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Santa Clara County retroactively Changing ESS Rules

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My 3 PWs are planned to go in an unfinished portion of my basement (concrete walls/floor), although I do have to walk through a finished portion to get there. Will that be allowed with the new rules?

Also, sorry if this has been stated already, all PWs will have to be 3’ from each other (no stacking anymore) after July 1st in Ca?

If this is over fire/overheating concerns, is there any real world examples of this sort of problem? I’ve never heard of any incidents.

3 PW are over the 40 kWh maximum for basements.

I have not heard of any Powerwall ESS units failing with catastrophic fire, at all. I have heard of large battery installations going up in flames though.
 
I have this light well at the back of my house. I originally wanted the Powerwalls placed there, stacked against the retaining wall furthest from the house on the upper level. The installers said that they couldn't do that because they didn't have a lift or crane to safely lower the heavy Powerwalls down there. Given the new restrictions, would this be an allowable location? The separation from the house would be more than 6 feet with nothing but concrete around the Powerwalls.

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Will the PW be more than 3' from doors and windows that enter the living space then maybe yes. You'd have to clear that with the city as I am not the arbiter of these rules, just the user and contributor. Still looks like a heck of a place to put them, will need to be creative to get a 300 lb battery into that spot, then twice more lol.
 
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Tesla Installer -- They came out to install and then said "Nope, gotta be 3' because your city sucks" and then left :(


Can these batteries be added to Tesla installations perchance? :)

Just FYI last I checked a month or 2 ago Sunnyvale has a restriction on only the distance from doors and windows.

There is no restriction between the ESS themselves, though they will follow CBC when it changes July 1.
 
My 2 x PW installation in Los Altos (Santa Clara County) was completed last week and successfully passed city inspection.

Powerwalls were mounted on the outside wall of a garage next to a door and beneath an inoperable window. It took multiple discussions with Tesla as well as a site visit from them to convince them, thanks to the info in this thread, that the door was to a non-habitable area (i.e., the garage) -- and therefore PW could be placed adjacent -- and window placement was OK because it was non-operable. They ended up installing them 30" apart due to stud placement, the Tesla team said "don't worry about it", and in the end the city inspector never even looked at the batteries, just the loads / breakers in my main panel and load center.

This project took forever to get installed (originally ordered Jan 2020) because several times my assigned PM left Tesla and my project just sat in limbo without me realizing it. I did end up with a second-gen Gateway which I gather is much quicker at detecting Grid outage, and the Tesla electrician who finished my project installed a Neurio which he said is not always done. (Of course that Neurio is providing faulty data and causing my PW to discharge to the Grid, but that's the subject of another thread).

Overall I'm satisfied and hoping to one day be allowed to stack a third and fourth battery on top of existing pair of PWs.

David
 
My 2 x PW installation in Los Altos (Santa Clara County) was completed last week and successfully passed city inspection.

Powerwalls were mounted on the outside wall of a garage next to a door and beneath an inoperable window. It took multiple discussions with Tesla as well as a site visit from them to convince them, thanks to the info in this thread, that the door was to a non-habitable area (i.e., the garage) -- and therefore PW could be placed adjacent -- and window placement was OK because it was non-operable. They ended up installing them 30" apart due to stud placement, the Tesla team said "don't worry about it", and in the end the city inspector never even looked at the batteries, just the loads / breakers in my main panel and load center.

This project took forever to get installed (originally ordered Jan 2020) because several times my assigned PM left Tesla and my project just sat in limbo without me realizing it. I did end up with a second-gen Gateway which I gather is much quicker at detecting Grid outage, and the Tesla electrician who finished my project installed a Neurio which he said is not always done. (Of course that Neurio is providing faulty data and causing my PW to discharge to the Grid, but that's the subject of another thread).

Overall I'm satisfied and hoping to one day be allowed to stack a third and fourth battery on top of existing pair of PWs.

David
If you have a GW, why need a Neurio? I am getting all the info on use, etc. from the GW2'2
 
If you have a GW, why need a Neurio? I am getting all the info on use, etc. from the GW2'2

That's good to know. I've never not had a Nuerio so I'm not familiar with what data is collected without one. My Tesla electrician said that the Neurio current transformer positioned around my PGE feed to the main breaker is how the Tesla App actually knows what my current draw is.

Without a Nuerio, how does it know this?

David
 
That's good to know. I've never not had a Nuerio so I'm not familiar with what data is collected without one. My Tesla electrician said that the Neurio current transformer positioned around my PGE feed to the main breaker is how the Tesla App actually knows what my current draw is.

