I have a Guest charger, model number 2530A aboard. It has a blown, external fuse on the battery side of it. I'm looking for a slow-blow fuse and was told that Ancor makes it. The fuse is a large diameter (3/8"), tube type and is marked "5N 5AG" one one end with "30A 32V" beneath. Can anyone advise me where I can get a fuse like this? I've tried BoatUS to no avail and a web search of West Marine's site gave no joy. -Rich