The light of my Wave 2 flashes red three timesUpdated 10 months ago

Did you turn on your Wave 2 to start a session and you saw a red light flash three times? Your Wave is letting you know that the battery is low and will require a charge soon! 

You can probably get a 10-minute session out of it before the battery is critical, but that is your notice that you probably only have a session left before the battery dies and needs to be charged.