Hello there

I have a stock y6 that I bought used (2013 model A configuration). It has the APM 2.5 controller. I have changed the wiring on it to the y6 B configuration. I have 11" props on the bottom and the 10' props on top. I have run all the calibrations with my spectrum x8 radio plus have calibrated the esc's several times but I am unable to get the copter more that a few inches off the ground. It "seems like" the motors do not increase speed past the 50% stick setting. I have on one occasion got it about 8 feet in the air and it seems to fly ok once airborne but for some reason it is a dog and comes back to earth and stays in ground effect motors dont speed up or slow down. I double checked to make sure I was in stabilize mode.

Can the battery be the problem? I only have the one that came with it, a 3s 5400 20c venom. it is not puffed and takes a balanced charge ok. I would assume it would at least fly it for a few minutes. I am not sure what else to do to trouble shoot this problem and any help would be greatly appreciated.

Thank you 

Mike