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4 kW Tesla solar install (with existing solar) and Powerwall addition and what I learned

Flyguy

Member
Aug 17, 2017
297
171
94062
I got a price reduction on the Powerwall, which was pretty much the cost of the gateway 2. That was easy to justify because there was equipment that clearly was not going to be used. As I noted in my original write up, the installers/Tesla got off lucky with my install. I'm sure they spent less time that they budgeted. I'm good with that because I knew overall I was still getting bargain because the cost was lower than if I had a full concierge sales team that would have quoted a more "exact" installation price adjusted for the complexity of the job. I like the Tesla pricing model.

On the solar side it was a completely independent system from my two other existing solar systems. The only really easy part was I already had a generation panel so they could install without causing any outages (never lost power yesterday). They probably needed to do slightly more work because I had so much existing equipment to route around. So, all in, a wash.

If you have a Tesla Inverter for your existing solar then they could potentially just add panels to your existing inverter although if you look at how they price things, it is mostly on the install, so any cost reduction on not having to add an inverter is not going to be huge. Don't forget that you can get a self referral credit and discount.
Thanks again for the info. Unfortunately the beginning of this thread is no longer available because of the migration, so was not able to read your original post.
my system is Panasonic panels with optimizers into a solar edge inverter. The inverter only has room for another kilowatt, So any new installation would need its own inverter. Or, A new larger tesla inverter for everything. Although I don’t think the panels snd optimizers would integrate with a Tesla system. Anyway, all food for thought
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
8,147
9,003
Riverside Co. CA
Thanks again for the info. Unfortunately the beginning of this thread is no longer available because of the migration, so was not able to read your original post.
my system is Panasonic panels with optimizers into a solar edge inverter. The inverter only has room for another kilowatt, So any new installation would need its own inverter. Or, A new larger tesla inverter for everything. Although I don’t think the panels snd optimizers would integrate with a Tesla system. Anyway, all food for thought

The opening post in this thread is post number 2 in this thread... unless I do not understand what you are talking about.

Got call yesterday asking if I wanted to get my 4kW PV and Powerwall install tomorrow (today). I said yes and they just finished and here are some things I learned.

Background (existing systems)

19 year old system
128 BP-585 modules (85 watt STC rating)
3 Outback GVFX-3648 (3.6kW)

12 year old system
12 Kyocera KD205GX-LP (205 watt STC, 180 watt PTC)
1 Xantrex GT2.8-NA 240/208 (2.8kW)

3 year old system
2 Tesla Powerwall 2
Gateway 1
Whole house backup
Dedicated generation panel

Things I learned

Powerwall installs:

The new restrictions in Santa Clara county CA and what many of the cities (Cupertino in my case) have adopted are annoying. I forgot to take a picture of the sheet that the installers showed me. All of these I've heard about ins some form or another. Here the ones I could remember:

Can't stack (double deep), e.g. my existing system would not be allowed
Can't be within 5' of property line
Can't be with 3' of window or that leads to house
Can't install inside of garage

I had hoped that would have been a small matter of putting a 3rd one on the existing stack, also no joy. So my new powerwall is on outside wall of my garage about 6' from my front door. I now have Powerwalls on two outside walls of my garage. I also will need some forgiveness from my wife for taking out a plant to get access to the space where the Powerwall #3 went. I'm planning on planting a replacement.

Tesla Inverter:

Minimum string length apparently 5.
Rapid shutdown is achieved with an active part in the modules (@nwdiver , I think you were wondering about this) that is present in every 3rd module. The installer called it a "mick" (MIC?).
The inverter has a fan.
Commissioning is how others have described it, from an app connecting to a local WiFi network shortly after power up.
There is a hardwired Ethernet port but I wasn't prepared with a cable.
Apparently an external disconnect is still required in my area. I thought this was no longer the case but I might have fallen into the line of site rules. The new inverter is on the other side of the fence from my main panel.

PV panels:

They look real good (from the ground). Skirts installed I think all around (can't see the top), definitely side and bottom.

Scheduling and Install

As I mentioned, my install was originally for May 28th. I assumed when they called me yesterday that it was because of a cancellation. That doesn't appear to be the case. The two teams (PV and storage) are from Southern CA and were called up to assist here. It looks like they work about a week before going home.

I think they caught a break with my install. I was able to figure out some options that made the install go smoother. There were a couple of things that I would have had had them do differently had I been able to spend all my attention on them (I was doing work at the same time). I wish I had a more detailed plan before they came so I could have been better prepared to make suggestions on things like conduit routing.

They move fast. I think there 3 people on solar crew and 2 on the storage crew.

In the Tesla app I could see the 3rd Powerwall as soon as they "commissioned" it. Not surprising. I also can't see the new solar in the app yet, I'm told that will come after PTO, also not surprising.

They painted the conduit. If you have matching paint be ready, I didn't have any. Someone on the install team did an eyeball match with a paint kit they apparently travel with, it looks pretty good to me.

They generate a punch of small things for the inspection person to handle. For example, they were missing a nut to bond the inverter door.


Photo Album:


Note I know that some of the photos show the password for the solar inverter used during setup. If you are physically close enough to the inverter for that information to be useful then you are physically close enough to get it.

Sharp eyed viewers might also not an incorrectly sized breaker, that's on the punch list, they didn't have one on the truck.
 

h2ofun

Active Member
Aug 11, 2020
2,098
328
auburn, ca
Thanks again for the info. Unfortunately the beginning of this thread is no longer available because of the migration, so was not able to read your original post.
my system is Panasonic panels with optimizers into a solar edge inverter. The inverter only has room for another kilowatt, So any new installation would need its own inverter. Or, A new larger tesla inverter for everything. Although I don’t think the panels snd optimizers would integrate with a Tesla system. Anyway, all food for thought
Why do you say our inverter only has room for another kilowatt?
 

arnolddeleon

Supporting Member
Jul 21, 2012
745
829
SF Bay Area
Someone in the back office must have been doing a check on the install. The crew came back yesterday to quickly upsize the the ground wire from the arrays down to the inverter. Apparently there is a difference between Southern CA rules and rules in Santa Clara/Cupertino. Took 15 minutes.
 
  • Informative
Reactions: jjrandorin

SMAlset

Well-Known Member
Mar 4, 2017
8,987
9,691
SF Bay Area
Thanks for the photos. Unfortunately for you Cupertino lies in the Santa Clara County Fire Department's jurisdiction which seems to have the most restrictive backup battery restrictions (Campbell, Cupertino, Los Altos, Los Altos Hills, Los Gatos, Monte Sereno and Saratoga). We're in Santa Clara County but are under a different fire department. I know @Vines' install company has been dealing with your jurisdictional nightmare for some time for some of his installs in that area. I don't think our local department has changed rules from when we had our install in August/September (PTO in October) but am glad we had our install done already and not worrying about what and where we could put things (PW garage install and 2 units stacked inside). I would have liked to have added a 4th PW but we stayed with 3 which seem to be working fine for us so far, however Summer has not been experienced yet with A/C.

BTW I think they did a nice paint matching job too.
 

arnolddeleon

Supporting Member
Jul 21, 2012
745
829
SF Bay Area
Thanks for the photos. Unfortunately for you Cupertino lies in the Santa Clara County Fire Department's jurisdiction which seems to have the most restrictive backup battery restrictions (Campbell, Cupertino, Los Altos, Los Altos Hills, Los Gatos, Monte Sereno and Saratoga). We're in Santa Clara County but are under a different fire department. I know @Vines' install company has been dealing with your jurisdictional nightmare for some time for some of his installs in that area. I don't think our local department has changed rules from when we had our install in August/September (PTO in October) but am glad we had our install done already and not worrying about what and where we could put things (PW garage install and 2 units stacked inside). I would have liked to have added a 4th PW but we stayed with 3 which seem to be working fine for us so far, however Summer has not been experienced yet with A/C.

BTW I think they did a nice paint matching job too.
It's interesting that you said Santa Clara County Fire Department vs just Santa Clara County. That probably explains why San Jose appeared to have slightly different rules. I really wish I took a picture of the sheet. I've been regretting for a while that I didn't go with three Powerwalls when we did the original install 3 years ago.

