I decided to make a battery cover for my Flysky FS-i6 that allowed me to use a single 18650 battery stick that is rechargeable. Making it USB made it even more universal as i can now use any power source that has USB. The voltage will only go up as high as 5.21v as it has a 5v boost converter and when it gets lower the alarm will still sound as the boost converter will allow the transmitter to read 3.x volts. I did have to make some modifications to the model i used for the back door but otherwise (benbojangles) model was perfect (Thank you). I have tested the battery life using a simulator and have played 3 hours a day for 4 days before i decided to recharge it.
Use a brim to ensure good bed adhesion.