Hi.
We just built a home in the USA and have 100A split-phase service with about 20A of critical loads branched out from the main disconnect to a separate critical load panel. There, we have a manual transfer switch and an outlet where we can connect a generator to power the critical loads, but that's it right now.
We would like to consider connecting a battery and PV for self-consumption and automatic backup power for critical loads only. And we would also like it to be able to meet National Electrical Code and pass an electrical inspection.
I see the individual ones now appear to be certified to UL 1741 so must have been tested for anti-islanding, etc. Could we use those in the USA and would they pass inspection?
The following configurations seem possible:
1. Two MultiPlus-II 48/3000/35-50 120V in parallel? How would we wire the the two MultiPlus II in a split-phase application? Is an autotransformer needed here to rebalance the critical loads? With two MultiPlus and (presumably) one current sensor at the grid input, how would they know how to perform optimal self-consumption? Do the firmware settings support self-consumption with two in parallel?
2. One MultiPlus and an autotransformer wired for step-up? In this case, one leg of our main panel would go into the Multiplus II, and, and the AC critical load output would be to the autotransformer and then to the critical load panel. Here I guess we would probably give up the ability to offset the main loads, but it might be a little cheaper due to the single MultiPlus.
3. Other Victron products or other manufacturers' products that would do the job better or more economically?
Thanks in advance for any insights or suggestions!
Mike
