Extend Your iPhone's Battery Life By Quitting Apps

The apps you have "running" on your iDevice may actually be eating up a little battery life after all. Apple claims that its solution to multitasking — which is suspending apps rather than having them truly run in the background — is better for battery life. While that may be the case, it seems that having a bunch of apps in the multitasking queue may actually hurt your battery life a little bit after all.According to David Pogue, in his column for the New York Times, keeping a bunch of apps suspended in your multitasking queue is actually sucking up you device's battery life:

Background apps. Nicole the Genius discovered that my friend had a huge number of apps open - maybe 40 of them. She maintained that they were using battery power, too, in the background ... But I'd been led to believe that background apps are generally frozen into suspended animation precisely so that they don't use battery power ... Even so, Nicole quit all 40 of the apps that were still open ... The next day, my friend's battery, by the same time of day (5 p.m.), was still at 80 percent!

This does make sense, as suspending many apps likely does take minimal system resources which add up once you have a bunch of apps in your queue, but it's hard to say exactly what about multitasking is draining the battery. Nonetheless, it's easy to clear out your multitasking queue by double-tapping the home button, pressing and holding an app in the queue, and then tapping the "-" in the app's corner. Of course, you'll have to do this for a lot of apps if you haven't been quitting anything with regularity. Nonetheless, it's better than nothing. Hopefully Apple will add a "quit all" feature at some point down the line, but I wouldn't hold your breath.

Four Ways to Make Your Battery Last Longer [New York Times via TUAW]


Comments

    In theory, these apps held in memory are automatically disposed one at a time if the computer need more resources.

    The reason being would be due to the scheduling function of the operating system, after the current process has finished running it must choose which one to run next, this involves scanning and performing some decision on the 40 or so still suspended apps. So while your using the devive it will always have alot to do on the CPU and therefore use up more power.
    The reason apple claims that the suspended apps dont use up more power is because the scheduler issues a HALT command to the cpu when the screen in turned off, meaning the cpu isn't actually performing clock cycles and therefore not running when the phone is sleeping. As such the apps both do use more power while your using your phone but not when its sleeping. The reason it would use more power while sleeping is due to reception issues and tasks such as checking for sms's call's emails, location and badges

    Been doing this for yonks. Can definitely attest to better battery life if you close 'suspended' apps

    I have 98 apps in my MRU tray, perhaps its the cause of my erratic battery life, can take 6 hours to go fromm 100 to 90, then can be 50% a few hours later.

    I'll have to try it out and see how it goes.

    I just wish apple would let us have an advanced user option, where we can setup app profiles, saying what they can and cant do, like closing some apps kills them completely.

    Every problem listed above can be solved by jailbreaking and installing Activator and Multicleaner. You can then assign any gesture you want to kill all apps. In my case I simply double tap the status bar, and they all close instantly. There are tons of ways to customize it for your needs.

    If you notice, you will see that actually only about the first 5-10 apps in the multi tasking bar (at best) are actually open, the rest are just sitting there. They are not suspended, the first few are as I said before, but the iPhone does not have enough memory to keep 40 odd applications open, so a part of the system called watch dog kills them off automatically. Doing this all yourself is pointless, as I said only the first few are actually open and suspended, the rest are just icons like on the rest of the home screen

    Wow didn't know about the double tap home to kill active apps. Very useful app LH

    As far as I can tell, double tap home just brings up a list of recently opened apps, not necessarily just apps that are still running in the background. Deleting them will close those that are suspended, but there doesn't seem to be a way to find out what is actually suspended currently.

    nice post!

    Shouldn't go too overboard with killing apps though. In many circumstances, I find the suspend functionality of iOS helps to save battery, in the case of frequently used apps, as it saves you having to restart the app each time you use it.

    This entire article is bad advice. The apps do not run, and get paged out of memory fairly quickly.

    A random email from someone and then a single day of uncontrolled testing should not be the basis for published advice.

    This article could not be more wrong. There is no need to kill iPhone apps unless the app is not working properly. Apps stay suspended in the background and iOS frees up ram when it needs to. You're wasting your time if you're regularly killing apps to save battery.
    Source: worked for apple and spoke to engineers at apple headquarters in Cupertino.

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