Flat maximum energy production

[scrambler]

You must have optimizers on both strings, and they probably have a maximum power rating of 350W. Without optimizers, you'd see 400-430V under full sun, and around 12A current.

He only has a one or two panels with optimizers, and I don't see how Optimizer would create clipping for the whole string...
These are different from Micro Inverters that do create Clipping.

That said, it would not hurt to know which model of optimizers have been used a a few of the panels.
Tigo TS4 for example have a rating of 700W (16-80V with 15A)

[scrambler]

Graphing Voltage Amps and power, we can see the Amps being clipped around 7.5 Amps, While the voltage is around 450V which is in the acceptable range.

I am not the expert here, but that seems perfectly acceptable for the MPPT, which would rule out MPPT being out of range


Solar.jpg

[nerdralph]

Right, sun came out. Both units putting out 3440 watts or thereabout. Turned off unit 1. Unit 2 did not change output. Watched for 5 minutes, no change. Turned on Unit 2, it returned to putting out 3400 watts. Its mid day here in NZ so peak output right now

Unit 1, 3,415 watts, 474.6 volts and 7.3 amps
Unit 2, 3,316 watts, 474.9 volts and 7.2 amps

You must have optimizers on both strings, and they probably have a maximum power rating of 350W. Without optimizers, you'd see 400-430V under full sun, and around 12A current.

[smbunn]

Right, sun came out. Both units putting out 3440 watts or thereabout. Turned off unit 1. Unit 2 did not change output. Watched for 5 minutes, no change. Turned on Unit 2, it returned to putting out 3400 watts. Its mid day here in NZ so peak output right now

Unit 1, 3,415 watts, 474.6 volts and 7.3 amps
Unit 2, 3,316 watts, 474.9 volts and 7.2 amps

[smbunn]

I have added the XLS output files from that day. It has all the voltage and current settings for units 1 and 2


We have also been in drought here for 2 years which is unheard of in New Zealand. Typically we suffer too much rain. At least the water utiity dams are filling and we hopefully wont be on water restrictuions this summer again

[scrambler]

On the next sunny day with a production plateau, check the MPPT voltage and amps before the plateau and during the plateau
And make that test of shutting down one Inverter

ANd please send us some of your rain here in CA

[smbunn]

One MPPT. Single string with 10 panels
The SolaX unit has an informative LCD display amd I can also view this data over the web portal. ...but it pissing with rain at the moment so only getting a couple of kW total right now

[scrambler]

At first glance, 428V is within the MPPT range, and 11.69A is just below the max of 12 Amps...

Are you using the model with One or two MPPT?
Are you using a Single String and MPPT of 10 panels?
Is there any monitoring or panel on the inverter that would show the Actual String Voltage and Amp during the plateau?

[scrambler]

The panel specs say the max power voltage is 42,8V so the string will be 428Volts, and the max Power Amps for panel and therefore String is 11.69 Amps
So now we need to compare that with the Inverter MPPT specs

[smbunn]

https://www.solaxpower.com/wp-conten...-Air-Boost.pdf

My units are the last column, the X1-5.0T

If useful there are also these installer test figures.
MPPT1 Open circuit voltage 566.5 Vdc, Short Circuit Current 12.2 Adc
MPPT2 Open circuit voltage 566.5 Vdc, Short Circuit Current 12.2 Adc

[scrambler]

We may have cross posted, we need the inverter model and spec sheet too to verify the MPPT acceptable input range

[smbunn]

wrong link, sorry, this is my panel https://static.trinasolar.com/sites/...(II)_2021B.pdf
I had the right name but wrong link

[scrambler]

Good point, we do need to check what is the MPPT range of the inverter to see if it matches the string current and voltage.

Please give us the exact model of the inverter and spec sheet, so we can find what is the acceptable range of the MPPT for both Volts and Amps
And we do need the correct spec sheet for the panels to be sure of their output...

[nerdralph]

Solar panels are Trina TSM-DE18M(495). Attached is spec sheet (https://static.trinasolar.com/sites/...II)_202011.pdf)

That link is for 380W panels. I think the DE18M are 210mm cell high-power panels with high MPPT current (13-14A). If your inverter has a 10A MPPT limit per string, that would explain the clipping you are seeing.

[scrambler]

Also, Rule 21 does not apply in New Zealand but I am pretty sure New Zealand does have Smart Inverter regulations.

These basically define various ways the inverter would reduce production based on specific Grid circumstances.
The ones that could affect DC production would be Volt Watt and Frequency Watt modulations.
I don't know in New Zealand, but here and as part of Rule 21, Volt watt is triggered by high grid voltage and Freq Watt by high grid frequency
So it may be useful to investigate what type of smart remote controls are mandatory in smart inverters over there, and if so what settings activate them

That said, the fact this is a consistent daily thing does not really match the above which would normally be occasional.

One other test worth trying (after trying to shutdown one), is try to set the max export of one inverter to something like 2500W, see if it does clip at that to confirm the option works, then if it does, change it to 4500W and see what happens.