I installed another battery for amp had to add another battery switch for 2 batteries also. Here is where it gets weird when i hook the 2nd battery to the #2 switch with the wires that turn on cockpit power the everything stays turned on but when I only have one battery connected to the switch I can hook the cockpit power wires to the #2 switch and everything works like it should. I thought you were supposed to have both batteries connected to the switch? Any insight on my problem would be great. Thanks

I too just added another battery and a dual switch to my 27.The way I wired the switch was starter,acessories to the common post. Batt one post goes to port side batt, the jumper receptical under the rear bench and full time 12 volt (ie,bilage pump)Post 2 goes to starboard batt.Hope this helps out?

that is where I screwed up I had a single switch and put accesseries on post 1 but on a 2 batt. switch they go to common THANKS I APPRECIATE IT!!