If there is a long-term blackout, and the system with Powerwall does not have enough energy to make it through the night, will the system self-start again when the solar panels come on the next day?
Yes, as soon as the solar picks up to cover your home usage needs, the PW2 will begin to charge up. I live in Edmonds, WA and have not used any grid energy since the last week in February, supplying our all electric home, charging both our Tesla's (MS and M3) and are exporting ~70 percent of our solar energy back to grid. We have 1 13.2 kWh solar system and two-PW2 batteries. I love the Powerwall batteries, which are an incredible complement to our solar system. We don't have a lot of brownouts/blackouts here, but the PW2's would work to keep the lights on during a power outage.
"the PW2's would work to keep the lights on during a power outage"
Is there a way to test this ? (e.g. Flip the Gateway switch to simulate power outage?)
There should be a way to interrupt grid power to simulate an outage. We (myself and a Tesla technician) did this when our system was started up to ensure that the switchover was operational under a variety of load conditions.
However, since the grid interconnect for different system is likely different, It would not be wise for me to advise you how to perform this operation. I wouldn't want to be responsible for anything "crashing" due to advice that was not applicable to your system.
I am surprised that this was not tested when your system was not started up. I advise that you contact Tesla for instructions.
Tesla-Dave almost answered my question, but not quite. It makes sense that if it has enough stored juice to make it through the night, it will continue to operate. What I'm wondering is if it can restart on its own from a dead condition (battery exhausted), without needing grid power to power the inverters during initial power on.
@william, our 2 PW2’s drained to zero for 5 days during February, and charged back fully once the snow cleared off of the solar panels. So the answer to your question is yes.