Wireless charging mats have been around for a while. Throw your smartphone on one, and it juices up plug-free. But until now, the mats required the use of a bulky phone receiver case to get a charge. The Powermat Wireless Charging System upgrade fixes that problem by replacing a phone's battery with one that includes a built-in receiver, eliminating the need for a special case. Starting in July, the packs, which work with Powermat's charging mat, will be available for seven phones, including the Motorola Droid and BlackBerry Curve 8530, with more to follow.