Most builders have noted that if the battery box is built and installed per plans, the battery cannot be removed upward as intended, as the engine mount is in the way. So I am builing mine with a side panel that will have hinges and removeable pins, so I can take it out sideways.
I am mounting my battery box on the starboard (passenger) side, to help equalize weight when flown with just me in the left seat. So that means the starboard side of the battery box will be removeable, as seen here.
The starboard side of the battery box will be removeable.