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Adding to existing system

Adding to existing system

I currently have 6 kW on my roof. Would like to increase it to 10 kW. Will Tesla add panels to existing inverter or require a second inverter? And if a 2nd inverter, how does that effect adding a PW(s) to handle all 10kW's?

lpjakob | 08. August 2019

Just want to add that I have the very same request. Current system is from Sunrun but they are not offering batteries to existing customers, only new installs. I purchased two Teslas since putting in Solar 6-years ago, need to increase to 10 - 12kW and want to add battery storage. Would love to know if Tesla Energy can provide a solution.

Tesla-David | 08. August 2019

I am confident you can add to your solar and also add battery storage through Tesla. We started with 9.84 kWh solar system, and added an additional 3.36 kWh when we got our first Tesla (MS) in 2013, and added 2-PW2 batteries last year. We had a local solar vendor (A&R Solar) not Tesla, who also did our PW2 installation. Everything is working exceptionally well, and the PW2 batteries were an incredible addition, reducing our grid energy usage to zilch in self-powered mode.

Patrick | 08. August 2019

William - depends on which inverter is already installed. For example I believe Solar Edge offers options for 5, 6, 7.6, or 10kw inverters. If you have a 10kw unit you can add more panels up to 10kw total power.

Powerwalls will work fine with either 1-2 inverters.

glerucicer | 12. August 2019

I have Tesla solar panels at the moment, and I want to add some more panels from Tesla. My average electricity usage has increased more than the average quoted usage previously. Is it still possible, in this case, for me to add more panels?

subbarao.vadapalli | 13. August 2019

I have a Solar City system 2.65kW capacity for 5 yrs.
I recently contacted Tesla for adding more capacity, and their solution was to add a second system 4.095kW capacity.

Currently waiting for utility company clearance to turn on the 2nd system.

So, in a nut shell, i think it is a lot easier to deal with utility permissions, paper work, etc. if they are adding a whole new system to work along side the existing one..

Hope it helps..

dubaijayengereh... | 16. August 2019

Has anyone uncovered reliable information regarding Tesla’s manufacturing yield management plans for the next few years? Meaning how are they going to toggle efficiently between cars, battery packs, and solar to reach max production capacity and margins? Seems if Ford, GM, VW, etc all ramp auto production, and Tesla’s factories do multiple different things that there could be a big margin advantage from this.

kollamala | 18. August 2019

Good luck getting a response from Tesla energy. Have been trying for the last month.
Wanted to install a second system but need a written agreement from tesla. Or I would like to purchase the system at the end of the 7th year/PPA. No luck in getting a response. If the big companies dont have time for customer service they should not be in the biz selling the products.

gregbrew | 19. August 2019

Tesla is currently dealing with a flood of support calls due to their transition from the MySolarCity web-based customer interface to the Tesla smartphone app. Getting through to them is nigh impossible.

As for the original question: The additional equipment will be treated as if it's an entirely new system, with all of the necessary utility and municipal approvals that it entails. You're essentially starting over.

mujherangderang... | 19. August 2019

Has anyone uncovered reliable information regarding Tesla’s manufacturing yield management plans for the next few years? Meaning how are they going to toggle efficiently between cars, battery packs, and solar to reach max production capacity and margins? Seems if Ford, GM, VW, etc all ramp auto production, and Tesla’s factories do multiple different things that there could be a big margin advantage from this.

my issue got solved!!
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garyrogersfilm | 22. September 2019

