Adding more panels to Tesla system after installed?

[SanDiegoM3]

Hey everyone! So I have an install date for Friday on a 7.2kwh system but I want the option to future proof myself on NEM 2.0 by getting a permit for more panels just in case I get a second EV, add a pool/hot tub, etc.

What’s the best way to add-on to a Tesla system? Do I have to go through Tesla? Should I have a completely separate system? I can probably find someone to do a permit for me but it has to be compliant so I’m looking for a general path to take. Thanks!!!

 

[secprotocol]

I looked into this recently, if you go through Tesla, it's a whole new system. They won't touch anything on the old system.

 

[arnolddeleon]

As a rule any "expansion" will generally be a new system (unless you are a DIYer).

These days the primary reason for that is that there is minimum size that an installer will install in order to have enough margin to make it worthwhile. Some will install a smaller system but the unit price will be higher so effectively the same thing.

There are technical reasons that make it harder as well. Examples: max voltages for strings in a string inverter, inverter inputs, inverter capacity.

 

[SanDiegoM3]

As a rule any "expansion" will generally be a new system (unless you are a DIYer).

These days the primary reason for that is that there is minimum size that an installer will install in order to have enough margin to make it worthwhile. Some will install a smaller system but the unit price will be higher so effectively the same thing.

There are technical reasons that make it harder as well. Examples: max voltages for strings in a string inverter, inverter inputs, inverter capacity.

Sure. I get all that, but I’m looking for technical limitations and whether I would need a completely separate 4.8kw or something system and properly planning it when there’s an in-place system or am I just being a lunatic the sky is falling NEM 3.0 person when I have a 7.2kwh getting installed.

 

[jjrandorin]

Sure. I get all that, but I’m looking for technical limitations and whether I would need a completely separate 4.8kw or something system and properly planning it when there’s an in-place system or am I just being a lunatic the sky is falling NEM 3.0 person when I have a 7.2kwh getting installed.

Unless you are a DIY er, the technical limitations are not really a concern. No one is "Adding on" to any system they didnt install, full stop. In general, installers wont even "Add on" to a system they installed.

"Add on" meaning "hey can you just add some more panels on there and perhaps swap out the inverter to a larger size one?"

Anything "later" is going to be a new system, with new inverters, and new install, that feeds back to your main panel in some way. Its not going to be any add on, or add on pricing, or anything like that at all. Regardless of who is doing your install now, any changes are going to be an entirely new system, that is not connected to the current one in any manner, that feeds back to its own inverter and ties into your home at the panel.

 

[h2ofun]

Sure. I get all that, but I’m looking for technical limitations and whether I would need a completely separate 4.8kw or something system and properly planning it when there’s an in-place system or am I just being a lunatic the sky is falling NEM 3.0 person when I have a 7.2kwh getting installed.

Your attitude should be, IMO, put on as many as you can fit, and get approval for now! Going back and adding is just about impossible. Trust me, I have been there

 

[SanDiegoM3]

Interesting, what about If solar improves massively in future technology where it makes sense to swap out a couple panels while staying under the 10% NEM 2.0 allowable increase.

 

[SanDiegoM3]

Your attitude should be, IMO, put on as many as you can fit, and get approval for now! Going back and adding is just about impossible. Trust me, I have been there

I get installed on Friday haha. I don’t think I should make changes now or I could miss the deadline.

 

[holeydonut]

Your attitude should be, IMO, put on as many as you can fit, and get approval for now! Going back and adding is just about impossible. Trust me, I have been there

Yeah, and when he was able to get more Powerwalls added, they didn't match up his disconnects so now he's got two brands of disconnects.

 

[holeydonut]

Unless you are a DIY er, the technical limitations are not really a concern. No one is "Adding on" to any system they didnt install, full stop. In general, installers wont even "Add on" to a system they installed.

"Add on" meaning "hey can you just add some more panels on there and perhaps swap out the inverter to a larger size one?"

Anything "later" is going to be a new system, with new inverters, and new install, that feeds back to your main panel in some way. Its not going to be any add on, or add on pricing, or anything like that at all. Regardless of who is doing your install now, any changes are going to be an entirely new system, that is not connected to the current one in any manner, that feeds back to its own inverter and ties into your home at the panel.

Adding on to this point so anyone lurking understands the folly of expanding solar "later..."

My system was originally designed for 35 total panels utilizing Enphase IQ7+ microinverters feeding 2x Powerwalls 2. This would be 10 kWp-AC and would basically max out the solar potential of the Enphase Envoy/3C and use my available rooftop space.

PG&E said "no" to this system because it was too big, and they deemed the Powerwalls were unsafe in the proposed build. So they capped me at 23 total panels on the solar side, and I had to add a 3rd Powerwall to make the ESS side "safe." They told me it was easy to expand solar later. PG&E lied.

