I strapped the battery onto a 1/8 ply that is just slightly longer than the battery with packing tape.
The front of the " tray" slides into a small pocket I installed into the fuselage...the rear is held down to a small block with an 8/32 machine bolt. CG adjustments can be made by moving the battery along the plywood tray...then when you get it right, you can measure the spot on the little " tray", install the other sets of batteries on their trays, and batteries all go in exactly the same place every time. The whole thing weighs less than an ounce, and does away with that pesky velcro. the batteries are also very secure in this mounting system. for transport, I installed the little slotted piece and blind nut into my flight box for each battery... This keeps the batteries " safely tied down" in transport.