Rule No 1 this is a ratz nightmare. No more than ONE wire per battery terminal. One four gauge to terminal blocks
https://www.ebay.com/itm/K4-Common-BusBar-100-Amp-300-Max-Volt-AC-48-Max-Volt-DC-10-32-Terminal-Studs/112827469729?hash=item1a450a8fa1:g:IFsAAOSwPzhaHlHp
This is 100 amp continuous rated. Mark Red for positive. This will really clean up the wiring situation. One wire max on any one stud.
Yellow for NEG if there is a lot of 120vac and 12vdc in the unit. Any other color other than yellow or white for 12 volt negative.
The idea is to keep wires intrinsically color coded for organization. A number 10 stud will handle a number 8AWG wire.
This setup is inadequate for a power inverter larger than 300 watts.
