Battery Saver is one of numerous apps that offer several user profiles customized to specific smartphone user profiles. Pick the right profile and you’ll save power; pick the wrong one and you may use more power than without the app.

Screenshot by Nathan Chandler

Battery SOS

Task killers might be a dubious way to save your battery charge. Other apps are more judicious in the way they lop off the heads of energy-sucking monsters. JuiceDefender is one such app. Rather than killing apps, it automatically turns off power-greedy components when you're not using them. For instance, when you're not near a WiFi signal, the app knows to turn off the WiFi transceiver in your phone.

Easy Battery Saver works similarly. Furthermore, you can engage various modes (General Saving, Super Power Saving, etc.) customized to your preferences and schedule. Still, you'll need to be mindful of the way you deploy such apps.

Abhinav Pathak, a Ph.D student candidate in the computer engineering department at Purdue University, worked with a team of researchers who tracked smartphone energy expenditures. He compares a smartphone to a house; battery-saving apps make sure the lights are turned off when no one's home and that the furnace is off when it's hot outside. For these purposes, an app may help.

But Pathak says these apps can't detect problems with other apps that use far more energy than they should. Specifically, he found that many apps are improperly programmed, and as a result, use far more energy than they should. For example, an app that uses GPS services may fail to shut off your phones GPS device even after you exit the app, meaning your phone relentlessly hemorrhages power.

For these kinds of problems, users have to hope that developers start taking more care when creating apps. In extreme circumstances you may just have to uninstall a problematic app instead of letting it suck the life out of your phone.

On the next page, we'll explain more about the best ways to slow battery drain and maximize your smartphone power serenity.