Top of a huge pile I've used a million apps of this type, and this one is simply the best of all. Only two caveats: (1) you can't install non-market apps when the battery bar is on, but you only have to turn it off until the install is done, and (2) there's really only one style for the widget that isn't ugly as sin, but at I guess at least there's one...
This app really lets the user know what's going on with the device's battery. Graphically displays usage, and what apps are using what % of the battery. The one and only widget is fortunately at a glance useful. Never mind the so-called "battery saver" apps, which are all placebos. Battery life is something you monitor and handle yourself, and this app performs that function oh so very well.
I wanted to find out why my tablet was running down the battery and dying in the middle of the night. (Not plugged in, but starting with a full charge.) All this app tells me is the screen was off, but the device was awake, and WiFi was on - nothing about what apps were using the battery before it died.
Good app but, I REALLY wish you could control the theme (background color/shade) of the notification in the notification panel.
How do I get the widget's temperature reading to update more frequently???
v6.0.0-6.0.3 : Added new icon and fixed bugs
v5.6-5.8 : Fixed bugs for Android 5.1.1
v5.5 : Global release
v5.4 : Fixed bugs and battery status bar graphics