We had ordered solar shingles or tiles and power wall 18 months ago. A team came out to evaluate our home. We have a 1884 house which in Florida is considered historical. We can't put solar panels on the house that would be seen from the street. Our south facing roof is metal and about 12 years old. The Tesla team said they could not put their panels on the metal roof. I would be willing to remove the metal roof and replace it with the new photo-voltaic tiles or shingles but they are not available in Florida for the foreseeable future . We got our Tesla 3 in Aug 2018 and had the charger installed by a Tesla approved local company. Solar Fit a local contractor also install 10 solar panels on the southeast part of the metal roof which put us a bit in the right direction . We had $1000 down on the Tesla power walls and when they became available a month ago we went ahead because it is hurricane season and we reasoned that would serve as a alternate power source in the event of a power loss from the grid as is quite common in these climes and times. We paid just south of 20K for that and are awaiting Duke Energy to clear us to use our power walls while we hopefully dodge the remaining hurricanes of the season. My two questions are. Any hope Florida may soon have the option of solar shingles or tiles, or Tesla will learn how to put panels on metal roofs and perhaps does our purchase of the Power Walls make us eligible for any mileage on super charges for trips we may take in our Tesla 3?

loricorbino | 23. September 2019

Interested in adding what I refer to as the Battery Packs or back up - but it may be the power walls mentioned above. We don't have a Tesla - we are the old Solar City customers with solar panels. Happy with the product to date - just want to learn more about using it for back up - just had a power outage (planned and not so planned) here in So Cal. We are part of SDG&E.

gregbrew | 23. September 2019

I added two PWs to an existing 5kW Solar City PV install from December 2015. I reserved the PWs last year in early October. They were turned on in Early February this year. ~$8k each. Working as designed, through three grid losses totaling 15 hours in HB, CA with SCE. Used in "backup only" mode, but I test them occasionally. The customer service experience for each installation was exemplary.

nvjx | 06. Oktober 2019

gregbrew, How does your backup only system work? I have a 5 kW PV system and live in the Bay Area. With PG&E TOU rates it is a wash at the end of the year but with increasing threats of power outages I have ordered a PW for a partial backup. One PW2 including straight forward installation is going to cost approximately $11800.

gregbrew | 06. Oktober 2019

I added two PWs to an existing 5kW array, and the PWs are configured as whole-house backup. Whole-house backup is actually *easier* to install than only backing up critical circuits, because the critical circuit wiring must be re-done to connect them to their own sub-panel that's then connected to the PW through the Tesla Energy Gateway (TEG). Once it's done, the TEG does it's magic, and your only task is to monitor it, if you wish. Otherwise it's effortless, and you can forget about it until the grid fails, which is when your neighbors will come knocking...wondering why you have power.

jrweiss98020 | 06. Oktober 2019

For people looking here in anticipation of buying a PV system, look into using microinverters if you think you may expand the system later, or if your PV panels will not get equal sun all the time (e.g., 2 different roof sections). Microinverters cost a bit more up front, but are MUCH more flexible in use. You will get max available output from each PV panel all the time, and you can add more panels at any time without worrying about maxing out a string inverter.

nvjx | 06. Oktober 2019

Thanks gregbrew.

Passion2Fly | 10. Oktober 2019

@gregbrew
2 PWs for a 5kW solar system is overkill. Your solar system will never produce enough power in a day to charge them both and supply your house. 2 PW = 26 kWh.
Unfortunately, as a whole house backup, Tesla recommends two power walls.... no choice there...

gregbrew | 10. Oktober 2019

Passion2Fly, your post is completely wrong.

I don't need to fully charge the two PWs and run the house in the same day when the grid is up. When new, the PWs *did* take two days to fully charge (from my normal 30kWh+ per day in Summer), while the PV was still running part of the house and taking the rest from the grid. That was a one-time event.

In an emergency, only critical loads will be running, to the tune of about 10kWh per day. My daily PV production easily surpasses 20kWh regardless of time of year, which is plenty to recharge the ~5kW used from the PWs overnight, plus run the critical loads during the day. The only exception is during a rain event, which is few and far between in So. CA. My PWs are configured for "Backup Only", except when I test them.

I *chose* to install two Powerwalls. Tesla policy wasn't even considered.

