I charged my iPhone 7 (iOS 11.3.1) from car for about 3-4 hours during the ride and Waze app was on all the time. Next day I noticed that phone discharges really fast. Power saving mode helps, but also the problem still appear. And the problem is not in apps running in background that could take power too much. Now it also gets very hot when charging, like never before. What could be the problem? Could it be that the battery life is almost over?