powerwall installation checklist? (existing solar)

[astrorob]

has anyone put together a good checklist for tesla energy PW2 installations (with existing solar)?

i have an install scheduled in 3 weeks. i expect that they are going to test everything that needs to be tested, however, i know that once these guys leave my property i'm probably never going to see them again, or at least for a few months anyway. so i thought it would be prudent to compile a list of things that i should make sure they do before they disappear.

since i have a subpanel inside the house, i'm thinking of stressing to them that they should do nothing to reduce the capacity of that sub-panel (for instance, use smaller breakers from the main panel to the sub-panel.)

i also want to ask about the "cutoff frequency" - i understand that some home UPSs have problems with the 66Hz "safe" default cutoff frequency. although it does sound like this can be reconfigured after the fact. anyone know how low of a frequency > 60Hz an SMA-5000 will cut off?

anything else anyone can think of that are important to ask/make sure of while the installers are around? anything you wish you had asked or had taken care of on the day of install? anything that was a hassle to get fixed after the fact?

thanks

 

[gnumeric]

• Make sure the “Power Flow” screen in the app is correct. I toggled on/off big things like A/C, oven, dryer to verify. Incorrectly installed CT clamps are not uncommon.

• Simulate an outage and verify the powerwalls are working as expected. Wait a few minutes to make sure your solar turns back on during the outage. Your solar should be able to power your house + charge your powerwalls during the outage. Hopefully they finish the install while there’s still sunlight!

In my experience, Tesla Energy has always been responsive and quick to come back to address any issues. I’ve always been able to reach someone quickly on the phone when I call the energy support number.

 

[power.saver]

i also want to ask about the "cutoff frequency" - i understand that some home UPSs have problems with the 66Hz "safe" default cutoff frequency. although it does sound like this can be reconfigured after the fact. anyone know how low of a frequency > 60Hz an SMA-5000 will cut off?

The SMA-5000 will cut off at 60.5Hz. I have one, and my system is configured to limit the max frequency to 61Hz.

 

[astrorob]

thanks @gnumeric - great tip about the current clamps. i hope the installers themselves will test the grid down condition but i'll try to be present.

@power.saver i'll ask them to configure for 61Hz then. strangely the other day, the morning after a power failure, the inverter could not sync to the grid with the first sunlight and spent most of the day not generating anything. that's either a testament to the 60.5Hz threshold, or my inverter is starting to fail. not once in 4 years have i seen that problem.

 

[jjrandorin]

has anyone put together a good checklist for tesla energy PW2 installations (with existing solar)?

i have an install scheduled in 3 weeks. i expect that they are going to test everything that needs to be tested, however, i know that once these guys leave my property i'm probably never going to see them again, or at least for a few months anyway. so i thought it would be prudent to compile a list of things that i should make sure they do before they disappear.

since i have a subpanel inside the house, i'm thinking of stressing to them that they should do nothing to reduce the capacity of that sub-panel (for instance, use smaller breakers from the main panel to the sub-panel.)

i also want to ask about the "cutoff frequency" - i understand that some home UPSs have problems with the 66Hz "safe" default cutoff frequency. although it does sound like this can be reconfigured after the fact. anyone know how low of a frequency > 60Hz an SMA-5000 will cut off?

anything else anyone can think of that are important to ask/make sure of while the installers are around? anything you wish you had asked or had taken care of on the day of install? anything that was a hassle to get fixed after the fact?

thanks

If I were you, If tesla itself is installing your powerwalls, I would contact the scheduling department and ask them if they can email you a copy of the install schematic. I am not an electrician, so I dont know exactly why they did it this way, but in my case, I had no sub panels at all, just 200 amp service coming into my home.

I have 2 powerwalls and wanted whole home backup, with the exception of the one circuit that has my tesla HPWC, which is a 60 amp circuit. They took all my breakers but that one, and put them into another load center (breaker box) and that breaker box has a 125amp breaker going to my main panel. Translation, they took my whole home, with the exception of the wall connector breaker, and put it on a load center that has 125amp service even though my main panel has 200 amp.

I asked them why, when they were installing, and they said " our engineering team does a load calculation, and you were not using anywhere near 200 amps, this is how we setup the backup load center". I have had no problems at all, and had seen on the schematic (and posted previously here somewhere), but your statement of "stressing to them they do nothing with my sub panel" makes me think that you should be looking at the install schematic because they will be doing whats on that document, from a electrical scheme prospective.

 

[cwied]

One note: the installers probably will have no idea how to do anything like the 61 Hz adjustment. As far as I can tell, that needs to be done from Tesla's Powerwall support group directly.

