Wireless charging has been around for a long time. It’s what powers electric toothbrushes and cordless shavers and well as a lot of medical devices. But it has been very slow to make it to mobile electronic devices, but the Wireless Power Consortium aims to change that as it pushes ahead with its Wireless Qi (pronounced Chee) standard.
To date, wireless charging of mobile devices has been associated mainly with companies on the brink of doom. Palm and, briefly, Hewlett-Packard offered the Touchstone wireless charger for both Pre phones and the TouchPad tablet. Nokia is now offering it on its Lumia phones.
The principle of wireless charging, called resonant inductive coupling, is simple. An alternating current in a coil induces a current in a nearby coil. If the two coils are tuned to the same resonant frequency, the power transfer between them can be very efficient. And if the two coils are the same size, the magnetic field will be contained in the space between them.
The current Qi standard provides for 5 watts of power, adequate for smartphones but not for tablets, which take too long to charge at low wattage. A 10 W standard is on the way, but like all standards bodies, the WPC moves slowly and may take a while. But this is an area where standards are crucial. One of the reasons previous efforts failed to catch on is they were proprietary and the advantage of wireless charging lies in the ability to power a variety of devices from a single charging pad.
A number of handset makers, including Samsung, LG, and Motorola, are members of the consortium and while that doesn’t guarantee they will offer products, it at least shows interest. Delphi, the former General Motors electronics and parts division has just joined, increasing the prospect of automotive charging systems. But Apple is prominently missing from the membership list.
Apple marketing chief Phil Schiller recently dismissed wireless charging as bringing no real advantage to consumers. But WPC Chairman Menno Treffers, of Philips Electronics, says he was off the mark: “That’s a real misconception about what the point is. The point is the difference in the charging experience. I can best explain it by talking about my own experience. I used to have a USB charger on my desk, but in practice, I didn’t use it; it’s a hassle and you tend not to do it.If you have a Qi phone, you just put it on the pad and you pick it up. People keep their batteries charged much better.”