Someone on the crew knows to blend paint.
 

Odobo

Member
Feb 16, 2021
28
16
USA
Got call yesterday asking if I wanted to get my 4kW PV and Powerwall install tomorrow (today). I said yes and they just finished and here are some things I learned.

Background (existing systems)

19 year old system
128 BP-585 modules (85 watt STC rating)
3 Outback GVFX-3648 (3.6kW)

12 year old system
12 Kyocera KD205GX-LP (205 watt STC, 180 watt PTC)
1 Xantrex GT2.8-NA 240/208 (2.8kW)

3 year old system
2 Tesla Powerwall 2
Gateway 1
Whole house backup
Dedicated generation panel

Things I learned

Powerwall installs:

The new restrictions in Santa Clara county CA and what many of the cities (Cupertino in my case) have adopted are annoying. I forgot to take a picture of the sheet that the installers showed me. All of these I've heard about ins some form or another. Here the ones I could remember:

Can't stack (double deep), e.g. my existing system would not be allowed
Can't be within 5' of property line
Can't be with 3' of window or that leads to house
Can't install inside of garage

I had hoped that would have been a small matter of putting a 3rd one on the existing stack, also no joy. So my new powerwall is on outside wall of my garage about 6' from my front door. I now have Powerwalls on two outside walls of my garage. I also will need some forgiveness from my wife for taking out a plant to get access to the space where the Powerwall #3 went. I'm planning on planting a replacement.

Tesla Inverter:

Minimum string length apparently 5.
Rapid shutdown is achieved with an active part in the modules (@nwdiver , I think you were wondering about this) that is present in every 3rd module. The installer called it a "mick" (MIC?).
The inverter has a fan.
Commissioning is how others have described it, from an app connecting to a local WiFi network shortly after power up.
There is a hardwired Ethernet port but I wasn't prepared with a cable.
Apparently an external disconnect is still required in my area. I thought this was no longer the case but I might have fallen into the line of site rules. The new inverter is on the other side of the fence from my main panel.

PV panels:

They look real good (from the ground). Skirts installed I think all around (can't see the top), definitely side and bottom.

Scheduling and Install

As I mentioned, my install was originally for May 28th. I assumed when they called me yesterday that it was because of a cancellation. That doesn't appear to be the case. The two teams (PV and storage) are from Southern CA and were called up to assist here. It looks like they work about a week before going home.

I think they caught a break with my install. I was able to figure out some options that made the install go smoother. There were a couple of things that I would have had had them do differently had I been able to spend all my attention on them (I was doing work at the same time). I wish I had a more detailed plan before they came so I could have been better prepared to make suggestions on things like conduit routing.

They move fast. I think there 3 people on solar crew and 2 on the storage crew.

In the Tesla app I could see the 3rd Powerwall as soon as they "commissioned" it. Not surprising. I also can't see the new solar in the app yet, I'm told that will come after PTO, also not surprising.

They painted the conduit. If you have matching paint be ready, I didn't have any. Someone on the install team did an eyeball match with a paint kit they apparently travel with, it looks pretty good to me.

They generate a punch of small things for the inspection person to handle. For example, they were missing a nut to bond the inverter door.


Photo Album:


Note I know that some of the photos show the password for the solar inverter used during setup. If you are physically close enough to the inverter for that information to be useful then you are physically close enough to get it.

Sharp eyed viewers might also not an incorrectly sized breaker, that's on the punch list, they didn't have one on the truck.
Hmm.... Can't install inside of garage is a Cupertino thing? I am in San Jose and installed mine inside and stacked without problem.

The 5' requirement is for everything to prevent noise as I was told when I installed my AC...
 

arnolddeleon

Supporting Member
Jul 21, 2012
745
829
SF Bay Area
Hmm.... Can't install inside of garage is a Cupertino thing? I am in San Jose and installed mine inside and stacked without problem.

