We had a planned grid outage that lasted most of the day and this is what happened with our setup. I was very curious to know what would happen when the PW2 was full and solar was running but the house unable to use all the power.
So there you go.
- The grid outage started around 9am when the battery was about 40% charged. Solar continued to generate what it could, running the house and the excess going to PW2.
- The PW2 was filled by about 11am. When this happened, the solar inverters were shut off completely and the house ran purely off the battery. Shown in the chart below by the sudden drop of solar production to zero.
- This lasted for about an hour and the PW2 charge reduced to 96% supplying the house. But then the solar inverters came back fully on and proceeded to charge the battery back up to 98%. That is the brief spike in the chart below.
- BUT this time, once the battery reached 98%, the solar inverters were not shut off completely, but instead exactly tracked the house usage. The PW2 stayed at 98%, no solar was diverted to the battery, and the solar generation showed a pulse due to our refrigerator compressor turning on and off at roughly 30 minute intervals.
- When the grid came back on, normal operation resumed.
So there you go.