Do I have to charge my roku?

so for a few days now my roku has been saying it's battery life has been going down which i find very odd since it is plugged in. Today it game me the red light. It isn't an xbox or anything i don't have to worry about it over heatting or anything right? so i need to put it in life support and charge the power thing or the roku it's self? it's a few years old and just now giving me problems. Maybe upgrade it because i just got it the way i wanted it.