After the headset is connected to the phone, the phone's notification bar icon will show the headset's battery capacity, and you can check the battery balance by the status of the battery cell. When a single headset is connected, the battery power displayed in the notification bar is the battery power of the single headset in use. When two headphones are connected, the phone notification bar displays the battery charge of the lower of the two headphones.
Check the charge of the charging box: the indicator light will always show red when charging, about 1 hour later, the charging box will be full, and the indicator light will turn green when it is full.