Powerwall 2: Installation

[Frankman60]

It’s good to know that APN works with the IOS app, because I am using the Tesla IOS app. So during the day I will know if the grid goes down. But when sleeping, I set my phone in Do-not-disturb (DND) mode and in that mode push notifications will not occur. That is something I wish Apple would change and allow “favorite” apps to push notifications through the DND mode. I think the only thing that can get through DND on IOS is a phone number (SMS text or phone call). That is done using an Emergency bypass setting in the Contact for a specific phone number, or including the specific phone number in the Favorites list. So when sleeping, I don’t think the Tesla APN would work for me.

Another method might an audible device that can detect the brief power interruption and beeps like a smoke detector. My home automation controller can detect a power outage and announce the outage, but I doubt it would detect the brief several hundred millisecond interruption.

Yes, I have the meter/main combo that you described. Thanks for the information.

People here have reported that the latest app does. At least on iOS, it generates APN (Apple Push Notifications). I'm still unclear on Android.


I take it you currently have a 200A combo meter/main with a 200A bus, and the plan is to have only one distribution breaker that panel, a 200A breaker to feed the new equipment? Then your contractor is correct, if you wanted to leave a 50A breaker in that panel for your 40A EVSE, then you'd have to use a 150A breaker to feed your new equipment to protect the bus. Or if you don't have solar, you could change the main breaker in that panel to a 175A breaker, then you can put as many breakers as you want in your main panel (without backup power), via the 120% rule: 175 + 30 * 2 < 120% * 200.

Otherwise, you would need a separate panel for the EVSE breaker, and this panel would be supplied via a feeder tap on the feeder from your meter/main to the Backup Gateway. That panel could be as small as a 2 space panel, like this one:

Murray 60 Amp 2-Space 4-Circuit Surface Mount Main Lug Load Center-LC002GSU - The Home Depot

Actually you'd probably want a physically somewhat bigger one, to provide space for the insulated mechanical connectors used for the tap. But you only need a 2 space, main lug panel with a single 50 amp 2 pole breaker: you can backfeed the breaker (meaning it needs a hold down) with the feeder tap, and then take your EVSE circuit off of the main lugs (using them as subfeed lugs).

It would still cost you a few hundred dollars to do that. You might be able to devise an alternative method to shut off you EVSE during a power outage for a comparable cost, with the added ability to manually enable EVSE charging off the Powerwalls if required.

Cheers, Wayne

 

[NuShrike]

3) For the first time, they said Tesla now will file commercial SGIP applications for residential install and they just got approval to file on my behalf for this project, allowing me to go beyond 2 powerwalls and still use SGIP. The trade-off is a lower rebate (29 cents / W I believe), but it can be applied to all the equipment used.

Can you define all equipment used?

The SGIP Handbook says the incentives apply only to the batteries themselves (as far as I can tell), and not all the ancillary costs of installation, Backup Gateway, power-panel changes, etc.

Tesla never gave me these options when they were up-selling me to 4 PW2s when I started the order for only one.

 

[GenSao]

I have been thinking about how I could be notified when the house switches over to PW during a grid outage for the same reasons that arnolddeleon mentioned. If there is a grid outage while I’m sleeping and my Model S is charging, the PW will get drained pretty quickly and I would rather just stop charging the car when the grid goes down. But if the Model S is charging at 40 amps, would that be enough kWs to overload the 2 PWs and force the PWs off line because it exceeds the 10 kW capacity of 2 PWs? It would actually be more kWs than just the car charger because rest of the house load would also be on the PWs.

I don’t believe that the Tesla app pushes notifications when a grid outage occurs. The Tripp UPS that eml2 mentioned seems good, but is there a non-UPS product that could detect the brief (a few milliseconds) power interruption and push a notification? Ideally the Tesla app should do this because doesn’t it record the power interruption in a log?

I would hope there is a future software setting/option incorporated with a Tesla car that would stop or limit charging. No need for complicated hardware setup since it is possible via software. This can be done via the mobile connector, Tesla wall connector, or third party unit.

This all can be set via the Tesla app which already can control the Powerwall and car. If there is enough energy in the Powerwall battery, there can be an option to continue to charge a Tesla car up to the set reserve energy amount.

 

[wwhitney]

The SGIP Handbook says the incentives apply only to the batteries themselves (as far as I can tell), and not all the ancillary costs of installation, Backup Gateway, power-panel changes, etc.

That is not my interpretation of SGIP Handbook 3.2.2. However, as the SGIP Step 2 rebate is $4,640 per Powerwall, and the Powerwalls cost $5,500 each, the Powerwalls alone are sufficient to qualify for the full rebate.

