However, make sure that you cut the rectangular clear plastic sheet to at least the size of outer edges of the battery carbon rods. The goal is to have the plastic tray sit on top of the frame rods so the battery will not pull the tray down.

I then continue by drilling 4 holes for the tie wraps. The holes should be 3-4mm away from the edge of the plastic tray so incase of a crash the holes will remain intact and not open up. I also drill one additional hole at the center of the plastic tray. This enables me to pull out the main shaft below the main frame without having to remove my plastic tray.

I continue by inserting the 4 tie wraps and wrapping the plastic tray in place. Check that the tie wrap head faces away from Heli so it will not get in the way of the battery. I then complete the setup by pasting Velcro underneath the tray and on top of the batteries. I also cut the Velcro tape around the drilled hole so the Velcro will not interfere with the shaft removal. This setup will work great and inherits the advantage of battery release during a crash. Most of the damage in a crash is usually to the CF rods due to the massive weight of the battery against the rods. This setup will enable the battery to eject from the Heli saving the structural setup of the CF construction.

If you wish you can secure the battery with an additional two way tie wrap (the kind that can be opened) but this should only be necessary when executing fast forward flight and aerobatic maneuvers.
Another method that I had good luck with was using balsa instead of clear plastic. You will then use Epoxy to glue the balsa plate in place. However, I did find that during severe crashes the balsa plate will break in half; a good thing because it absorbs some of the energy but bad since you will now need to re-setup the complete construction.