You got all kind of problems. At 1800 watts operating into 12 volt battery is nucking futs, dangerous, and a huge waste of money. To run 1800 watts of panel at 12 volt battery requires 2 very expensive ($600 per unit) 80-amp charge controllers. 1800 watts into 12 volts is 150 -Amps. At 1800 watts you are into 24 and 48 volt battery. At 24 volts with 1800 watts would require a single $600 80-Amp Controller. Smart money with 1800 watts of panels uses 48 volt battery using a much smaller and less expensive 40-Amp Controller less expensive. Not only would it save you over $1000 just in controller cost, but save hundreds more with much smaller wiring, and a lot less hardware. I am not even going to address the 1000-pound 12 volt 1500 AH battery monster required to handle that panel wattage. Hope you have a fire extinguisher and lots of baking soda handy.