But if your phone is constantly searching for a Wi-Fi signal on your commute, as you run errands, or when you’re out with friends, it can easily burn through a lot of power. What Is Data Usage? When it comes to cell phone plans, data usage is basically the amount of data you use in a billing cycle (usually a month). Your cell phone plan's data is used whenever you use your phone's internet connection to perform any task. iPhone's battery draining fast? Here's how to fix it. So you've carried out the tests and come to the conclusion that your iPhone suffers from a battery drain issue. My iPhone 7 battery draining fast suddenly. I don’t know why. Last night I saw the battery percentage. It was 98%. But today morning it was completely drained out. There was only 20% battery on my phone. I didn’t even touch the phone throughout the night. It happens only after upgrading my phone to iOS 11. Jan 02, 2018 · (Keep in mind that clearing your cache may close all open tabs on your browser, so be sure to bookmark them or write them down first just in case.) Tip #16: Backup files to the Cloud Cloud-based storage is a wonderful advantage to having an iPhone, and it’s designed specifically to optimize space on your physical device.