Security of Floor Under Battery Box

Boy Larry you sure do think things through an awful lot! (LOL!!).  I applaud anyone that makes a box from scratch!  If I make a box from scratch, it better be big enough to sit in and ride through the rapids.... (aka a kayak!  LOL!  ;D)

I guess one good technical note deserves another...

I agree with your point that aluminum is pretty fragile in the presence of H2SO4.  It will corrode much quicker than mild steel.

My metal shop will probably have equal amounts  of SS and Aluminum so I guess the extra weight of SS might be worth it.

However the inner and outer skins are both aluminum and seem to fare pretty well.  Plus I don't remember which SS is compatable with aluminum  ???(many will galvanically react with the aluminum ).

I still feel more comfortable with aluminum in the long run.  Anyone worried about the acid should purchase an acid neutralizing mat from JC Whitney or Pep Boys, which would protect the aluminum of the trailer.

And yes I hope Santa will bring me a shiny new AGM battery very soon

I'll keep the board posted on my progress to engineer a solution.

Oilspot,
You may have me figured out quite well! Actually, thinking too intensely about the solutions to any mechanical problem has been a problem with me all my life. I may be like you in that everything that I construct tends to have a safety factor of 6 or more! If I ever finish the homebuilt, 4-place airplane, that I've been working on, on-and-off for the past 9 years, it may be too heavy to fly!

I did build my stainless steel battery box from scratch. It wasn't too big a project and only took me a couple of days of leisure time (I spent more time than that thinking about how I would build it). I had some 0.06" thick SS sheet on hand that a friend had given me. I cut it to size, bent it partially in a simple brake I own but mostly by hand as my brake is not a box brake. I then welded it up with my GTAW (tungsten inert gas) welding unit. The box has an ample flange and loops on both sides through which the battery can be strapped down. The welding distorted the box a little (I haven't mastered the techniques of welding sheet metal without distorting it) so it isn't a thing of beauty. But beauty is in the eye of the beholder. When I finished this box, I stood back and smiled! Yes, making things from scratch may take time but there can be a lot of satisfaction in finishing something useful you've made with your own hands - even if someone else may think it's kind of ugly.