Battery Widget by DroidParadise is a lightweight and simple widget that displays your phone's battery level and temperature. With just a tap, you can access more detailed information about your battery. This app is available for free and contains no ads.

The widget comes in two sizes, 1x1 and 2x1, and is only 90KB in size. It won't drain your battery, and it doesn't require any unnecessary permissions. The only permission it needs is for in-app purchases if you choose to donate.

Using the app is straightforward. It's a pure widget app, so it won't show up in your app drawer. To add it to your home screen, touch and hold any empty space and select "Widgets". Then drag the Battery Widget to your home screen. Note that on some devices, you may need to allow the app to use battery in the background and not optimize battery usage. You can find these settings in "Settings" -> "Apps & notifications" -> "App info" -> "Battery Widget" -> "Battery". Overall, Battery Widget is a useful tool for anyone who wants to keep track of their phone's battery status in a simple and efficient way.