I know that the propane detector on mine does remain connected to the battery even though the battery disconnect is active. The load is minimal, but could be considered a parasitic drain. For seasonal storage, either disconnect the battery physically or if possible, provide a way to charge it monthly. The CO and smoke detectors have their own batteries. I remove them and the water filter battery when I winterized the trailer to avoid any battery leakage damage.
Air Safe Hitch, Reese Dual Cam 800#, Centramatics