Positive terminal one charge controller melted 2 batteries warm 2 batteries warm any ideas of causes
That would be (ideally) a minimum of 4/0 cable:
And is approximately a 1/2 inch in diameter of copper:
This is serious copper wiring...
I don't think you can draw that amount of current/power from your battery bank (to run 2kWatts for a few hours, you would need at least a 800 AH @ 12 volt flooded cell lead acid battery bank).
Anyway, more or less, 1,200 to 1,800 watt AC inverter is about the maximum I would suggest for a 12 volt battery bus voltage... It takes too much copper to manage the high current needed for larger inverters (and keep the voltage drop low from battery to inverter-- ~0.5 volt at max current load maximum recommended allowed drop)..