RED battery symbol says your battery voltage is too low. Do you have a multimeter and know how to use it? If so, check your house battery voltage, if not, get one (Free at Harbor freight with the right coupon) and goto Youtube university to learn to use it. It will come in handy with your RV use.
I also changed your OP references to "converter" since you are talking about an inverter. Let's not confuse the subject.