Two total batteries?Just one on top of the other. I don't see any reason to take the unit apart for any maintenance.
I think the bottom with the heat sink meeting another would be fairly strong with the weight being spread out.Mine came stacked 3 high on the pallet and they had a really rough trip to the west coast and they were fine. Having said that though I wouldnt trust the plastic ends to hold any more than their own weight for years on end.
Like I said in my earlier post I have something already.Take a look here, I found this today.
1000 lbs per shelf48" Wide EZ Connect Rack with Five 18" Deep Shelves - - Amazon.com
48" Wide EZ Connect Rack with Five 18" Deep Shelves - - Amazon.comwww.amazon.com
Said every guy ever...I like them stacked