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11.6kw Solar Roof, but only one Inverter?

wwhitney

Member
Nov 2, 2017
979
1,340
Berkeley, CA
I am comfortable at 11.6 for my setup because over this limit, I am considered Tier 2
Just double checking, your power company regulations are based on the DC system size, not on the AC inverter size? Because the latter is more directly applicable to the grid, so I would expect regulations to be based on that.

Cheers, Wayne
 
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Zinc_Saucier

Member
Jul 30, 2020
59
36
Massachusetts
For our solar roof, they did not guarantee production - just estimated it
Yea, that’s what they did with mine, and like yours it seems they are conservative in terms of estimates. Guess it’s one area where they under promise and over deliver… 😉
NOTHING with solar can be guaranteed.
I mean it 100% can be. My installer (non-Tesla) has production guarantees built into the contract where if my system doesn’t perform to certain levels over a span of years, I get cut a check.
 
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h2ofun

Active Member
Aug 11, 2020
3,028
658
auburn, ca
Yea, that’s what they did with mine, and like yours it seems they are conservative in terms of estimates. Guess it’s one area where they under promise and over deliver… 😉

I mean it 100% can be. My installer (non-Tesla) has production guarantees built into the contract where if my system doesn’t perform to certain levels over a span of years, I get cut a check.
good luck collecting
 

ericl

Member
Aug 19, 2021
68
25
florida
Just double checking, your power company regulations are based on the DC system size, not on the AC inverter size? Because the latter is more directly applicable to the grid, so I would expect regulations to be based on that.

Cheers, Wayne
based on DC size.
 

Zinc_Saucier

Member
Jul 30, 2020
59
36
Massachusetts
good luck collecting
I don’t think I’ll have to given that based on actual production so far vs. their guaranteed production figures, which is good, I want my system to produce, I don’t want to have to go after anyone. However, if push comes to shove, I got Lexus to buy back a SUV and reimburse me fully, so I’m not concerned about getting what’s in the contract if it comes to that.
 

Bitslizer

Member
Jun 16, 2021
237
82
IL
To my knowledge Tesla is marketing panels in units of 4.25 kW, so their inverter sizes are also going to increase accordingly. I.e. the standard DC/AC ratio is fixed and their price per watt covers both panels and inverters. I seriously doubt that if you have a 8.5 kW system being designed with them, and you say "oh, I can fit in two more panels, what would that cost?" that they will give you same price adder for 2 panels only vs 2 panels plus an inverter increment.

If you like, I'll amend my statement "if your not clipping, your system cost too much" with the footnote that maybe you got lucky and the system was mispriced and some of that cost was eaten by another party.

Also, depending on what you care about, certainly at DC/AC ratios just about 1.0, the net environmental impact of increasing the inverter size will be negative. As it will only slightly increase energy harvest, and that increase will not offset the environmental impact of building that extra inverter capacity.

Cheers, Wayne

I did exactly that. Tesla and me went back and forth on design several time. Arriving at a 46x 340w panels 15.64w still at $2.01 per watt. We went through several size from 10ishkw to 7ish kw Noticed that they all were not any standard increment of 4.08kw, 8.16, 12.24, 16.32 when they were doing 340w panels. They will customize the system to fit the roof. The op is also getting tile not panels. I think those are as customize as you can get
 

ericl

Member
Aug 19, 2021
68
25
florida
So today I received re-assurance that my single powerwall+ will be to go into "overdrive" (not oversize) through a software update and handle more than 7.6 for times such as noon. It will not clip at 7.6. This will give let me also give me the increased production during dusk and dawn because of the inefficiencies caused by adding another inverter.
 

Bitslizer

Member
Jun 16, 2021
237
82
IL
So today I received re-assurance that my single powerwall+ will be to go into "overdrive" (not oversize) through a software update and handle more than 7.6 for times such as noon. It will not clip at 7.6. This will give let me also give me the increased production during dusk and dawn because of the inefficiencies caused by adding another inverter.
Good luck! Get it in writing if you can

The 7.6 pw+ I have, get up to 7.7....7.8 max so far.

I for one won't "wait" for Tesla to release a new feature given Tesla history of significant delay in new product/feature release. Much less nobody else (afaik) have heard of this overdrive.
 

ericl

Member
Aug 19, 2021
68
25
florida
Good luck! Get it in writing if you can

The 7.6 pw+ I have, get up to 7.7....7.8 max so far.

I for one won't "wait" for Tesla to release a new feature given Tesla history of significant delay in new product/feature release. Much less nobody else (afaik) have heard of this overdrive.

Yeah I don't believe that crap one second. So this is what I did.

1. Asked for more oversize of array - Now I am going from 11.69 to closer to 14kw dc. Unfortunately these are direct North with 14 pitch but its still a bump.
2. Asked for an additional 3.6 inverter in combination to the Powerwall+ 7.6 = 11.2

I thought 11.2 inverter with 11.69 array would be overkill because it wouldn't capture the dusk to dawn due to efficiency.

Now I should be getting 11.2 inverter with a ~14kw Array. Bumps me from Tier 1 to Tier 2. Personal liability of $1MM = $250 per year. I should generate $300 more per year (or more) in electricity thus offsetting the $1MM insurance while keeping that DC/AC ratio closer to 1.2.
 

Bitslizer

Member
Jun 16, 2021
237
82
IL
Yeah I don't believe that crap one second. So this is what I did.

