Galaxy S 4 users already benefit from solid battery life, but if your Life Companion has become more of a compulsion, you're probably in need of a power solution that can go the distance. Naturally, one option is to swap out batteries, but a new charging case from Mophie could be a simpler route. The Juice Pack -- also available for the HTC One and iPhone 5 -- wraps around the phone and connects via micro-USB, adding an additional 2,300mAh cell to the 2,600mAh battery within the GS4. The Mophie Juice Pack is available now for $99, and is currently offered in black or white (with pink and red versions to follow). As an unfortunate consequence, the extra bulk prevents NFC functionality, but it could be a minor sacrifice if your phone's battery life regularly comes up short.