Dock power to boat

[Legend 13]

I have a 26 ft Sea Ray Sundancer. It has a guest 12v battery charger and supplies 2 batteries. I live in Cape Coral Fl. I am a snowbird, Boston to Florida 8 months. Last summer left boat on shore power came down both batteries died. Had checked out no good bought 2 new ones put in boat everything seemed ok
Then checked batteries after 2 weeks they were dying again, checked battery charger on then off if I loosened the fuse it would work then die. So asked around said need new charger, went and bought new prosport 12v charger.
Here is when everything gets screwed up. Put new batteries back after full charge and put in new charger( hard wire direct) and charger not working.so I metered my shore power dock and to boat all working. Checked electric panel inside has a meter said 110volts. So I unwired charger put a 3 prong on it and put into boat outlet and it start charging. So I turn on all the circuits and tried everything, microwave, lights, refrigerator, etc all work. Checked out hard wire to batteries. No power. I NEED HELP

[hellosailor]

I would suggest one of the books by Charlie Wing, Sherman, or Nigel Calder on boat systems and electrics, so you'll have a comprehensive picture of how the AC shore power should be safely brought into the bat, and from there, converted to DC and charge your batteries and power the boat. Marine booksellers like Bluewater Books in FLL will hve them. Amazon has them. And your local reference librarian can probably bring them in if your library doesn't have some.

If that whole picture seems too complicated, the best next step is to bring in a marine electrician. Someone needs to have a comprehensive picture of the whole thing--because electrical fires do burn down boats. It shouldn't be expensive, dangerous, or complicated to "do it right" but you need the bigger picture in order to do that.