. When will people learn? by Kuukai · · Score: 5, Funny

    Wireless power was simply never meant to be. Nikola Tesla tried it, and look what happened to him. He's DEAD!
     
    I wouldn't touch wireless power with a ten foot, umm... wire.

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  8. Wireless power? by Gavin+Rogers · · Score: 3, Insightful

    Already invented. Next!

    http://en.wikipedia.org/wiki/Tesla_Coil

    1. Re:Wireless power? by thatskinnyguy · · Score: 3, Insightful

      Even better than that, Tesla was able to power stuff at great distances. He was doing stuff like this as early as 1891. Really people ought to start giving Tesla his due and stop claiming his concepts for themselves. More on his wireless power experiments here.

      --
      The game.
  9. omnidirectional wireless power by sluke · · Score: 5, Informative

    I'm relatively pessimistic about both of the technologies mentioned due to the inherent limitations that they pose (large leakage of radiated power or short range). I'm looking forward to seeing products based on the wireless power idea that came out of the Joannopoulos group at MIT in 2006.
    The idea was that you can setup an RF wireless power transmitter in such a way that it does not actually transmit any power unless it resonantly couples to a precisely shaped receiver. This way there is little to no leakage and they claimed that the power transfer was quite efficient. I'm sure this was posted to slashdot, but I can't seem to find it. Here's a link to the paper if you are somewhere with access to Science: Science 6 July 2007: Vol. 317. no. 5834, pp. 83 - 86 and here's a link to the press release by the MIT news office (no subscriptions required).

    1. Re:omnidirectional wireless power by Big_Breaker · · Score: 3, Informative

      Sorry but you have this one wrong - converting mains AC to 1mhz is very easy. A common switch mode power supply chops the 50/60hz AC from the wall into a 100khz to 1Mhz waveform with a common (but fast) MOSFET. The chopped signal is then run through a stepdown transformer. The transformer and ripple filtering capacitors in the second stage can be MUCH smaller and more efficient due to the higher input frequency. In this way the high frequency generation is effectively free for a wireless power system, since most DC converter will have a high frequency first stage anyway.

      The resonant coupling is the hard part. Switch mode frequency chopping is bog standard.