I used bus bars to connect the solar controller, the converter, and the inverter to my batteries. Here's a picture of my DIY bus bar:
There are also commercial products that will do this type of connection/distribution.
You want to make sure that the wire size that leads from your batteries to your solar controller is large enough so that you are not losing too much voltage. The calculation for wire size revolves around amount of power and distance. Personally, I don't use any wire gauge smaller than 4 AWG to connect batteries. I paid good money for my solar system. There's no reason to throw away the power harvested by using too small of a wire. The alternative to spending $30 on wire upgrade is to lose harvested power continually, forever.
Voltage drop calculator
