Pretty sure the dc wiring for the inverter is already done
3000VA ~= 2400 ac watts
2400 ac watts / .85 conversion factor / 12 volts low cutoff = 235.294117647 service amps
235.294117647 service amps / .8 fuse headroom = 294.117647059 fault amps.
The multiplus is 2400 watts and has a configurable low voltage disconnect.
That said I would use 4/0 awg and a 400 amp fuse for the critical path.
We are talking about the dc distribution circuit which OP has not
You have a power management unit that does exactly what you thought it does.And I just realized that with that disconnected I have no DC to enable the AC unit. I'm assuming it switches between Microwave and AC to prevent an overload. Now I have to figure out if I should remove the jumper or not. The manual is pretty clear its suppose to be either/or..
See, you're figuring it out and will be all back together to go camping this weekend.
Aren't RV's fun?
(Actually I love them but ownership can be time-consuming).