Is this clipping?

[uscpsycho]

I called Tesla support about a couple of issues. One is being sent to Tier 2. The other was answered, but I think incorrectly.

The other issue is that my system is rated for 11.3 kW but I usually top out between 8-8.5. This is what my production on a typical sunny day looks like for me.

The response I got is that I am not seeing 11.3 due to clipping. However, the example below does not seem to match my situation. The example provided looks like clipping would show as a hard limit in production where it flat lines at the top. That's not what happens on my chart.

So am I experiencing clipping? And if so, does clipping really benefit me as claimed? If this isn't clipping, is there another possible problem I should ask them to investigate since they can't figure it out?

 

[darhall993]

Here is what clipping looks like, 11.4kW inverter

 

[jjrandorin]

There are a few different threads in this subforum where people seem to think they are supposed to get the max power rating of their system and thinking its broke when they dont.

If you have an "11.3kW" rated system, that doesnt mean you will ever see 11.3kW as an input number. That would only happen if all your panels were placed on one plane on your home, your home was situated such that the one plane they were installed on was perfectly positioned for solar, and you had an inverter at least as big as 11.3kW.

Its not clipping in your picture, but the fact that your 11.3kW rated system never hits 11.3kW doesnt mean there is any problem.

 

[uscpsycho]

There are a few different threads in this subforum where people seem to think they are supposed to get the max power rating of their system and thinking its broke when they dont.

If you have an "11.3kW" rated system, that doesnt mean you will ever see 11.3kW as an input number. That would only happen if all your panels were placed on one plane on your home, your home was situated such that the one plane they were installed on was perfectly positioned for solar, and you had an inverter at least as big as 11.3kW.

Its not clipping in your picture, but the fact that your 11.3kW rated system never hits 11.3kW doesnt mean there is any problem.

One of those threads is from me. And I now know not to expect 11.3 kW. However, when I am only getting 8 kW on a cloudless, sunny, summer day, that's a full 30% below what my system is rated for. Maybe that is just how it's going to be for me but that seems like a lot. Anyway, I called support about a different verifiable problem that they sent to Tier 2, and while on the call I asked them to look into my system performance to see if I'm topping out because something is wrong. In the past I asked Tesla about this and they claimed I would not see 11.3 kW because I am being throttled until I get PTO (which is BS) and not for any other reason, so figured I'd ask them again.

I started the thread because now Tesla tells me I'm not getting 11.3 due to clipping (which I'd never heard of) but based on the example they sent me, I didn't think I was experiencing any clipping. So I wanted a second opinion, and from the actual example of clipping shared above I definitely don't have clipping.

In the email above, the rep said to focus on overall production which she said should be 5 - 7 times my rated my rated production, so 56.6 - 79.1. On a good day I'm right in the middle of that. Good enough?

 

[uscpsycho]

Here is what clipping looks like, 11.4kW inverter

Looks like you are getting the full 11.4 kW and more than 7x your rated output (which Tesla told me is the high end). Lucky you.

 

[taphil]

No it is not clipping. You won't reach the rated 11kW unless the panels and sun are perfectly aligned and the temperature is 77F. There is efficiency loss as temp goes up.

 

[bkp_duke]

You live in LA, smog is going to impact your performance as well, even on a "clear" day.

I'm on a mountain, I look down into the smog, and it's been impressive this year.

 

[offandonagain]

PVWatts is useful to model the expected solar production given all the variables (roof orientation, location, time of year, weather, DC/AC ratio, etc.):

PVWatts

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations

pvwatts.nrel.gov

By default it will show monthly production totals, but you can also download hourly data which can give you a better idea of expected peak production. You'll want to look at several days of data around today's date to control for historical weather patterns.

 

[Redhill_qik]

One of those threads is from me. And I now know not to expect 11.3 kW. However, when I am only getting 8 kW on a cloudless, sunny, summer day, that's a full 30% below what my system is rated for. Maybe that is just how it's going to be for me but that seems like a lot. Anyway, I called support about a different verifiable problem that they sent to Tier 2, and while on the call I asked them to look into my system performance to see if I'm topping out because something is wrong. In the past I asked Tesla about this and they claimed I would not see 11.3 kW because I am being throttled until I get PTO (which is BS) and not for any other reason, so figured I'd ask them again.

I started the thread because now Tesla tells me I'm not getting 11.3 due to clipping (which I'd never heard of) but based on the example they sent me, I didn't think I was experiencing any clipping. So I wanted a second opinion, and from the actual example of clipping shared above I definitely don't have clipping.

In the email above, the rep said to focus on overall production which she said should be 5 - 7 times my rated my rated production, so 56.6 - 79.1. On a good day I'm right in the middle of that. Good enough?

I have 8.16kW of solar panels and a 7.6kw invertor, but the best that I will get is about 6.2kW due to the orientation of my roof surfaces and therefor where the panels could be placed. Tesla estimated that I would get 11.5MWh/year and I getting that plus about another 1-2%.

So, what did Tesla estimate your production would be on an annual basis? And are you getting that?

 

[darhall993]

Looks like you are getting the full 11.4 kW and more than 7x your rated output (which Tesla told me is the high end). Lucky you.

To clarify, my PV system is 16.24kW and my inverter is 11.4kW so that's why I'm able to clip in the springtime, when it gets hotter here in Georgia (upper 80's and 90's) during the summer the heat degrades performance enough to where clipping is very limited. The screen cap I sent was from April. Another key configuration piece is all of my panels face south, if you have a complex roof with different exposures then clipping is less likely.

 

[charlesj]

There are a few different threads in this subforum where people seem to think they are supposed to get the max power rating of their system and thinking its broke when they dont.

