Help with Off Grid Test

[jedmo]

I have 7.49kW system with two powerwalls. I went to turn off the service disconnect that was in the original panel (prior to the solar install). When I turned it off, Powerwalls were generating power to the house, but my solar was not generating. Is there a different disconnect I need to use? the one inside the TEG? Or does it take a few minutes for solar to kick in again?

 

[BrettS]

If the powerwalls were full (around 98% or higher) then it is normal for them to shut off the solar when you are disconnected from the grid. This is because there is nowhere for excess solar power to go and if the solar was still on then it could create a dangerous situation. The house will run from the powerwalls only until they get down to around 97% and then the solar power will come back on. If there is enough solar power to power your house and charge the powerwalls, then once they get back up to about 98% the solar system will shut off again and it will continue to cycle like this as long as the power is out and there is enough sun to charge the powerwalls.

If the powerwalls were lower than 98% at the time of the disconnect then it’s possible that the disconnect was enough to disrupt the inverters. If they detect too much of a variance in the voltage and frequency then they will shut off for safety. They will restart again, but there is a 5 minute delay before they restart so they can make sure that the power is stable before they come back online.

 

[jedmo]

If the powerwalls were full (around 98% or higher) then it is normal for them to shut off the solar when you are disconnected from the grid. This is because there is nowhere for excess solar power to go and if the solar was still on then it could create a dangerous situation. The house will run from the powerwalls only until they get down to around 97% and then the solar power will come back on. If there is enough solar power to power your house and charge the powerwalls, then once they get back up to about 98% the solar system will shut off again and it will continue to cycle like this as long as the power is out and there is enough sun to charge the powerwalls.

If the powerwalls were lower than 98% at the time of the disconnect then it’s possible that the disconnect was enough to disrupt the inverters. If they detect too much of a variance in the voltage and frequency then they will shut off for safety. They will restart again, but there is a 5 minute delay before they restart so they can make sure that the power is stable before they come back online.

Thank you BrettS, you are helpful as always. Can I use the service disconnect in the TEG to test? or do I always need to shut if off at the main panel?

 

[BrettS]

Thank you BrettS, you are helpful as always. Can I use the service disconnect in the TEG to test? or do I always need to shut if off at the main panel?

If there is a service disconnect in the TEG that should be fine to use. Not all installs have a service disconnect there. Either one will do the same thing.

 

[jedmo]

As a follow up. Looks like the service disconnect in the TEG disables the powerwalls. Powerwalls are at 83% charged. So I tried again with the service disconnect in the mainbox. The SE inverted lit with the red and green lights for a bit then eventually went into the blue/green blinking phase and kicked on the solar. Thanks for the help BrettS.

 

[BrettS]

As a follow up. Looks like the service disconnect in the TEG disables the powerwalls. Powerwalls are at 83% charged. So I tried again with the service disconnect in the mainbox. The SE inverted lit with the red and green lights for a bit then eventually went into the blue/green blinking phase and kicked on the solar. Thanks for the help BrettS.

That’s odd. Is the breaker in the TEG actually labeled “service disconnect”? Because the service disconnect should disconnect you from the electric service, not disconnect your powerwalls. That would be a generation disconnect or a battery disconnect.

But in any case it sounds like you found what you needed and things are working as they should be

 

[miimura]

Gateway 2 can have an integrated sub-panel for generation sources like Powerwalls. So, it might be that instead of Service Disconnect.

 

[jboy210]

My 2 cents is you would be best to test this by cutting the main power company breaker for the house. In my case, this is in the meter box.

That most closely resembles a real-world cut off, like the guys from PG&E last week that cut off power to my side of the street without telling people. And thanks to the Powerwalls we just kept on working and did not know about the power-cutoff until the neighbor mentioned it.

 

[wjgjr]

My 2 cents is you would be best to test this by cutting the main power company breaker for the house. In my case, this is in the meter box.

That most closely resembles a real-world cut off, like the guys from PG&E last week that cut off power to my side of the street without telling people. And thanks to the Powerwalls we just kept on working and did not know about the power-cutoff until the neighbor mentioned it.

Is this the norm where you are? I'm guessing a lot of these things vary by state and regionally. Around here, all the meters are outside, and there is no breaker at the meter - there is no breaker anywhere outside that the power company could use to shut off power to just our house (though they could, of course, remove the meter itself.) In fact, before our solar, we literally had no main breaker for our home.

So, for us, the service breaker in the TEG was the way to go (and, if it is labeled service breaker, it certainly should do what OP is requesting.) Tesla did also install a new 200A breaker between the TEG and the panel. And, they also installed a firemen's disconnect switch outside, which would kill solar and PW.

 

[jboy210]

Is this the norm where you are? I'm guessing a lot of these things vary by state and regionally. Around here, all the meters are outside, and there is no breaker at the meter - there is no breaker anywhere outside that the power company could use to shut off power to just our house (though they could, of course, remove the meter itself.) In fact, before our solar, we literally had no main breaker for our home.

So, for us, the service breaker in the TEG was the way to go (and, if it is labeled service breaker, it certainly should do what OP is requesting.) Tesla did also install a new 200A breaker between the TEG and the panel. And, they also installed a firemen's disconnect switch outside, which would kill solar and PW.

Yes, that is definitely the standard by us. There are switches in the same box as the meter. Been the same for the 5 houses we have owned on both coasts. My daughter just bought a house 30 miles away and when I checked the electrical it was the same. I assumed all homes were like that. I guess not.

 

[jedmo]

Thank you for the help jboy210. I did end up using the breaker that was near the meter. Test seemed successful, although solar did cut out a few times for the first 30 mins or so before the inverter seemed to stabilize. Ran off grid for about 3 hours, generated 9kWh of solar, used 4.4kWh of battery (charged 4.6kWh back to the battery). Was running the dryer during the test and didn't have any issues with power. I think my maximum draw during the outage was about 6.1kWh with the minimum being around .06kWh.

 

[jboy210]

Thank you for the help jboy210. I did end up using the breaker that was near the meter. Test seemed successful, although solar did cut out a few times for the first 30 mins or so before the inverter seemed to stabilize. Ran off grid for about 3 hours, generated 9kWh of solar, used 4.4kWh of battery (charged 4.6kWh back to the battery). Was running the dryer during the test and didn't have any issues with power. I think my maximum draw during the outage was about 6.1kWh with the minimum being around .06kWh.

Congrats! Sounds like a very successful test.

I don't know if this was your case, but the inverters will cut off as you near 100% Powerwall charge since there is no place to send the excess electricity. Normally it would flow back into the grid, but the grid was gone. As you draw more from the Powerwalls they can absorb any excess solar energy and inverters stay up. This solar generation control is a feature of the Tesla Energy Gateway.