The chances of your phone battery dying while you don’t have access to an outlet are about equal to the odds you’ll spill on yourself when you wear white pants: pretty much guaranteed. While we can’t help you with the spills--sorry!--there is an iPhone trick that can get you about 30 minutes of extra battery life in just four taps. Next time you need your battery to last just a little bit longer so you can charge it, follow these simple steps.
It takes a lot of phone battery to light that big, beautiful screen we all love staring at, which is why the best way to save battery is to change how much energy it uses. All iPhones, and Androids as well, can turn their screens from full color to black and white, which saves battery. By going to “Settings” then "General" then “Accessibility” on your iPhone, you have the option to change the color scheme of your phone. Just look for the option called “Grayscale.” Toggle it on to give your phone battery a little lift.
Whenever you have access to a plug, you can switch this option off by following the same directions and togging “Grayscale” off. It really is that easy.
NOTE: This will give you around 30 extra minutes of battery life if your phone is on but you’re not using it; this amount decreases if you continue to use your phone.
via <a href="http://www.purewow.com/tech/The-Easy-Trick-for-Making-Your-Phone-Battery-Last-Longer" target="blank">PureWow.com_