Powerwall Installation Fiasco

[greentee]

Just want to vent my frustration on the whole Powerwall installation experience.

I reserved 2 Powerwall 2s within the first couple of days when it was unveiled back in October 2016.
Ended up getting an installation date 21 months later in mid-July this year. I can understand the delay but what followed just got me fuming.

They originally said that it'd take 2 days but changed to 3 days in the last minute so I had to scramble to rearrange my work schedule so that I could stay home. The 2 Powerwalls were installed on the 3rd day but they also left a big hole on my outside wall without patching it. And they only patched it a month later after I repeatedly asked them to do so.

Now, back to the Powerwalls themselves, when I ordered them, I expected that I could charge them from the grid so that I could take advantage of the EV rate at night. I also have a very small and old solar system (2.5kW from maybe 12 years ago). It used to generated about 10kW per day but for various reasons it's only generating <2kW per day now. But I didn't know that it'd be factored into my Powerwall installation.

Now when they turned on the system, I realized that it could only be charged from the solar panels. It's been almost 2 months now and my powerwalls are still not fully charged at 77%. I called them multiple times to give me a solution and all they said was that it could not be charged from the grid if it's tied to the solar system. And they did not even bother to suggest anything to resolve this even though I told them that I'm willing to completely disconnect the solar system from my house.

If I knew that the powerwalls could not be charged from the grid, then I wouldn't install it at all consider that it'd still take multiple days to fully charge 1 powerwall, let alone the 2 that I've ordered.

So frustrating.

 

[dutchinchicago]

Is this Powerwall not being charged from the grid a California restriction or are none of them capable of doing this?

I always had assumed that they would be able to charge from either the grid or solar.

 

[mongo]

Is this Powerwall not being charged from the grid a California restriction or are none of them capable of doing this?

I always had assumed that they would be able to charge from either the grid or solar.

They charge from AC, so they don't care where the power comes from. The issue is with the an incentive/rebate program that requires them to be charged from solar.
2018 Energy Storage Tax Credits Explained | EnergySage

 

[Need]

Is this Powerwall not being charged from the grid a California restriction or are none of them capable of doing this?

I always had assumed that they would be able to charge from either the grid or solar.

This is from Tesla Powerwall FAQ:
Can Powerwall charge from the grid?
When Powerwall is installed without solar, it can charge from the grid to support backup operation.

When Powerwall is installed with solar, it is not currently able to charge from the grid. Powerwall installations on new and existing solar systems are designed to qualify for the Federal Investment Tax Credit, which requires 100% charging from solar. Powerwall installations must also comply with rules around grid charging which vary by utility.

So if OP wants to charge from the grid, he will lose the 30% Fed Tax Credit. And maybe his local utility also has rule that prevent charging powerwall from charging from the grid.

 

[Cirrus MS100D]

Sorry for your frustration, but as somebody who is likely to install a Powerwall at some point and is also debating solar, I’ve known this since I first started kicking the tires years ago and suspect most people in the same boat do too.

Not that this is applicable, but imagine the tremendous arbitrage you could gain from ToU by charging up your Powerall via he grid at night and then selling it back to the grid during the day via solar or even Powerwall. That ain’t gonna happen.

It stinks they didn’t make it more clear to you, but perhaps they’re confused why you’re confused?

 

[Camera-Cruiser]

Since it’s tied to energy tax credit legalities, fix or upgrade your solar. I’d want that done regardless.

 

[wwhitney]

If you're willing to go rogue, and you're not claiming the ITC, you can reconfigure the Powerwalls through the wizard as if you didn't have solar. This is not a supported option from Tesla, mainly due to obstinance as far as I can tell. And as Tesla has the ability to remotely reconfigure your Powerwalls, I'm not clear on whether they'd notice and change it back.

Anyway if you are interested I can explain.

Cheers, Wayne

 

[GenSao]

Just want to vent my frustration on the whole Powerwall installation experience.
Now, back to the Powerwalls themselves, when I ordered them, I expected that I could charge them from the grid so that I could take advantage of the EV rate at night. I also have a very small and old solar system (2.5kW from maybe 12 years ago). It used to generated about 10kW per day but for various reasons it's only generating <2kW per day now. But I didn't know that it'd be factored into my Powerwall installation.

Now when they turned on the system, I realized that it could only be charged from the solar panels. It's been almost 2 months now and my powerwalls are still not fully charged at 77%. I called them multiple times to give me a solution and all they said was that it could not be charged from the grid if it's tied to the solar system. And they did not even bother to suggest anything to resolve this even though I told them that I'm willing to completely disconnect the solar system from my house.

