Off-Grid Test with fully charged PowerWalls

[bob_p]

If you haven't run this test, recommend you do so, if you want to be sure you'll be able to run off-grid when the PowerWalls are fully charged (such as when Storm Watch has been triggered).

Our system has been running for about a month. I fully charged the PowerWalls yesterday (99%) and while the sun was out, took the system off grid by throwing the breaker inside the Tesla Backup Gateway panel.

The system correctly switched over to PowerWalls and shutdown the microinverters providing solar power (since there was nowhere for that power to go).

But, when I went inside, every UPS system had a warning alarm or had turned off (and refused to turn on). One of our air conditioners failed to start.

And when I restored grid power, I encountered several problems with getting the system back to normal, and draining down the PowerWalls to the reserve %.

Tesla confirmed the off-grid/full PW power frequency was too high (our microinverters should turn off at 60.5Hz). Our problem has been escalated to "tier 2" support, and should see them reconfigure our Gateway to use a frequency closer to 60Hz in the next few days.

If you haven't run this test and you want to have confidence the system will work correctly (when you need it), you should consider doing this test.

NOTE after running this test, I found that one of our UPS boxes refuses to come back on, and the breaker was thrown during test in the bedroom where we have exercise equipment. Hopefully (other than the UPS) we won't see any other equipment damaged by the high frequency power...

 

[jboy210]

Is there any way for them to handle the issue with frequency before being contacted? UPS systems are pretty common and we have 5 or 6.

 

[bmah]

Powerwall 2 + UPS Connundrum - and solution

Bruce.

 

[jjrandorin]

If you haven't run this test, recommend you do so, if you want to be sure you'll be able to run off-grid when the PowerWalls are fully charged (such as when Storm Watch has been triggered).

Our system has been running for about a month. I fully charged the PowerWalls yesterday (99%) and while the sun was out, took the system off grid by throwing the breaker inside the Tesla Backup Gateway panel.

The system correctly switched over to PowerWalls and shutdown the microinverters providing solar power (since there was nowhere for that power to go).

But, when I went inside, every UPS system had a warning alarm or had turned off (and refused to turn on). One of our air conditioners failed to start.

And when I restored grid power, I encountered several problems with getting the system back to normal, and draining down the PowerWalls to the reserve %.

Tesla confirmed the off-grid/full PW power frequency was too high (our microinverters should turn off at 60.5Hz). Our problem has been escalated to "tier 2" support, and should see them reconfigure our Gateway to use a frequency closer to 60Hz in the next few days.

If you haven't run this test and you want to have confidence the system will work correctly (when you need it), you should consider doing this test.

NOTE after running this test, I found that one of our UPS boxes refuses to come back on, and the breaker was thrown during test in the bedroom where we have exercise equipment. Hopefully (other than the UPS) we won't see any other equipment damaged by the high frequency power...

Thanks for the reminder. I havent had a chance to do this specific test yet because I am on self powered mode and my powerwalls do not get to 100% till around 4pm in the evening, and by the time I come home from work they have drained some, so I cant run it.

However, right NOW my system is in stormwatch mode due to high winds in my area. This is a reminder that I need to test it. I have "ABB" brand inverters, installed by Solar City in 2015. I have been trying to find what the documentation says is the proper frequency for them for this issue and have been having some challenges doing so.

Thanks for the reminder!

 

[jboy210]

Powerwall 2 + UPS Connundrum - and solution

Bruce.

Thanks. Will call when they get the PWs installed. Glad I won't have to spend $1,500 on replacement UPS units.

 

[jrweiss98020]

The off-grid test was the first thing I did - even before I got the final certification from the utility. I closed the Solar and Powerwall breakers. As soon as I saw power coming to both the house and the Powerwalls, I opened the grid tie breaker. I ran the house for 2 days like that before the Utility showed up to give their blessing. The only disconcerting event was when I closed the grid tie breaker, it took over 5 minutes for the Gateway to reconnect to the grid. Tech Support at A&R Solar told me that was normal, to prevent multiple reconnections during storms, brownouts, etc.

FWIW, I still have UPSes on all my computers, but they do not trip when the system cuts over. I do notice flickering in some LED lights, which appear to be even more sensitive than the computers to voltage fluctuations.

 

[gpez]

That Powerwall 2 + UPS Connundrum - and solution thread is great but super long and there is a few bits of misunderstanding/misinformation so it can be tricky to read

If you haven't run this test, recommend you do so, if you want to be sure you'll be able to run off-grid when the PowerWalls are fully charged (such as when Storm Watch has been triggered).

Our system has been running for about a month. I fully charged the PowerWalls yesterday (99%) and while the sun was out, took the system off grid by throwing the breaker inside the Tesla Backup Gateway panel.

The system correctly switched over to PowerWalls and shutdown the microinverters providing solar power (since there was nowhere for that power to go).

But, when I went inside, every UPS system had a warning alarm or had turned off (and refused to turn on). One of our air conditioners failed to start.

And when I restored grid power, I encountered several problems with getting the system back to normal, and draining down the PowerWalls to the reserve %.

