For trouble shooting I would run the plane with a separate ignition battery and see what happens. Also I would look at the wires going to the retracts and if they will flow enough current. Running on the ground is low demand; in the air servos are being loaded more.
I put the ignition on a separate battery and the gear worked perfectly fine. Flew the plane Sun and Mon with no problems. I have a spare Rx and I will use it with another battery to operate the gear.