Without a Nuerio, how does it know this?

David
Gateway 1 has a Neurio built in and it is the only way to measure Grid and Solar quantities. Gateway 2 has a different built-in measurement system and can additionally use an external Neurio to measure the Grid and/or Solar from a remote location or conductors other than the grid input to the Gateway. If a Gateway 2 is installed in a Partial Backup situation and the feed for the non-backup loads don't pass through the Gateway, then you need a Neurio in order to show the usage of and offset the usage of those non-backup loads when the grid is up.
 
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So something inside Tesla has realized my system is not behaving properly, so they texted me the below and requested I schedule service.

1. But I have no "Service" option on my Gateway Home page -- any tips on how I'm supposed to schedule service? Tried logout / login...
2. When they come out, if they try to remove my Neurio (thanks @miimura -- without it I wouldn't know when my not-backed-up Pool Pump is running or how much energy it's consuming -- should I acquiesce or insist the Neurio should work if configured properly?

David

"Our monitoring team has detected an issue with your system that requires service. Schedule service in your Tesla mobile app.
Steps to Schedule:
Open the app and view the home page for your energy system
Scroll down to the bottom and click "Service"
On the "Select Service" page, select your system's issue under the "Alert(s)" category"
 
So something inside Tesla has realized my system is not behaving properly, so they texted me the below and requested I schedule service.

1. But I have no "Service" option on my Gateway Home page -- any tips on how I'm supposed to schedule service? Tried logout / login...
2. When they come out, if they try to remove my Neurio (thanks @miimura -- without it I wouldn't know when my not-backed-up Pool Pump is running or how much energy it's consuming -- should I acquiesce or insist the Neurio should work if configured properly?

David

"Our monitoring team has detected an issue with your system that requires service. Schedule service in your Tesla mobile app.
Steps to Schedule:
Open the app and view the home page for your energy system
Scroll down to the bottom and click "Service"
On the "Select Service" page, select your system's issue under the "Alert(s)" category"
I don't have Service on my Powerwall page either. However, I have pre-existing 3rd party solar and Powerwalls installed by a 3rd party.

Just call them to schedule the service. The old number in my phone for Tesla Energy Support is 877-961-7652
Alternatively, text back the same number requesting the appointment, indicating that you don't have the Service option.
 
Interesting. I have Powerwall Service on my Tesla app. They recently did an update. Are you on the latest Tesla App version — version 3.10.12 posted 5/29?

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FBEB570D-DFD3-40D5-9DD6-A806BAEAEBA9.png
 
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Yes 3.10.12 but no SERVICE — bizarre. Did get an appt on the phone after a 25 min hold — 6 weeks out despite my explanation that PW was discharging to the grid, possibly illegally— for which they sent no email or text confirmation so now I will have to call back near then to reconfirm.

David
 
Yes 3.10.12 but no SERVICE — bizarre. Did get an appt on the phone after a 25 min hold — 6 weeks out despite my explanation that PW was discharging to the grid, possibly illegally— for which they sent no email or text confirmation so now I will have to call back near then to reconfirm.

David
Before our solar install, on our Tesla app for our cars we were both on the same app version but were seeing different things menu wise. Not 100% sure but think we signed out of the app and signed back in and whatever was missing on my husbands app menus did appear. Might try that.
 
Oh man just found this post, after I reviewed my plan proposal and found that my PWs were spaced 3' apart. Any idea if UL 9540A was ever completed for PowerWall 2 or PW +?
Per Tesla's latest specifications only UL 9450 is listed. So, no.

An example ignition of a battery energy storage system using 18650 lithium ion cells under UL 9540A certainly suggests the ability to ignite adjacent battery packs. (The report is an interesting read, if you are so inclined.)

The UL 9450A specification measures the behavior of a battery energy storage system with respect to thermal runaway fire. From browsing the specification, and having seen videos of Tesla vehicle battery fires, it would appear to be a challenge to contain a cell fire in a battery system in a way that would be unlikely to ignite adjacent battery packs. Lithium ion batteries are rather flammable in the grand scheme of things.

Separating Powerwalls by three feet would seem to be a prudent plan to reduce the probability that a single cell failure burns all of your Powerwalls in one go. I am not saying it is likely. I think it is rather like moving your firewood pile 30' from the house, and clearing pine needles out of your gutters if you live in a wildfire area.

