I recently bought a Noco from BCB, and love it. I plug it in the night before a trip, then the night before its stowed. Other than that, I unplug it. I refuse to allow anything creating a draw to be left unattended.Granted Im a fireman, but I have seen to many fires started by unattended electrical items. Anything drawing a current can be a potential problem.Btw, if a battery does completely lose a charge (accessory switch left on), the Noco light will flash for that battery, the same as if its connected incorrectly. I just stick that battery on a dumb charger for a few hours, then re-power the Noco, and the flashing light goes away, and you just get the constant red charging light.