When my 3012 Magnum burned up I was told by the tech support folks that they did not recommend powering an air conditioner with the unit. They suggested the 4024 (iirc).
The issue was simple. The cooling fans require 120 volts to operate. I do not know if that is the control circuit or the fans themselves. So after running a heavy load do NOT turn off the inverter. My RV has scorch marks on the wall above where the inverter lives.
They did replace it, as it was under warranty.
I'd recommend Victron or Outback.
I'd recommend jumping to 24 or 48 volts.
