Off-Grid Test with fully charged PowerWalls

[jjrandorin]

I checked on the spec sheet for my UPSes (CyberPower) and it says 60 Hz +/- 3 Hz, i.e 57 to 63 Hz.

BTW, how do you know when Tesla completed this change and you could run you test. Did they send you a message?

In my case, yes they sent me an email stating they had completed the change. I asked them if they would contact me when I reported the issue and asked for resolution on the feb 20th, and the tier 1 rep told me "they will let me know when they have resolved it for you, and I will reach out and let you know".

In my case, it happened exactly like they said it would.

 

[aesculus]

I got a call from someone in Executive Resolutions noting that I had made many requests via email and phone to have my PTO issue resolved. They said they were working on it. They also noted I had reported an issue with the frequency (the one the 1st line refused to deal with because I did not have a PTO). The caller just wanted to verify I was having issues with some devices not liking the 65 hz setting. She then transferred me to Tech Support who validated my concerns and opened a ticket for Level 2 to make the adjustments based on my inverters.

So some progress. We'll see what next week brings on both fronts.

 

[JPP]

So after multiple phone calls and a 'live' grid disconnect test over the phone with Tesla Powerwall Support a week or so ago, finally, I got a return call Thursday that engineering had pushed out the update to set my cutoff frequency to 62.5 Hz (and also updated firmware to 1.44.4). So yesterday after a sunny morning, and Powerwalls at 100%, I pulled the main disconnect. Momentary power interruption as expected, but appliance clocks all OK. My frequency sensitive UPS were fine. CyberPower read 62.6 Hz and on line. I did uncover a bad/failing battery on a 5 year old small APC UPS protecting some networking equipment and Apple TV and Airport devices. All good.

 

[dwolf725]

I finally ran an off-grid test (with 100% charge) for my Powerwalls that were installed back in late Jan. Thanks to everyone on this forum, I also had my Powerwalls configured to 65hz and both a Cyberpower and APC UPS both didn't like it. The other thing I noticed was that our microwave didn't like it either and wasn't powering on, not even the display clock or any buttons. Most other appliances I checked were fine.

I called the Tesla phone # someone else posted and the guy seemed to know exactly what I was talking about. He took down my info and said he'd forward the ticket to tier 2 to make the change and I should hear back in a few days. My Sunpower micro inverters are UL 1741 compatible and should shutoff at 60.5 hz or something like that. The whole call took like 5 minutes. I'll see what I hear back and what happens next time I run a test. Thanks again to everyone on this thread and the long UPS thread.

 

[bob_p]

Tesla really needs to add this to the installer interface on the TEG - since 65Hz is probably going to be much higher than needed to shut down the solar power, and many devices aren't rated to run above 63Hz.

A fully charged/off-grid test should also be part of the verification process by the installers to ensure everything in the system works when switching to off-grid operation and that the solar panel power is shut off until the PowerWalls have room to hold more power.

These shouldn't be tasks left up to the consumers...

 

[bmah]

Tesla really needs to add this to the installer interface on the TEG - since 65Hz is probably going to be much higher than needed to shut down the solar power, and many devices aren't rated to run above 63Hz.

A fully charged/off-grid test should also be part of the verification process by the installers to ensure everything in the system works when switching to off-grid operation and that the solar panel power is shut off until the PowerWalls have room to hold more power.

These shouldn't be tasks left up to the consumers...

I agree with you in principle, although this is a little complicated by the fact that the Powerwalls need to be fully charged to do this test, and that might preclude being able to do that while the installers are on-site.

Trying to think of a reliable, safe way this off grid test could be automated by the Powerwall gateway. I’m not sure there is one.

At the very least, informing the end user that there’s an issue of tuning the solar curtailment and that they should follow a set of steps to do that, would be useful. Maybe that coupled with a slightly less aggressive default curtailment frequency?

Bruce.

 

[charlesj]

While I can understand that PW needs to be at 100% to do the test we seem to know that the default frequency is at 65 Hz. That 65 was set somehow beforehand without being at 100% So, why not set it knowing the solar inverter's cut off frequency 1 Hz above that without testing in the first place?

 

[bemyax]

My microinverters are supposed to ride through 61 Hz for 300 seconds. And 62 Hz for 15 milliseconds. So here's my suggestion that's most likely easier said than done:

At battery state of charge 96%, raise the system frequency to 61 Hz. At 97%, raise it to 62%. 98% - 63%. 99% - 64%. 100% - 65 Hz.
After making sure it's a solid update, push it where it's requested, or to everyone. I think that would eliminate much gnashing of teeth by the users and the technical support folks.

David

 

[power.saver]

At battery state of charge 96%, raise the system frequency to 61 Hz. At 97%, raise it to 62%. 98% - 63%. 99% - 64%. 100% - 65 Hz.
After making sure it's a solid update, push it where it's requested, or to everyone. I think that would eliminate much gnashing of teeth by the users and the technical support folks.

No, because if your battery is at 100% when the grid fails, you'd be outputting 65Hz right away, exactly what I don't need or want to happen.
.

 

[bemyax]

Yuh. I thought of that a little late. I have a small system from two months ago. Never been above 90 percent.

David

 

[bob_p]

I agree with you in principle, although this is a little complicated by the fact that the Powerwalls need to be fully charged to do this test, and that might preclude being able to do that while the installers are on-site.

