This shows how to successfully hook up 3 batteries
Inverter main Red wire, to one end of fuse block.
Opposite end of fuse block red wires will go to batteries # 1, 2 & 3 (shown in next photo) Stack all red wire connections together and secure to one side of fuse block
Inverter main Black wire, to battery#1 only! Then daisy chain the negative terminals together.
