So ask for help if you. You can simply remove the negative lead from your battery but a better solution would be to install a manual disconnection switch.

Battery Master Disconnect Switch Review Armadillo Times
How to disconnect rv battery. To prevent such draining of power its best to tap the battery disconnect switch. Manufacturers recommend that you remove the batteries every month and have them conditioned by a professional. Keep in mind that car batteries can weigh 40 lbs. How to revive or restore a dead rv battery. Rv batteries which run the interior lights refrigerator computer and any other electrical appliance you have installed are built to last 5 7 years ideally. After the battery is disconnected unscrew the brackets that hold it in its tray.
Using an old toothbrush brush the tray and battery cables with a diluted baking soda mixture. Remove the battery cables from the battery using a wrench. Try to avoid overcharging your rv batteries. This conditioning breaks up the sulfur solids and other contaminants. It sounds like your disconnect switch is set up from the fuse panel to the battery and then to the converter. Some rvs disconnected switches just remove the battery from the system others disconnect the whole 12v system when the switch is set to off which is what yours is doing.
When its hot outside and during periods of high battery usage check the water levels in battery cells more frequently. If your rv is equipped with a battery disconnect switch make sure it is in the off position when you are not using the rv or when it is in storage. Your rv may already have a battery disconnect switch. When you turn the switch it will disconnect between these two cables and you wont have to get out a wrench every time you want that done. Its a red switch with a battery figure drawn on the top panel. Lift the battery straight up out of its tray.
They are cheap and take only a few minutes to install. Wear heavy gloves when removing the cables and always remove the black cable the negative side first before removing the red cable positive side. Hot temperatures can also lead to batteries lasting shorter than they should. In case your rv does not have one you can opt for an aftermarket rv battery disconnect switch installation. Usually to install the switch you run the negative battery cable that comes from the rv to one side of the switch and then a shorter one from the switch to the battery. You should find it easily as there should be labels like battery or battery disconnect inside the trailer.
Hot temperatures and overcharging will kill batteries. Rv batteries can die of a number of reasons most of which are mentioned in the earlier sections.