You do not want to connect the inverter to the DC circuits in the converter.
Place the inverter as close as you possibly can to the battery. Use 8 gauge wire within 10 feet of the battery. That will be 20 feet of wire if you are unable to ground it to the frame closer. Use an inline fuse holder.
There are many ways to do this hook up but the key is the larger the wire and the closer to the battery the better.
I would not use the DC circuits from the converter panel for anything over a 100 watt inverter.
Hope this helps.
Chuck - Sparta, TN
2012 Jay Flight 22FB, 2 x Honda EU2000i
2013 GMC Yukon XL Denali AWD
EDUCATION is what you get when you read the fine print.....
EXPERIENCE is what you get when you don't.