You can check the current battery level of your Thermomix® Sensor at any time directly on the Thermomix® TM6 or TM7 as well as in the Cooking Center App. This way, you always keep track before you start cooking.
On the Thermomix® TM6 or TM7
Open Settings → Connected Devices → Thermomix® Sensor → Thermomix® Sensor Version and Update.
In the Cooking Center App
Open the Cooking Center App → select the Thermomix® Sensor card → tap on "Settings" at the top right to access the device screen.