BTW, two PWs is 27kWh, not 26kWh.

bruceplmail | 11. Oktober 2019

I have a solar-Powerwall system controlled with the Tesla Gateway through ethernet and Tesla app on my cell phone. Does the Powerwall backup mode work if both the grid and internet are down? This could happen in an earthquake or fire in SoCA. Because the Tesla app connects to Tesla by cell or internet I'm curious about what the app would be used for if no cell or internet is available. Is everything down?

Passion2Fly | 11. Oktober 2019

PW has it's own WiFi router functions, SSID: TEG-XXX.

Passion2Fly | 11. Oktober 2019

@greg
Obviously we have a different view on backup system sizing. Even Tesla recommends 1 PW per 7.5 kW of solar.
I own an EV and I cen get 200 wh/m out of it if needed. In an extended blackout I need to drive 50 miles per day to help family members and loo for supplies. That's 10kWh per day just for the car...

Passion2Fly | 11. Oktober 2019

If I had a limited amount of money and had to choose between 2 PWs or 1 PW+5kW solar upgrade, I would go for the solar upgrade in a heartbeat.
Over sizing your backup system offers you additional reserves for "cloudy days". But that's about it.
Over sizing your solar system allows you to live a more "normal life" and use your car...

gregbrew | 11. Oktober 2019

I don't give a rats patootie what "Tesla recommends". I've had Solar (with battery backup) longer than they've been in business. My twenty years of experience with PV and EVs led me to the system sizing that fits my needs perfectly. It will meet the needs in an emergency of my residence, my Bolt, Volt and Leaf.

Each installation is going to be different, just as each individual will decide what best fits their needs. There is no "one-size-fits-all solution", and stating that there's one "right way", is just silly.

jrweiss98020 | 12. Oktober 2019

"Unfortunately, as a whole house backup, Tesla recommends two power walls.... no choice there..."

Passion2Fly: Actually, there IS a choice. Nobody HAS to buy their solar system from Tesla. Nobody HAS to buy a standard Tesla-dictated configuration.

There are many other vendors around that can do an analysis and recommend a system configuration based on the customer's wants and the realities of the installation. These vendors can also successfully integrate Powerwalls into those systems, again based on the customer's base specifications.

jrweiss98020 | 12. Oktober 2019

"Does the Powerwall backup mode work if both the grid and internet are down? This could happen in an earthquake or fire in SoCA. Because the Tesla app connects to Tesla by cell or internet I'm curious about what the app would be used for if no cell or internet is available. Is everything down?"

Bruce, The Powerwall doesn't need the Internet to operate; it only needs the Internet to report to Tesla and to download software updates. If the Internet goes down for a while, it can either store the data temporarily or just lose some of it. As long as it can communicate internally to the house system, there should be no problems.

Passion2Fly | 12. Oktober 2019

@jrweiss
I wish that was true. I wanted a whole house backup but my installer (not Tesla) refused to install one PW. They said that a whole house backup is two units. I ended up installing a partial backup with a sub panel for backup loads...
The Tesla “approved” installers don’t have much freedom. They have to follow Tesla’s guidelines. Otherwise they lose their certification. It’s not that simple...

sleeper service | 13. Oktober 2019

When I ordered my Powerwalls I was told that each can output 30 amps. So the maximum panel breaker determines the number of Powerwalls needed. I had two installed because of a 60 amp breaker.

gregbrew | 13. Oktober 2019

The maximum continuous output of a single Powerwall is 5kW (21A) and 7kW (30A) momentary peak.

rlwrw | 14. Oktober 2019

I have a small house with a smaller central air system, but even the compressor for the air conditioning has a large in-rush startup current. One Powerwall is not enough to handle that in-rush. Therefore, my compressor is on the grid.
If I want whole house backup, then I will need one or more additional Powerwalls.
This is probably what a lot of people do not realize needs to be factored into the electrical load calculation for whole house backup.

gregbrew | 15. Oktober 2019

Inrush current limiters are pricey, but *much* cheaper than a Powerwall.

peter.s.athans | 29. Januar 2020

Back to the original topic, I have the same issue...

