A free program for Android, by IJP.
Energy Bar - A pulsating Battery indicator is a simple and configurable indicator for Android devices, which can show you the current battery level at any time and also how much charge you have left. It can work as an Accessibility Service, to make it more reliable and to have a better user experience.
This is a great app for people with battery issues because you can set it to show the current level or how much charge you have left, depending on your needs.
It works silently and does not need to be constantly running. The app will wake up when the battery level is changed, and then it will display the new level.
You can also set it to show the battery level and how much charge you have left on your phone, on your lock screen, or on your home screen.