BatON - Android Apps on Google Play. If you are like me, you are always connected by Bluetooth to more than one device. Typically, I have a Bluetooth headset around my neck, a Smartwatch on my wrist (sometimes two), and a Bluetooth speaker somewhere in the room. While the speakers are usually connected to power, sometimes they are mobile, and I need to know the battery level. This handy little app will attempt to check battery levels on all your Bluetooth devices, and you can check them at a glance. Very useful.