it depends on what the max amps you plan to use or charge at. On my 220ah lifepo4 its 4x 55ah 12 volts batteries connected together in parallel, I been using 12 gauge wires to connect everything together since I rarely use more then 15 amps. You can probably use 10 gauge on those batteries if you plan on using alot of amps. Whatever wire you use, make sure its pure copper, they sell cheaper copperclad wire (speaker wire) that I would avoid for connecting batteries together.
Once all batteries are connected together in parallel, the main wires that will go to your load or charger can be much larger. Those are the wires that will get warm when current passes through them.
To connect them I been using xt60 connectors on each battery then I connect those xt60 to a 4 way "Y" connecter. Once you got them all connected, you have one giant battery. You can add more batteries as you buy more, just get more "y" connectors as required.
My other li-ion battery bank is 12x 26ah batteries connected together in parallel (4 connected to 4 way, then those 4 ways connected to a 3 way), I can add more if I wanted to and had room for them. Just make sure the extra batteries you are adding are at the same voltage as all the other batteries when you add them to the system and that all the wires are the same length on each battery. I use xt60 connectors because of there price and there ability to handle 60 amps, but there are other connectors available, just avoid the SAE connectors due to they can be connected backwards.
This are the terminals you talking about
xt60 I use to connect together, shown is a 2 way "y" connecter, you can use a 4 way, 6 way or whatever size you need. or use 2x 2 ways to connect 4 batteries. On your battery, the blade connectors would be on the end of the xt60 male connecter and then connected to the "y" female connectors.