All the best,

BG
 
Per Tesla's latest specifications only UL 9450 is listed. So, no.

An example ignition of a battery energy storage system using 18650 lithium ion cells under UL 9540A certainly suggests the ability to ignite adjacent battery packs. (The report is an interesting read, if you are so inclined.)

The UL 9450A specification measures the behavior of a battery energy storage system with respect to thermal runaway fire. From browsing the specification, and having seen videos of Tesla vehicle battery fires, it would appear to be a challenge to contain a cell fire in a battery system in a way that would be unlikely to ignite adjacent battery packs. Lithium ion batteries are rather flammable in the grand scheme of things.

Separating Powerwalls by three feet would seem to be a prudent plan to reduce the probability that a single cell failure burns all of your Powerwalls in one go. I am not saying it is likely. I think it is rather like moving your firewood pile 30' from the house, and clearing pine needles out of your gutters if you live in a wildfire area.

All the best,

BG
I hear you, but if my battery catch fire, I would worry more not burning down the house than the next battery catching on fire. it isn't like our houses are build from bricks and concrete :) I hear you I read already that Tesla is only UL 9540 not UL 9540A but others were able to get certified so I am pretty sure tesla is in the works to get it, just wondering if anyone has inside info if they are in process.
 
UL 9540A is not a "yes/no" certification. From a cursory reading:

First you do a cell level test and try to drive a cell into thermal runaway. If you can't, then you get "cell level" certification, which is the only way to get approval for the product to be installed in habitable space, rather than basement/garage/outside.

Then if you want to get approval for installing the units closer than 3' apart, you need to do a larger scale test and show that thermal runaway induced in one unit's cells (which you now know how to do, from the first test) doesn't induce thermal runaway in the neighboring units at that spacing.

I may be skipping some of the details, as there is also a module level test. Are there any ESS products available that pass the cell level 9540A test? I looked at Enphase's Encharge, which is based on LiFePO4, purportedly one of the safest Li chemistries, but they only advertise module level 9540A compliance.

Cheers, Wayne
 
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Well the saga continues:
Currently Tesla has completed the 9540A testing but the AHJs so far won't accept it, and I really don't understand why. Some made noise about the accreditation of the testing lab, others just said to keep spacing them at 3' apart until we work it out with Tesla. Other manufacturers like Enphase who have this same test report from different labs have been accepted in these same places.
UL 9540A is not a "yes/no" certification. From a cursory reading:

First you do a cell level test and try to drive a cell into thermal runaway. If you can't, then you get "cell level" certification, which is the only way to get approval for the product to be installed in habitable space, rather than basement/garage/outside.

Then if you want to get approval for installing the units closer than 3' apart, you need to do a larger scale test and show that thermal runaway induced in one unit's cells (which you now know how to do, from the first test) doesn't induce thermal runaway in the neighboring units at that spacing.

I may be skipping some of the details, as there is also a module level test. Are there any ESS products available that pass the cell level 9540A test? I looked at Enphase's Encharge, which is based on LiFePO4, purportedly one of the safest Li chemistries, but they only advertise module level 9540A compliance.

Cheers, Wayne

As to the Cell level testing, it is the highest level of success. As I understand it, no current Lithium technology can reach this cell level test. It requires that the battery never contributes to thermal runaway, or exhausts flammable gasses. Theoretically a battery that was this safe could be installed in your bedroom if you wanted and would be marked "For use in residential dwelling units" This is currently the "unicorn battery" as all other lithium technologies will eventually go into thermal runaway if enough heat is applied. This however is an evolving part of the standard. It doesn't really make sense that you force a cell into thermal runaway regardless of the heat input required. Really the heat input should be porportinate to what the adjacent cells could possibly produce. If it takes 3x more energy than is in the adjacent cells to cause 1 cell to go into thermal runaway, you are testing for a condition that is pretty impossible to accomplish.

The ranking of test importance goes like:
1. Cell
2. Module
3. Unit
4. Installation

So if you pass cell level you can forgo any further testing.

I am not familiar with Enphase testing, but if the testing at the module level passes, then there is no reason to progress to unit level or installation level testing, as those are assumed to have passed since the module level passed.
So if Enphase is safe at the module level, it does not need to progress to the unit level testing.

There is much more work happening behind the scenes to improve battery safety, and the UL 9540 standard itself is in significant flux. There are nearly 100 industry members working right now with UL to improve this standard as we learn more about fire performance. I think there are near a dozen proposals to the UL 9540 STP this cycle.
 
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