You can use Logitech Options to check the battery level of your device. if you don’t have Logitech Options, you can download it from the Download page.

You can also disable or enable the battery status notification in Logitech Options. This lets you know when your battery level is critically low.

To enable the battery status notification:

1. Open Logitech Options, and in the lower left corner, click More.

   

2. In the More settings window, select This device, and under Notifications, check Device battery becomes low to enable onscreen notification of your trackball's battery status. Your change is automatically saved. ​

   

   Uncheck the box to disable notification.​