While getting my newly acquired 98 SMB E250 ready for our first camping trip with it (a week in Maine and NH), I determined that the two house batteries that came with it were pretty much dead. This was a serious bummer, as they were nice Lifeline AGM batteries. Choking a bit on the $350/each price, I looked around at options, finding a battery that is relatively new on the market and sold by Sam's Club: a Duracell AGM deep-cycle size 31 battery for $166, with a 105 amp-hour rating and 18 month replacement warranty. These batteries are made by East Penn, the maker of Deka batteries.
http://www.samsclub.com/sams/shop/produ ... rod3590232
Since the price was right, I bought three to up the reserve capacity in my battery bank. The problem was how to fit them in the battery area under my dinette. SMB had installed two smaller batteries there originally, each in its own plastic box, which took up basically all the room in the dinette base (plus the inverter). The install was really a mess, with the boxes not sealed right and hoses all over the place. I took everything out, finding two holes that SMB cut in the floor for battery drains, each with a ground wire going down through it and to the frame. There was also the vent hole in the side wall of the van. A lot of space for critters and dust to get into the van (I'm going to seal up the floor drain holes and put screen over the wall vent).
The three batteries fit side by side near the wheel wheel, leaving me extra storage space at the rear of the compartment. I created a box out of 3/4" pine, installing the sides via L-brackets into the floor, sides and front. The new box encompasses the wall vent hole to allow any gases to escape (they are AGM batteries, but I figured better safe than sorry). A 1/4" luan top seals it up nicely, fitting snugly via magnetic catches between the front and rear of the dinette an creating a "solid" box. I may update it a bit when I get some time to have foam weatherstripping between the top and the sides to create a really tight seal, but I'm not too worried about it at the moment. The batteries are separated by 3/4" spacers and are held down across the top by the wood retainer strip and screws.
The new batteries seem to be working really well, and definitely provide more reserve than the previous batteries. Three of them cost less than two Lifeline batteries, so I figured I'd take a chance on them and see how they hold up. It was also nice to gain some extra storage space in the dinette base; it fits my tool box perfectly!