Adding powerwalls to existing Solar Panel installation. Is it possible?

[dutchinchicago]

I have been impatiently waiting for my powerwalls I ordered over 2 years ago. Every so often a Tesla representative contacts me but as soon as they find out that I already have Solar panels they say that they will get back to me but then never call back.

When I try to call Tesla I am always told that they can't help but an Energy representative will get back in touch but nobody ever calls back.

So I am hoping that there is someone out here that knows the answer.

I currently have a 2.7kW array with a Power One PVI-3.0 inverter. Is it possible to add two Powerwalls to this existing installation?

Paul
Chicago

 

[cwied]

From this page: Powerwall & Solar Integration | Tesla Support

"Yes, Powerwall can be integrated with your existing solar system. Powerwall is compatible with solar inverters from SMA, SolarEdge, Fronius, Enphase micro inverter, Delta and ABB. We continue to explore compatibility with other inverter companies."

I don't know if they keep this page up to date. In principle, the only thing they need from the inverter is for it to shut down in response to frequency shifts, which as I understand it is required of all grid-tied inverters anyway. They may want to test with a given brand before installing with it, though. They may change the Powerwalls frequency response based on quirks of particular inverters.

 

[dutchinchicago]

I know that is what Musk said three years ago when he launched it and that is what the page said but in practice is this actually happening?

When speaking with Tesla representatives they can't get of the phone quickly enough as soon as they hear that you want to add the powerwall you have on order to an existing installation. They seem to think that in real life this is not possible no matter what the web page says.

 

[cwied]

I suspect it's a regional thing. My Powerwalls were added to an existing installation. I have a SolarEdge inverter.

My guess is that they may not have Powerwall availability out there and are just trolling their reservation lists to see if they can pick up a few solar installs in the meantime.

 

[dutchinchicago]

That is great to hear.

Then the next question is what is going to happen given that I have a Power One inverter that is not on the list of the supported inverters. Has anyone been in that situation already?

Paul

 

[arnolddeleon]

I had an two existing PV systems when I got Powerwalls added a little over a year ago.

 

[TheTalkingMule]

It's all about the inverter I believe. Mine was described as "battery agnostic", meaning any AC based battery can be added to the array.

 

[TessiFan]

Hey guys

i am new to the forums but having been following for a while now. So i have an existing solar system (7.3Kw with a 40A breaker) and want toadd two powerwalls and a second solar system. My toatal back feed amperage will be 140A (breaker values) and i have a 200A/200A main service panel. Can anyone tell me how difficult this might me with my existing setup. Thank you for all your help and advice.

 

[nyprepper]

I think the reluctance to sell PW's without new solar is about economics. I originally ordered my PW's standalone, without ANY solar....existing, new, or otherwise. It was only after i decided to add Tesla solar that anyone at Tesla or my regional Solar City office showed any interest and was able to get the ball rolling. i came away with the distinct impression that the sales reps were only comped on Solar sales....NOT on the Powerwalls.

 

[Dan123]

I had a similar experience. They were willing to install it with solar, but not without solar. I had to bug them repeatedly, calling their number every couple of months, and eventually they said that they were willing to move forward.

 

[Dan123]

Hey guys

i am new to the forums but having been following for a while now. So i have an existing solar system (7.3Kw with a 40A breaker) and want toadd two powerwalls and a second solar system. My toatal back feed amperage will be 140A (breaker values) and i have a 200A/200A main service panel. Can anyone tell me how difficult this might me with my existing setup. Thank you for all your help and advice.

The Powerwall, most likely, will not be backfed into your panel. They will install the gateway, and the gateway will be connected to the supply side of your main panel.

With a 200 amp panel, you are likely limited to your 40 amps. To add another solar system, you would either add it outside (connecteced to the Powerwall gateway, and not backed up). Or you could upgrade your panel. Or you could derate your panel main breaker to 175 or 150 (depends on what appliances you have in the house, if tankless water heater - not going to work).

 

[wwhitney]

My toatal back feed amperage will be 140A (breaker values) and i have a 200A/200A main service panel. Can anyone tell me how difficult this might me with my existing setup. Thank you for all your help and advice.

When you say a 200A/200A main service panel, does that mean a 400A service with (2) 200A main breakers? If so, the Powerwall Backup Gateway is only rated for 200A, so it will go on only one of the 200A main breakers. That means only loads on that main breaker can be backed up.

