Make your smartphone or tablet battery last longer!

Good range to aim for when charging a Li-ion battery is from about 40 to 80 percent in one go. A bunch of tiny charges throughout the day is your second best bet, and going from zero to 100 and then 100 to zero on a regular basis will put the most strain on your lithium-ion battery.

This app notifies you when to charge or unplug the phone from your charger in order to improve the battery life.

For those who want to know more technical details about Li-ion batteries:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries