Off-Grid Test with fully charged PowerWalls

[gpez]

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.

And the Powerwall is pretty conservative with determining at what point it has "some capacity" - anecdotally the state of charge needs to get substantially in the 90s before it brings the frequency back down to nominal range and allow the PV to kick back in. In my experiment (Utility outage simulation data dump) the SoC was 93% before the frequency returned to 60hz. This is why I set my Enlighten configuration to ramp down rather than just drop off!

 

[jjrandorin]

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

If you already have solar from Tesla and are just adding powerwalls, yes. If you are getting solar (or solar roof) + powerwalls, then likely not.

EDIT.. .sorry this was already answered a couple times up thread but I had not seen that when I clicked reply..

 

[charlesj]

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.

Thanks again. I do understand that power needs to go someplace. So then, If the house can use all the power the panels output, it continues to operate? And, if say that happened before full power output but then as power production increases, house cannot use it all, the PW sends high enough frequency to shut the panels down but then PW needs to supply the power to the house at a higher than normal frequency to keep the panels off line.
Then, possibly when the panels decrease production to level fully capable supplying the house, will the battery shut down unless power is needed for the house as production will keep getting less as the sun starting to go down?

Maybe the answer then would be to not have the PW fully charged so it can be charged with excess solar power? Some balancing act.

 

[charlesj]

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.

Looks like I will need to call Enphase after installation and see if they can set this for me.

 

[jjrandorin]

Thanks again. I do understand that power needs to go someplace. So then, If the house can use all the power the panels output, it continues to operate? And, if say that happened before full power output but then as power production increases, house cannot use it all, the PW sends high enough frequency to shut the panels down but then PW needs to supply the power to the house at a higher than normal frequency to keep the panels off line.
Then, possibly when the panels decrease production to level fully capable supplying the house, will the battery shut down unless power is needed for the house as production will keep getting less as the sun starting to go down?

Maybe the answer then would be to not have the PW fully charged so it can be charged with excess solar power? Some balancing act.

Power spikes up and down, so there has to be space in the powerwalls for the solar to go. It sends a signal to shut the solar down if the powerwall is full, then starts using the powerwall till it goes down to a level where it can accept solar. Reports are thats 90-93%. If your inverter supports a ramp down, then that can be done.

The solar will not power the house if the powerwall is full, it will be shut off.

 

[charlesj]

Thanks @jjrandorin
I'll have to keep my eye on it closer to summer when production is much more.

 

[bob_p]

After installation, I ran an off-grid test with the PowerWalls around 50% and sun - and everything worked as expected. This is a useful test to run to verify the system switches to off-grid, with the PowerWalls, microinverters, and house devices all work correctly.

The fully charged PowerWalls test is different, it forces the Tesla Backup Gateway into a different mode, to turn off the microinverters - which can cause the power frequency to be so high that devices like UPS, air conditioners, pumps, ... to fail.

If the high frequency the Gateway should set in this situation is dependent upon the specific microinverters being used, Tesla should add this setting to the installer interface, so the installers can configure this as part of installation, and not require calling Tesla to do the setting behind the scenes...

 

[miimura]

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

Fully commissioned means that the system is fully active in Tesla's system. I have heard that some solar-only customers can't get Tesla to commission the system until PTO, but Powerwall systems should or could be commissioned as soon as the installation is complete.

 

[Gray468]

Had two PW2s installed last Nov to my existing (6 years) solar system. The installer came back for the permit sign-off and while waiting I had the him pull the main to test (PWs were at at least 98%). Everything in the house seemed fine except for the lights on our two ceiling fans. The lights were flickering on/off. He called and Tesla made a real time adjustment. Everything went off momentarily and when back on, voila, all was well. Yes, they adjusted the frequency to cut out the solar panels.

Not wanting to waste solar rays, I typically draw the power down to 60-70% (depending on forecast) before a planned outage so the excess power goes into the batteries. Not sure if this is an efficient way to manage, the system, but it feels better....

 

[jjrandorin]

Had two PW2s installed last Nov to my existing (6 years) solar system. The installer came back for the permit sign-off and while waiting I had the him pull the main to test (PWs were at at least 98%). Everything in the house seemed fine except for the lights on our two ceiling fans. The lights were flickering on/off. He called and Tesla made a real time adjustment. Everything went off momentarily and when back on, voila, all was well. Yes, they adjusted the frequency to cut out the solar panels.

Not wanting to waste solar rays, I typically draw the power down to 60-70% (depending on forecast) before a planned outage so the excess power goes into the batteries. Not sure if this is an efficient way to manage, the system, but it feels better....

