what happens when a powerwall2 fails?

[astrorob]

that is similar to mine - the bulk of the house is on a 200A subpanel in the pantry, but unfortunately there are 9 more 120V circuits with breakers in the main panel, most of which need to be backed up. so it looks like they'll have some work to do there.

come to think of it there's a 240V outlet in the laundry room for a dryer but we have a gas dryer. i think that might not actually be wired up since there's no breaker in the main panel corresponding to it.

 

[miimura]

that is similar to mine - the bulk of the house is on a 200A subpanel in the pantry, but unfortunately there are 9 more 120V circuits with breakers in the main panel, most of which need to be backed up. so it looks like they'll have some work to do there.

come to think of it there's a 240V outlet in the laundry room for a dryer but we have a gas dryer. i think that might not actually be wired up since there's no breaker in the main panel corresponding to it.

9 circuits to extend into the Generation panel is no big deal. Remember that they're only extending one the hot wire per circuit. The Neutrals are all tied together whether the grid is up or not. I don't think your installation is anything out of the ordinary at all.

 

[astrorob]

that's good to hear... i don't know when they will actually get back to me given the insane demand, but i will follow up monday or tuesday to make sure they got all the pictures and stuff.

 

[ElectricOrgan]

that would be really helpful.

it's not the expense for the new sub-panel(s) that concerns me... at this point it's the actual installation that has me worried.

i think my house could be somewhat unusual in the fact that the panels are set into the wall and then stuccoed around. seems like breaking out some number of the circuits into a generation panel might be really difficult. i suppose there is a risk tesla looks at this job and 10,000 other easier jobs and just elects to drop this one. or, maybe they just charge me a lot more than the $2500 they have quoted for installation. we'll have to see. it might be the kind of job they need to send someone out to to evaluate rather than just going off the photos i have provided them.

Trust me, a little stucco is not going to deter an electrical contractor. Not for a moment.

You do know that stucco is not concrete or anything, right? Wait a minute... is this interior or exterior? Exterior stucco is a bit like cement. Interior stucco is more like plaster. I seem to recall seeing a circuit panel on the outside of the house in South Carolina.

 

[astrorob]

this is all exterior work... really what i'm concerned about is that they don't come in and bodge it all up and do whatever it takes to get it done in a day or whatever. i guess i should have said "might be really difficult to do right" because i'm sure it can be done quickly in a substandard way.

 

[chrisbailey13]

I can post a picture later, but my install only has the Disconnect switch on the outside wall next to the Meter/Main Panel back. Inside the garage, is the Gateway, Essential Load panel, and a panel that has breakers for the powerwalls and inverters. (and the powerwalls of course) @miimura, I don't see your disconnect switch in your picture.

 

[cwied]

I can post a picture later, but my install only has the Disconnect switch on the outside wall next to the Meter/Main Panel back. Inside the garage, is the Gateway, Essential Load panel, and a panel that has breakers for the powerwalls and inverters. (and the powerwalls of course) @miimura, I don't see your disconnect switch in your picture.

A separate disconnect is not required out here in California. I live in the same area, and no disconnect switches were installed with the Powerwalls.

 

[miimura]

A separate disconnect is not required out here in California. I live in the same area, and no disconnect switches were installed with the Powerwalls.

In addition to the Powerwalls not requiring a disconnect here, I have micro-inverters and the breakers are the only solar disconnect as well. Very clean installation. I see other jurisdictions with all these extra meters and disconnects and I just shake my head.

 

[chrisbailey13]

OK...In FL, there is a required Disconnect outside that terminates the Solar/Battery connection to the grid. In addition to the Gateway, Essential Load, and Generation panel. and the two solar inverters

View media item 120489

 

[charlesj]

My question would be if the powerwall fails will my solar still power my needs in the daytime.
And, can that Gateway also fail? If so, will the panels provide power to the house and grid as needed?

 

[astrorob]

My question would be if the powerwall fails will my solar still power my needs in the daytime.
And, can that Gateway also fail? If so, will the panels provide power to the house and grid as needed?

are you talking about a situation where the grid is up or down? if the grid is down, my understanding is no - if the powerwall fails then the solar will stop generating, as the solar needs to see some other 'thing', be it the powerwall or the grid itself, generating a proper AC waveform for it to lock on to.

if the powerwall fails while the grid is up, then based on the answers in this thread the solar and grid should continue to work the way they did before you installed the powerwall.

if the gateway fails (which maybe was a better initial question for me to ask, but i didn't understand how it was all wired together), then i suppose whether or not you still have power after that failure depends on if the gateway fails into an "open" or "closed" state with respect to the grid cutoff switch.

 

[charlesj]

are you talking about a situation where the grid is up or down? ...

I was thinking when the grid is up but PW and Gateway is down as I know my micro inverters need the voltage tickle.

 

[cwied]

I was thinking when the grid is up but PW and Gateway is down as I know my micro inverters need the voltage tickle.

When the grid is up, they micro inverters sync to the grid, not to the Powerwalls. It's only if the grid is down and the transfer switch opens that they're cut off from the grid.

The thing to realize is that the Gateway is several components. The failure that would take you out is if the transfer switch fails open. It seems unlikely to me that that would happen. More likely would be a failure of the controller, in which case it is likely that the Powerwalls would go into standby mode and the rest of your system would operate as if they weren't there.

 

[Ulmo]

The Powerwall 2 has two fundamental operating modes, grid interactive, and grid master (for lack of a better term).

