I'm running a real nice 5S from RcJuice.....he's great to do business with.
Look at your battery tray, you can see that the mounting holes can allow the tray to slide over toward the center diff. You can just fill those slots up with some hot glue. Another thing I did was....I just cut a piece of hard plastic and double sided tape it to the side of my soft pack and hard packs also. If the battery does go over near the gear....it has some protection. Velcro the entire bottom of the tray also.. then use those plastic battery strap clamps on top of the battery...Velcro those to the top of the battery... Shim the slack in the tray with some foam....mostly use it in front of the battery. Locks it all in real nice. I'll show you pics of my battery strapped in if you want.