I was not a fan of the plastic Camco battery box that was strapped to the trailer frame of our 16 ft Bambi Sport so I decided to install a locking tongue box to replace it. It is the Harbor Freight Haul-Master and while it is not heavy duty it is light weight (right at 25 lbs) and it will at least keep the lazy thief out and protect the battery from the elements. It also adds a little extra storage to the front by offering enough room inside to keep my Lynx Levelers and wheel chocks which is nice. Now I won't have to go digging them out of the locked rear compartment anymore.
Install was pretty easy. I cut a hole in the bottom of the plastic battery box as well as the trailer tongue box and folded the steel over to have rounded edges against the cables (which I also wrapped with some Tesa tape) to keep them from wearing. The battery box is bolted to the bottom which will keep the battery from sliding around and the steel box is held to the frame with two U bolts.
In the future, if needed, there is enough room to add a second battery inside, but for now the single AGM has been enough for our needs.
Total cost was $77.93 with a 20% off coupon.
Front View (hidden behind the propane tanks)