There is something wrong that Tesla needs to address with your existing solar system. A reduction of 80% (10 to 2 kWh) of solar output is not good. I assume production numbers given exclude household consumption.

Also, even at a reduced solar production, the Powerwalls should eventually charged to 100% in Backup-only mode. Backup-only mode is where all solar goes to the batteries and household use is powered by the grid. If your solar output is too low, then it is possible that the batteries will not charge to 100% in the other modes.

 

[MP3Mike]

There is something wrong that Tesla needs to address with your existing solar system. A reduction of 80% (10 to 2 kWh) of solar output is not good. I assume production numbers given exclude household consumption.

Why would Tesla need to fix his 12-year old solar system? (That they obviously didn't install.)

 

[GenSao]

Why would Tesla need to fix his 12-year old solar system? (That they obviously didn't install.)

Prehaps a misread on my part. The OP stated: "It used to generated about 10kW per day but for various reasons it's only generating <2kW per day now." Not clear if the Powerwall installation affected solar production after they were installed or the <2kW per day was existing prior to installation of the Powerwall.

 

[Shygar]

Yea seems like the confusion is that powerwalls are generally installed with the solar system so you can take the 30% ITC federal tax credit. Since you had solar, maybe they just assumed that's what you wanted and you assumed it would not be connected to solar (or both solar/grid?). But yea they probably went through a PTO with your power company and confirmed it would be charging with solar so it might be hard to officially change it now. Maybe take up Wayne on his offer.

 

[greentee]

If you're willing to go rogue, and you're not claiming the ITC, you can reconfigure the Powerwalls through the wizard as if you didn't have solar. This is not a supported option from Tesla, mainly due to obstinance as far as I can tell. And as Tesla has the ability to remotely reconfigure your Powerwalls, I'm not clear on whether they'd notice and change it back.

Anyway if you are interested I can explain.

Cheers, Wayne

Hi Wayne, I'd love to know how to reconfigure the powerwalls to not use solar at all.
I do not intend to claim the tax credit anyway since the SGIP rebate is much bigger than that.

 

[greentee]

Sorry for your frustration, but as somebody who is likely to install a Powerwall at some point and is also debating solar, I’ve known this since I first started kicking the tires years ago and suspect most people in the same boat do too.

Not that this is applicable, but imagine the tremendous arbitrage you could gain from ToU by charging up your Powerall via he grid at night and then selling it back to the grid during the day via solar or even Powerwall. That ain’t gonna happen.

It stinks they didn’t make it more clear to you, but perhaps they’re confused why you’re confused?

What do you mean by "I've known this..."? The tax credit? SGIP? hook up of an existing solar system to powerwalls?
Powerwall cannot charge from both solar and grid?

There are many things going on here and a lot of things were not clear when they introduced the powerwall (even the 1st gen) some 3 years ago. Early adopters also indicated that they could charge from both solar and grid.

What irks me the most is not the powerwall limitation. It's their unwillingness to solve the issue proactively.

 

[cwied]

Hi Wayne, I'd love to know how to reconfigure the powerwalls to not use solar at all.
I do not intend to claim the tax credit anyway since the SGIP rebate is much bigger than that.

Just checking that you know you can claim the ITC on the portion remaining after the SGIP rebate. They're not mutually exclusive

Tesla doesn't really support charging from the grid when solar is installed, so you need to be aware that you may run into issues after the reconfiguration.

What are you primarily using your Powerwalls for? Is it just backup, or are you also trying to offset your peak rate usage? PG&E may not like your charging at night and discharge during the day, and that might be reflected in the interconnect agreement. Chances are they can't detect it easily, but still something to be aware of when you could possible claim the ITC instead.

Edit: just to give context - I originally wanted to do what you want to do, but after researching what the firmware currently does I resigned myself to taking the ITC instead. My solar array does generate normally though, and I also missed the SGIP, so the ITC has more value to me than it would to you.

 

[Sylvia Else]

If I knew that the powerwalls could not be charged from the grid, then I wouldn't install it at all consider that it'd still take multiple days to fully charge 1 powerwall, let alone the 2 that I've ordered.

Does it still not charge from the grid if you set the reserve to 100%?

 

[cwied]

Does it still not charge from the grid if you set the reserve to 100%?

In the US, Powerwalls are programmed never to charge from the grid if they're installed alongside a solar system in order to preserve eligibility for a 30% tax credit. The credit is phasing out, so this may eventually change.

 

[wwhitney]

OK, here is what I figured out about reconfiguring a US Powerwall system with solar to ignore the solar and charge from the grid (thereby precluding taking the ITC). I haven't tried any of this, so it all requires field testing and verification:

First, in the event of a power failure, my understanding is that the computer in the gateway is not involved in the management of the microgrid. So changing the gateway's software configuration shouldn't affect off-grid functionality. [I recommend testing this after reconfiguring by flipping the service disconnect to simulate a power failure.]