1. Asked for more oversize of array - Now I am going from 11.69 to closer to 14kw dc. Unfortunately these are direct North with 14 pitch but its still a bump.
2. Asked for an additional 3.6 inverter in combination to the Powerwall+ 7.6 = 11.2

I thought 11.2 inverter with 11.69 array would be overkill because it wouldn't capture the dusk to dawn due to efficiency.

Now I should be getting 11.2 inverter with a ~14kw Array. Bumps me from Tier 1 to Tier 2. Personal liability of $1MM = $250 per year. I should generate $300 more per year (or more) in electricity thus offsetting the $1MM insurance while keeping that DC/AC ratio closer to 1.2.
It's 3.8 inverter. Not 3.6 so 11.4

7.6+3.8 Is what I have and I have seen it peak 11.8 once but 11.7 fairly often.
 

ericl

Member
Aug 19, 2021
68
25
florida
It's 3.8 inverter. Not 3.6 so 11.4

7.6+3.8 Is what I have and I have seen it peak 11.8 once but 11.7 fairly often.
They just backtracked on this and now is only sticking to the power wall+ and the 11.69 array after promising for a week they could do this lol…
 

fragchild

Member
Nov 21, 2020
31
22
Florida
I have an 11.56 system in Central Florida. You will never see anything close to the 11s for generation. I think I hit 10.2 back in April/May with most of my panels facing south with a few facing east. I have a solaredge inverter though so I'm not sure if the Tesla one will clip or not.
 
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ericl

Member
Aug 19, 2021
68
25
florida
I have an 11.56 system in Central Florida. You will never see anything close to the 11s for generation. I think I hit 10.2 back in April/May with most of my panels facing south with a few facing east. I have a solaredge inverter though so I'm not sure if the Tesla one will clip or not.
Testing out my system, I hit 7.7kw by 11:30 AM. After hitting the 7.7 it goes down to 3 then 5 then back to 7.7 consistently. I’m just watching the screen to see if it ever can go to 8. What they promised me as overdrive sounds like pure BS at this point.
 

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irev210

Member
Nov 8, 2018
49
40
Baltimore
Did you look in PVWatts to see the exact loss you would have? I am quoted to receive a 10.6kW system and I ran into the same issue with the 7.6kW inverter. I looked at PVWatts and loaded in the info from my 01 from Tesla. Seems that it is about $50/year of solar I would lose, so doesn't seem worth it to have them add another 3.6kW inverter.
 

h2ofun

Active Member
Aug 11, 2020
3,028
658
auburn, ca
Testing out my system, I hit 7.7kw by 11:30 AM. After hitting the 7.7 it goes down to 3 then 5 then back to 7.7 consistently. I’m just watching the screen to see if it ever can go to 8. What they promised me as overdrive sounds like pure BS at this point.
And you believed them?
 

ericl

Member
Aug 19, 2021
68
25
florida
i wanted another inverter and 2kw of array but they didn’t approve it. “FSD in 2 weeks” lol.

it def looks like the inverter is maxing out and clipping, doesn’t look like it can even consistently push out 7.6. Granted it’s a slightly cloudy day.

Just kinda pissed I'm better of an engineer than their engineers. I hit the max inverter of 7.6 at 11:30 which is around 2 hours prior to Solar Noon..... and this is the summer too at 90 degrees with clouds.
 

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h2ofun

Active Member
Aug 11, 2020
3,028
658
auburn, ca
i wanted another inverter and 2kw of array but they didn’t approve it. “FSD in 2 weeks” lol.

it def looks like the inverter is maxing out and clipping, doesn’t look like it can even consistently push out 7.6. Granted it’s a slightly cloudy day.

Just kinda pissed I'm better of an engineer than their engineers. I hit the max inverter of 7.6 at 11:30 which is around 2 hours prior to Solar Noon..... and this is the summer too at 90 degrees with clouds.
I do not see that at all like clipping. When I clip, which very seldom happens, it his my inverter output of 11.4K, and it is flat.
 

ericl

Member
Aug 19, 2021
68
25
florida
I do not see that at all like clipping. When I clip, which very seldom happens, it his my inverter output of 11.4K, and it is flat.
Are you on the power wall+ ? The project manager for power wall said for the power wall , clipping is when it keeps spiking down and not a flat line. I specifically asked about this. I don’t know if the power wall can continuously handle 7.6kw? I previously was under the assumption it plateaus which is aligned with you.
 

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h2ofun

Active Member
Aug 11, 2020
3,028
658
auburn, ca
Are you on the power wall+ ? The project manager for power wall said for the power wall , clipping is when it keeps spiking down and not a flat line. I specifically asked about this. I don’t know if the power wall can continuously handle 7.6kw? I previously was under the assumption it plateaus which is aligned with you.
Again, if you are asking those folks for technical guidance, ......
 
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fragchild

Member
Nov 21, 2020
31
22
Florida
Testing out my system, I hit 7.7kw by 11:30 AM. After hitting the 7.7 it goes down to 3 then 5 then back to 7.7 consistently. I’m just watching the screen to see if it ever can go to 8. What they promised me as overdrive sounds like pure BS at this point.
Here's mine from today. So I would hope yours would be close. Casa Tripod 11.560kW I definitely thing the Tesla Inverter is keping you from more power.
 

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