Now that I can demonstrate the home demand to utilize the energy generation from a total 35 panels, I cannot find someone to add in the 12 panels to get me back to 35 total panels. I just need someone to rack the new panels, add a new home run through the existing conduit, and terminate the home run in the existing Envoy 3C.

There's literally an empty breaker spot on my Enphase Envoy to land the home-run for a string consisting of 12 panels/Enphase IQ7+. The conduit diameter is large enough for all the extra conductors, and my conductor gauges don't need to be upsized. I even have the configuration/login to my Enphase Enlighten system and can provision 12 new microinverters myself. @Vines also generously found the retrofit kit so I could remove my 200A breaker from my Tesla Gateway and remove the improperly bonded neutral-to-ground.

Only one company offered to take on this job... everyone else said "no" because it touches existing equipment. But when the one company tried to get county permits to add the solar, the county rejected the project citing various reasons around how the new 2022 rules have changed vs 2019 when the original system was put in. Apparently there's no "like for like" provision to allow old equipment to remain, while the new approval and code only affects the expansion. The County views the modified PV+ESS system to need to adhere to all the new codes.

So yeah, do what @h2ofun fun says. Get the maximum solar you possibly can day one. It's too late for @SanDiegoM3 , but for anyone else... go big ASAP.

 

[h2ofun]

Adding on to this point so anyone lurking understands the folly of expanding solar "later..."

My system was originally designed for 35 total panels utilizing Enphase IQ7+ microinverters feeding 2x Powerwalls 2. This would be 10 kWp-AC and would basically max out the solar potential of the Enphase Envoy/3C and use my available rooftop space.

PG&E said "no" to this system because it was too big, and they deemed the Powerwalls were unsafe in the proposed build. So they capped me at 23 total panels on the solar side, and I had to add a 3rd Powerwall to make the ESS side "safe." They told me it was easy to expand solar later. PG&E lied.

Now that I can demonstrate the home demand to utilize the energy generation from a total 35 panels, I cannot find someone to add in the 12 panels to get me back to 35 total panels. I just need someone to rack the new panels, add a new home run through the existing conduit, and terminate the home run in the existing Envoy 3C.

There's literally an empty breaker spot on my Enphase Envoy to land the home-run for a string consisting of 12 panels/Enphase IQ7+. The conduit diameter is large enough for all the extra conductors, and my conductor gauges don't need to be upsized. I even have the configuration/login to my Enphase Enlighten system and can provision 12 new microinverters myself. @Vines also generously found the retrofit kit so I could remove my 200A breaker from my Tesla Gateway and remove the improperly bonded neutral-to-ground.

Only one company offered to take on this job... everyone else said "no" because it touches existing equipment. But when the one company tried to get county permits to add the solar, the county rejected the project citing various reasons around how the new 2022 rules have changed vs 2019 when the original system was put in. Apparently there's no "like for like" provision to allow old equipment to remain, while the new approval and code only affects the expansion. The County views the modified PV+ESS system to need to adhere to all the new codes.

So yeah, do what @h2ofun fun says. Get the maximum solar you possibly can day one. It's too late for @SanDiegoM3 , but for anyone else... go big ASAP.

This is why I added two more PW's, even though a total waste of money. With codes changing, it was now or never. And since I now have non solar since both of my inverters just died, so glad I have grid charge so I can keep the batteries at 100% and hope I do not need. With the big new wet storms coming, this should be interesting with it raining on lots of snow. Flooding

 

[holeydonut]

This is why I added two more PW's, even though a total waste of money. With codes changing, it was now or never. And since I now have non solar since both of my inverters just died, so glad I have grid charge so I can keep the batteries at 100% and hope I do not need. With the big new wet storms coming, this should be interesting with it raining on lots of snow. Flooding

Lol yeah the news just talked about some lady in Nevada county being stuck without power for like 2 weeks under like 5 feet of snow. I don't understand how we went from a generational drought, to a generational flood, to a generational blizzard in the span of 2 years. (actually, I do understand, but we can't talk about that in this sub hehe).

BTW, any chance your installer will drop SolarEdge and try a different type of inverter? I feel like you burn through one every year.

 

[h2ofun]

Lol yeah the news just talked about some lady in Nevada county being stuck without power for like 2 weeks under like 5 feet of snow. I don't understand how we went from a generational drought, to a generational flood, to a generational blizzard in the span of 2 years. (actually, I do understand, but we can't talk about that in this sub hehe).

BTW, any chance your installer will drop SolarEdge and try a different type of inverter? I feel like you burn through one every year.