When the grid is up, the Powerwall inverter is grid interactive. That means that the Gateway is giving it power flow commands to charge or discharge to accomplish whatever strategy is desired at that moment. For example, it can charge to absorb All Solar, or charge to absorb Surplus Solar or discharge to match the household loads. If there is a failure when the grid is up, it should just shut down and do nothing and your loads will be supported by the grid. If a Powerwall really goes haywire, it will probably trip the circuit breaker.

When the grid is down, the Powerwall inverter is acting as the grid master and is trying to maintain the voltage and frequency for the islanded micro-grid. It will charge or discharge as needed to maintain those parameters. It can also change those parameters off nominal to signal solar inverters that they should curtail their output or shut down. If the Powerwall cannot maintain the voltage and frequency due to low battery or excessive load, it will shut down.

I agree with this answer. It is specific enough, and exactly fails to answer the parts we can't answer anyway (because we don't really know). We can infer that the Tesla Backup Gateway will pass through the maximum* capability during PowerWall failures. For instance, in my testing, when I turned off one PowerWall, the gateway would continue with the remaining capability including the capability of my remaining PowerWall.


* In my tests, there were some suboptimal "edge" cases. (The thing is designed to handle edge cases, so that's not much of a compliment.)

 

[Ulmo]

I don't know for sure, but I'm relatively certain that all power to the home does not go through the powerwall in the same way a UPS powers your computer. This would require a very large generation circuit in the powerwall.

Right: not all power is required to go via the PowerWalls. It's more like a bus (such as a computer bus or power circuit bus). We call it a (tiny house-sized) microgrid. It's often (usually, even) as simple as bidirectionally fed circuit breakers on a common breaker box panel. Jack Rickard jokingly called it "A/C coupled", and the industry salesmen ran with that term, so that term is also used for practically the same concept (but in some type of salesmany expression of increased capability; big whoop -- they're slowly catching up with Tesla, and what customers have been asking for for the last 40 years).

The way this works without letting the bus crush users when it crashes (extending the metaphor a little), the controllers quickly disconnect offending users of the bus before the bus runs out of control. That's the job of every smart device on the bus. The Tesla PowerWall Gateway must quickly disconnect the exterior utility grid when it misbehaves, for instance (extremely rapidly kicking it off the bus), and the PowerWalls quickly respond by supplying power to the users of the bus (ok, the metaphor crumbled here; the bus doesn't have intrinsic power unto itself, and the users want and provide power, so that didn't fit the schoolbus metaphor at all. Think Apple ][+ bus, or IBM PC ISA bus, or more appropriately, an electric bus bar. No, they don't serve drinks on public transit; look up electric bus bar.) electric bus bar at DuckDuckGo. This is an appropriate example: https://i.stack.imgur.com/smOxC.jpg (i.e., a circuit breaker panel.)

 

[Ulmo]

When the grid is up, they micro inverters sync to the grid, not to the Powerwalls. It's only if the grid is down and the transfer switch opens that they're cut off from the grid.

The thing to realize is that the Gateway is several components. The failure that would take you out is if the transfer switch fails open. It seems unlikely to me that that would happen. More likely would be a failure of the controller, in which case it is likely that the Powerwalls would go into standby mode and the rest of your system would operate as if they weren't there.

If the gateway components failed, then all bets are off. Maybe Tesla electrical engineers that engineered the gateway could weigh in and explain the (known) intended failure modes. I think they'd be satisfied with (and maybe hope for) non-lethal failure modes.

I've never witnessed anything like this (except for known upgrade encumberments; when upgrading at ~3:34AM, it might not back up power failures). Of course failures will happen (aged components, defects, vandalism). Let's find out by sharing if this ever happens to us! It's not supposed to happen any time soon or often.

A certain amount of logic is in the PowerWalls themselves (even if only as a side effect of their programming and design).

 

[Ulmo]

Wow. Apple iPad sucks! It rewrote every word wrong, and redid every punctuation wrong. I had to fight it each step. Tim Cook sucks! What a crock.

 

[GenSao]

If the gateway components failed, then all bets are off. Maybe Tesla electrical engineers that engineered the gateway could weigh in and explain the (known) intended failure modes. I think they'd be satisfied with (and maybe hope for) non-lethal failure modes.

I've never witnessed anything like this (except for known upgrade encumberments; when upgrading at ~3:34AM, it might not back up power failures). Of course failures will happen (aged components, defects, vandalism). Let's find out by sharing if this ever happens to us! It's not supposed to happen any time soon or often.

A certain amount of logic is in the PowerWalls themselves (even if only as a side effect of their programming and design).

Speculation:

In the event of a Tesla Gateway failure, I imagine the gateway would default to a "connect to grid" state to maintain power to the home as it may no longer communicate to the appropriate devices in a "backup" state. Power would be maintained by the grid (if available) until the Tesla Gateway is repaired or replaced.

Solar (if installed) would function as normal being a grid tied system. Without communication with the gateway, The Powerwall(s) would likely default to a standby state: On, not pushing or pulling electricity.

 

[charlesj]

When the grid is up, they micro inverters sync to the grid, not to the Powerwalls. It's only if the grid is down and the transfer switch opens that they're cut off from the grid.

The thing to realize is that the Gateway is several components. The failure that would take you out is if the transfer switch fails open. It seems unlikely to me that that would happen. More likely would be a failure of the controller, in which case it is likely that the Powerwalls would go into standby mode and the rest of your system would operate as if they weren't there.

Thanks.
But how do I give you a like here? Clicked on thumbs up but nothing.

 

[charlesj]

Wow. Apple iPad sucks! It rewrote every word wrong, and redid every punctuation wrong. I had to fight it each step. Tim Cook sucks! What a crock.

An infant AI in Apple