Before expressing my doubt(s), I would like to briefly explain how the self-consumption system I am analyzing is structured:
On the DC power side, has a BlueSolar MPPT 100/30 charge controller sandwiched between the PV panels and a bank of two batteries. A Multiplus inverter/charger is used to supply the loads with AC power. The system can use the grid voltage to supply the loads or inject the surplus power from the panels into the grid. All systems monitored by Color Control GX.
As can be seen in the image below, the MPPT charge controller is in "external control" mode, which according to its manual means that it "will appear when another device controls the charging behavior of the solar charger, ignoring its normal charging algorithm". By this I interpret that the control is being performed by the inverter/charger.
I would like someone to explain to me, for my specific case, what does it mean that it works in external control mode.
Is the charging of the batteries done from the power of the panels by the charge controller or from the AC grid power with the inverter charger? If it is done with the charge controller, being in external control mode, is it doing it from the charging algorithm of the inverter/charger? On the contrary, is the charging and management of the batteries done only by the inverter charger and the MPPT charge controller is used simply to get the maximum power from the panels? Are my assumptions wrong?
I believe that from the grid, the inverter/charger gets the power needed to supply the AC loads in case the panels and batteries cannot during the day and, at night, it demands the power from the grid needed to keep the batteries from discharging. On the other hand, I believe that the management and charging of the batteries are done during the day from the power generated by the panels. Being in external control mode all the doubts that I have presented in my comment appear.
I would be grateful if someone could explain it to me, since I do not have much experience in photovoltaic systems.
Thank you very much.