Yep, I have been driving up the hill the last 2 weeks to nevada city. One trip we got stuck in the snow in a tesla. Next day stuck in a big van. I helped a friend shovel snow for hours.
It was snowing again heavy up until 9 this morning. I have to again try and get up the hill to nevada city this afternoon. Lived here for 33 years, and have never seen this much snow since 1990.
Now as far as the heavy rains now coming in, have seem many years of flooding. If it really dumps, with all the snow, this could get real interesting.
I know folks who have been out of power for weeks now. They come to my house to shower. I guess this is a good time to have the inveters go bad since with the clouds, not much solar was being produced anyways.
Maybe by late March this will all be behind us.

 

[holeydonut]

Yep, I have been driving up the hill the last 2 weeks to nevada city. One trip we got stuck in the snow in a tesla. Next day stuck in a big van. I helped a friend shovel snow for hours.
It was snowing again heavy up until 9 this morning. I have to again try and get up the hill to nevada city this afternoon. Lived here for 33 years, and have never seen this much snow since 1990.
Now as far as the heavy rains now coming in, have seem many years of flooding. If it really dumps, with all the snow, this could get real interesting.
I know folks who have been out of power for weeks now. They come to my house to shower. I guess this is a good time to have the inveters go bad since with the clouds, not much solar was being produced anyways.
Maybe by late March this will all be behind us.

Nah, once March hits, I'm sure the generational locust swarms and generational earthquake will happen. Probably at the same time.

 

[holeydonut]

BTW, just in case someone is still on the fence and believes it's "easy" to add solar to an existing PV+ESS system as a future expansion...

I'm looking into the PG&E interconnection portal to get my own PTO for a owner-installed 12 solar panels. After getting through the hurdle of getting SNEM treatment (paired energy storage over 10 kW with a CRD-PCS), there's another new hiccup.

According to the PG&E data, my meter had a "consumption" of 4,000 kWh last NEM cycle. This is the NEM deficit created by charging my wife's Model 3 since PG&E originally barred me from oversizing my solar system to anticipate this demand load.

The 12 new solar panels facing North will add about 4,000 kWh annual generation. I thought this was a slam dunk rationale since now I have an EV in the garage, and proven net energy consumption across the meter where my existing/old solar system is clearly undersized.

But it turns out PG&E's interconnection portal won't allow you to simply submit for PTO for a new solar array. You have to include all existing hardware plus the new solar panels. Since the old panels + new panels generate way more than 4,000 kWh, I got my self-initiated-PTO placed under review since it seems my home only consumes 4,000 kWh per year. Which makes PG&E wonder why I'd need over 15,000 kWh solar capacity.

TLDR This whole process sucks. Get as much solar as you can as fast as you can.

Remember though, I am an absolute flipping idiot moron. So maybe you all will have better luck than me.

 

[h2ofun]

BTW, just in case someone is still on the fence and believes it's "easy" to add solar to an existing PV+ESS system as a future expansion...

I'm looking into the PG&E interconnection portal to get my own PTO for a owner-installed 12 solar panels. After getting through the hurdle of getting SNEM treatment (paired energy storage over 10 kW with a CRD-PCS), there's another new hiccup.

According to the PG&E data, my meter had a "consumption" of 4,000 kWh last NEM cycle. This is the NEM deficit created by charging my wife's Model 3 since PG&E originally barred me from oversizing my solar system to anticipate this demand load.

The 12 new solar panels facing North will add about 4,000 kWh annual generation. I thought this was a slam dunk rationale since now I have an EV in the garage, and proven net energy consumption across the meter where my existing/old solar system is clearly undersized.

But it turns out PG&E's interconnection portal won't allow you to simply submit for PTO for a new solar array. You have to include all existing hardware plus the new solar panels. Since the old panels + new panels generate way more than 4,000 kWh, I got my self-initiated-PTO placed under review since it seems my home only consumes 4,000 kWh per year. Which makes PG&E wonder why I'd need over 15,000 kWh solar capacity.

TLDR This whole process sucks. Get as much solar as you can as fast as you can.

Remember though, I am an absolute flipping idiot moron. So maybe you all will have better luck than me.

I sure would not want to tell PGE now why I need my 30kw of solar. I love to offer free EV charging to my friends

 

[KenRico]

Have a small Tesla system 4k . Maybe easier to replace all 12 panels with the latest 420/450w ? no wiring no mounts - same setup with more capacity .

Now have a Model S & did not plan for that .

 

[aesculus]

But it turns out PG&E's interconnection portal won't allow you to simply submit for PTO for a new solar array. You have to include all existing hardware plus the new solar panels.

This is true. They need a SLD and the calcs for each component too. Been this way forever.

It's when you just an ESS that you don't have to go through all of this from my experience.

 

[jgleigh]

TLDR This whole process sucks. Get as much solar as you can as fast as you can.

And avoid PG&E...

 

[CrazyRabbit]

I believe Powerwall2+ curtails thru canbus. So if adding enphase or third party solar might require reprogramming to curtail by frequency shift, if possible at all..
I have enphase with tesla solar/powerwall and tesla said PW2+ not compatible…