Those of us with smartphones know what it's like to barely make it through the day with a single charge, desperately turning down brightness and Wi-Fi in the hopes of eking out a few extra minutes of mobile goodness. The Technocell PowerPak XT and PowerPak DUO are the latest clever solutions to smartphones' power hunger.

This combination charger and battery pack, in the form of a wall-wart power adapter, works with any USB-equipped device. Just plug the adapter into the wall, and it charges itself and your phone at the same time. When you leave for the day, take it with you, and it functions as an external battery. Though this is not the first attempt to address the needs of frequent mobile gadget users (Energizer offers a similar product), its dual-purpose charger and battery design is undeniably convenient.

The product's manufacturer, Technocel, claims an additional 4.5 hours of talk time from the XT and its 1,600mAh cell and an additional 6 hours from the DUO's 2,500mAh. Given that the iPhone and Droid's batteries generally run in the 1,200mAh-to-1,400mAh range, expect around double the battery life you'd usually get from the phone with the XT and triple with the DUO. For those who take more than one USB-powered gadget on the go, the DUO offers two USB ports instead of the XT's one. Both models will be available January 31st, with the XT's MSRP at $50 and the DUO's at $60.