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  1. - Top - End - #31
    Titan in the Playground
     
    Lizardfolk

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    Default Re: Why does comercially available wireless charging have such a short range?

    Not to mention Tesla's version had big plasma flares that started fires, and would interfere with communications.
    Quote Originally Posted by The Glyphstone View Post
    Vibranium: If it was on the periodic table, its chemical symbol would be "Bs".

  2. - Top - End - #32
    Troll in the Playground
     
    Flumph

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    Default Re: Why does comercially available wireless charging have such a short range?

    Quote Originally Posted by louisg View Post
    ... (both the amount of cooper wire needed to make the coil and power).
    I realise that it's a simple typing error, but my immediate thought reading this was "oh, that's how to keep Battery hens?"...
    Warning: This posting may contain wit, wisdom, pathos, irony, satire, sarcasm and puns. And traces of nut.

    "The main skill of a good ruler seems to be not preventing the conflagrations but rather keeping them contained enough they rate more as campfires." Rogar Demonblud

    "Hold on just a d*** second. UK has spam callers that try to get you to buy conservatories?!? Even y'alls spammers are higher class than ours!" Peelee

  3. - Top - End - #33
    Firbolg in the Playground
     
    Rockphed's Avatar

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    Default Re: Why does comercially available wireless charging have such a short range?

    Quote Originally Posted by Tvtyrant View Post
    Not to mention Tesla's version had big plasma flares that started fires, and would interfere with communications.
    So that theory that Tesla was actually some sort of avatar of an elder god sent to corrupt our world... is this entity also responsible for the aethetics of metal musicians ?
    Quote Originally Posted by Wardog View Post
    Rockphed said it well.
    Quote Originally Posted by Sam Starfall
    When your pants are full of crickets, you don't need mnemonics.
    Dragontar by Serpentine.

    Now offering unsolicited advice.

  4. - Top - End - #34
    Dragon in the Playground Moderator
     
    Peelee's Avatar

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    Default Re: Why does comercially available wireless charging have such a short range?

    Quote Originally Posted by Rockphed View Post
    So that theory that Tesla was actually some sort of avatar of an elder god sent to corrupt our world... is this entity also responsible for the aethetics of metal musicians ?
    The entity known as Steve Harris?
    Cuthalion's art is the prettiest art of all the art. Like my avatar.

    Number of times Roland St. Jude has sworn revenge upon me: 2

  5. - Top - End - #35
    Titan in the Playground
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    Default Re: Why does comercially available wireless charging have such a short range?

    Quote Originally Posted by Eldan View Post
    So much easier to just vaporize the entire atmosphere off the planet.
    Really, if a person isn't willing to solve minor cooking problems with weapons of planetary destruction, is it worth talking to them at all? Now excuse me, I need to go make asteroid bombardment chicken schnitzel. Really bakes that out of this world lithium flavor right in.
    Blood-red were his spurs i' the golden noon; wine-red was his velvet coat,
    When they shot him down on the highway,
    Down like a dog on the highway,
    And he lay in his blood on the highway, with the bunch of lace at his throat.


    Alfred Noyes, The Highwayman, 1906.

  6. - Top - End - #36
    Bugbear in the Playground
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    Default Re: Why does comercially available wireless charging have such a short range?

    Quote Originally Posted by Manga Shoggoth View Post
    Off the top of my head:

    I suspect our old friend the Inverse Square Law is involved. The further away the device is, the less power it will pick up from the charger, and so the more power the charger will have to put out (and also a sizable proportion of this power will be wasted). Since these are domestic devices you can't put too much power in them as it will affect device size and heat disappation.

    Also, the more powerful the field generated by the charger, the more likley it is to intefere with other devices. So it could be as simple as regulations on emmissions.

    EDIT: This article may be of help.
    Worse, you have an inverse *cube* law. There are two ways to transmit electric energy. First is normal EM waves that fall off at an inverse square law. But this isn't remotely efficient (and you create the waves and use the power whether or not anything is being charged).

    The other way is through inductive coupling. This has to be done on an order of the wavelength being used, and falls off at the cube of the distance. This can be extremely efficient and is more or less how AC step up/step down transformers work (thanks, Tesla!). Note that energy is only "used up" when there is something to receive it (just don't leave half of your transformer shorted out and nothing on the other side...).

    So the range is dependent on both the distance from the charger and the frequency used. Since (US) AC wires run 60Hz, it is entirely possible you could run ordinary high-voltage power lines above a highway, and build receivers into cars to power them (just don't ask me to design the electric motor that functions in such a field), as I've heard of people powering their homes (admittedly requiring less power than an electric car) by stealing power from the electric company this way (just keep wrapping wire around a steel engine block...). But for commercial chargers, I'd expect that you want both low power (similar to USB power levels) and ultra short distances (such as lying directly on a pad).

  7. - Top - End - #37
    Firbolg in the Playground
     
    Rockphed's Avatar

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    Default Re: Why does comercially available wireless charging have such a short range?

    Fun fact: if the power company is paying attention, they can tell when and about where somebody installs a device to steal power from the high-voltage lines.
    Quote Originally Posted by Wardog View Post
    Rockphed said it well.
    Quote Originally Posted by Sam Starfall
    When your pants are full of crickets, you don't need mnemonics.
    Dragontar by Serpentine.

    Now offering unsolicited advice.

  8. - Top - End - #38
    Ogre in the Playground
     
    ElfPirate

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    Default Re: Why does comercially available wireless charging have such a short range?

    I watched the Mythbuster try this out. The amount of copper wire you needed to power a lowgrade quartz digital clock was daft.

    Basically, just pay your electricity bill.

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