When operating in grid-tie mode, the computer in the gateway tells the inverters in the Powerwalls how much to charge or discharge. It does this based on its programming, the data from the CTs (current transformers), and the inputs via the Powerwall wizard. See Powerwall Wizard for screenshots of each step of the wizard. See other threads (I don't have a link handy) for information on how to log into the gateway via your local network.

On an installation with solar, the backup gateway, and all loads connected behind the backup gateway, there are typically two sets of CTs. One measures the solar production, the other measures the net flow to/from the grid. In the wizard these are identified as "Solar" and "Site" respectively. For ITC-compliance, the Powerwall's US programming when configured with Solar limits the Powerwall's instantaneous charge rate to whatever the Solar CTs are measuring.

If you want to configure the Powerwall to ignore the solar generation, then you just want it to measure total household consumption. If you configure it just to use the Site CTs, it would only be measuring net consumption after solar production. So what you need to do is change the Solar CTs into a second set of Site CTs, so it will add the two measurements together (with the appropriate sign) to get your total household consumption.

With that in mind, the first step is to go through the wizard without changing anything, just to record all of the current settings. Pay particular attention to the Generation page (6/12) and the Current Transformers page (8/12), as those are the ones you will need to change by running the wizard again, as follows:

On the Generation step (6/12), go ahead and delete your solar production. On the Current Transformers page, likely CTs 1 and 2 are set to Site and CTs 3 and 4 are set to Solar. In which case change CTs 3 and 4 to Site. [CTs 1 and 2 also have a third option, Load, but that option isn't presented for CTs 3 and 4, and I don't know what the distinction is between Site and Load.]

So that's it, with a few caveats:

1) For all I know, the wizard only lets you have one set of Site CTs at a time, i.e. changing CTs 3 and 4 to Site might reset type of CTs 1 and 2. In which case I would try setting CTs 1 and 2 to Load, to see if that works.

2) I haven't sorted through the sign convention on the CTs, it is possible that you will need to check "Flip" for both CTs 3 and 4 after changing them to Site. To test whether you've got the right sign is relatively easy: during the day when your PV is producing, load up the main Powerwall web page showing the instantaneous power flows. Then flip off your PV breaker, shutting down its production. The power flows shown should not change (or if that page shows both CTs separately, their sum shouldn't change). If instead the number changes by about twice what the PV was producing, then the sign is wrong in the wizard and the "Flip" box needs toggling for CTs 3 and 4.

If you try this, let us know and post pictures. Good luck!

Cheers, Wayne

 

[cwied]

You might also want to try just removing the solar generation portion to see if it's enough. I also think there may be a way to disable CTs.

One caveat: in a backup situation you might want to be extra careful when the Powerwalls are getting full. It's conceivable that the solar configuration also configures how (and whether) the system tells the solar inverter(s) to shut down. It's possible that won't work correctly if the Powerwalls are unaware there's a solar system attached.

 

[wwhitney]

You might also want to try just removing the solar generation portion to see if it's enough. I also think there may be a way to disable CTs.

With the covert solar generator, the gateway needs data from both CTs in order to determine the true household load, it is not otherwise possible. So if the goal is to export all solar generation during peak periods, you'll need to reconfigure the CTs as I described. Also, if you disable the second set of CTs and let the Powerwall just see the net import/export, who knows how it will behave during net export (which it would see as negative consumption).

One caveat: in a backup situation you might want to be extra careful when the Powerwalls are getting full. It's conceivable that the solar configuration also configures how (and whether) the system tells the solar inverter(s) to shut down. It's possible that won't work correctly if the Powerwalls are unaware there's a solar system attached.

I agree that it is conceivable, but I'm pretty sure that when the Powerwalls are running as a micro-grid, it's an entirely different, lower level mechanism that controls the charge/discharge behavior (edit: internal to the inverters in the Powerwalls themselves), and the gateway computer isn't involved in that. I spoke with someone at Tesla about this and she agreed, although she didn't seem 100% certain. So I would say it is worth testing.

Cheers, Wayne

 

[NuShrike]

You might also want to try just removing the solar generation portion to see if it's enough. I also think there may be a way to disable CTs.

One caveat: in a backup situation you might want to be extra careful when the Powerwalls are getting full. It's conceivable that the solar configuration also configures how (and whether) the system tells the solar inverter(s) to shut down. It's possible that won't work correctly if the Powerwalls are unaware there's a solar system attached.

This would be the part where the inverters/micro-inverters may auto-shutdown or back-off if they sense over-current/power in the micro-grid.