If you have an "11.3kW" rated system, that doesnt mean you will ever see 11.3kW as an input number. That would only happen if all your panels were placed on one plane on your home, your home was situated such that the one plane they were installed on was perfectly positioned for solar, and you had an inverter at least as big as 11.3kW.

Its not clipping in your picture, but the fact that your 11.3kW rated system never hits 11.3kW doesnt mean there is any problem.

Also, if the actual total panels are rated for 11.3 it still may not get that with an inverter of that size or large as the rating is not geared for real world performance but lab conditions.

 

[charlesj]

Looks like you are getting the full 11.4 kW and more than 7x your rated output (which Tesla told me is the high end). Lucky you.

We know you have a 11.4kW DC rated panels. What is your inverter size so we can see the DC/AC ratio to compare with darhall.
@darhall993 has a 1.4 DC to AC ratio system and that is why he is getting such a great daily energy production. He would get more per day with a higher DC/AC ratio.

 

[charlesj]

I have 8.16kW of solar panels and a 7.6kw invertor, but the best that I will get is about 6.2kW due to the orientation of my roof surfaces and therefor where the panels could be placed. Tesla estimated that I would get 11.5MWh/year and I getting that plus about another 1-2%.

So, what did Tesla estimate your production would be on an annual basis? And are you getting that?

Your DC/Ac ratio is only 1.07. Perhaps that is why it is so close to the estimated production.

 

[Redhill_qik]

Your DC/Ac ratio is only 1.07. Perhaps that is why it is so close to the estimated production.

My actual results are close to the estimated results because the weather has been close to the weather model used be the Tesla and PVwatts estimators. The estimators take all of the system components, orientations, pitches, losses, etc into account.

My DC/AC ratio is actually about 0.82 as the max my panels will ever produce is 6.2kw (except for rate cloud edge effects).

 

[ucmndd]

I am only getting 8 kW on a cloudless, sunny, summer day, that's a full 30% below what my system is rated for. Maybe that is just how it's going to be for me but that seems like a lot.

How are your panels oriented? Are they all on a single roof plane facing the same direction, and is that direction optimal (roughly South)?

 

[jrweiss98020]

My system is rated at 11,765 Watts DC, 10,325 W Peak AC and 10,150 W continuous AC. When brand new, I got a peak of 10,260 W; last month it was 10,024 W. This is in Seattle, with slightly less than ideal positioning. You should be able to get very close to your inverter's rated output in LA!

 

[Redhill_qik]

My system is rated at 11,765 Watts DC, 10,325 W Peak AC and 10,150 W continuous AC. When brand new, I got a peak of 10,260 W; last month it was 10,024 W. This is in Seattle, with slightly less than ideal positioning. You should be able to get very close to your inverter's rated output in LA!

The inverter is just one component in the system and while it can be the limiting factor it is not always the limiting factor. How much the panels can produce is more likely to be limiting factor. Putting 11.8 kW of panels on direct south facing roof will produce more than panels that are split east/west which will produce more than the panels that are only placed on the north roof. Panels in cooler late spring will also produce more than panels in the hot summer.

The OP has indicated in another thread that they have a Tesla Solar Roof, but not how many panels are on that roof. It is highly likely that a significant portion of the active panels on the solar roof are not placed in an ideal location, but so far the OP hasn't provide any specifics beyond the invertor size and the production graphs.

 

[charlesj]

... OP hasn't provide any specifics beyond the invertor size and the production graphs.

Do you have his inverter size? It might be in another thread. Also, does he have panels or Tesla tile roof.

Yes, advertised panel capability is only a lab-based data, not real-world capability.

 

[Redhill_qik]

Do you have his inverter size? It might be in another thread. Also, does he have panels or Tesla tile roof.

Yes, advertised panel capability is only a lab-based data, not real-world capability.

I hate to put words in someone else's mouth, but here is what I have seen.

• Tesla Solar Roof 13.376kW - installed 158 SR tiles at 72 watts a tile, 158 x 72 = 11,376
• Two Powerwall+ - I have two PW+
  • Likely a 7.6kw and 3.8kW - my system is rated for 11.3kW and the system abruptly dropped to 3.8kW
  • Might be two 7.6kw - I have two Powerwall+ inverters so that's two 7.6 inverters
• Tesla Annual Production is 16,577 kWH - Estimated energy produced: 16,577 kWh /yr
• PVwatts annual estimate was 19,504 kWh - system should generate 19,504 kWh annually
• PVwatts estimated peak 9.4kW measured was 8.9kW - the peak was estimated to be 9.34kW ..... the screenshot that shows 8.9kW peak

So basically, we went through this whole thing with @uscpsycho and they forgot all about. Facepalm!

 

[Pearl1!]

One of those threads is from me. And I now know not to expect 11.3 kW. However, when I am only getting 8 kW on a cloudless, sunny, summer day, that's a full 30% below what my system is rated for. Maybe that is just how it's going to be for me but that seems like a lot. Anyway, I called support about a different verifiable problem that they sent to Tier 2, and while on the call I asked them to look into my system performance to see if I'm topping out because something is wrong. In the past I asked Tesla about this and they claimed I would not see 11.3 kW because I am being throttled until I get PTO (which is BS) and not for any other reason, so figured I'd ask them again.

I started the thread because now Tesla tells me I'm not getting 11.3 due to clipping (which I'd never heard of) but based on the example they sent me, I didn't think I was experiencing any clipping. So I wanted a second opinion, and from the actual example of clipping shared above I definitely don't have clipping.

In the email above, the rep said to focus on overall production which she said should be 5 - 7 times my rated my rated production, so 56.6 - 79.1. On a good day I'm right in the middle of that. Good enough?

Overdriving is BS. It will cause the inverter to fail. Ask me how I know. Lower DC/AC is better IMHO. Higher just lowers install cost.