They make 3 sizes. The group 31 last the longest. It goes kinda like this
Group 27 = poor
Group 29 = better
Group 31 = best
However, the group 31 are bigger so if fit is an issue, better measure first. I have my camper set up to hold 3 group 31s. And I buy Deka because they give me the best service.
Where do you put group 24? (Grins)
