Charging the earphones
The earphones are charged from the charging case simply by inserting them in the charged charging case. Even if there is no access to power when on the go, the earphones can be charged.
If you open the lid of the charging case, the status LED displays the amount of charge remaining in the charging case. link
If you close the lid of the charging case, the status LED displays the amount of charge remaining in the charging case. link
A fully charged charging case can fully recharge earphones that have zero remaining charge three times.
It takes approximately 2 hours to fully charge the rechargeable battery from the state of no remaining battery power.
When the rechargeable battery built into the earphones is low, a notification sounds. Charge the earphones.
Even if you insert only one earphone into the charging case, it can be charged.
If the charging ports of the earphones and charging case are dirty, charging may not be possible. Wrap a clean cloth soaked with anhydrous ethanol around a toothpick and gently wipe the ports regularly.
If the earphones get any moisture, thoroughly wipe it off before inserting them in the charging case.
Check the remaining battery power of the earphones on the screen of the connected Bluetooth device.