Tesla confirmed the off-grid/full PW power frequency was too high (our microinverters should turn off at 60.5Hz). Our problem has been escalated to "tier 2" support, and should see them reconfigure our Gateway to use a frequency closer to 60Hz in the next few days.

If you haven't run this test and you want to have confidence the system will work correctly (when you need it), you should consider doing this test.

NOTE after running this test, I found that one of our UPS boxes refuses to come back on, and the breaker was thrown during test in the bedroom where we have exercise equipment. Hopefully (other than the UPS) we won't see any other equipment damaged by the high frequency power...

I found that my Eaton AFCI/GFCI breakers tripped when the Powerwall kicked in and after Tesla lowered the max frequency of my system the breaker issues all went away. Hopefully your experience is similar.

 

[gpez]

The off-grid test was the first thing I did - even before I got the final certification from the utility. I closed the Solar and Powerwall breakers. As soon as I saw power coming to both the house and the Powerwalls, I opened the grid tie breaker. I ran the house for 2 days like that before the Utility showed up to give their blessing. The only disconcerting event was when I closed the grid tie breaker, it took over 5 minutes for the Gateway to reconnect to the grid. Tech Support at A&R Solar told me that was normal, to prevent multiple reconnections during storms, brownouts, etc.

Hi neighbor! I was really impressed with A&R but they didn't have the Powerwall delivery timeline I was looking for and ultimately went with a different provider. I believe my (down the street) neighbor went with A&R and has been really happy.

Their tech support agent is correct in that the Powerwall will wait 5 minutes to ensure stability during reconnect however it is a configurable parameter. Now, will Tesla let you configure it? Don't know and haven't tried

The Powerwall is IEEE 1547 compliant (https://www.tesla.com/sites/default.../Powerwall 2_AC_Datasheet_en_northamerica.pdf), from https://www.nerc.com/comm/OC_Reliab...rter-Based_Resource_Performance_Guideline.pdf (page 41):
Intentional Time Delay: Some inverters may use an intentional, programmed time delay to return to service following a trip. IEEE Std. 1547-2018 Requirement 4.10.3 requires an adjustable range of the minimum intentional delay between 0–600 seconds, with a default of 300 seconds (five minutes).

FWIW, I still have UPSes on all my computers, but they do not trip when the system cuts over. I do notice flickering in some LED lights, which appear to be even more sensitive than the computers to voltage fluctuations.

I have the same experience - most times my UPSs don't complain but a light flicker happens. Do you have a line interactive or online UPS? Mine are all line interactive (fairly inexpensive CyberPowers) and I hear them click sometimes but not much more.

 

[miimura]

When the Powerwalls are operating off-grid, they also take some time to resynchronize their waveform to the grid before closing the Gateway switch and returning to full grid-interactive operation. However, I've never seen mine take more than one minute to resync.

 

[charlesj]

...
I found that my Eaton AFCI/GFCI breakers tripped when the Powerwall kicked in and after Tesla lowered the max frequency of my system the breaker issues all went away. Hopefully your experience is similar.

Do you know what frequency it was lowered to so I can ask the install crew to do that if they are able.

ps. just got off the phone to Enphase. My inverter frequency range is 57Hz to 61Hz. Hopefully the PW can be set to be withing that range.

 

[charlesj]

Can I assume this test can be performed with less than fully charged PW?
Also, did you see the micro shut down and not delivering solar energy on the Tesla app or some other way?

 

[jboy210]

The off-grid test was the first thing I did - even before I got the final certification from the utility. I closed the Solar and Powerwall breakers. As soon as I saw power coming to both the house and the Powerwalls, I opened the grid tie breaker. I ran the house for 2 days like that before the Utility showed up to give their blessing. The only disconcerting event was when I closed the grid tie breaker, it took over 5 minutes for the Gateway to reconnect to the grid. Tech Support at A&R Solar told me that was normal, to prevent multiple reconnections during storms, brownouts, etc.

FWIW, I still have UPSes on all my computers, but they do not trip when the system cuts over. I do notice flickering in some LED lights, which appear to be even more sensitive than the computers to voltage fluctuations.

Does the Powerwall app run before you get the power company's blessing?

 

[miimura]

Can I assume this test can be performed with less than fully charged PW?
Also, did you see the micro shut down and not delivering solar energy on the Tesla app or some other way?

The test should have different results if the PWs are not full. However, that is another useful case to test. The solar should stop generating for 5 minutes regardless of PW SOC. If it is full, the solar should stay off longer.

If you leave the app on the Power Flow screen with the 4 circles, you should see what is happening in near real time.

 

[miimura]

Does the Powerwall app run before you get the power company's blessing?

The app will start working after your system is full commissioned. In my case, in 2018, I did not get PTO for nearly 7 weeks after PW install, but the app was working that whole time.

 

[jboy210]

The app will start working after your system is full commissioned. In my case, in 2018, I did not get PTO for nearly 7 weeks after PW install, but the app was working that whole time.

Can you define "full commissioned" versus PTO. Somehow I thought they were the same thing.

