Yamaha RM-WCH-8 Owner's Manual page 15

NOTE
:Up to eight microphones can be charged at the same
time.
:The charging status (remaining operating time) is
indicated by the Battery indicator on the microphone.
Indicator
Lit red
Lit orange
Lit green
When charging is finished, the indicator goes off.
Battery
indicator
Remaining operating time
3 hours to less than 15 hours
RM-WCH-8 Owner's Manual
Less than 3 hours
15 hours or more
15