If the red light fails to shine when attached to your charger, then there is a chance there could be a battery issue within your earphones, your charging cord, or your charging port.
1. Make sure you are using Sudio’s charging cable.
2. Make sure the cable is fully inserted into the earphones and that there is no dust or dirt blocking the port.
3. Try to get power from a different source i.e. laptop USB port or from a wall outlet.
4. Try using a different micro USB cable if you have one accessible.
The battery meter on your phone reads in increments of 20%. So it will go from 100, 80, 60, etc.