Maybe this 30AMP Wiring configuration will help...
I installed my high wattage INVERTER as close to the battery terminals as possible...
This is my layout around the WF8900 series Power Distribution Panel... The WF8945 Original CONNVERTER was just left in place as a turned OFF spare unit and I use the PD9260C Converter as primary.
In your case a 3000WATT INVERTER will require alot of DC CURRENT coming from your battery bank if loaded down full. This will draw over 250AMPS DC CURRENT from your battery bank so you will have to have many batteries in the bank if you want to run in this mode for even just a few hours. You already know how fast a single 12VDC Deep Cycle battery lasts when just pulling 5-6AMPS DC load over night. I can only get maybe one hour using my 255AH Capacity Battery Bank to operate my 1500WATT PSW INVERTER running pretty much full load. I actually have a 600WATT PSW INVERTER being used as my workhorse Inverter and only use my 1500WATT PSW Inverter to just power up the 120VAC 15AMP Receptacles are the trailer. I switch OFF all of the 120VAC circuit breakers in power panel and just have my Converter and 120VAC receptacles connected.
INVERTERS need alot of DC CURRENT from the batteries to operate. Check with the guys on here that live 24/7 in their motorhomes and see how much Battery Capacity and Solar Panels they have on their trailers...
Roy Ken