Under Large Scale Storage with ITC, the Step 2 rebate is $3,364 per Powerall, independent of any other ancillary costs. The ancillary costs, however, probably qualify for the 30% ITC (as does the Powerwall cost after deducting the SGIP rebate).

Cheers, Wayne

 

[NuShrike]

That is not my interpretation of SGIP Handbook 3.2.2. However, as the SGIP Step 2 rebate is $4,640 per Powerwall, and the Powerwalls cost $5,500 each, the Powerwalls alone are sufficient to qualify for the full rebate.

Under Large Scale Storage with ITC, the Step 2 rebate is $3,364 per Powerall, independent of any other ancillary costs. The ancillary costs, however, probably qualify for the 30% ITC (as does the Powerwall cost after deducting the SGIP rebate).

True, there hasn't been a situation yet where the rebate is more than the battery cost.

I'm in SCE's Step 3 area for large-scale, so it's:
* $2900 (Energy Storage + ITC @ $0.25 per Wh, then $0.125 per Wh > 2h) per PowerWall
* $4060 per PowerWall (Energy Storage only @ $0.35 per Wh, then $0.175 per Wh > 2h) per PowerWall

 

[1208]

Can't believe we in the UK can't use the powerwall as backup in event of power cut. Hospitals have simple breakers and relays. Just reeks of preventing the individual having freedoms from the clutches of the state/companies.

 

[wwhitney]

I'm in SCE's Step 3 area for large-scale, so it's:
* $2900 (Energy Storage + ITC @ $0.25 per Wh, then $0.125 per Wh > 2h) per PowerWall
* $4060 per PowerWall (Energy Storage only @ $0.35 per Wh, then $0.175 per Wh > 2h) per PowerWall

So your breakeven for taking the ITC is $6,767 per Powerwall: $2,900 + 30% * ($6,767 - $2,900) = $4,060. This assumes that committing to 100% solar charging to take the full ITC is costless; calculating the actual cost is difficult.

Cheers, Wayne

 

[SoundDaTrumpet]

I would hope there is a future software setting/option incorporated with a Tesla car that would stop or limit charging. No need for complicated hardware setup since it is possible via software. This can be done via the mobile connector, Tesla wall connector, or third party unit.

This all can be set via the Tesla app which already can control the Powerwall and car. If there is enough energy in the Powerwall battery, there can be an option to continue to charge a Tesla car up to the set reserve energy amount.

It appears to me that Tesla's mobile connector and home wall connectors are un-smart EVSEs seeing that a control wire is used to sync multiple home wall connectors in a home to prevent overloading EVSE dedicated circuit by charging two cars at a time. (I hope I am correct, here.) Considering the controls of a Tesla automobile is via cellular communication, one hopes the cellular network is working during a grid outage. This may work assuming cellular towers have some sort of battery backup which may long enough to trigger the car to not charge. I have a WiFi EVSE (juicenet) which afford another means to control charging via Internet, which may or may not be working during an outage (I had a power outage where cellular towers were immediately knocked out). It seems to me that maybe Z-wave automation hub may work, but it would be an elaborate system of current measurements at the service panel, and a smart switch. Downsides to this are this assumes the hub can work without internet, and some of these appliance rated smart switches are limited to 30/40A. Seem like too much trial and error. I am leaning to keep the EV charger on main service panel instead of on the backup load panel. It may be liberating not to wonder if any chain of computer logic fails along the way during an outage.

 

[wwhitney]

some of these appliance rated smart switches are limited to 30/40A.

If you are willing to modify the EVSE, it would be fairly simple to interrupt/modify one of the control lines, rather than just switch power on and off to the EVSE itself. Then the switch/relay power requirements would be trivial.

Cheers, Wayne

 

[Frankman60]

I found this product on Amazon that says it will produce an alert tone when power is interrupted. This one is supposed to be very sensitive and will detect power interruptions of 50 milliseconds or greater. When the PW goes into backup mode during a grid outage, how long of an interruption is it (e.g. more or less than 50 milliseconds)? There is some discussion about his further back in this thread where I was looking for a way to be awakened if there is a grid outage while sleeping so I can save energy by turning off power hungry devices. We have up to three cars charging during the night and if there was a grid outage I would want to stop charging the cars and preserve the PW capacity in case the grid outage lasts a long time.

https://www.amazon.com/PFA-1-Power-...rd_wg=lzdhH&psc=1&refRID=0FMDE1DR1N9V86R4YG44

 

[arnolddeleon]

It turns out things weren't quite done yet. Today Tesla was back to meet with the city for the *final* inspection. A homeowner was needed because someone needed sign the affidavit that asserts that the house had the required smoke and carbon monoxide detectors. Tesla also added stickers to the panels. Here is a photo:

arnold

 

[mongo]

