On Sat, 19 Sep 2009 18:20:44 +0200, you wrote: >2009/9/19 John Fields <[email protected]>: > >> I don't know the intensity of the fields shown in the videos, but my >> concern would be that in a field of sufficient intensity to charge a >> cell phone battery would also be capable of heating rings, necklaces, >> and the like. > >In the photo here: > >http://cheeju.files.wordpress.com/2007/06/wireless-grp1-enlarged.jpg > >one of the guys in the beam is wearing what looks like metal rimmed >glasses, with no sign of discomfort.
--- Blowing up the picture makes it seem like they're rimless but, in any case, he's not in the concentrated part of the beam between the coils, he's on the outside of that area, where the field strength is much, much lower. On top of that it appears that the optical axes of the lenses aren't normal to the magnetic field, which would also reduce the current induced in the rims. --- >> Do you have any actual numbers relating the extension of battery life >> and its savings on replacements to the cost in manufacturing and >> operating the large charging system you envisage? > >I haven't got precise numbers but the cost of electricity from a >battery is a few thousand times more than that of electricity from the >grid, so it shouldn't be hard to make savings by drawing a little less >from the battery and a little more from the grid. --- Without numbers to back up your conjecture, your case is, essentially, moot. --- >> What I disagree with is that any system designed to send electricity >> "wirelessly" will ever exceed the efficiency of a properly designed and >> operated wired system, and will, consequently, waste power. > >Not if you consider the global cost and energy balance for equipment >which would otherwise be battery powered. --- Again; without numbers to back up your conjecture, your case is, essentially, moot.
