Chris' mobile phone battery is draining really fast. Leo says that if he has the latest OS for both iOS and Android, it gives him a lot more data on what's taking up his battery life. But there's also third party apps like GSAM Battery Monitor for Android. Often though, poor cell signal coverage can cause depleted battery life as the phone works harder to find a signal. A higher resolution screen can drain the battery more as well. If his phone is constantly checking for data like email, notifications, social media updates, etc, that can also drain battery life. The problem is, mileage may vary because of habits, usage, and apps.