I can see that wireless charging is convienent since all you have to do is place your device on a mat and it will get chaged. Has there been any information about the efficiency of this system? I expect that it is very poor. With the push to save power and create new technologies that are more efficient, I don't understand the push for wireless charging. I will continue to plug in my devices even if it only saves me a few pennies.
I think much of the "push" for wireless charging has to do with limited access to charging throughout the day and the constraints that are placed on mobility by the current system. It's troubling to see how as devices become more and more complex they continue to offer little in terms of power-saving and endurance. Performance is one thing, but devices need to be operational in order to accomplish what they are intended to accomplish. That isn't being done right now and so the demand for wireless charging is on the rise.
The last point from Lachman I think nicely summarizes things. There is no one single magnetic standard and there will need to be more than one power source as well. A receiving system that can easily be integrated into a device based on that device's shape and size is also very important.
To me, wireless charging provides the conveience with the price of low energy efficiency. The development is primarily focused on efficiency improvement. It is way better than the first generation inductive charging; yet, it can't be as good as direct contact simply by Law of Physics. Anyone can provide some measurement data of efficiency vs different method will help the community to understand. :)
Congrats on a well-researched and well-written overview article. A growing number of articles have tried to accomplish an overview of the wireless power standards development, and I find this to be the most accurate. This is speaking from 4+ years of experience as an antenna developer for wireless power devices.
There have been some very positive changes in charging with the standardization on microUSB as a common plug standard. Reading this article reminded me of the bad old days where each device needed a special cable. All that I see is a multiplicity of standards that will be going away within a couple of years. It does not make me want to commit, either as a device designer or a consumer.
I would love to see some direct comparisons as well - I found very little data on power efficiency/time in my research. Seems to me that the next hurdle to overcome in charging will be getting the efficient power transfer of inductive with resonance's ease of placement.
My company has just finished developing a Qi based phone charger design for one of the world's largest car manufacturers. Having this built into production cars is bound to boost the Qi standard over any competing standard.