First of all it is essential that all batteries involved are identical and have the same state of charge.
Hooking batteries to a solar panels.
Generally to achieve the 12vdc to 120 230vac system both pv panels and batteries are connected in parallel.
However keep in mind that it s safest if you have a way to tell the positive and negative wires apart.
12v is the most common solar panel wiring connection with batteries.
Secondly it is important to use short electrical cables of the same length and with suitable cross section for the connection of the batteries.
How to connect solar panel to a battery connecting charge controller to battery connecting solar panels to charge controller connecting the ac power inverter.
You can either do this by wrapping bare wires around the battery posts securing the wires to the posts with clamps or by using wires with ring connectors that fit over the posts.
Connecting solar panels in series.