The best battery isn't dependent on what RV you have, it is dependent on how you camp.
If you always camp with electric hookups, you will be okay with the cheapest 12v battery you can find, even a $25 lawn tractor battery. However if you dry camp battery capacity can be critical.
Most come originally with a single group 24 flooded lead acid (fla) battery.
We have two RVs and each have two batteries. One has two 6v golf car (fla) batteries on the tongue and one has two 12v gel batteries inside under the seat. Different batteries for different uses.
Originally Posted by Steve_N_Janna
My experience with AGM batteries...The downside is that they cost more....
For me, the main disadvantage is that they typically have less amphours. The main advantage of an AGM or gel battery is that they can be carried inside without added venting like is needed for a (fla) battery.