The main thing the installers need to get right is putting the CT's on the right wires. If they accidentally reverse them, that can be reconfigured from the setup pages (although obviously it would be best if they get them right).

The installers who set up my Powerwalls didn't register them right, so they didn't show up in the app until I self-registered: Powerwall Self Registration | Tesla

 

[gnumeric]

Translation, they took my whole home, with the exception of the wall connector breaker, and put it on a load center that has 125amp service even though my main panel has 200 amp.

Tesla did the same with my system, except I also backed up my HPWC breaker. I too was alarmed when they put the load center on a 125 amp breaker even though my main panel is 200 amp. I haven’t had any issues either.

 

[astrorob]

If I were you, If tesla itself is installing your powerwalls, I would contact the scheduling department and ask them if they can email you a copy of the install schematic. I am not an electrician, so I dont know exactly why they did it this way, but in my case, I had no sub panels at all, just 200 amp service coming into my home.

I have 2 powerwalls and wanted whole home backup, with the exception of the one circuit that has my tesla HPWC, which is a 60 amp circuit. They took all my breakers but that one, and put them into another load center (breaker box) and that breaker box has a 125amp breaker going to my main panel. Translation, they took my whole home, with the exception of the wall connector breaker, and put it on a load center that has 125amp service even though my main panel has 200 amp.

I asked them why, when they were installing, and they said " our engineering team does a load calculation, and you were not using anywhere near 200 amps, this is how we setup the backup load center". I have had no problems at all, and had seen on the schematic (and posted previously here somewhere), but your statement of "stressing to them they do nothing with my sub panel" makes me think that you should be looking at the install schematic because they will be doing whats on that document, from a electrical scheme prospective.

i actually did request that and i have it in my possession but it is apparently just what's barely needed to get the thing thru permitting. now that i look at it more carefully unfortunately they've only got a 100A breaker going to the backup gateway. since the backup gateway backs up more than just the sub-panel inside the house, it does look like they have under-sized this.

i currently have 200A available to the sub-panel and this installation would cut that in half. it's actually worse because there are a bunch of circuits on the main panel that i also need to have backed up.

there is apparently another error as my solar inverter seems to have two AC outputs - one is reported by the inverter as 240V and the other is reported as 120V. there are 2 breakers in my main panel for the inverter, however, they are only showing one breaker in their schematic.

this isn't really something that is properly determined after the fact. if the house was spec'd with 200A to the sub-panel then i want it to stay that way, even if it is overkill. you don't want to find out one night that you blew the 100A breaker because you turned the oven on and then someone turned on a hairdryer.

 

[jjrandorin]

i actually did request that and i have it in my possession but it is apparently just what's barely needed to get the thing thru permitting. now that i look at it more carefully unfortunately they've only got a 100A breaker going to the backup gateway. since the backup gateway backs up more than just the sub-panel inside the house, it does look like they have under-sized this.

i currently have 200A available to the sub-panel and this installation would cut that in half. it's actually worse because there are a bunch of circuits on the main panel that i also need to have backed up.

there is apparently another error as my solar inverter seems to have two AC outputs - one is reported by the inverter as 240V and the other is reported as 120V. there are 2 breakers in my main panel for the inverter, however, they are only showing one breaker in their schematic.

this isn't really something that is properly determined after the fact. if the house was spec'd with 200A to the sub-panel then i want it to stay that way, even if it is overkill. you don't want to find out one night that you blew the 100A breaker because you turned the oven on and then someone turned on a hairdryer.

I dont think they do the backup panel with the same breaker as the main one. shrug.. I just dont think they do that, and I believe there is likely some electrical reason I dont understand for it. In any case, what they will be doing at your house is whats on that permit, nothing more or less, from a schematic point of view. If you dont agree, you better cancel your appointment because they will not be changing the breakers / flows etc from that diagram.

Thats whats on the permit that they applied for, so unless they get another permit, thats what they are going to do. I couldnt even get them to add an outlet for me on the backup side that I had all the parts for. The installer said "I dont mind doing it for you, but its not on the plans so I dont want the inspector to fail you because of it.. .call me back after inspection and I can do it for you then".

So, if you dont like what you see, you need to halt everything in its tracks, and talk to someone to get them to re do it. With that being said, I believe they know what they are doing electrical wise, but its your house so you should get an explanation if you want one. Just dont expect them to change breakers listed on that document without re submitting.

