What would cause plateau in production like this?

On a sunny day, in November, with 30, 310W panels facing mostly south in Northern Illinois, I'm getting this plateau right at 3.5kW, way early in the morning (see graph).

If it peaked midday-ish, I might not be concerened. I'm new to this (2 weeks in), but so I'm not even sure what to expect. When I google production of a 300W panel it says 3.5kWh in a 8 hour sunny day. To me it seems like I'm way under producing even accounting for November Illinois.

Further, the exact plataeu of 3.5 kW on several days, way early in the day, almost makes me suspect something is limiting production. I have a Solaredge se10000H I believe, which shouldn;t cap out at 3.5kW. Right?

Any other reasons for teh 3.5kW early plateau with 30 * 310W panels?

How are your panels configured? Series/Parallel? Do you have batteries?

Agree with the above, how are the panels configured? Bet your hitting the current limit of the MPPT tracker cause your string voltage is too low.

google fu of the manual and wild speculation, im guessing its 27A, 3,500/27 is 129v, so 3 x 43 volts in series, then 10x parallel is my guess.
do you have them 3s10p by any chance?

(although im not sure TBH cause the way i read it, the max current being 27Ax480v still doesn't equal its max 15,500 DC watts, the spec sheet has me confused lol)

Aaron_85 said:

Agree with the above, how are the panels configured? Bet your hitting the current limit of the MPPT tracker cause your string voltage is too low.

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That's not how his system works.

He's got some odd hardware. It requires "power optimizers" on each of the panels. Its super unclear to me what these little black boxes do. The instructions say that the voltage on the string of optimizers should equal the number you have in series. Sounds like all the panels are (should be) in series and the "check sum" voltage should be 30v in OP's case.

How/what the little black boxes do however is somewhat of a mystery. I suspect they must all comunicate to each other/the central unit and do a some sort of at panel variable voltage conversion to ensure that whatever number of panels you have in series are always converted into ~400vDC input to the central unit. I suppose with the right circitry you can do odd things like "virtually" cut off a panel that is 100% in the shade, as if it wasn't in the array.

As for what his issue is. NFC based on the odd hardware he has. Thats a tech support call to the people that make it/installed it.

I didn't install it, but I guess this is all in series? When I log into Solaredge I see the logical diagram as 1 string like seen below. No battery.

So to clarify, everyone agrees that the 3.5kW plateau is not good and the installers should fix?

zendad said:

So to clarify, everyone agrees that the 3.5kW plateau is not good and the installers should fix?

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I would not expect a plateau like that on any system no. If it was a typical system I would agree with the others that the SCC has hit its limit and is "clipping" the input power. So along those same lines, It would apear as if something isnt configured right to have ~9Kw of pannel watts and clipping at 3.5kw. Even in winter.

Wow, that is strange. I would expect that with their smaller models with large arrays, but not the inverter that you have.

On my first solar edge inverter, the installer sized it too small, and I had this same problem. But once I got the larger inverter it was good to go.

Look on the side of your inverter and take a picture of that label, and post it here (without product ID numbers if you wish). It should state the max output capacity.

I would contact the installer. Do you have multiple strings connected? I think that model has terminals for 2 strings. Maybe one of them is not connected, or enabled (optimizers need to communicate with inverter during setup).

"Optimizers Power (Length String) ... 25"


if 30 in series, could be too many and they operate well off peak performance to avoid delivering excess voltage.

I think your model supports 3 strings, so as Will said, maybe not all connected. Maybe 30 into 1, instead of 3x 10 into 1.
Perhaps it is limited to 3.5 kW per string?

Well it turns out it was set to a se10000H but it is actually a se7600H. Installer claims that will fix the issue.

But I have 2 concerns.

1. All 30 panels are on 1 string. Someone mentioned that might be too many.

2. Does the Solaredge se7600H have the capacity to deal with 30, 310W panels during peak season? The side of the says 7600Wac for Max continuous Output Current. But the manual says Maximum DC Power: 11800 Watts.

RTFM.
Then tell the installers to RTFM and do it correctly this time.

You can pump 30 gallons of gas into an 18 gallon tank.
I did that on purpose one time, so I could demonstrate to the gas station attendant that there was no way in hell I had actually bought the amount of gas shown on the pump. It was getting sucked back into the vapor recovery hose but didn't shut off. He then wanted to charge for 18 gallons, but I said the tank was half full when I arrived, so I paid for 9 gallons.

If the inverter you were given is 7600W AC, that's all it will produce. You can over-panel with 11800W of PV panels, but the extra capacity will go to waste during middle of the day. It will continue to produce 7600W AC earlier/later in the day and off season compared to a smaller PV array.

Look up what they sold you. If it said 7600W then OK. If it said 10000W then they owe you a larger inverter.

Yeah agreed.

Hedges said:

RTFM.
Then tell the installers to RTFM and do it correctly this time.

You can pump 30 gallons of gas into an 18 gallon tank.
I did that on purpose one time, so I could demonstrate to the gas station attendant that there was no way in hell I had actually bought the amount of gas shown on the pump. It was getting sucked back into the vapor recovery hose but didn't shut off. He then wanted to charge for 18 gallons, but I said the tank was half full when I arrived, so I paid for 9 gallons.

