Advice on whether this installation is possible

[Vines]

Holey, we talked a little bit via PM. Did the other installer that I recommended say the same to you? They should know better!

If you are ready to consider 3 Powerwalls give us a ring, and we can discuss. I am 100% confident we can find a solution that works for you. Installs are being scheduled for November/December right now.

Alternately if you want me to design and draft a CAD package for your PV/PW system so someone else can install it let me know.

 

[holeydonut]

Hi Vines,

No, I didn't get in touch with your installer since I was able to get my a installer on board with the schematic you helped me put together. Thanks for your help on that!

Tesla literally put the ideal diagram for me on to Page 55 of their PW2 + GW2 manual. I guess it's not that uncommon of a request haha.
https://www.tesla.com/sites/default...erwall_2_AC_GW2_NA_EN_Installation_Manual.pdf

But to anyone reading this that is on the fence for PV + Powerwall... I think the best approach is to get PV from a dedicated PV installer; then go through a PW expert to get the Powerwall installed. The amount of pain and suffering it takes to get both the PV and Battery installed at the same time isn't worth it.

The combo installers all seem to be stuck with their Generac and LG Chem use cases. They had difficulty to accept what the Powerwall 2 + Gateway 2 are capable of. I had one guy tell me during a phone consult "You don't know what you're talking about! The Tesla gateway just a relay... it has no smart functionality the way you're describing to backfeed so many parts of your home!!".

 

[Vines]

I am super glad that I was able to help, and hopefully your installer can help others now too. The energy revolution is coming and no way any single installer can support it all.

The Gateway 2 has functionality in it that will soon blow minds and those guys wont even see it coming.

 

[SoundDaTrumpet]

@holeydonut The TEG2 (Tesla Energy Gateway 2 (GW2)) installation manual appendices will be valuable in answering many installation questions on the Tesla Energy forum here. Thumbs up!

Worth posting again: https://www.tesla.com/sites/default...erwall_2_AC_GW2_NA_EN_Installation_Manual.pdf

My installation resembles Figure 24. I have TEG version 1, which has no distribution in the TEG, so my solar & powerwalls are tied to the backup load center. The A/C and EV charging are on the meter load center. One thing Figure 24 should note is that TEG is connected to the meter load center via a branch circuit breaker limited to 125A, which is a limitation of my Siemens meter load center (and other brands).

 

[jjrandorin]

@holeydonut

Sorry to hear about the A/C situation you detailed. Thats the exact type of situation I try to avoid (a contractor underperforming, or not setting something up optimally), and so far I have been lucky. Its a struggle for sure though, dealing with anything having to do with home improvements especially. Something about the construction industry in that, sometimes even the best people / companies dont perform as expected.

 

[holeydonut]

@holeydonut The TEG2 (Tesla Energy Gateway 2 (GW2)) installation manual appendices will be valuable in answering many installation questions on the Tesla Energy forum here. Thumbs up!

Worth posting again: https://www.tesla.com/sites/default...erwall_2_AC_GW2_NA_EN_Installation_Manual.pdf

My installation resembles Figure 24. I have TEG version 1, which has no distribution in the TEG, so my solar & powerwalls are tied to the backup load center. The A/C and EV charging are on the meter load center. One thing Figure 24 should note is that TEG is connected to the meter load center via a branch circuit breaker limited to 125A, which is a limitation of my Siemens meter load center (and other brands).

Yeah I've directed my installer to page 55 (Figure 24) and identified that is the diagram that should work in my home. Hopefully they will be able to do it.

I'm still running the risk that I'm their first customer out of thousands that they've ever installed a partial home backup solution. They've been doing total backups for so long (and reaping the higher margins with the over-sized generators and batteries) that I may be the last customer they do this for as well haha.

I'm assuming you had your installation through Tesla directly? I can't imagine another combo PV + Battery installer that would think to do this (other than the one Vines recommended).

 

[holeydonut]

@holeydonut

Sorry to hear about the A/C situation you detailed. Thats the exact type of situation I try to avoid (a contractor underperforming, or not setting something up optimally), and so far I have been lucky. Its a struggle for sure though, dealing with anything having to do with home improvements especially. Something about the construction industry in that, sometimes even the best people / companies dont perform as expected.

Yeah, I feel that dealing with experts for home ownership issues requires decades of experience to slowly build upon. Which means first time homeowners can get hosed since it's easy to pull a fast one on them.

I get it though; some these folks are running on tight margins and will take the path of least resistance to minimize labor hours worked so they can move on to the next gig. They believe the average customer only cares if something is working or is not working. All the stuff on the peripheral would be things they'd do for their own homes, but they wouldn't expect the customer to appreciate the extra effort.

Like when I had my kitchen remodel last year, I had the in-wall oven + microwave stack replaced. There was a 240v J-box available with two sets of hot wires. The installer decided to just use one lead and wire up both devices. I didn't know any better to inspect for this type of short-cut, and the installer got the sign-off since the stuff worked. Sure enough a few weeks later when I ran both units on high... the bullet connector melted and it screwed everything up.

I kind of wish all those online guides would advise people on all the shortcuts contractors take when they know the customer isn't smart enough to ask haha.

 

[SoundDaTrumpet]

I'm still running the risk that I'm their first customer out of thousands that they've ever installed a partial home backup solution. They've been doing total backups for so long (and reaping the higher margins with the over-sized generators and batteries) that I may be the last customer they do this for as well haha.

I recommend speaking in terms of which sub-panels to backup. Often times the "partial home backup" is viewed as extra complication; therefore, simplifying the conversation will keep the work scope and conversations focused for both the installer and customer, respectively.

I'm assuming you had your installation through Tesla directly? I can't imagine another combo PV + Battery installer that would think to do this (other than the one Vines recommended).

I had my installation through Tesla directly. It did take some engineering discussions to steer the design. @Vines and @wwhitney provided some valuable input specific to MLO service panels. This saved me thousands of dollars.

 

[holeydonut]

I recommend speaking in terms of which sub-panels to backup. Often times the "partial home backup" is viewed as extra complication; therefore, simplifying the conversation will keep the work scope and conversations focused for both the installer and customer, respectively.

I had my installation through Tesla directly. It did take some engineering discussions to steer the design. @Vines and @wwhitney provided some valuable input specific to MLO service panels. This saved me thousands of dollars.

For real, Vines has been the most helpful person I've spoken with about Powerwall haha.

My house is kind of weird; I have two sets of breakers. The interior house panel is in the garage and the exterior panel is next to the ACs.

Initially I wanted to backup the entire interior garage panel. I tried to tell the installers that I'm more than happy to manually shed interior loads if there's an outage; I just need to be alerted that there was an outage. So I'll halt my dryer, only use one element of my electric stove, and turn off a ton of lights. This would simplify the engineering aspect and wouldn't even require a new sub-panel.

But the majority of local installers said "no way" and wanted to back up the ENTIRE house for both the interior garage panel and exterior AC panel. This would involve at least 3x Powerwalls and required soft starts on the AC (but I wasn't allowed to install them per my HVAC manfacturer's guidance).

Tesla went the other way, they wanted to create a sub panel of "non backup heavy loads" and integrate that alongside my ACs. This way I'd still keep my interior panel for backup; but some stuff would need to be rewired.

But in the end, the installer I went with was fine just backing up my entire interior panel and leaving the ACs on the non-backup side (but connected with a CT)