as suggested you can go with any group 24 or group 27 battery .
I disconnect my RV batteries after every trip so that they maintain their charge .
If you are feeling flush you might consider an AGM construction battery .
Do a Wikipedia for AGM to learn the advantages of the AGM construction battery .
I have gone to Exide EDGE AGM batteries over time in my cars, truck, TT , and boat .
In Oregon I have picked up the exide EDGE AGM batteries for $140 each at BiMart .
That is a cheap price for an AGM battery made in the USA .
With conventional lead acid batteries I did the annual routine clean up with baking soda and a toothbrush .
With the AGM , which do not leak , I do not have that chore anymore .
An EDGE AGM recharges faster than conventional , will not make an acid mess , in your battery tray , and will take more abuse from serious discharge episodes .
The car / truck EDGE is a 100 % replacement guarantee for 48 months .