BRUCEMAZER

Does anyone know why you have to disconnect the negative battery terminal for flat towing a 2020 Jeep Grand Cherokee? I want to install an RVi Towed Vehicle Battery Charger but that wont work with the terminal disconnected. I've asked FCA but can't get a straight answer. If it's just to solve for battery drain the charger will take care of that but if you have to disconnect the battery for another reason I won't be able to use the charger.