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How to tell after power outage if you are using PW Batteries or if the grid is back on?

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Our power went out and the Power Walls started up providing service. However, now it seems the power grid is back on. How do you tell if you are using the Power Walls or the Grid.

This is important because if you have an extended power failure, you need to turn off house A/C, large power users, etc.

It is not clear to me looking at the app how to easily tell when power comes back on.

Comments????
 
Hi Bob, it's usually very clear on the Tesla App if you are off grid. Here's @SMAlset 's screenshot from Tuesday. The app will tell you the grid is out, and estimate your remaining energy if the home uses energy at what Tesla has measured lately within the home.

So in this screenshot SMAlset seems to have a spike of loads going up to 7kW. There's no way 22 hours remaining makes sense at 7 kW of load. But it's likely the average experienced load in the home recently was around 1.5 kW.

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How do you tell if you are using the Power Walls or the Grid.
The neighbors stop cursing when power comes back on.
Seriously though, as mentioned by others, the App and notifications are pretty clear as to what is going on. Also, there are products on the market that will automatically turn off the breaker for selected high energy items when the grid goes down. They connect to your panel.
 
The neighbors stop cursing when power comes back on.
Seriously though, as mentioned by others, the App and notifications are pretty clear as to what is going on. Also, there are products on the market that will automatically turn off the breaker for selected high energy items when the grid goes down. They connect to your panel.
The app will show you if power is coming from Solar, the PowerWall or grid.
 
So the power came back on almost immediately. About five minutes or so after the power came back on, I did get a notification saying the house was being powered from the power walls, it was not. I never have received any of those screen shots when running from power walls during a power failure on the smart phone app.

Wondering why not?

Thanks
 
You know, the best thing about this thread is that you have to ask someone how to determine when the grid is back. That illustrate how seamless the transition is. With Powerwalls you just don't notice that the grid is gone, or has come back, without checking an app. Think about how different that is and give you Powerwall a hug, or at least dust it off.
 
Hi Bob, it's usually very clear on the Tesla App if you are off grid. Here's @SMAlset 's screenshot from Tuesday. The app will tell you the grid is out, and estimate your remaining energy if the home uses energy at what Tesla has measured lately within the home.

So in this screenshot SMAlset seems to have a spike of loads going up to 7kW. There's no way 22 hours remaining makes sense at 7 kW of load. But it's likely the average experienced load in the home recently was around 1.5 kW.

View attachment 820037
Yes, @holeydonut is correct. The app will refresh every so often to reflect anticipated battery hours up or down based on current draw and app’s refresh rate.

Here’s a screenshot after the A/C use got picked up:
222E117A-7C7F-4BD9-BFF6-946F3C5C5F44.png


We adjusted our A/C temp upwards to I think 78-79F after seeing what was projected running A/C at the lower temp range. Gave us “back hours to run off battery”. Very helpful way on app to gauge things. It was such a hot day and night. We had a bedroom fan on circulating air as well and just didn’t want to be without any A/C. Didn’t want to deplete our batteries to our set reserve level either if we could help it, and we did drop our reserve bit too. Still wanted to maintain some battery for when morning sun would start filling the batteries up again but keeping in mind A/C would likely be kicking on earlier as well.
 
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You know, the best thing about this thread is that you have to ask someone how to determine when the grid is back. That illustrate how seamless the transition is. With Powerwalls you just don't notice that the grid is gone, or has come back, without checking an app. Think about how different that is and give you Powerwall a hug, or at least dust it off.
True. I only knew when it happened as our intercom system’s speakers make a static noise when the Grid system comes back up for some reason. We do have whole house back up.
 
Question indirectly related to this thread - How can one estimate the Powerwall potential duration in a long outage?

I have very reliable service from MidAmerican Energy here in town. Our longest recent outage was one and a half hours. Problem: there is no more 3G here and my internet fails when the grid goes down. At that point the gateway is incommunicado. api/system_status says I have nominal pack energy 10725, but I don't know how that correlates to time to system shut down.

