Use This Simple Trick to Preserve Battery Life on iPhone by Stopping “Searching…” | iPads, MakerEd and More  in Education | Scoop.it
If you’re traveling through areas of weak cellular signals and generally poor reception, you can save a significant amount of iPhone battery life simply by toggling the AirPlane Mode feature on. That may sound weird, but it really works, with the idea being that when an iPhone has an intermittent cell signal, the cellular modem continuously searches for another available cell tower, which happens to use a lot of battery power. Thus, the solution is to simply stop the iPhone from looking for a cell signal if you’re not going to have one anyway.