We purchased a 6kw Solar City system three years ago, it was sized for 102% of our usage at that time. Since then have also purchased a Model X and of course would like to expand our system to help offset that new usage.

Contacted Tesla about adding panels and changing the inverter, and they were adamant that they will not expand any systems -- their only offer was to sell us a whole new second system, and even then it has to be of a minimum size (and we don't have the roof space for that many additional panels).

This seems crazy as much of the infrastructure is already in place for the first system (conduit, etc) and from an engineering perspective it should be a matter of using a new inverter, plus maybe upsizing some conductors (assuming the conduit is adequately sized).

The really frustrating part is that we discussed the possibility of getting an EV with our original salesman (SolarCity) and he made it sound like it would be possible to expand at a later date.

Tesla-David | 29. Januar 2020

Wow, @peter.s.atthans, if you read my response above, we had zero problems adding to our existing solar for the same reasons you want to add to cover your EV charging. If Tesla is giving you that ridiculous answer, which makes no sense, I would look at other non-Tesla vendors to see what they say. I live in Edmonds, WA, and my solar vendor in 2012/2013 installations was A&R Solar, who also did our PW2 installation in 2018. Good luck in resolving this and report back. I do not understand why Tesla is giving you such a ridiculous answer.

Jones | 29. Januar 2020

I have 10kW solar (SunPower) installed as three systems. New systems added as I successively added Leaf, Bolt and now Model 3 to my garage. Added two powerwalls due to recent outages from fires and earthquakes (tired of having inactive solar on the roof during an outage). Consolidating all three systems into the PW installation was not an issue (2 large inverters and one string of micro inverters). Also had the issue of a large current inrush starting my A/C. The A/C is not an issue (even if off grid) so long as solar is running. The PW will trip off if the A/C is used after dark - but that is an easy issue to deal with in real time....just turn off the A/C at sunset during an outage. Car charges are also on the PW with the intent that someday vehicle to grid will be implemented so that I have the equivalent of about 10 powerwalls sitting in the garage. Until then - scheduling charging is a trivial issue.

peter.s.athans | 30. Januar 2020

@Tesla-David, thanks for the comments, but I thought I was having trouble because:
- Solar City did the original install, and I think they used their own installers. If they subcontracted to a local group, I didn't know about it.
- I thought Tesla keeps tight control over their products, to the point that if I add panels and/or upgrade the inverter, they will void their warranty and end support of my installation

Thanks again for the feedback, I don't expect I'll get anywhere with Tesla but it feels better to be able to gripe about it...

Tesla-David | 30. Januar 2020

@peter.s.athans, I would keep agitating, and perhaps write a letter to EM. Back in 2013 I had an issue with my 2012 MS and was getting nowhere with the Tesla folks I was interacting with. I wrote a letter addressed to Blankenship who was one of the senior Tesla folks at the time, and I promptly got a satisfactory response and resolved my issue. I can't understand why they would take the position, that you can't add to existing solar system. which is frankly unsupportable. You need to keep agitating until you get the attention of someone in senior management who will address your reasonable request. Likewise I had a ridiculous 3 year long wait to get my PW2 installation, and kept getting the runaround from Tesla-Energy contacts. I demanded to speak with a senior level official, and when contacted got my PW2 installation completed within several months, so the agitation works.

ken | 31. Januar 2020

I was told at time of purchase that Tesla will NOT expand an installation after the fact. If I wanted more solar, I would need to purchase a second system. Thankfully this did not apply to PowerWalls and I was able to add a second one of those rather easily.

gregbrew | 01. Februar 2020

Company policy to only install new systems, rather than expand an existing one, goes back to Solar City days. As far as I know, it's always been their policy, and doing otherwise would be an exceedingly rare occurrence.