If the inverter you were given is 7600W AC, that's all it will produce. You can over-panel with 11800W of PV panels, but the extra capacity will go to waste during middle of the day. It will continue to produce 7600W AC earlier/later in the day and off season compared to a smaller PV array.

Look up what they sold you. If it said 7600W then OK. If it said 10000W then they owe you a larger inverter.

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That's what I'm thinking.

I assume they will quote the other number - 11800W DC for input. Sorry for these noob questions, but why does the manual quote max 11800 W for DC for input and then 7600W AC for output. Is the conversion that bad?

Bottom line I really suspect I should have the 10000H, but I want be able to fend off their arguments. The proposal they gave says 10000H, but the contract (of course I missed it) says just the brand. They did have to scale back the system from 33 to 30 panels because they apparently couldn't measure the first time, which I'm sure will also be another reason given for using the 7600.

Does anyone know what calculation and numbers from inverter and panels I can use to see if I max out? Is it as simple as:

30panels * 310W = 9,300W

Probably 95% efficient converting from DC to AC? so 9,300W * 95% = 8,835W

So that would be higher than the 7600 WAC reported on the Invertor.

Does that all sound good, or am I missing something?

Yes, 9300W STC. That's what they would put out in 1 full sun (1000W/m^2 of light) and panel at 25 degrees C. Occasionally you'll see that, usually less because panel heats up.

If their proposal says 10000H and contract doesn't change that to a different model, insist on the 10000H. Or a partial refund.
Having the higher wattage inverter will deliver more watts and more watt-hours from your panels. It will also let you add more panels later.

It is OK to put in more panels than the inverter can make use of under ideal conditions. That improves output morning, evening, winter.
Inverters these days are typically 98% efficient. But PTC of panels might be 85% of STC. So inverter manufacturer recommends some greater maximum amount of panel wattage.

Does the contract say how many watts of panels? Did the proposal?

33 to 30 panels is about 10% decrease, but 10000 to 7600 is about 25% decrease. Make sure you get what you paid for, or they only charge for what they gave you.

The fact it maxes out at 35% of proposal and 40% of panels, < 50% of inverter installed is a black eye for them.

Here was their response in red as I suspected it would be. Is he right or just trying to get rid of me?

So more concerns:

• My system was supposed to include the se10000H We went with an SE7600 HD inverter because this inverter will give you the better performance. An SE1000 HD inverter was outside the SolarEdge recommended DC to AC ratio.
• Can the 7600 handle 30, 310W panels during peak summer? Yes, an SE7600 HD inverter can handle up to 11800 wats DC. You have 9300 wats DC installed on your roof.

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Then when I was concerned about clipping at 7600W, his response was:

Optimum performance?
Not clear that 7600 will deliver more power from 9300 watts (STC) of PV than would a 10000 inverter. Only if the 7600 is more efficient at 100% loading than the 10000 is at 75% loading (not likely.)
Besides, on peak sun days, the 7600 will clip output and the 10000 will not.

Yes, you can put 11800 W PV into a 7600W inverter without causing harm. But you won't get the extra power.

1) The proposal listed the 10000 model. The contract didn't specify a smaller model. Did the contract have a lower price than the proposal, lower by more than just the (3?) PV panels not part of the final system?

If not, they owe you the model proposed.

2) Something isn't working right. I think it should be 2 strings of 15 panels going to the 7600 (if it has 2 inputs), or 3 strings of 10 panels going to the 10000.

Path of least resistance from them might be to refund to you the difference in price between inverter named and inverter delivered. 9300W PV on 7600W inverter is a reasonable and small amount of over-paneling. Are they all oriented identically? If multiple orientations may not clip at all.

zendad said:

Here was their response in red as I suspected it would be. Is he right or just trying to get rid of me?


Then when I was concerned about clipping at 7600W, his response was:

7600 is the AC wattage output of the inverter. 11800 is the DC input into the inverter. To obtain optimum performance of an inverter you need to have a 1.2 ratio of DC to AC.​

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You mean clipping at 3500w?

I would think that even the smaller unit listed would still do better than 3500w.

zendad said:

On a sunny day, in November, with 30, 310W panels facing mostly south in Northern Illinois, I'm getting this plateau right at 3.5kW, way early in the morning (see graph).

If it peaked midday-ish, I might not be concerened. I'm new to this (2 weeks in), but so I'm not even sure what to expect. When I google production of a 300W panel it says 3.5kWh in a 8 hour sunny day. To me it seems like I'm way under producing even accounting for November Illinois.

Further, the exact plataeu of 3.5 kW on several days, way early in the day, almost makes me suspect something is limiting production. I have a Solaredge se10000H I believe, which shouldn;t cap out at 3.5kW. Right?

Any other reasons for teh 3.5kW early plateau with 30 * 310W panels?

View attachment 28799

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I am wondering if this was figured out. I have exactly the same problem, clipping at 3.5 kW with 9.3 kW DC capacity installed on 2 strings using a SE7600H inverter. The installer is currently trying to figure this out and has contacted SolarEdge. If you know what the solution was, please post because it will save me some time. Thanks.

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