This is one reason i am having a 14-50 put on the backup side, even though I have a Tesla HPWC already that is on the grid side. IF I was in an outage situation, AND the house was producing enough power to fill the batteries and want to shut off the solar, I would rather put a little of that into my car. The car is the biggest load I have in my house, and its fully discretionary.

I didnt want the HPWC on the backup side in case there was a power outage while I slept or something... didnt want the car draining the powerwalls. This was the alternative that I came up with (putting a 14-50 in that I hope to almost never use, lol).

 

[CounsellorTroy]

I didn't need to run the test, the power company forced it on me last week. After installing the Powerwall2, we started having problems with our heat pumps. After much finger-pointing, it was finally determined that the Grid supply was too high voltage (ranging from 244 to 255 volts) although supposedly within tolerances. (Tesla indicating that is was a coincidence of the timing.) There is a single transformer (single-phase) that powers the 3 houses in my immediate neighborhood and I along with one of my neighbors have solar. The power company swapped the transformer out and did some changes down at the sub-station (they would not say what), and all is working better now. Even though the power company would not admit it, my guess is that they found something aberrant which is why they went through the exercise of swapping out the 30+-year-old transformer and other linework feeding the area. Obviously, for them to do this, they had to shut the power off for more than several hours. During that time, the battery worked flawlessly, and I had no problem with any of my electronics. All of the sensitive electronics (e.g.: computers, networking equipment, computer peripherals, VOIP phones, etc.) are all on UPS's. When we have sufficient solar to keep the battery charged, we run off the battery during the peak electrical times of the day, and then the battery is charged in the morning. We did lose power for about 3 hours in December, and the system seemed to work flawlessly. So far, I have been very happy with the Powerwall2 and how it manages the electrical delivery to the house. Hopefully they will figure out what is going on with the heat pumps and get them fully operational again.

 

[Doom Man]

I have a new PV system with PW2. In lieu of me decoding the 13-page UPS thread linked here, can someone recommend a UPS that will be PW2-compatible even if the gateway default puts out 65hz to shut down the inverters? I don't have a UPS yet, but I did notice that my router and/or cable modem restart at the start of a power outage. All I need is a bare-bones UPS to bridge the flicker-gap between utility power and PW power, and I figure it's easier to buy a UPS that doesn't require calling Tesla to request special settings.

Alternatively, do any power conditioners have capacitors that fill the gap on flickers? With PW's I don't really need a UPS apart from that instant where I switch to battery. Thanks!

 

[MorrisonHiker]

I have a new PV system with PW2. In lieu of me decoding the 13-page UPS thread linked here, can someone recommend a UPS that will be PW2-compatible even if the gateway default puts out 65hz to shut down the inverters? I don't have a UPS yet, but I did notice that my router and/or cable modem restart at the start of a power outage. All I need is a bare-bones UPS to bridge the flicker-gap between utility power and PW power, and I figure it's easier to buy a UPS that doesn't require calling Tesla to request special settings.

Alternatively, do any power conditioners have capacitors that fill the gap on flickers? With PW's I don't really need a UPS apart from that instant where I switch to battery. Thanks!

I think a quick recap of that thread is that the EATON UPS units don't complain about higher frequencies. Because of this, they wouldn't need to run if the Powerwalls are putting out a high frequency. Other brands run when the frequency is high, causing them to be drained.

 

[woferry]

Alternatively, do any power conditioners have capacitors that fill the gap on flickers? With PW's I don't really need a UPS apart from that instant where I switch to battery. Thanks!

No, AC power simply doesn't work that way. Something has to maintain an AC waveform, caps can't do that.

 

[Gray468]

This is one reason i am having a 14-50 put on the backup side, even though I have a Tesla HPWC already that is on the grid side. IF I was in an outage situation, AND the house was producing enough power to fill the batteries and want to shut off the solar, I would rather put a little of that into my car. The car is the biggest load I have in my house, and its fully discretionary.

I didnt want the HPWC on the backup side in case there was a power outage while I slept or something... didnt want the car draining the powerwalls. This was the alternative that I came up with (putting a 14-50 in that I hope to almost never use, lol).

I do too and when the power went out, I tested it. Middle of the day, bright sunshine, Plug in my car and powerwall reported negligible solar available. Almost like powerwall couldn’t deal so blocked the solar. You can see that all the power was coming from the powerwall initially. And no, the big dip in solar was not due to the sun going away. At least I don’t think so.

