imalama, what gyro and tail servo do you have? I have a Telebee gyro and E-sky 8g servo and mine will balnace with the 3S1250 battery mounted as far forward on the ledge as the canopy will allow. I use velcro plus a rubber band around the battery and tray. It also balances fine with a Zippy 3S1800 pushed all the way back.