RV Repair: batteries hooked up, 12 volt, 5th wheel

Question
  how do you hook up 3 three batteries together for a big 5th wheel to run the power to all the inside things??

Answer
Phill, What voltage are the batteries? If they are 12 volt you need to hook them up positive to positive and negative to negative. One battery should have the negative from the coach and another should have the positive. The one in the center just needs to be hooked into the system. If they are 6 volt then you need to hook one to the positive side of the coach wires and the other one to the negative side. Then hook the negative from one battery to the positive of the other and this will give you 12 volts. The third battery would be pointless. Thanks, Bill