RV batteries are deep cycle batteries and they can be damaged if the battery completely discharges and sits for a period of time. To remove the battery or not depends on a couple things, like how long will the trailer be sitting, what kind of weather is it exposed to. If the trailer will be sitting unused for a month or more, especially in extreme cold or heat, it would be better to remove the battery and store it where it is not directly exposed to the elements, and where you can have a trickle charger hooked to it. If you use the trailer every week, or every couple weeks, use the 12 volt power disconnect switch to keep it from discharging compleley and you should be fine. I am not a fan of having the house power hooked to the trailer for long periods unless I am using the trailer, but thats just me!!
2006 Nissan Xterra
B&M Trans Cooler
2011 Nomad 206
Panasonic/Pioneer/Kicker ~ Audio/Video System
Days Camped /2009 / 33