I have a MultiPlus II 2x120 in my RV along with solar and 10.4kWh of LiFePO batteries. This system is incredibly flexible and provides a lot of benefits including the ability to operate for extended periods of time without hook-ups (shore power) and the ability to operate as if I had 50A service when I only have 30A.
I have added a PHEV to my vehicle line-up and would like the ability to share 50A service with the other electronics in my RV. I would like for the PHEV to have "priority" on the electric service if that makes sense -- it wants to draw 7.5kW when plugged in and I have a Level 2 charger with a 14-50R plug.
My thinking is that I will install a 14-50R receptacle in the RV that I can plug the Level 2 charger into. My question, though, is where to draw power from. One option would be to add a breaker and pull off of the same 50A service (shore power). If I do this, one issue I could have is drawing too much current from shore power unless the MultiPlus II knows about the Level 2 charger. I do have a current monitor but have never used it. Could I connect the current monitor on the main feed from shore power and then parallel the MultiPlus II and the 14-50R for the charger. Would the MultiPlus II restrict it's current knowing how much total current is being drawn and the limit in the MPII?
Another option would be to put the plug on the output of the MultiPlus II. I don't expect to be able to charge without any shore power (my PHEV has a 17.2kWh capacity and my RV only 10.4kWh so it makes no sense to let it draw down the battery if I'm not on shore power). My MPII is a 3kVA unit, but I believe this is just the rating for the inverter. If I was plugged into a 30A service (providing only 3kW of power), the MPII can only make up another 3kW so I'm shy of the current required to charge the PHEV, BUT my charger will allow me to lower it's current draw so I could set that at say 5kW and allow it to charge from both batteries and the shore power. This would allow me to quick-charge the vehicle (this would take about 3h at that rate), draining the batteries some during that time and then when I leave in the vehicle, the MPII would continue to charge the batteries in the RV from the 30A shore power.
Has anyone tried this? Any ideas on the best approach? I've attached a drawing of my current setup without the PHEV power connection for reference.