Friday, July 26, 2013

Wireless charging, is it a myth?


I currently use the Samsung Desktop Dock for Infuse 4G on my nightstand for my GS4. It fits the phone quite well, has a port out the back that lines up nicely with the speaker and activates dock mode (which launches Dock Clock). I decided to replace this setup with the Tylt Vu, a recent kickstarter project. The Vu allows the phone to wirelessly charge at a 45 degree angle so you can still see it while charging (one of the major problems with Qi). Unfortunately, it doesn't stay connected to the phone as there is some sort of incompatibility with the official Galaxy S4 back plate. Both are fully Qi compliant so very frustrating. It's also worth mentioning that the Desktop Dock worked with both my GS3 and GS4 and cost a whopping $10. It takes the same amount of time to dock in either the Vu or the Infused dock but the Infuse dock charges twice as fast. Strike 2.


First off, wireless charging is a bit of a misnomer when it comes to the Qi standard (pronounced chee, Chinese for energy). There is still a wire from the power source to the charger, just none from the charger to the battery. I have a great car-mount setup from ProClip USA that is customized for my Jeep Commander and I wanted to add Qi charging to it. I like to run my mobile fully engaged when I'm in the car. During daylight hours, I have brightness maxed out, some sort of GPS app running and audio over Bluetooth to my car audio system. This is a heavy use scenario and typically sucks down about 1000 ma of juice from my battery. In my tests with Qi, it turns out that the official Qi setup I have for my Samsung Galaxy S4 allows a maximum of 640ma of current to charge my battery with the screen on. Doing some quick math, you can see that while this lessens the drain of the battery, it doesn't charge at all. My GS4 will last longer but it will still eventually die. If I run with the screen off, Qi is able to push a full 1000ma into my battery, coupled with the fact that my screen is off and my power drain is greatly reduced, my battery will actually charge in this scenario. If I use a properly configured 12V DC to USB adapter and the right shielded cable, I can get 1900 ma into the phone allowing full usage and charging. Strike 1.

As mentioned in my last post, I decided to fully embrace the concept of wireless charging. It's a very cool concept but doesn't fit the mold for some of the typical charging scenarios. I've been on a quest to build a platform agnostic in-car setup for my mobile. I was very frustrated when Apple kept changing the connector for audio/charging and therefore went with Bluetooth for the audio portion. The last thing I needed was a way to universally charge and I thought Qi wireless charging might be it.




Finally there is already a format war going on for wireless charging. Apparently Qi and PMA are duking it out HDDVD-vs-Bluray-style. Any investment in either technology could quickly become outdated. Not only will this stifle adoption, it will cause problems with publicly provided charging points already being installed at McDonalds (Qi) and Starbucks (PMA). Strike 3, it's out for me.

Now that you have learned a bit more about wireless charging, you can decide if it's the solution for you.

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