Not sure I am getting full output from 10.8KW system

[CentralMo]

I have 24 - 450W panels (10.8 KW system) with a Sol-Ark 12K and Tigo optimizers. What seems to happen is as String B increases with output String A decreases. C is not affected. This is apparent in a 7 minute swing from cloudy to sunny. I believe when the installer was setting this up he put A and B on the same MPPT and C on the other. The installer told me I was getting the correct about of power the system was rated. I don't know, just looks strange to me.

Any idea what may be going on?

 

[Nobodybusiness]

I have 24 - 450W panels (10.8 KW system) with a Sol-Ark 12K and Tigo optimizers. What seems to happen is as String B increases with output String A decreases. C is not affected. This is apparent in a 7 minute swing from cloudy to sunny. I believe when the installer was setting this up he put A and B on the same MPPT and C on the other. The installer told me I was getting the correct about of power the system was rated. I don't know, just looks strange to me.

Any idea what may be going on?

View attachment 210859View attachment 210862View attachment 210864

I can tell you the Sol-Ark 12K only has 2 MPPT channels.

It’s possible he put 2 strings in parallel on one channel.
Not sure why.

The inverter can handle 6500Watts per channel.


What is the panel Manufacturer and model#?

 

[CentralMo]

They installed these panels.

Model	Manufacturer	Max Power	Count
phono solar twinplus	Phono Solar	450 W	24

 

[Nobodybusiness]

According to the specs for those panels you should have

2 strings of 7 panels in parallel with each other per MPPT channel.

That would give you 14 panels in Channel 1 and 14 panels in channel 2.

Given you only have 24 panels you are short 4 panels for a full input.


Why they did it that way I have no idea.

 

[BentleyJ]

Two observations may help clarify:
1) In partial cloud conditions the system still produced 7191W and in full sun total output increased to 9624W. That is 89% of the STC rating which is very good to excellent. Time of day and ambient temperature are important factors.
2) The number of panels in strings A & B are not the same. If the strings are connected in parallel to a single MPPT input then the optimizers have to boost the voltage of string A to match B otherwise string A cannot contribute. Boosting voltage requires current but higher current pulls the voltage down on each panel.
My theory is as follows but I could be wrong. String A voltage boost requires current in such a quantity that it drags the PV panels down below their individual maximum power point capability in order to optimize the entire string A relative to string B with regard to total voltage supplied at the MPPT input.

In other words, It is not possible to optimize both Voltage and Current for the individual panels in string A based on their maximum power point when the additional requirement of having to match the voltage of the larger string B is added into the mix.

 

[Zapper77]

I have 24 - 450W panels (10.8 KW system) with a Sol-Ark 12K and Tigo optimizers. What seems to happen is as String B increases with output String A decreases. C is not affected. This is apparent in a 7 minute swing from cloudy to sunny. I believe when the installer was setting this up he put A and B on the same MPPT and C on the other. The installer told me I was getting the correct about of power the system was rated. I don't know, just looks strange to me.

Any idea what may be going on?

View attachment 210859View attachment 210862View attachment 210864

show me the wiring diagram from tigo.

How many strings to you have feeding your inverter?

Edit: I see you think A and B are on the same string. Thats may not be correct.

2nd Edit: Need to see voltage and Current

 

[Nobodybusiness]

show me the wiring diagram from tigo.

How many strings to you have feeding your inverter?

Edit: I see you think A and B are on the same string. Thats may not be correct.

2nd Edit: Need to see voltage and Current
View attachment 211691

He’s got three strings, and only two inputs so something is getting parallel somewhere

 

[CentralMo]

Hopefully I was able to get all the information.

Here are the inputs to the SolArk 12K. String A and B are on one and C is on the other.



Here is the wiring diagram from Tigo. Strings A and B face south while C faces west.
When we signed up we were told after energy audit that 10.8KW was the size we needed from the contractor and Amren.



The time these three readings occurred were between 1:15 - 1:19 p.m.
Here is what the SolArk was showing that day also.





Here is the voltage and current for each of the times above.

 

[LydMekk]

In comparison with my 8kW models the polarity of the PV are swapped.
Is this correct?
On my 3 the plus are to the left and the minus to the right side.

 

[Zapper77]

Sting that are parallel should be identical. Also appears that you are hitting the MPPT 1 cap.