Earlier this week a colleague came to me with a problem with his iPhone. When he arrived at work that morning his battery was fully charged. By lunchtime it had dropped to 30%. He’d only made one call and has the data turned off. I asked him if he ever closes the apps and he just looked blankly at me so I explained.

iPhone Battery

Since iOS4 the iPhone and iPad can multi-task in terms of allowing apps to run in the background. Prior to this when you switched from one app to another, the app you switched from would automatically close. The app has to support background processing and most apps do. The benefit of apps running in the background means, for example, that you could be reading your email whilst, for example, Skype or your IM client is still running in the background, listening out for calls and ‘pings’.

The downside of multi-tasking is that it might be a drain on the battery. There’s no conclusive proof of this but if your battery level is dropping like a stone, it’s probably worth closing apps that are currently running. Unfortunately there’s no quick way to “close all”, at least not in iOS4 (who knows what iOS5 might bring) and turning the phone off completely doesn’t clear all apps from memory either. When the phone is switched back on, the apps that were running are still running.

To close an app, double tap on the Home button (that’s the big round one at the bottom) to reveal a panel of icons. These icons represent the apps that are currently running. The iPhone can only show 4 icons at a time. To display “hidden” icons, simply swipe your finger across any of the icons in a leftward direction.

Closing an iPad or iPhone app

Press and hold on any of the icons and after a second or two all the icons will start to jiggle and each one will have a “close” symbol (red circle with white horizontal line) displayed at the top left hand corner.

Closing an iPad or iPhone app

Tap the close symbol of the app that you want to close and the app is immediately closed. Repeat this process for each app you want to close.

Closing an iPad or iPhone app

Double tap the Home button again to close the “currently open apps panel”

As for my colleague’s iPhone, at the end of the working day, his battery was still showing 30%.