Teardrops n Tiny Travel Trailers

I need to mount my battery box on trailer tongue and wondering if bolting 3/4" treated plywood to the tongue and securing box to the plywood will provide a platform. Any thoughts/experience out there?
Th

I bolted one of these to my tongue:

http://www.ebay.com/itm/NEW-Diamond-Plate-Aluminum-24-Tote-Tool-ATV-Box-RV-Camping-Truck-/121085219346?pt=Motors_Automotive_Tools&hash=item1c313dd212&vxp=mtr