I'm thinking I could flip the main breaker and chart the estimates over a period of time to get an idea of time to shut down. Any thoughts?

David
 
Question indirectly related to this thread - How can one estimate the Powerwall potential duration in a long outage?

I have very reliable service from MidAmerican Energy here in town. Our longest recent outage was one and a half hours. Problem: there is no more 3G here and my internet fails when the grid goes down. At that point the gateway is incommunicado. api/system_status says I have nominal pack energy 10725, but I don't know how that correlates to time to system shut down.

I'm thinking I could flip the main breaker and chart the estimates over a period of time to get an idea of time to shut down. Any thoughts?

David
10725 is 10.725 kWh, how long to shutdown is dependent on the house load. If it is drawing 1 kW then you have about 10 hours, if it is drawing 2 kW then you have about 5 hours. You can see the instantaneous house load on the first screen after logging into your TEG.

You don't need to have access to the broader internet to access your TEG, you can get there with just your local network.
 
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Question indirectly related to this thread - How can one estimate the Powerwall potential duration in a long outage?

I have very reliable service from MidAmerican Energy here in town. Our longest recent outage was one and a half hours. Problem: there is no more 3G here and my internet fails when the grid goes down. At that point the gateway is incommunicado. api/system_status says I have nominal pack energy 10725, but I don't know how that correlates to time to system shut down.

I'm thinking I could flip the main breaker and chart the estimates over a period of time to get an idea of time to shut down. Any thoughts?

David
If you check the app, you should be able to see what your average household load is, such as 1 kW, 1.5 kW, 2 kW, etc. Then you can take the number of Powerwalls you have and multiple it by 13.3 kWh (IIRC), reduce it by 5% (since the Powerwalls will keep 5% in reserve) and then divide by your average kW.

For example, we have 4 Powerwalls so 4*13.3*.95 = 50.54 kWh.
Assuming our average household load is 1.5 kW: 50.52kWh/1.5kW = 33.68 hours.

We have solar and lots of sunshine so we can typically go a lot longer than 33.68 hours. We once did an off-grid test of over 200 hours back when we only had 3 Powerwalls and could've gone longer but we were losing out on selling our excess back to the grid so we stopped the experiment. You can also extend the number of hours if you reduce your average household load.

Ah, I missed the nominal pack energy part. Just use that as @Redhill_qik mentioned but I'd reduce it by 5% since the Powerwalls will shut down once they hit 5%.
 
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I do wish there was better way of notification of a power outage. The Tesla notifications are unreliable, sometimes I don't get them until hours later if at all. And I turn off my phone audio notifications at night anyway. PG&E also sends email notifications which are a little more reliable and does have an option for phone notifications. But PG&E often goes down for a few minutes where I live and I don't want constant calls during the night.

It would be nice if I could set an outage duration to get notified during the night and somehow set it to give me a phone call when the threshold is exceeded. My heat pump can really eat into the reserve if I'm running on batteries.
 
Did the requisite maths, adding in my average daily solar production, and dividing by my average daily consumption. (November 1 - 7) Result: 1.4 days.

Note: House heat is high efficiency natural gas with 4 zones. Also hot water. It's a leaky 108 year-old house, but natural gas here is about three cents per kilowatt hour.
 
With Powerwalls you just don't notice that the grid is gone, or has come back, without checking an app.
That is not my experience. When the grid goes there is a noticeable delay before the Powerwall cuts in, enough to cause clocks on devices to reset and PC to reboot etc. The return of the grid is invisible, so we do have to keep checking the app to see if we have grid power or not.

Anyone know why I'm not getting the smooth switchover @jboy210 experiences?
 
Anyone know why I'm not getting the smooth switchover @jboy210 experiences?
It depends on what state your PWs are in when the power is cut. If they are currently supplying power (like peak periods in Time Based Control), there will be no delay at all. But if they are in standby, then there could be a fraction of a second or more where they need to detect the loss and switch over to providing power.

This is why for critical device that are time sensitive (like servers), you still need to have UPS's. But you only need them to act for a few seconds at best, so a tiny one is all that is needed.