Pretty bird.... Nice price too...

Almost makes me want to buy one.

I'll echo what has been said. The biggest challenge will be accessing the batteries.

Looking at the pictures, I'd probably cut a hatch that includes the canopy area, and extends forward to about the rear of the center support/cabanes. Leave the rear support of the canopy in place. Then the batteries go in, and slide forward.

See picture. I outlined (in red) about where I'd cut the hatch. The canopy would still go where it is. The back of the canopy would overlap the fuselage a little. A pin in the front of the hatch, and magnets in the back of the hatch.

The next challenge would be the ESC. I'd cut the cowl with a hole in the bottom for air to escape. I'd try to mount the ESC under the cowl along with the motor. That way, the two things you need cooling the most, are up there in the fresh air.

Good luck.

Hope you come back and report on the conversion..