miimura
Well-Known Member
If you want to be able to survive an extended power outage, you should find out what your 3-phase solar inverters will do when only one phase is alive. If it shuts down completely, you won't be able to charge the Powerwalls when the grid is down. Best case, you will still generate on one phase, up to the capacity of that one line (nominially 1/3 of the inverter AC power).Again, I could live with 1-phase power backup, just need to know it works.
Also, you should ask about the 3-phase metering. If you want to be "Self Powered" and charge the Powerwall(s) from the solar and discharge from the Powerwalls at night, you need to be sure that the metering is net of all three phases because the power flows could be significantly different on the three phases at any given time. For example, during the mid-day your solar could be generating 9kW spread across all three phases but the Powerwall could be charging with 5kW on only the L1 phase. The flows on L2 and L3 would be 3kW negative and the Powerwalls plus critical loads could be 9kW positive. The net flow is zero but it is very imbalanced. Maybe the utility doesn't care. I don't know, but I'm pretty sure that is what will happen in a 3-phase Gateway 2 installation. If you have a 63A per phase service, you also won't be able to install more than 2 Powerwalls because this imbalance situation would overload one phase if you had more than that.