I just installed the Battery Minder so that it was always connected to the battery and plugged into a 120vac outlet so that it got power any time the rig was powered either by shore power or the generator. As I understand the Battery Minders, they de-sulfate constantly, whether the battery needs charged or not. This connection method allows the Battery Minder to work on the batteries even if the batteries are disconnected from the rig as in storage, as long as they have 120vac power. I really like the Battery Minders!