Results 31 to 38 of 38
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2020-06-17, 11:44 AM (ISO 8601)
- Join Date
- Oct 2010
- Gender
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2020-06-17, 12:01 PM (ISO 8601)
- Join Date
- Nov 2006
- Location
- England. Ish.
- Gender
Re: Why does comercially available wireless charging have such a short range?
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
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2020-06-17, 04:00 PM (ISO 8601)
- Join Date
- Nov 2006
- Location
- Watching the world go by
- Gender
Re: Why does comercially available wireless charging have such a short range?
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2020-06-17, 04:06 PM (ISO 8601)
- Join Date
- Dec 2009
- Location
- Washington D.C.
- Gender
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2020-06-17, 06:09 PM (ISO 8601)
- Join Date
- May 2007
- Location
- Tail of the Bellcurve
- Gender
Re: Why does comercially available wireless charging have such a short range?
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.
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2020-06-20, 01:14 PM (ISO 8601)
- Join Date
- Mar 2007
Re: Why does comercially available wireless charging have such a short range?
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).
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2020-06-20, 03:08 PM (ISO 8601)
- Join Date
- Nov 2006
- Location
- Watching the world go by
- Gender
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.
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2020-06-22, 02:14 AM (ISO 8601)
- Join Date
- Aug 2013
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.