I’ve built many FT planes and not a one has the battery where the plans say it should be. Everyone builds differently and needs to adjust where things are to make the CG come out where it should. I build and finish the plane then, with tape, put all the electronics on the plane and test the CG. I will move things about until the CG is correct. Then and only then will mount everything permanently.
The plans are only suggestions, you will need to adjust to meet your situation.