Windows 10 RS5 build 17639 and later builds show you the battery level of your external Bluetooth device.
If you have connected a Bluetooth mouse, keyboard, headphone or another device to your Windows 10 PC, you can now check the battery level of the external device with ease. The good thing is that you don’t need to open your mouse, keyboard or that Bluetooth device’s software to check its battery level when it’s connected to your Windows 10 PC. The same is the case with Bluetooth devices from other manufacturers as well. The Logitech SetPoint even sends out a notification when the battery level is low, although there are indicators on the mouse to display approximate battery level. For instance, I have installed Logitech SetPoint software to know the exact status and change default button actions of Performance MX mouse (MR0007), which I bought a few years ago (an excellent mouse at its price range). Most of the Bluetooth devices come with their software to change default actions and provide information about the device’s battery status as well.