Just keep in mind the thieves tools of choice is these two items. It will only take a few seconds to remove straps and PAD locks. My way of thinking is to install a locking metal box that is mounted to your frame using rounded head stove bolts on the bottom. You of course cannot install any secure method to keep them from stealing your batteries but you can slow them down and perhaps that will be just enough for them to go steal your neighbors battery.
Again the best defense I have learned over the years is to slow them down or install things out-of-sight out-of-mind...
Now how long do you really think this prime choice item would last at an unattended camp site...
just my thoughts...
Roy Ken