[anthem]

My recommendation at this point is to try and look at the connections on the battery charger you can get to and see if 2 of the banks are connected. On my 12405, 40 amp not 60 as I stated above (my bad), there is a small screw on the cover that once removed you can slid the cover up to see the connections. My guess is that this one charger is charging both port and starboard battery banks. If 2 banks are connected with a thick wire, then that is most likely the case. 

Look behind the aft back cushion in the dinette.  Not the seat cushion, but the back cushion.  Mine is just Velcro'd there.  There is a compartment there and that's where the Charles Charger is.  Mine I think is 40 Amp and does just fine with all my 31 Series batteries.  I have a 2002 38 Open