However the physical aspects of big batteries on a small boat mean that I essentially had to take everything apart anyway... so as long as I have to go this route, may as well test, inspect and clean everything in and around the battery boxes and switches... and figure out what those "extra wires" are. (don't you just hate "extra wires?")

No doubt on your boat it just means switching some cables about in a fairly accessible battery compartment. (I recall crewing on a 51 foot boat and seeing their battery setup... awesome).

Much like Greg Delezynski, I can't even top off the liquid on my batteries without pulling them out of the boxes. Up until just the other day, I had no idea how big the batteries actually were. (now know group 27)