Get Powerwalls to charge from Grid? Install Powerwalls first ? Then non-Tesla panels?

[NYUES88]

I was thinking of a work around with Powerwalls, trying to get the best of both worlds in terms of my Powerwalls pulling from the grid and charging from solar or the grid.

Would having them installed first and then having non-tesla solar panels installed after make this possible? Has anyone done this and had success since technically speaking the Powerwalls shouldn't have code blocking them from charging from the grid.

 

[gpez]

I was thinking of a work around with Powerwalls, trying to get the best of both worlds in terms of my Powerwalls pulling from the grid and charging from solar or the grid.

Would having them installed first and then having non-tesla solar panels installed after make this possible? Has anyone done this and had success since technically speaking the Powerwalls shouldn't have code blocking them from charging from the grid.

I doubt it's a setup configuration thing - if solar panels are installed then don't charge from the grid seems to be the most likely default for all US installs. Remember that when you have solar installed (Tesla or otherwise) and want it connected to the PW you need to route those circuits to the Gateway and re-configure the gateway's CT and configuration to recognize the solar panels so that it can monitor and manage accordingly. It's not as simple as sneaking panels in after and everything is good.

Have you tried talking to Tesla? As you note there is nothing physically preventing them from charging from the grid, it's a software configuration they've decided on which this board has broadly speculated is due to the ITC requirements that batteries be charged from solar power to qualify. It'd probably take some calls, emails, escalations, and frustrating phone calls but I imagine it's at least possible (though maybe not likely) to convince Telsa to allow your PW to be configured to charge from the grid.

 

[NYUES88]

I have emailed Tesla as to the reason why it cannot charge from the grid, and I have asked if it was to do with the ITC, if they would allow it after the 5 year period or when ITC is phased out. They have not responded yet

I doubt it's a setup configuration thing - if solar panels are installed then don't charge from the grid seems to be the most likely default for all US installs. Remember that when you have solar installed (Tesla or otherwise) and want it connected to the PW you need to route those circuits to the Gateway and re-configure the gateway's CT and configuration to recognize the solar panels so that it can monitor and manage accordingly. It's not as simple as sneaking panels in after and everything is good.

Have you tried talking to Tesla? As you note there is nothing physically preventing them from charging from the grid, it's a software configuration they've decided on which this board has broadly speculated is due to the ITC requirements that batteries be charged from solar power to qualify. It'd probably take some calls, emails, escalations, and frustrating phone calls but I imagine it's at least possible (though maybe not likely) to convince Telsa to allow your PW to be configured to charge from the grid.

 

[zanary]

I have emailed Tesla as to the reason why it cannot charge from the grid, and I have asked if it was to do with the ITC, if they would allow it after the 5 year period or when ITC is phased out. They have not responded yet

I think Tesla is just following the IRS rules here, so they probably won't respond back with the reason beyond they are required by the IRS.

URL = https://www.irs.gov/pub/irs-wd/201809003.pdf

Page 2 specifically indicates

When the Battery is constrained to charge only from solar, the software monitors these signals (every 0.1 seconds) and controls the Battery such that charging only occurs when the Solar Energy System is producing energy and only up to the instantaneous solar power. Thus all energy that is used to charge the Battery can be effectively assured to come from the Solar Energy System.

I had inquired about this, and even indicated that since PG&E requires me to have an NGOM, it's impossible to NEM more than I generate without getting flagged, but even with an NGOM, they don't allow charging the battery from grid and NEM solar back to PG&E if I claim the Investment Tax Credit.

Plus with PG&E introduce EV2-A (as a replacement for EV-A), it is subtly pushing residents to self generate and self store vs.. trying to get NEM2 credits.

Legacy EV-A Rate Plan = https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_EV (Sch).pdf
Replacement EV2-A Rate Plan = https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_EV2 (Sch).pdf

 

[gpez]

I think Tesla is just following the IRS rules here, so they probably won't respond back with the reason beyond they are required by the IRS.

URL = https://www.irs.gov/pub/irs-wd/201809003.pdf

Page 2 specifically indicates

​

I had inquired about this, and even indicated that since PG&E requires me to have an NGOM, it's impossible to NEM more than I generate without getting flagged, but even with an NGOM, they don't allow charging the battery from grid and NEM solar back to PG&E if I claim the Investment Tax Credit.

Plus with PG&E introduce EV2-A (as a replacement for EV-A), it is subtly pushing residents to self generate and self store vs.. trying to get NEM2 credits.

Legacy EV-A Rate Plan = https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_EV (Sch).pdf
Replacement EV2-A Rate Plan = https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_EV2 (Sch).pdf

The problem is its not Tesla that is "required" to do this by the IRS - only those (read: taxpayers) taking the ITC are required to charge entirely by solar.

If I were @NYUES88 I would challenge Tesla, if this was indeed their response and this were true, that I am not taking the ITC and would be willing to document so and to please change the functionality of my Powerwall. This is of course assuming that he would not take the ITC. (pay your taxes!)

 

[zanary]

The problem is its not Tesla that is "required" to do this by the IRS - only those (read: taxpayers) taking the ITC are required to charge entirely by solar.

If I were @NYUES88 I would challenge Tesla, if this was indeed their response and this were true, that I am not taking the ITC and would be willing to document so and to please change the functionality of my Powerwall. This is of course assuming that he would not take the ITC. (pay your taxes!)

Good point, however when you are filling in all the forms when you purchase Solar and or Powerwalls, it is one of the questions on the form. If you plan to take the ITC credit or not. The expectation is that you're telling the truth.

Now, what Tesla does with that info, I don't know.

 

[bob_p]

It should be possible to purchase PowerWalls for backup power, charged from the grid.

You can configure a non-solar PowerWall system on the Tesla website.

In this configuration, the installers would configure the Tesla Gateway to charge the PowerWalls from the grid. And if you later installed solar, the Gateway should charge the PowerWalls from solar or grid power.

But...

Doing it in this sequence would likely prevent you from using any of the financial incentives that come with solar power. If you install PowerWalls and solar panels together, you'd qualify for the 26% federal tax credit - which requires the PowerWalls are charged only from solar.

Plus, charging from the grid for the PowerWalls will change the warranty from the unlimited charges for use with solar panels to a limit of how much charging is allowed before the warranty expires.