Only getting solar when grid is up...this is a new one for me..... ???

[MorrisonHiker]

I dont think thats what happens, based on what I have read here. Havent experienced it myself yet, but from the reading I have done here, with grid power OFF, if the powerwalls hit somewhere around 94-96%, they trigger the frequency to shut the PV system down. Some inverters have the ability to "ramp" down (see post from @GenSao on subject). Otherwise, the powerwall just tries to shut the PV system down.

When we did our extended 200+ hour test, we saw the percentage decreased slightly each day. I think the first day off-grid, the Powerwalls were charged up to 96% but then on subsequent days they only charged up to 95%, 94%, etc. When we ended the test, I think they were only charging to 88% or so before they would raise the frequency to shut down the solar system.

As you mentioned, I did charge one or two cars during the day when solar was at its peak. I sometimes do that even when the grid is up. It's just nice to be able to charge directly from solar, even if I miss out on a few Netmetering credits.

 

[jboy210]

When we did our extended 200+ hour test, we saw the percentage decreased slightly each day. I think the first day off-grid, the Powerwalls were charged up to 96% but then on subsequent days they only charged up to 95%, 94%, etc. When we ended the test, I think they were only charging to 88% or so before they would raise the frequency to shut down the solar system.

As you mentioned, I did charge one or two cars during the day when solar was at its peak. I sometimes do that even when the grid is up. It's just nice to be able to charge directly from solar, even if I miss out on a few Netmetering credits.

Did consuming energy by charging cars have an impact on the amount of charge that Powerwalls ended up with for the day? Also, were there any consecutive days when the amount of charge in the powerwalls failed to top off.

 

[Sylvia Else]

It appears to me that that inverter has an LCD, and there should be additional information there relating to what the problem is.

But it should work, and it did work for me (albeit with a different PV inverter) over a day and a half outage we had a couple of months back. On the two successive days, the PW charged from the PV, and then cut the PV output down when the PW was nearly full.

Time to make a warranty call, I'd say, because there's something wrong with it.

 

[MorrisonHiker]

Did consuming energy by charging cars have an impact on the amount of charge that Powerwalls ended up with for the day? Also, were there any consecutive days when the amount of charge in the powerwalls failed to top off.

Usually when the grid is up and I decide to charge the cars via solar, I do it in the morning/early afternoon when I know there will be several hours of peak solar production. In the video, if you look at the daily graphs from the app, you can see that we charged the cars on some days later in the afternoon because the Powerwalls were cutting the solar back since they had nowhere to send the energy. While we had 8.5" of snow one night, it was nice and sunny the next day and the Powerwalls were still able to charge up all the way. On the last day, it snowed all day and we had no solar so the Powerwalls didn't charge up at all.

In the image below, you can see that there were a few clouds in the afternoon but the solar just totally dropped off because the Powerwalls were full. If you look closely, you can see that it was totally shut off at some periods between 2 pm and 4 pm and would then turn back on as the Powerwalls drained a bit. Once I noticed, I started charging one of the cars so that the solar could stay on longer. I worked from home some days and was able to go out and adjust the amps that the car would charge at. On other days, I was in the office and could just turn charging (of a third car) on or off but couldn't adjust the amps. It would be nice if Tesla added that functionality to the app.