SOS! Battery died while hooked to shore power.

Roy, the picture you posted would not open so I Googled "reverse polarity fuses". The two images I found show panel boxes with the two reverse polarity fuses clearly marked, and as you mentioned, they are much higher amperage. I have only 15 amp fuses in my panel box, none of which is labled reverse polarity. I will keep looking around for other fuses, but I am very reluctant to try to take the panel box off to get behind it unless you think there is a good chance it is in there.