Weird Solar energy curve, or not…?

[CaboSud]

Hi,
The shape of my solar energy curve seems not right to me, please can anyone advise, thank you.

New install
11kW
20 x 550W panels
Pitch 11°
3 rows: 4 landscape, 8 portrait, 8 portrait
Optimisers on every panel
Orientation: 2° from due south
Location: 38.7°N, 7.9°E
Installed on carport roof
No obstructions from 10:00 am to 5:00 pm, as per the red lines on the photo
Trees before and after those times
Average daily energy 65kW

Every full sunny day is the same shape, it just doesn’t seem right to me.

Many thanks indeed for your input, much appreciated, thank you

 

[johnb2713]

What doesnt look right to you? what are you expecting?

 

[CaboSud]

Every full sunny day is the same shape, it just doesn't seem right to me. I feel as if I am missing energy between 12:30 onwards.

The second photo is a neighbour down the road, I anticipated my curve to be like his

Many thanks indeed for your input, much appreciated, thank you

 

[johnb2713]

Every full sunny day is the same shape, it just doesn't seem right to me. I feel as if I am missing energy between 12:30 onwards.

The second photo is a neighbour down the road, I anticipated my curve to be like his

Many thanks indeed for your input, much appreciated, thank you

Maybe temperature related ? When panels get hot their performance decreases.

 

[Chrisbee]

I agree, most likely is panel temperature or maybe inverter temperature?

But also, mine clips at the inverter output spec from the moment my batteries are full.

See pic attached showing Thursday/Friday/Saturday.
Blue is SE roof, red is SW roof, orange is total.

 

[binky]

So it's a split array? What size inverter?

If it's a split array, then the peak will be flatter and wider. But it also sounds like the inverter is possibly limiting output to suit the batteries. Do you have any export limitation in the system?

 

[Chrisbee]

Yes indeed. 7x440W panels on each roof. So total panels is over 6KW.

Inverter is Solis 3.6KW hybrid with 4.8KW of Pylontech batteries.

Clearly a bigger inverter would be better but I think my next investment will be to add to the batteries.

The excess of panels does at least help on duller days and with spring and autumn generation.

 

[Chrisbee]

Oh, also, if I time charging the Nissan Leaf correctly, then that slows the battery charging which in turn allows sustained periods of say 4.5-5.5KW of generation. (Say 3KW to the car, 0.6KW to house & 1 to 2KW to batteries).

Once house Batts are full, only 3.6KW is possible.

 

[binky]

Ok, that's quite a lot of panels for that inverter, and it would suggest the inverter is struggling to cope. One of the reasons I don't believe in undersizing inverters, it's irritating to have the system 'choked' on a bright sunny day. However, getting back to your question, I would say it's working fine and doing what it's supposed to do.

 

[Chrisbee]

Apologies if I've hijacked the thread. My intention was just to show the OP a similar graph to his.

 

[CaboSud]

I agree, most likely is panel temperature or maybe inverter temperature?

But also, mine clips at the inverter output spec from the moment my batteries are full.

See pic attached showing Thursday/Friday/Saturday.
Blue is SE roof, red is SW roof, orange is total.

Thank you Chrisbee, I’m leaning towards the inverter which sits in a small-ish housing unit, with some but maybe not enough ventilation, is getting too hot perhaps…

I have no batteries, the excess goes straight to the grid

 

[CaboSud]

Ok, that's quite a lot of panels for that inverter, and it would suggest the inverter is struggling to cope. One of the reasons I don't believe in undersizing inverters, it's irritating to have the system 'choked' on a bright sunny day. However, getting back to your question, I would say it's working fine and doing what it's supposed to do.

It’s an 10kW inverter, with 11kW panels on the roof. Supposedly anything made over what I’m consuming, and obviously 10kW, goes straight to the grid automatically…

 

[CaboSud]

So it's a split array? What size inverter?

If it's a split array, then the peak will be flatter and wider. But it also sounds like the inverter is possibly limiting output to suit the batteries. Do you have any export limitation in the system?

It’s just one array, split into to two strings.
The inverter is 10kW, panels are 11kW.
Max inverter allowed in Spain without a lengthy process for a permit (classed as a commercial operation) is 10kW.
No batteries.
I occasionally make over 10kW according to the graphs, like today, photo below, and everything seems to keep on working when that happens.
Just a bizarre shaped graph, not the typical full sunny day graph shape.
The supplier said he’s done loads of these size systems, and they all work fine, of course!
I’m starting to think the inverter is struggling, re over-input, or over-temp in its housing perhaps…
Very many thanks for your input everyone, appreciate that, thank you

 

[binky]

It’s just one array, split into to two strings.
The inverter is 10kW, panels are 11kW.
Max inverter allowed in Spain without a lengthy process for a permit (classed as a commercial operation) is 10kW.
The supplier said he’s done loads of these size systems, and they all work fine, of course!
I’m starting to think the inverter is struggling, re over input, or over temp in its housing perhaps

I hadn't noticed your location - doh! Chances are it's just overheating then. Not sure if the Solis displays internal temperature, but inverters can get upto 70C even in the UK, which is when they start to self protect themselves by basically shutting down a bit. 11 kW of panels on a 10Kw inverter is fine, it's not often panles outptut at their maximum as there's nearly always some dust / other dirt on them, atmospheric water/clouds and dust in the air. You tend to get peak outputs just after it's rained, when the panels have cooled down a bit, hopefully had a good wash off, and the air is clean.

Mind you, the irradiance down your way is far stronger than the UK, so maybe a few more panels than you need for summer?

 

[CaboSud]

I hadn't noticed your location - doh! Chances are it's just overheating then. Not sure if the Solis displays internal temperature, but inverters can get upto 70C even in the UK, which is when they start to self protect themselves by basically shutting down a bit. 11 kW of panels on a 10Kw inverter is fine, it's not often panles outptut at their maximum as there's nearly always some dust / other dirt on them, atmospheric water/clouds and dust in the air. You tend to get peak outputs just after it's rained, when the panels have cooled down a bit, hopefully had a good wash off, and the air is clean.

Mind you, the irradiance down your way is far stronger than the UK, so maybe a few more panels than you need for summer?

Thank you binky, appreciate that.
I have a 10kW Goodwe inverter, (Chrisbee who hijacked the thread a little has a Solis).
I’ll try ventilating the housing it sits in better, and maybe put an extractor fan in there too, that might help also.
The inverter does get hot. It doesn’t have a temperature readout, but I’ve just bought an infrared thermometer so will give that a go and see what figures I’m getting at the unit, and in the housing