The 5' requirement is for everything to prevent noise as I was told when I installed my AC...
It might be a slight misunderstanding on my part. I was looking at a sheet and I read "Santa Clara County". It might be be Santa Clara County *Fire District* thing based on what @SMAlset wrote up thread.
 

nwdiver

Well-Known Member
Feb 17, 2013
7,743
9,958
United States
Looking at the pictures, it's obvious that it's water cooled instead of directly air cooled. I can clearly see that there are no heat sink cooling fins and there are tubes and tube fittings that are used for liquids.

I guess time will tell if that's a good idea. One of the features I liked about Solar Edge is that it's 100% passively cooled. Not even any fans. Even their 11.4kW inverter has no fans IIRC. Crazy.
 

dareed1

Member
Jan 15, 2021
63
60
Belmont, CA
String inverters dissipate most of their inefficiency in the inverter, while the SolarEdge dissipates a fair amount in the optimizers.

It looks like Tesla is using mostly the same components for the small or larger version. The power dissipation in the 8kW inverter could be 200+ watts. That's quite a bit to handle passively.
 

nwdiver

Well-Known Member
Feb 17, 2013
7,743
9,958
United States
String inverters dissipate most of their inefficiency in the inverter, while the SolarEdge dissipates a fair amount in the optimizers.

It looks like Tesla is using mostly the same components for the small or larger version. The power dissipation in the 8kW inverter could be 200+ watts. That's quite a bit to handle passively.

Yeah. A string inverter w/o optimizers needs to dissipate ~2x as much heat as one with optimizers. But even SMA inverters are mostly passive. I think the biggest tradeoff is the amount of Aluminum needed. ~80% of the weight of a SMA inverter is thermal mass.
 

SMAlset

Well-Known Member
Mar 4, 2017
8,987
9,691
SF Bay Area
It might be a slight misunderstanding on my part. I was looking at a sheet and I read "Santa Clara County". It might be be Santa Clara County *Fire District* thing based on what @SMAlset wrote up thread.

I had read a thread @Vines started maybe last year about the changes in code that were affecting his business here in the SF Bay Area. Helped educate us about what was going on around us and what might be coming our way depending on if changes were adopted and implimented by other jurisdictions or State level. Until his thread I actually had no idea there were so many fire department jurisdictions in the Bay area.
 
  • Like
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Vines

Active Member
Jul 20, 2018
1,870
2,185
Silicon Valley, CA
I had read a thread @Vines started maybe last year about the changes in code that were affecting his business here in the SF Bay Area. Helped educate us about what was going on around us and what might be coming our way depending on if changes were adopted and implimented by other jurisdictions or State level. Until his thread I actually had no idea there were so many fire department jurisdictions in the Bay area.
As the codes have evolved, Santa Clara County Fire have pushed for early adoption of the interim code cycle which is coming everywhere July 1 2021.

Cupertino currently takes their very aggressive view, same as Santa Clara County pushed for in other places like Los Altos Hills, Campbell, Los Gatos. Woodside Fire Protection, for Woodside and Portola Valley have also made the new rules code early. Oakland and City of SF have also adopted new rules. The city of SF is taking a stance that is basically nonsense, but extremely strict and effectively requires 36" separation of the ESS among other things.

This does not mean garage installations are impossible, just more difficult. Many installers are turning customers who want them in the garage to outside just to get away from the onerous requirements. Where WFD took a reasonable look at the impact protection and heat alarm/detector requirement, SCC Fire have been absolutely rigid and unreasonable. I have literally sent their leaders emails for months with little to no progress. They and the president in the NorCal FCAC seem to be pushing ESS to where only exterior installations are practical.
 

jboy210

Supporting Member
Dec 2, 2016
4,929
3,020
Northern California
I guess time will tell if that's a good idea. One of the features I liked about Solar Edge is that it's 100% passively cooled. Not even any fans. Even their 11.4kW inverter has no fans IIRC. Crazy.
One of my Delta M series inverters has a fan and the other does not. According to the spec sheet, 8kW and up (8 & 10 kW) have a fan and the others (4,5,6 kW) do not.
 
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Reactions: nwdiver

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