These people claim they can improve over direct connection charging: http://www.wipower.com/
Terry On Tue, Sep 15, 2009 at 9:37 AM, John Fields <[email protected]> wrote: > The efficiency I was referring to was for a pair of untuned loops > loosely coupled, but even at 50% for a more closely coupled resonant > system, half the power out of the transmitter would be lost before it > got to the load. > > And, no matter how efficient the system can be made to be, it can never > be made more efficient than the direct ohmic contact made between a plug > and a socket. > > I doubt whether the impact on batteries will even be noticeable, since > devices designed to be mobile will still need to be powered by batteries > when they're not in the vicinity of a transmitter, the only "advantage" > being that their batteries can be charged without having to directly > connect a charger to the device. > > As far as electric vehicles goes, I think the idea of a non-plug-in > charger is pure insanity. > > Why? > > Arbitrarily pulling some numbers out of thin air, if we assume that the > battery needs to be charged from a 120 volt source at 20 amperes for 8 > hours, that's 19.2 kilowatt-hours, and at US$0.15 per kilowatt-hour, > that's $1.92. > > Not bad... but, with a non-plug-in charger running at 50%, that's $1.92 > thrown away for every $1.92 used. Worse is the fact that it's not just > money being thrown away, it's resources being squandered because of > laziness. > > > > > > On Tue, 15 Sep 2009 11:28:26 +0200, you wrote: > >>A more informative video on the subject of witricity here: >> >>http://www.ted.com/talks/eric_giler_demos_wireless_electricity.html >> >>Transfer efficiency is not 5% like John suggested but more like 50% >>and growing. I suspect the energy loss compared to traditional >>solutions will be globally more than made up by the savings in >>disposable batteries or rechargeable battery cycles in many nomadic >>battery powered applications such as hearing aids and cell phones. >> >>Not sure about electric cars though, unless the efficiency can be >>significantly improved, which I guess can be done by bringing the >>coils closer together (either the coil in the car or that in the floor >>could be mobile and automatically brought into close proximity of the >>other one before charging begins). >> >>Michel >> >>2009/9/15 OrionWorks - Steven Vincent Johnson <[email protected]>: >>>> From: John Fields >>>> >>>> On Mon, 14 Sep 2009 16:11:48 -0400, you wrote: >>>> >>>> >As John Fields says, this is a harebrained scheme. >>>> > >>>> >My guess is that if the power is high enough to useful work, they >>>> >will eventually discover it can harm your health. >>>> > >>>> >I suppose there are some narrow applications that would benefit from >>>> >this technology. >>>> >>>> --- >>>> You're right; there are. >>>> >>>> One of them is battery powered toothbrushes with resting stations that >>>> allow recharge of the cells, in the toothbrush, between brushings >>>> without the need for ohmic contacts between the load and the source. >>> >>> I suspect medical implants, like pacemakers would benefit as well. I believe >>> they are working on this. >>> >>> Regards, >>> Steven Vincent Johnson >>> www.OrionWorks.com >>> www.zazzle.com/orionworks >>> >>> >>> > >
