If you're in the midst of an epic storm, the state of your cell phone might seem a secondary consideration. But as we saw during 2012’s Hurricane Sandy, the work the wireless carriers put into adding battery and generator backups to their towers after Hurricane Katrina can leave them the one functioning telecom system after the power goes out.
I’m not a weather expert, but years of experience at phone-battery-destroying events like CES have given me a little insight about keeping a phone going for as long as possible.
The first thing to do, before you even finish reading this, is to recharge anything that can itself recharge your phone. If you have an external battery pack for your phone, top that off. If you have a laptop, do that next. Remember that some Windows laptops can charge phones over their USB ports even when they’re asleep or shut off.
Next comes reducing your phone’s battery drain as much as possible. Apple and Google both have good general power-management advice; a key part in both is to check how much each app contributes to draining your phone’s battery, in which case you should force the app to start or even uninstall it.
In Android, open the Settings app and touch Battery to see your apps ranked by power consumption. In the current 6.0 Marshmallow release, this screen also displays an estimate of how long your phone will last on its current charge.
In iOS, you also open the Settings app and touch Battery to get a similar list. This will also call out apps that used some energy while running in the background, which can reveal some surprises--a while back, I was confused to see YouTube chewing up my iPad’s battery when I wasn’t using it.
Hopefully, this won’t reveal any unpleasant surprises. Both iOS and Google’s Android are pretty good these days about policing apps and keeping them from hitting your phone’s GPS too often, so you shouldn’t have to obsess about shutting down particular apps.)
After you’ve gone things like dimming your phone’s screen, Android Marshmallow includes a feature that will prolong the battery life if you just put the phone on a table instead of carrying it around. Its Doze mode uses the phone’s sensors to see if the device isn’t moving; if so, it puts apps in a sleep mode until the phone moves again.
Turning of cellular data and then turning it on once an hour or two can further extend the phone’s runtime by ensuring that no apps can go crazy with data usage while still letting you make phone calls and send and receive text messages. In Android, open Settings and tap Data usage; in IOS, open Settings and tap Cellular.
Finally, both iOS and Android have low-power modes that will throttle back most of the phone. You can verify that each is enabled on either an iPhone or an Android device by opening Settings and tapping Battery.