Trying to think of a reliable, safe way this off grid test could be automated by the Powerwall gateway. I’m not sure there is one.

At the very least, informing the end user that there’s an issue of tuning the solar curtailment and that they should follow a set of steps to do that, would be useful. Maybe that coupled with a slightly less aggressive default curtailment frequency?

Bruce.

Actually there is a way for the TEG to automate this off-grid test. Tesla could add a "test mode" that would put the system into "backup mode" to fully charge the PowerWalls, and once that is achieved while there is power coming from the solar panels, turn off the grid power and then have the TEG verify the solar panels have stopped producing energy - and then switch the system to go back to the grid. This would verify the system properly handled off-grid/on-grid and solar panel power cutoff.

Tesla could also add a "calibration mode" that would take the system off-grid, set the powerline frequency to 65Hz, and then start stepping that down by .5 Hz until the solar panels begin generating power again. And once that point is determined, set the solar cutoff frequency.

 

[jjrandorin]

Actually there is a way for the TEG to automate this off-grid test. Tesla could add a "test mode" that would put the system into "backup mode" to fully charge the PowerWalls, and once that is achieved while there is power coming from the solar panels, turn off the grid power and then have the TEG verify the solar panels have stopped producing energy - and then switch the system to go back to the grid. This would verify the system properly handled off-grid/on-grid and solar panel power cutoff.

Tesla could also add a "calibration mode" that would take the system off-grid, set the powerline frequency to 65Hz, and then start stepping that down by .5 Hz until the solar panels begin generating power again. And once that point is determined, set the solar cutoff frequency.

I like the second part of your suggestion, because it theoretically could be accomplished by tier 1 if the firmware was setup this way, with an end user on the phone. I dont think its realistic (or fair) to expect an installer (tesla or third party) to be on hand while the powerwalls charge up to 100%. Your second suggestion doesnt require that, however and I like it.

I think that could absolutely be (once programmed in that manner by tesla) be an installer calibration. The only thing I would add is, from my own experience it appears tesla sets the frequency a bit higher than "necessary" to ensure cutoff. My system is set to 62 hz for example, and I believe the information I found with help here shows it is supposed to turn off at 61hz. Your calibration mode sounds great, in having the system step down from 65 hz till the solar panels shut off, and then set the frequency .5 to 1hz higher than that number, and then have the system repeat the test again.

Tesla could even set it up as a installer triggered calibration mode, and default it to 65hz like you said.. and if the system does not respond to turning off definitively at a lower frequency, it could stay at 65hz.

@bob_p I really like that second suggestion... in fact I bet that at some point, when there is enough people calling to get this changed, tesla will implement something similar. Too bad you cant feed that suggestion up chain to them somewhere, as it seems elegantly simple and I bet they could automate it fairly easily.

 

[cwied]

I've heard that solar inverters generally don't turn back on for 5 minutes, so such a test might take a long time. It also may not be a safe assumption that turning back on happens at the same frequency as turning off. I'm sure there are more things Tesla could do, but I would be worried that there isn't a simple solution that works without knowing what solar inverter you're dealing with. This wouldn't necessarily be in the installers' area of expertise.

 

[miimura]

The "calibration mode" does not have to have the batteries at 100%. It just has to disconnect from the grid and vary the frequency and observe the solar output. It should not start the test at 65Hz, it should start at 60.0Hz and slowly increment it up to see if the solar inverters have ride-through or proportional curtailment. In addition, pulses of higher frequency along with frequency ramps would be instructive. By starting at the lower frequency, you don't have to run the test for so long waiting for the 5 minute time-outs on the solar inverters.

 

[aesculus]

It should not start the test at 65Hz, it should start at 60.0Hz and slowly increment it up to see if the solar inverters have ride-through or proportional curtailment. In addition, pulses of higher frequency along with frequency ramps would be instructive.

What happens if the grid goes out during periods of non solar production in this scenario (like evening or when it's cloudy)?

 

[miimura]

What happens if the grid goes out during periods of non solar production in this scenario (like evening or when it's cloudy)?

You obviously should not run the test in the evening or on a cloudy day.

 

[bob_p]

The 5 minute delay appears to be a requirement for connecting to grid power.

When operating off grid and the grid comes back online, the TEG will wait for 5 minutes before shifting back to grid power.

The same appears to be true for the solar panels. Once the TEG sets the power frequency to turn off the solar panels, the TEG will wait for 5 minutes before adjusting the power frequency back to 60Hz to turn the solar panels back on.

For testing purposes, another option Tesla should add is the ability to turn off the grid power from the Tesla app or TEG web interface, rather than having to throw the physical switch inside the TEG panel.

Our alarm system recommends the system be tested periodically (something most people probably ignore) - and there's a test mode that can be used to test the system and make sure everything is working (sensors, phone/cellular, ...).

The TEG should support something like that so owners can verify everything is working correctly - especially in advance of when off-grid could be needed (prior to a hurricane).

 

[aesculus]

You obviously should not run the test in the evening or on a cloudy day.

OK. I sort of miss understood your statement. Rather than a one time, initial test, I was thinking you wanted to run this test every time the grid disconnected. Sorry for the confusion.

 

[charlesj]

What happens if the grid goes out during periods of non solar production in this scenario (like evening or when it's cloudy)?

Cloudy days may still produce some solar generation, not much depending on cloud coverage but some at least.