I use 1 1/2 or 2 inch hook and loop (velcro) glued (epoxy)to the inside of the fuselage. Wrap the battery in foam and then place it into the velcro, fold over the hook and loop with a little compression on the foam, this keeps it all tight and in place. Do the same for the receiver. I like to keep the battery in front of or below the receiver. Wrap the battery either in the same velcro or by it self depending on the placement for balance.

You can find the hook and loop at places like Joan Fabric or most stores of this type that sell fabrics and supplies. I buy the type that doesn't have adhesive on the back.

Leo