My TX outage experience with Powerwall/Solar/Vehicle

First off, I want to say that I’m very, very happy right now to have power. Power has been down in my neighborhood for about 30 hours at this point, and many of my neighbors are hitting below-freezing temperatures inside their houses at this point. Between my solar, Powerwall, and the fact that I’ve got gas heating (so not much power use), I’ve been able to stay warm.

But, I have noticed a bit of weirdness I wanted to share with people:

1) My Tesla car seems to have freaked out my solar production. Look at this graph:
https://imgur.com/a/92Hs4GC

That big chunk in the middle where there’s no power, I started watching it, and what I’d see is my house using ~1kW from the PowerWall, my solar panels would kick on providing ~5kW, a moment later my house would kick up to using ~6kW, then the solar would turn off and I’d go back to using ~1kW. I have the app set to not charge my car during outages unless the Powerwall is above 95% (it was below 80% at this point), but it seems like when solar would kick on it would try to charge it off the solar but had problems, possibly with the car trying to pull more than the solar could put out. The car had barely dropped enough from vampire drain that it wanted to charge, so I dragged the slider for how much to charge it down to 50%. It still happened, so I flipped the breaker for the car charger, and that’s when the whole thing started working again.

Also, I am curious about the random smaller dips where it stops providing solar power, but less worried about those than the big cutoff that seemed to be from the car.

2) Storm Watch is great before the issue (it charged my Powerwalls up to 100% and left them there before things got serious), but I worry it’s bad for the grid during the issue. I did have power try to come back on a couple times. The first time, I saw that the Powerwall immediately started trying to charge from the grid as fast as it could. For an already strained grid where they don’t want surges from turning areas back on (they’ve asked that people unplug everything and have just a single lightbulb on so they can see when power comes back), having the Powerwall try to charge itself from the grid during this is probably bad. I turned off Storm Watch mode and changed it back to Self-Powered and a low %, so that my house doesn’t yank from the grid as soon as it comes back online. Tesla probably needs to consider some changes to Storm Watch so that it doesn’t charge when there’s requests to conserve in an area, and maybe even slowly ramps up using grid power when it does return.

submitted by /u/Rygnerik
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