Performance and How it Works
As we've mentioned, the Powermat charging system works on Nikola Tesla's principle of magnetic induction. But while this is the mechanism for the transfer of power to the device, there are other items at work.
One of the first items is the most simple and part of the actual workings of the charging mechanism. This is the magnets that are in both the receiver and the pad. These will connect and hold the two together in the proper alignment and also help to maintain good and solid contact between the two.
Once the magnetic contact is made, the receiver sends a signal to the pad identifying the device. This RFID handshake helps with charging efficiency. Once the RFID handshake is successful you will hear an audible confirmation and an LED on the side of the pad will light.
From there the receiver and pad will maintain the charging connection until the device sends a signal saying that it is full. Once the battery is full the Powermat will shut off power and enter a listening mode. In this mode it will check the charge level of the device and begin charging again if it detects the battery has been used.
The upshot of all of this is that the Powermat pair (receiver and pad) are very efficient. They are able to charge almost as fast as the regular wired adapters while lowering the amount of power drawn from the wall.
In our testing we found that the iPhone 3G S would charge from a drained battery only two minutes slower than the traditional corded charge and as much as ten minutes faster than charging the iPhone from a USB port.