If your trying to double up your capacity then by all means go grab another new group 24 batt and parallel them. Personally I have given up on "dealer" batteries and get them to leave them out of the deal. Going up in size to a group 27 or 31 or better yet pair of golf cart batts from Cosco is the best way to get longer life when dry camping. Before you spend good money on a second one...maybe decide if adding a second small battery is better than buying two of the largest deep cycles you can afford. You could probably sell off the new group 24 locally to fund a more robust system. Just some ideas.
Daryll
