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Question on Gateway / Powerwall behavior when off grid.

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I had a Powerwall+ with 8.6kW solar installed late last year, and now I'm finally getting good sunny weather to see how it performs. I have confirmed the 7.6kW on grid limit, as well as the 9.6kW off grid limit.

Today I was doing a test when the battery was at a 95% state of charge and full solar (about 6.8kW) was hitting the panels near noon. In the test I was charging my car using the Charge-on-Solar feature. I wanted to see how the system would behave if I tripped the breaker to go off grid. Here's what seemed to happen:

1. The system goes into island mode.
2. The system reduced solar power to about 100W.
3. My car stopped charging (as expected).
4. The battery starting providing the balance of power to my house (which was drawing 300-400W total).

This situation persisted for about 5 minutes. I would have expected the inverter to increase panel power to charge back to 100%, but this did not happen. So what I did next was do what I was told is a "system reset", which is to open the DC disconnect, open the AC disconnect, and then turn the Powerwall battery off, wait perhaps 20 seconds, then turn it back on. Then I reclosed the AC disconnect and DC disconnects.

When I did that, solar production dropped to 0W and never restarted.

After another few minutes, I reconnected the grid to the gateway. This didn't have any immediate effect (I am aware that it takes several minutes to resynchronize and reconnect). After another few minutes, there was still no solar production.

What I did next was log into my Gateway using the "Tesla One" app, and pushed System Stop. I then flipped it back to Operate. After running the diagnostics, the system restarted and almost immediately solar went back to producing full power.

Is this kind of behavior expected? Can anyone confirm behavior when the grid cuts out during full solar production?
Anytime the grid goes down my solar stops producing for 5 minutes. If my Powerwalls are below ~90%-95% and the grid remains down then the solar will start charging the Powerwalls. The solar production starts being curtailed when the Powerwalls around 95% and the house loads aren't sufficient to consume all the solar.
In order to know what's going on, you need a device like a Kill-A-Watt that can display the frequency of your power. When you go off-grid the Powerwalls will raise the frequency in certain situations to shut down the solar. High battery state of charge or low battery temperature or high solar output relative to Powerwall charge capacity can all lead to high micro-grid frequency and solar curtailment.
  • Informative
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