Recharging batteries wirelessly

From c/net News

A Pennsylvania start-up says it has the answer to one of the biggest problems in mobile phones: battery life.

After three years of keeping its technology under close guard, Powercast has come to CES 2007 to get consumer and manufacturer attention. Powercast is a radio frequency that is transmitted over a small area, and its energy is "harvested"--wirelessly--to give power to small devices like cell phones.

While it's presented as wireless power, Powercast isn't just a replacement for a universal charger. Instead, it's meant to either continuously charge a battery or replace the need for them altogether.

It works like this: a transmitter can be placed anywhere--in a lamp, for example, that is plugged into the wall and sits on a table. The transmitter in the lamp sends out a continuous, low RF signal. Anything with either AA or AAA batteries set within its range--and equipped with a Powercast receiver, which is the size of your fingernail--will be continuously charged.