 

[jjrandorin]

I have a new PV system with PW2. In lieu of me decoding the 13-page UPS thread linked here, can someone recommend a UPS that will be PW2-compatible even if the gateway default puts out 65hz to shut down the inverters? I don't have a UPS yet, but I did notice that my router and/or cable modem restart at the start of a power outage. All I need is a bare-bones UPS to bridge the flicker-gap between utility power and PW power, and I figure it's easier to buy a UPS that doesn't require calling Tesla to request special settings.

Alternatively, do any power conditioners have capacitors that fill the gap on flickers? With PW's I don't really need a UPS apart from that instant where I switch to battery. Thanks!

The super quick TL ; DR version is, as @MorrisonHiker mentioned, the EATON brand UPSs work for this purpose. I bought one based on recommendations here.

One like this https://www.amazon.com/Eaton-Electr...?keywords=eaton+ups+350&qid=1580510272&sr=8-8

Should be fine for routers switches etc. They make a 350-550 and 750 in that form factor. Since I am going to plug my router, switch and a 8HD NAS box into it, I got the 550 model.

I think these allow up to 70Hz or something but you would want to check Eaton's website to be sure.

 

[power.saver]

The problem in getting a UPS that runs at that high a frequency when the PW outputs it for a long time due to high solar production and low house load, is that the UPS can run down and then shut off whatever it is protecting. A UPS should be used as a short-term bridge when the PW switches to off-grid operation, not for maintaining power during an extended outage. The proper fix is to have the PW frequency lowered to a value that shuts off excess solar production and does not keep critical loads running on the UPS.

 

[charlesj]

I didn't need to run the test, the power company forced it on me last week. After installing the Powerwall2, we started having problems with our heat pumps. After much finger-pointing, it was finally determined that the Grid supply was too high voltage (ranging from 244 to 255 volts) although supposedly within tolerances. (Tesla indicating that is was a coincidence of the timing.) There is a single transformer (single-phase) that powers the 3 houses in my immediate neighborhood and I along with one of my neighbors have solar. The power company swapped the transformer out and did some changes down at the sub-station (they would not say what), and all is working better now. Even though the power company would not admit it, my guess is that they found something aberrant which is why they went through the exercise of swapping out the 30+-year-old transformer and other linework feeding the area. Obviously, for them to do this, they had to shut the power off for more than several hours. During that time, the battery worked flawlessly, and I had no problem with any of my electronics. All of the sensitive electronics (e.g.: computers, networking equipment, computer peripherals, VOIP phones, etc.) are all on UPS's. When we have sufficient solar to keep the battery charged, we run off the battery during the peak electrical times of the day, and then the battery is charged in the morning. We did lose power for about 3 hours in December, and the system seemed to work flawlessly. So far, I have been very happy with the Powerwall2 and how it manages the electrical delivery to the house. Hopefully they will figure out what is going on with the heat pumps and get them fully operational again.

Did they check line frequency by chance or just voltage?

 

[gpez]

I have a new PV system with PW2. In lieu of me decoding the 13-page UPS thread linked here, can someone recommend a UPS that will be PW2-compatible even if the gateway default puts out 65hz to shut down the inverters? I don't have a UPS yet, but I did notice that my router and/or cable modem restart at the start of a power outage. All I need is a bare-bones UPS to bridge the flicker-gap between utility power and PW power, and I figure it's easier to buy a UPS that doesn't require calling Tesla to request special settings.

Alternatively, do any power conditioners have capacitors that fill the gap on flickers? With PW's I don't really need a UPS apart from that instant where I switch to battery. Thanks!

The short answer is: it's just as easy and much, much better just to call Tesla and get your settings fixed.

Too high frequency causes all sorts of other issues - clocks don't run right, inductive cooktops will not function, lights will flicker, anything with a motor will run incorrectly (and burn up quicker). Your electrical devices are designed to run at 60hz, every hz higher and lower is worse and worse for them.

Just call Tesla and get your settings changed.

 

[jjrandorin]

The short answer is: it's just as easy and much, much better just to call Tesla and get your settings fixed.

Too high frequency causes all sorts of other issues - clocks don't run right, inductive cooktops will not function, lights will flicker, anything with a motor will run incorrectly (and burn up quicker). Your electrical devices are designed to run at 60hz, every hz higher and lower is worse and worse for them.

Just call Tesla and get your settings changed.

The issue I am having is trying to figure out what frequency my inverter(s) need. I have (2) ABB brand inverters, not the popular solar edge that many have. I have managed to find the manual for my inverter online, but not quite sure where to look in there to ensure I am relaying the correct information to Tesla to get this corrected.

Would any of you very smart people be able to look at the manual if I uploaded it to tell me what frequency these need, or alternatively tell me what I should be looking for in the manual?

 

[power.saver]

Sure, we'll give it a try if you can post a PDF.