 

[astrorob]

it's possible that the backup gateway can't handle more than 100A. but thats not an excuse for undersizing my existing electrical system. if they can't provide what i want, then i guess i have to pass.

this house is brand new, and has beefy electrical circuits and whether or not tesla thinks i need it, it's what i have and what i want to maintain on this house.

so i suppose cancel is what i'm going to have to do, unless they are willing/able to fix this. i'm OK with a new permit unless that runs afoul of the 20KWh rule that's been talked about. in that case i guess i'll just have to abandon my plan to have backup power. obviously i have most of the year to get it done before fire season hits again.

 

[astrorob]

according to the installation manual:


Electrical service connection: The Backup Gateway is service-entrance rated, and can be
located between the service entry and the main electrical panel. If overcurrent protection is
required, a circuit breaker can be added to the Backup Gateway at the service entry. The
Backup Gateway can accommodate two different circuit breaker sizes: 100/125A, and
150/200A.


so i guess if they wanted to they can put in bigger breakers. we'll see.

 

[power.saver]

The backup gateway is capable of 200A. The 20kWh rule is for battery size, not breaker size. Besides, the PW should be exempt from that due to its UL listing.

Anyway, you should get in touch with your advisor and explain your concerns and needs. There should be no reason why they can't accommodate your situation once they know what it is.

 

[jboy210]

it's possible that the backup gateway can't handle more than 100A. but thats not an excuse for undersizing my existing electrical system. if they can't provide what i want, then i guess i have to pass.

this house is brand new, and has beefy electrical circuits and whether or not tesla thinks i need it, it's what i have and what i want to maintain on this house.

so i suppose cancel is what i'm going to have to do, unless they are willing/able to fix this. i'm OK with a new permit unless that runs afoul of the 20KWh rule that's been talked about. in that case i guess i'll just have to abandon my plan to have backup power. obviously i have most of the year to get it done before fire season hits again.

Regarding the 20KW rule. My installation is moving along with the 2 PowerWalls side by side mounted inside my garage. The paperwork is into permitting now. Someone else pointed out that the Homeowner firecode and rules trump the 20K rule for homes. I sure hope that is correct.

FWIW, I am also in Alameda county, Pleasanton.

 

[astrorob]

The backup gateway is capable of 200A. The 20kWh rule is for battery size, not breaker size. Besides, the PW should be exempt from that due to its UL listing.

Anyway, you should get in touch with your advisor and explain your concerns and needs. There should be no reason why they can't accommodate your situation once they know what it is.

thanks. yes i know the 20kwh rule is for batteries; the concern was that you can not hang >1 powerwall on a, well, wall, due to this rule. i know there was someone here in San Francisco that had their installation fail inspection in late 2019 because of this, but hopefully that was an anomaly.

thanks for the confirmation that the gateway is good for 200A.

i've already sent my advisor an email but it usually takes days for her to get back to me.

Regarding the 20KW rule. My installation is moving along with the 2 PowerWalls side by side mounted inside my garage. The paperwork is into permitting now. Someone else pointed out that the Homeowner firecode and rules trump the 20K rule for homes. I sure hope that is correct.

FWIW, I am also in Alameda county, Pleasanton.

right - in my case the installation was supposed to take place late last year and the permit was pulled in 2019, so my situation is not a good test case for the 20kwh rule. anyway here's hoping that was all a false alarm.

 

[gpez]

has anyone put together a good checklist for tesla energy PW2 installations (with existing solar)?

i have an install scheduled in 3 weeks. i expect that they are going to test everything that needs to be tested, however, i know that once these guys leave my property i'm probably never going to see them again, or at least for a few months anyway. so i thought it would be prudent to compile a list of things that i should make sure they do before they disappear.

since i have a subpanel inside the house, i'm thinking of stressing to them that they should do nothing to reduce the capacity of that sub-panel (for instance, use smaller breakers from the main panel to the sub-panel.)

i also want to ask about the "cutoff frequency" - i understand that some home UPSs have problems with the 66Hz "safe" default cutoff frequency. although it does sound like this can be reconfigured after the fact. anyone know how low of a frequency > 60Hz an SMA-5000 will cut off?

anything else anyone can think of that are important to ask/make sure of while the installers are around? anything you wish you had asked or had taken care of on the day of install? anything that was a hassle to get fixed after the fact?

thanks

@astrorob

#1 - If you can, do an outage test in varying combinations of Powerwall states of charge (SoC) and solar production. If your PV system can out produce the Powerwall(s) inverter limits test that too (5kW per Powerwall). I had issues with my backed up panel breakers tripping due to frequency issues, those were resolved when I did the same thing as #2:

#2 - @power.saver's suggestion of changing the maximum frequency is a great recommendation. I poked around on the SMA docs and it's interesting that their inverters have such a tight frequency window by default (59.3-60.5). https://www.cedgreentecheast.com/files/SB5678 INSTALLATION(3).pdf I didn't see it in my quick glance of the literature but if they have a production "ramp down" functionality to make the PV levels a linear function rather than an all or nothing it can be very helpful in grid outage scenarios to keep your PWs topped by a few extra %. Not a huge deal but an optimization if it's available.

