How to Prolong Your Cellphone’s Battery (Hint: You Don’t Need to Close Your Apps)

— -- You are so disciplined about closing apps on your cellphone to preserve battery life, but now, a shocker.

According to the Apple blog 9to5Mac, an iPhone user emailed Apple CEO Tim Cook a question that's top of mind for many iPhone users: “Do you quit your iOS multitasking apps frequently and is this necessary for battery life? Just wanting you to put this controversy to rest.”

While Cook didn’t respond, the head of Apple’s IOS team, Craig Federighi, gave a definitive answer in the reply: “No and No.”

What? Closing apps is religion for those of us who worship at the altar of battery preservation. While Apple would neither confirm nor deny Federighi’s email exchange, it did point to an Apple support page that outlines why apps running in the background don’t consume resources.

“After you switch to a different app, some apps run for a short period of time before they're set to a suspended state," the website states. "Apps that are in a suspended state aren’t actively in use, open, or taking up system resources."

When you double-click the home button on your phone, you see a cascade of apps, and while this makes you think they are fully active back in that stack, apparently they freeze shortly after you switch into a different app. I like to think of it as your apps being frozen in carbonite like Han Solo was when Jabba had him. In that frozen state, they are not consuming power. Controversy resolved.

But what about Android? Dave Burke, a vice president of engineering at Android, echoes Apple's comments.

“There's this big myth on phones that we have to swipe away your applications to save battery," he said. "It's just completely not true."

In fact, Burke says closing all those apps actually activates them momentarily and may consume more battery than leaving them open in the background. Burke explains that battery optimization is primarily done through tweaks to the phone’s software and that is a huge priority for Apple and Android engineers.

But there are a few exceptions, including apps using power-draining location services. Music playing in the background consumes power, as do cellular and Wi-Fi connections.

So what can you do to maximize your phone's battery life?

1. Dim the screen or turn on auto-brightness. The biggest single draw on a phone is the screen.

2. Turning the screen-lock timer to 30 seconds can also minimize the draw on the battery.

3. Turn off push notifications.

4. Manage background refresh settings. While Apple is freezing most apps, you can whitelist some to stay current. Go to Settings, then General, then Background App Refresh, and turn on those that you specifically need to have updating in the background.

5. Wi-Fi draws less power than a cell signal, so if receiving calls isn’t an issue and you just require text and email, turn the phone to airplane mode and instead use Wi-Fi.

6. Turn off or limit location services in apps. Because location and GPS services draw so much power, go to Settings, Privacy, Location services and choose never or “only when using the app” for most apps.

7. Update software as new updates come out. So much of battery optimization happens in the operating system, so every new upgrade has some changes that should positively affect battery life. With the newest version of Android Marshmallow, phones last 30 percent longer.

8. Low-power mode on iPhones and Battery Saver on Android can eke out extra life by turning off maintenance services that the phone normally performs.

9. It’s not just about running out of battery -- also think about how fast your device charges. Google's Nexus 5X and 6P support fast type-C charging, so 10 minutes of charging provides nearly four hours of battery life.

10. If you are charging an iPad make sure you are using the 12-watt charger that came with it instead of the 5-watt chargers for iPhones. The iPod can pull power faster from the 12-watt charger and the 5-watt version slows it dramatically.