John, OK so you want actual numbers regarding battery savings. Let's study the case of the latest version (3G-S, July 2009) of the popular iPhone smartphone:
http://www.apple.com/batteries/iphone.html : "A properly maintained iPhone battery is designed to retain up to 80% of its original capacity at 400 full charge and discharge cycles" http://www.apple.com/support/iphone/service/battery/ : "iPhone Out-of-Warranty Battery Replacement... The program cost is $85.95 per unit." http://en.wikipedia.org/wiki/IPhone : "3GS: 3.7 V 1219 mAh[5] Internal rechargeable non-removable lithium-ion polymer battery[6]" So total delivered energy is 3.7V*1.219Ah*0.4kcycles = 1.8kWh, that's a cost per delivered kWh of 85.95/1.8 ~= USD 48 per kWh So that's "only" ~ 500 times the cost of grid power (which is ~ USD 0.10 per kWh, right?), the several thousands factor I had in mind must have been for non-rechargeables. A factor 500 is still huge, it means that all the time you're on 50% efficient witricity power instead of battery power, consuming what would cost you x USD/s if you were operating off the grid with 100% efficiency, instead of spending 500x you spend 2x, that's a saving of 99.6%. Note that even if the factor was only 50 (10 times lower than calculated above) and the witricity efficiency was only 10%, instead of spending 50x you spend 10x, that's still a saving of 80%, for each second you spend on witricity instead of battery power. So witricity is not just practical, it also saves money. If it also complies with health regulations regarding radiation levels which they claim it does, it is definitely a good thing. Michel 2009/9/19 John Fields <[email protected]>: > 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. > >
