All RV's have several devices that all suck a little 12v power all the time and will totally drain a battery to zero volts over time, which will really hurt the battery. All the decent rigs have a disconnect switch (sometimes not plainly marked) that should always be turned off when the rig is not going to be used for a while. If yours doesn't have a switch you should add one to save your batteries. The switches are in all kinds of configurations:
https://www.amazon.com/s/ref=nb_sb_n...cut+off+switch