I’ve always resorted to closing all the apps on my iPhone when the battery is running low. The thought was that if I close the apps, the phone won’t use as much energy and therefore extend my battery life. Chances are, you’ve done it too.
Apparently, we’ve been wrong this whole time. A former Genius Bar technician and writer helps explain why this isn’t the case on Apple iOS devices (iPhones and iPads). Apple has specifically designed the software to not use any processing time when apps are in the background.
Here’s how Scott explains it:
Yes, it does shut down the app, but what you don’t know is that you are actually making your battery life worse if you do this on a regular basis. Let me tell you why.
By closing the app, you take the app out of the phone’s RAM . While you think this may be what you want to do, it’s not. When you open that same app again the next time you need it, your device has to load it back into memory all over again. All of that loading and unloading puts more stress on your device than just leaving it alone. Plus, iOS closes apps automatically as it needs more memory, so you’re doing something your device is already doing for you. You are meant to be the user of your device, not the janitor.
The truth is, those apps in your multitasking menu are not running in the background at all: iOS freezes them where you last left the app so that it’s ready to go if you go back. Unless you have enabled Background App Refresh, your apps are not allowed to run in the background unless they are playing music, using location services, recording audio, or the sneakiest of them all: checking for incoming VOIP calls , like Skype. All of these exceptions, besides the latter, will put an icon next to your battery icon to alert you it is running in the background.
So there you go. Next time you are running low on battery, think twice before closing all your apps. For the entire 8 step plan to reduce battery drain, read the full article here.
The Ultimate Guide to Solving iPhone, iPad, and iOS Battery Drain | AppInstructor
With Apple’s new operating system, iOS 9, there is a new featured called “Low Power Mode”. When your battery gets low, you can turn this on and the phone will do its magic to save as much battery as possible.