Eli5 Battery percentage in bluetooth earphones

Question

This morning I linked my bluetooth earphones to my cell phone and I noticed that my cellphone displays the battery left in the earphones.

How does my cellphone knows the battery percentage left on them?

In: Technology

Answer 1

Bluetooth is a two-way communication method. The bluetooth device has a way to measure the charge from the internal battery and simply reports that to your phone, allowing your phone to know the charge remaining on the bluetooth device.