A Brand New iOS Update
Downloading the latest version of iOS can cause significant problems with battery drainage. iOS 13 was a particularly good example of this, with numerous people reporting serious battery problems after installing it. It was especially annoying because new iOS versions are designed to use energy more efficiently to save battery life. So what’s going wrong here?
Well, part of it is simply the cost of downloading and implementing a lot of changes. A new iOS may have to reindex the entire system, all of your photos and videos, your apps, and more which takes time and power.
Sometimes, simply waiting a few days for your iPhone to fully “get used” to the new iOS will fix battery problems. That’s true for the Apple Watch as well.
Other times, new iOS versions come with bugs that can affect battery life. In this case, a patch is usually implemented quickly, so the best course is to wait and watch for any iOS updates that you can download.