 

[jrweiss98020]

Hi neighbor! I was really impressed with A&R but they didn't have the Powerwall delivery timeline I was looking for and ultimately went with a different provider. I believe my (down the street) neighbor went with A&R and has been really happy.
. . .

I have the same experience - most times my UPSs don't complain but a light flicker happens. Do you have a line interactive or online UPS? Mine are all line interactive (fairly inexpensive CyberPowers) and I hear them click sometimes but not much more.

I have the Cyberpower AVR UPSes, which are line-interactive. The only surge that regularly trips them is when my laser printer powers up. Apparently the heater coming on drops the voltage sufficiently for a split second to trip the 2 UPSes near the printer.

My system was fully functional, including phone app and PC interface, immediately after commissioning and before PTO, except that the old electric meter did not like power being sent to the grid. It actually registered as if I was taking power from the grid when connected to the solar system (turns out is was an anti-tamper "feature" of the meter)! As long as the breaker between the meter and the house was open, the solar and powerwalls worked fine to power the house.

"Fully commissioned" means the installer has it all hooked up physically, and all devices are registered with the network and manufacturers (Tesla for Powerwalls, Enphase for micro-inverters). Interfaces and functionality are tested. Off-grid use is possible.

PTO means the utility company inspects the installation and puts in the appropriate net meters to register production and use. Then you can legally connect the solar system to the grid.

 

[gpez]

Do you know what frequency it was lowered to so I can ask the install crew to do that if they are able.

ps. just got off the phone to Enphase. My inverter frequency range is 57Hz to 61Hz. Hopefully the PW can be set to be withing that range.

I have Enphase IQ6 inverters and my Powerwall max frequency is set to 62hz. I've applied the "PREPA off grid frequency-watt 83/hz" profile to my Enphase system which disconnects at 62hz but ramps down production between 60.2hz and 61.4hz at the rate of 83%/hz. This helps prevent the on/off see-saw effect you may experience with high PV production and a grid outage.

 

[Dan123]

Do you know what frequency it was lowered to so I can ask the install crew to do that if they are able.

ps. just got off the phone to Enphase. My inverter frequency range is 57Hz to 61Hz. Hopefully the PW can be set to be withing that range.

If you have access to Enlighten Manager, you can see what your grid profile looks like. Mine is like this. So the Enphase microinverters will ramp down between 60.2 and 61.8, and turn off at 61.8. The Tesla Powerwall people need to know these profile settings. I think they set the frequency to 62 or 62.5. So when the grid goes out, and the PW is charged, it changes the frequency to 62 and your Enphase inverters will shut down



PREPA off-grid frequency-watt 83 /Hz
Parameter Name Value
VOLTAGE LIMITS
Over voltage disconnect Time Magnitude
Limit (fast) 160 ms 144.00 V
Limit (slow) 1,000 ms 141.00 V
Average over voltage 144.00 V
Under voltage disconnect Time Magnitude
Limit (fast) 160 ms 54.00 V
Limit (slow) 2,000 ms 102.00 V
Reconnect voltage Magnitude
High 139.70 V
Low 103.00 V
FREQUENCY LIMITS
Over frequency disconnect Time Magnitude
Limit (fast) 160 ms 65.00 Hz
Limit (slow) 1,000 ms 61.80 Hz
Under frequency disconnect Time Magnitude
Limit 160 ms 50.00 Hz
Reconnect frequency Magnitude
High 61.00 Hz
Low 59.30 Hz
RECONNECT
Start / Reconnect time 5 s
Anti-islanding reconnect time (long) 5 s
OVER FREQUENCY POWER LIMIT
Over frequency power limit enabled Yes
Start frequency 60.20 Hz
Start delay 0.0 ms
Ramp down rate 83.00 %/Hz
Hysteresis No
Ramp up frequency (max) 60.10 Hz
Ramp up frequency (min) 56.00 Hz
Ramp up delay time 15.0 s
Ramp up rate 4.000 %/s
Ramp up rate (low) 2.000 %/s

 

[charlesj]

If you have access to Enlighten Manager, you can see what your grid profile looks like. Mine is like this. So the Enphase microinverters will ramp down between 60.2 and 61.8, and turn off at 61.8. The Tesla Powerwall people need to know these profile settings. I think they set the frequency to 62 or 62.5. So when the grid goes out, and the PW is charged, it changes the frequency to 62 and your Enphase inverters will shut down



PREPA off-grid frequency-watt 83 /Hz
...

Thanks. I don't think I have this Manager.
I am just wondering why the panels would get shut off with grid down, PW fully charged, the house has a demand, solar capable of production. Shouldn't solar be first to power the house to solar capacity and PW with excess needs?

 

[Dan123]

Thanks. I don't think I have this Manager.
I am just wondering why the panels would get shut off with grid down, PW fully charged, the house has a demand, solar capable of production. Shouldn't solar be first to power the house to solar capacity and PW with excess needs?

If the PWs are fully charged, and panels are producing power, then you will have a situation that there is no place for that power to go. Your house may be consuming some of that power now, but the demand may drop, and you will have too much power.

Therefore, solar panels have to be shut down, unless the batteries have some capacity to absorb a sudden spike in power.