Dual Battery Hookup on 2010 Elite V C4

[2010 Elite V Oldman WB SS 1]

I just bought a 2010 Centurion Elite V C4.  It has a starter battery and a deep cycle house battery with a selector switch and automatic charging relay.  Currently, all the cables (two positives, two negatives, and a small black wire connected to the negative terminal) are connected to the starter battery.   My question is how do I hook up the house battery. 

My original thought was hook the smaller positive and negative to the house battery but I was not sure which battery to hook the smaller black wire to.  Doing some research, I saw many diagrams and pictures showing a cable connecting the negative terminals of each batteries to each other.  I don't have that cable so I am not sure it is needed for this setup.  Any help would be appreciated.

[TexP51 6]

I put new cables on my dual battery setup this past winter on my 2002 Elite V when I added a dual battery maintainer.  If you have the normal Perko marine battery Selector switch you should be able to easily get back on the water.  The ground (-) / negative wiring you are seeing is that both batteries negative cables come to the same single point to ground probably on the engine.  See if this diagram helps.

https://www.perko.com/help_guides-wiring_a_battery_switch/

 

[Jlagos 23]

The wire could be a couple of things. 1. Direct wire to the bilge pump in order to ensure that power is available if the bilge float is activated by water. It could also be coming from the ignition switch which allows the automatic charging relay to send a charging current to the house battery. It depends, a pic or brand of charging relay would help give further insight.

[Wylie_Tunes 146]

If the OP has a blue sea dual circuit plus switch and ACR, any diagram from Perko will get you in trouble. Need to clarify the switch type.