I found this product on Amazon that says it will produce an alert tone when power is interrupted. This one is supposed to be very sensitive and will detect power interruptions of 50 milliseconds or greater. When the PW goes into backup mode during a grid outage, how long of an interruption is it (e.g. more or less than 50 milliseconds)? There is some discussion about his further back in this thread where I was looking for a way to be awakened if there is a grid outage while sleeping so I can save energy by turning off power hungry devices. We have up to three cars charging during the night and if there was a grid outage I would want to stop charging the cars and preserve the PW capacity in case the grid outage lasts a long time.

https://www.amazon.com/PFA-1-Power-...rd_wg=lzdhH&psc=1&refRID=0FMDE1DR1N9V86R4YG44

To keep everything happy, it should switch in less than one AC cycle (60Hz/16.66667mS), 50mS seems long. Guessing you don't have any unbacked up loads to attach it to.

 

[Frankman60]

Has anyone measured how long the power is interrupted when PWs take over during a grid outage? I think there are a few people who said that their UPS detected the switchover. I am also wondering how smooth the switchover is and whether it is harmful to electronic equipment? Ironically, while waiting for my PW installation to begin, there was a 10 minute grid outage recently and when the power came back up several surveillance camera power adapters were destroyed. For those with working PWs, have you had any instances where the switchover between grid and PW caused damage to any electronic equipment?

To keep everything happy, it should switch in less than one AC cycle (60Hz/16.66667mS), 50mS seems long. Guessing you don't have any unbacked up loads to attach it to.

 

[MP3Mike]

there was a 10 minute grid outage recently and when the power came back up several surveillance camera power adapters were destroyed.

How do you know it was when the power came back that the power adapters were damaged? I would think it is most likely that they were damaged when the power went out. (From over/under voltage.)

I assume Powerwall would protect from under voltage, but does it disconnect the grid in overvoltage situations? (Or when only one phase goes out?)

 

[mongo]

Has anyone measured how long the power is interrupted when PWs take over during a grid outage? I think there are a few people who said that their UPS detected the switchover. I am also wondering how smooth the switchover is and whether it is harmful to electronic equipment? Ironically, while waiting for my PW installation to begin, there was a 10 minute grid outage recently and when the power came back up several surveillance camera power adapters were destroyed. For those with working PWs, have you had any instances where the switchover between grid and PW caused damage to any electronic equipment?

PW should be better regulated than a grid restart.

I assume Powerwall would protect from under voltage, but does it disconnect the grid in overvoltage situations? (Or when only one phase goes out?)

Other than the droop between the final transformer and the house, the PW won't help against undervoltage unless the GW isolates the system. Should also isolate in over voltage and frequency shifts, but reaction time (esp for OV) likely won't save sensitive elecryonics.
Interesting whether it senses per split phase for loss of neutral to the house.

 

[arnolddeleon]

It turns out things weren't quite done yet. Today Tesla was back to meet with the city for the *final* inspection. A homeowner was needed because someone needed sign the affidavit that asserts that the house had the required smoke and carbon monoxide detectors. Tesla also added stickers to the panels. Here is a photo:

arnold

I guess links to images don't work. Let's try a link instead 2018-02-06 10.21.59

 

[arnolddeleon]

The local webserver on my powerwall always said "Registration incomplete". When I called Tech Support they told it fine. But I found it annoying. So I finally ran the wizard myself and now it doesn't says "Registration Incomplete" anymore. I suspect the reason it was saying "incomplete" was because there was a step where the homeowner needed to agree to terms of service (I wasn't home for the commissioning). There was an option to skip that which I would guess required a follow up step to complete which Tesla had not done.
arnold

 

[IanN]

They are developing a 400A gateway, which should be available before the end of the year (sound familiar?)

Any updates on the 400A gateway. This would save alot of wiring between two 200a boxes. Looking to add Powerwall 2, but would like a simple install.

 

[mongo]

Any updates on the 400A gateway. This would save alot of wiring between two 200a boxes. Looking to add Powerwall 2, but would like a simple install.

Curious, with a 400A gateway, won't all loads be on the backed up side? If so, how many Powerwalls are we talking about? Or is there a different way to automatically disable loads during outages?

 

[IanN]

Curious, with a 400A gateway, won't all loads be on the backed up side? If so, how many Powerwalls are we talking about? Or is there a different way to automatically disable loads during outages?

Got the site survey Sunday. Rep says 400A Gateway is "under development". Getting quote on 200A but really want 400A, saves allot of wiring to get all important loads into the same panel. Wiring is across 6 breaker boxes and 2 buildings.

Looking at 4 PW2's. With existing solar should give continuous power (with appropriate usage).

400A transfer switches are common, but not yet from Tesla.

Any one know when 400A gateway might become available?