There are two things involved and these are amps (current) and voltage. The current rating might be 30 amps but it will not flow until the voltage is high enough in relation to the impedance of the load. For example if you have a battery
charged to 12 volta amd place a power supply with an output of 10 volts no current would flow into the battery
If that voltage applied was 15 volts then current would flow. The amount would be determined by the load state of the battery
and it's state of charge.
I think that the Bogart charge controller (and battery monitor) would take any source of charging current at a high enough voltage and pulse width modulate it to properly charge the battery. A MPPT controller would be slightly more efficient since it would find the optimum voltage and current for the panel as well. I don't think this would do any good for us , but it might since I think it can increase the output voltage if it has to to charge the battery.
Given enough voltage you could use diodes to automaticallytransfer to the on board charger if the solar
was not producing power or more likely if the system were plugged in and available. The typical voltage drop across a diode is 0.6 volts so there would be this loss in any circuit using them. The 12 volt converter could engage a relay or contactor as well. The losses in the coil would be negligible when under shore power.
After the basic battery monitor and controller are done then the solar
panels can be added at any time.
I will see if I can draw up some doodles for the electrical
systems when I get a chance,
Right now I am hoping someone who had doen it or knows more than I do about solar
and eggs chimes in. As above I would like to be second or third.
Also if you are waiting on me I am th the stage in my rebuild that I am finishing up cabinets, tops beds and A/C and the batteryes and charging are n the future.