I have an alarm on my power converter that while plugged to shore power will alarm if polarity is not correct and a switch that when toggled will "I assume" reverse the polarity. The problem is when I'm disconnected from shore power that any hard rocking of the boat sets the alarm off for the polarity and only another bounce or hard pounding will stop the alarm. The switch dosn't effect it in either position. I have no manual for it. It's made by Shurtron. I have no other power problems with it and believe that being disconnected their shouldn't be any polarity problem.
