Walk into the wilderness with your iPhone with the GPS function blazing away and the battery is sure to drain in no time flat. Mophie, who has long made battery packs for the iPhone is well aware of this and in fact encourages ...

Dropping $200+ on a GPS watch can be a deterring experience.  And that probably explains why a large number of runners and hikers hit the trail with their iPhone in hand.  The handset, with the right app running, can track dist...