Scotty Loveless wrote at his blog Overthought.org about optimizing iOS battery life:
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.
Nothing makes me sadder or aggravates me more than the people who insist on force quitting apps in iOS on the theory that it’s “bad” or draining their battery. People have such a fundamental misunderstanding for how these things work this article is pitch perfect on explaining what does or doesn’t happen.
iPhone battery life is good when the power and utility of the iPhone is taken into consideration. It should not have to be charged more than once a day unless use is extremely heavy or there is tethering at play. That is what makes the whole focus of this article so interesting. What kind of battery life is making people so desperate to kill all the apps on their phone all the time?
It’s clear that people not only don’t understand what doesn’t affect their battery life, but it’s almost certainly true that they don’t truly understand what does either. Apple doesn’t do the best job of explaining this to people, and based on overheard conversations in Apple stores, it does not sound like their employees know exactly how it works either.
The biggest tips to take away are:
- Only let apps run in the background (via the System Preferences, NOT force quitting them!) that you absolutely need
- Turn off Wi-Fi and Bluetooth when they are not in use
- Keep brightness down to the lowest possible level where it doesn’t hamper usability
- Realize that the screen is the biggest battery killer, and the more the screen is on, whether in use or not, the faster the battery drains