Also, achieving 140A (after 125% factor) of backfeed on a 200A main breaker is a bit tricky. You basically need to have the Backup Gateway directly after the 200A main breaker, before any other breakers. So if your 200A main breaker is an enclosure with other branch/feeder breakers, you'd need to move them all out to a separate enclosure, with the Backup Gateway wired in between the main breaker and the new enclosure.

Cheers, Wayne

 

[TessiFan]

When you say a 200A/200A main service panel, does that mean a 400A service with (2) 200A main breakers? If so, the Powerwall Backup Gateway is only rated for 200A, so it will go on only one of the 200A main breakers. That means only loads on that main breaker can be backed up.

Also, achieving 140A (after 125% factor) of backfeed on a 200A main breaker is a bit tricky. You basically need to have the Backup Gateway directly after the 200A main breaker, before any other breakers. So if your 200A main breaker is an enclosure with other branch/feeder breakers, you'd need to move them all out to a separate enclosure, with the Backup Gateway wired in between the main breaker and the new enclosure.

Cheers, Wayne

Sorry for he confusion, its a 200A rated panel with one 200A preaker. the 140A is the toatl amps for the 3 breakers ($)A each of the 2 solars and 60A for the two powerwalls). So today i received a diagrm sketch to show how the setup would be, my MSP will be load free, goiung directly to the TBG which in turn will land on a 200A sub panel containing the house load. That will be fed from a load panel housing he existing solar (40A), a second solar array (40A) and two powerwalls(60A). THis load panel will be 200A with a 150A breaker.

 

[TessiFan]

The Powerwall, most likely, will not be backfed into your panel. They will install the gateway, and the gateway will be connected to the supply side of your main panel.

With a 200 amp panel, you are likely limited to your 40 amps. To add another solar system, you would either add it outside (connecteced to the Powerwall gateway, and not backed up). Or you could upgrade your panel. Or you could derate your panel main breaker to 175 or 150 (depends on what appliances you have in the house, if tankless water heater - not going to work).

Derating in not possible, nor is a panel upgrade due to the proximity of a gasline. So that leaves only the one option

 

[TessiFan]

When you say a 200A/200A main service panel, does that mean a 400A service with (2) 200A main breakers? If so, the Powerwall Backup Gateway is only rated for 200A, so it will go on only one of the 200A main breakers. That means only loads on that main breaker can be backed up.

Also, achieving 140A (after 125% factor) of backfeed on a 200A main breaker is a bit tricky. You basically need to have the Backup Gateway directly after the 200A main breaker, before any other breakers. So if your 200A main breaker is an enclosure with other branch/feeder breakers, you'd need to move them all out to a separate enclosure, with the Backup Gateway wired in between the main breaker and the new enclosure.

Cheers, Wayne

I believe the fuses are all rated at or close to the 125% factor.

 

[Pale_Rider]

Just added 3 powerwalls (two were from referrals) about a month ago to my existing system. So they definitely can do it if they are doing installs in your area.

 

[ctslc]

I will concur: I ordered two PW2s in November, 2017 and they were installed in October 2018 and, at the time, I had a single 5kW solar system - which I later upgraded to include another 3.8kW PV system - both series-string SMA. The "addition" of the second SMA simply involved putting the wires for the second inverter through the same CTs (current transducers) as the first, observing current phasing so that the Neurio could "see" the combined current of both inverters.

FWIW, About 5 months after installation Tesla called me and informed me that the gateway needed to be replaced - which they did: I never could get out of them the reason for the swap-out.

 

[werneruk]

but can anyone recommend a company who will actually do this? I have solar from West Coast Solar, who will not do it. any recommendations welcomed!

 

[astrorob]

i had tesla do mine - i'm in the east bay. i have a sunpower system with a 5KW SMA inverter.

 

[jjrandorin]

but can anyone recommend a company who will actually do this? I have solar from West Coast Solar, who will not do it. any recommendations welcomed!

You will need to just look around. Due to the demand on powerwalls now, many companies are not interested in doing powerwalls on existing solar, or if they do, its for prices that are "premium" ones (like 14-15k for one, or 25k for 2 or something).

Tesla doesnt offer powerwalls without solar currently. It isnt a technical limitation, its a "we cant even make enough for all the people who want them for more lucrative solar + powerwalls, so we are not doing them separately) decision.