Hi,
I have 2 x Multiplus II units (48/5000), both same series so I can parallel in the future. Right now (due to not yet having approval in Australia for grid connected inverter status,) I have one (call it M21)connected to the Grid and is a battery charger only. No connections on AC out 1 or AC out 2. I have the second (call this M22) with No AC input connection, however the ACout1 is supplying my home, it also has a fronius PV set to MG on out1 no grid feed required / desired. I use the Generator function based on SOC in the Cerbo to turn on the AC to M21, it then starts charging the battery should I need it in bad weather. On occasion we have had cloudy weather, the Fronius outputting 4kw, we have put 5 or 6kw of load (oven being intermittent 2kw) and it works fine, until that moment in time when the oven element turn on and a cloud passes over the solar array and the array drops off suddenly.
Generator function note: Initially I had it on the remote power on of M21 through the cerbo, but it would be charging the batteries at 50 amps fans on as it was working and then instant off. I didnt like this as it had no fans to then cool down, so now I switch the AC. The AC drops, charging stops and the cooling fans ramp down over time as it cools.
My question is:
Am I able to connect the output of the M21 to the AC input of M22 and use the same generator function to "on load of x " turn on Generator, and use the remote on off control of the M21. At present I have the M21 switched to charge mode 24/7 and the only change is the Mains is turned on and off, by the cerbo. I think this would take too long as the M22 would need to sync to M21 first.
Alternatively
I could use M21 as the master unit (only turning on AC with Low SOC) and then have the second unit set to assist mode with AC input limit of 3000W. The only thing here is I would likely run into trouble with the grid code again, even though the AC in to M22 is predominantly off and controlled by contactor. I dont see how this is any different to mum and poops caravan being plugged in when in a caravan park. but I cant find any thing solid on this in the regs.
Which configuration is preferential, which would have cons that I haven't considered, have you done this in your installation, what was the outcome?
Also I cant plug M21 into the Cerbo to track the data, as soon as I do the entire system shuts down with an out of sysc error as it thinks the two M2's should be configured as one, is there a way around this? Id really like to be able to trend the AC input to M21 so that I can graph / tantalize the amount of power I am buying from the grid in the bad weather times to work out if its cost effective to add additional solar. I have a power meter on this AC line, but I cant configure it correctly, if I select generator it doesn't show up as the M22 never sees the AC on input 1, if I set it as AC it doubles the output value on the load side...