 

[charlesj]

I dont think they do the backup panel with the same breaker as the main one. shrug.. I just dont think they do that, and I believe there is likely some electrical reason I dont understand for it. In any case, what they will be doing at your house is whats on that permit, nothing more or less, from a schematic point of view. If you dont agree, you better cancel your appointment because they will not be changing the breakers / flows etc from that diagram.

Thats whats on the permit that they applied for, so unless they get another permit, thats what they are going to do. I couldnt even get them to add an outlet for me on the backup side that I had all the parts for. The installer said "I dont mind doing it for you, but its not on the plans so I dont want the inspector to fail you because of it.. .call me back after inspection and I can do it for you then".

So, if you dont like what you see, you need to halt everything in its tracks, and talk to someone to get them to re do it. With that being said, I believe they know what they are doing electrical wise, but its your house so you should get an explanation if you want one. Just dont expect them to change breakers listed on that document without re submitting.

This is what is happening with me. Glad I checked the permit schematic at the permitting office and before it was approved.
Seems like a boilerplate schematic. A 100A breaker for the house that has 2-100A breakers now in the main panel?
So, they are revising or a no-go.

 

[astrorob]

This is what is happening with me. Glad I checked the permit schematic at the permitting office and before it was approved.
Seems like a boilerplate schematic. A 100A breaker for the house that has 2-100A breakers now in the main panel?
So, they are revising or a no-go.

right - makes no sense. my installation adviser is apparently stonewalling me. not sure who i should call at this point.

 

[jboy210]

This is what is happening with me. Glad I checked the permit schematic at the permitting office and before it was approved.
Seems like a boilerplate schematic. A 100A breaker for the house that has 2-100A breakers now in the main panel?
So, they are revising or a no-go.

Did you have to go down to the permit office to see the schematics? I check my city's online permit system and it showed only the information below. No diagrams.

photovoltaic 12.74kw 218 solar modules
photovoltaic 12.74kw, 218 solar modules, two new battery storage system, one new 125 amp load center and one new 200 amp load center

 

[bob_p]

For new installations, recommend two tests:

• Charge the PowerWalls to have at least enough charge to operate the house for an hour or two, and while the sun is running, simulate a power outage by throwing the breaker in the Tesla Backup Gateway panel - and then verify the solar panels & PowerWalls are operating as expected and that all house devices (UPS, air conditioners, pumps, ...) are working correctly. This test verifies the system correctly switches off grid power and then back on again.
• Charge the PowerWalls to 99-100% charge with the sun out and then do the off-grid test. The Gateway will likely set the power frequency higher than 60Hz to turn off the solar microinverters (since there's no where for that power to go). Verify the PowerWalls are providing power and check house devices to ensure everything is working (UPS, air conditioners, pumps, ...). In our case, the UPS systems failed and we may have had problems with at least one air conditioner and at least one of the pool pumps (plus a breaker was thrown on one of the house circuits). If this test fails, Tesla or the installer should be notified, and based on the microinverters being used, the Gateway should be reconfigured to use a frequency high enough to turn off the microinverters but low enough to prevent problems with house devices.

 

[charlesj]

For new installations, recommend two tests:

• Charge the PowerWalls to have at least enough charge to operate the house for an hour or two, and while the sun is running, simulate a power outage by throwing the breaker in the Tesla Backup Gateway panel - and then verify the solar panels & PowerWalls are operating as expected and that all house devices (UPS, air conditioners, pumps, ...) are working correctly. This test verifies the system correctly switches off grid power and then back on again.
• Charge the PowerWalls to 99-100% charge with the sun out and then do the off-grid test. The Gateway will likely set the power frequency higher than 60Hz to turn off the solar microinverters (since there's no where for that power to go). Verify the PowerWalls are providing power and check house devices to ensure everything is working (UPS, air conditioners, pumps, ...). In our case, the UPS systems failed and we may have had problems with at least one air conditioner and at least one of the pool pumps (plus a breaker was thrown on one of the house circuits). If this test fails, Tesla or the installer should be notified, and based on the microinverters being used, the Gateway should be reconfigured to use a frequency high enough to turn off the microinverters but low enough to prevent problems with house devices.

Thanks. I guess I could also turn off the main breaker by the meter before the Gateway, right?