The can charge an iPhone at least three times--3.3 for a 3G, 3 times for a 3GS, and 2.6 times for an iPhone 4, according to Scosche--and juice up an iPad to by just over half (55 percent) of its capacity. It can also charge two devices at the same time, thanks to its two USB ports.

It takes six to eight hours to charge the backup battery; at full, charging an iPad and an iPhone will drain the goBat II in about an hour; an iPad will do the same in three hours; and it will take two-and-a-half hours to discharge it when hooking up an iPhone.

The battery retails for $90 and is available for purchase at Scosche's Website.