My 6 year old Interstate battery was acting like it life would soon end, so I visited a local store where I had a credit to check out their battery offering. They sell the Exide line. In looking at the Marine / RV category they had both a dual purpose and a deep cycle for the same price. Based on what I have learned from this forum, I thought the size 27deep cycle would be a good choice. After I got home I checked the Exide web site and found that the Deep Cycle battery weighs 9 pounds more than the dual purpose. I would guess this means the plates are thicker and it is a true deep cycle battery. I tried on line to find the weight of an Interstate, Wal-Mart, Duracell etc. battery and no one seems to publish it. Based on the many times we have discussed batteries on this forum and the advantages of a true deep cycle vs. a marine / RV dual purpose, the Exide Deep cycle would seem to be a good choice at a good price. Home Depot also sells this line and they have a group 31.
Happy dry camping to one and all...