Based on my interpretation of your post I'm assuming you mean diconnect batteries while parked but still living in the RV. Your lights, AC t-stat, likey your refridgerator and furnace run off of 12 volts from the batteries. Disconnecting the batteries will disable these things.
2010 Eagle Super Lite 315RLDS
2018 GMC Sierra 3500HD 6.6L Duramax
2010 Nights 45
2011 Nights 70
2012 Nights 144
2013 Nights 46
2014 Nights 49
2015 Nights 57
2016 Nights 73
2017 Nights 40
2018 Nights 56
2019 Nights 76
2020 Nights 68