Figuring out how to split solar panels to match inverter limitations

[Loay Odeh]

Hello everyone,

This is my first post here - I am also new to solar in general. I am hoping I can get some clarification.

I currently have 18 panels from TommaTech (model TT665-132PM12), and I am planning on getting a Sungrow inverter (model SGRT10).
Here's the issue: The panels have a maximum power current (Imp) of 17.46A. The inverter spec sheet says the maximum input current is 37.5A (25A/12.5A).

I am assuming that means that one input has a limitation of 25A while the other input has a limit of 12.5A (please correct me if i'm wrong). I was thinking of connecting all the panels in series and using only the 25A input. Would something like this work fine?

I would appreciate any help on this matter. If there is any information that I didn't provide, please let me know and I will.

Solar Panels Data Sheet
Solar Inverter Data Sheet

 

[DIYrich]

The inverter has an MPPT voltage rage of 160-1,000v, and max voltage of 1,100v.
The panels have an operating voltage of 38.1, and VOC of 45.8
18 panels would have an operating voltage of 686v, and a max voc of 825v (unadjusted).
686v is within the operating range of the MPPT, and near the "rated pv input voltage" of 600v.
825v is well under the 1,100v max.
825v is well under the Max system voltage for the panels of 1,500v.

Looks good to me.
The trick is finding wire rated for 1,000v.

 

[Loay Odeh]

The inverter has an MPPT voltage rage of 160-1,000v, and max voltage of 1,100v.
The panels have an operating voltage of 38.1, and VOC of 45.8
18 panels would have an operating voltage of 686v, and a max voc of 825v (unadjusted).
686v is within the operating range of the MPPT, and near the "rated pv input voltage" of 600v.
825v is well under the 1,100v max.
825v is well under the Max system voltage for the panels of 1,500v.

Looks good to me.
The trick is finding wire rated for 1,000v.

Appreciate your response! The panel spec sheet says that the maximum system voltage is 1500V. So do I only need to worry about the wires at both ends connecting the pv system to the inverter from the DC side?
Also, thank you for checking the voltage requirements, but would there be any issue in regards to the current being limited?

 

[DIYrich]

Appreciate your response! The panel spec sheet says that the maximum system voltage is 1500V. So do I only need to worry about the wires at both ends connecting the pv system to the inverter from the DC side?

All the wires that connect between your panels and the inverter should be rated for 1,000v. If you have a short anywhere along the circuit, it could be at more than 600v.

Also, thank you for checking the voltage requirements, but would there be any issue in regards to the current being limited?

As long as your are under 25 amps, you should be fine connecting to MPPT 1 (you are way under the 25a limit). If you add panels later, and want to connect to MPPT 2, then you need to be careful about the 12.5a limit. You have big commercial panels. If you use MPPT2, you might want more traditional residential panels (probably in the 300 watt range to stay under 12.5 amps).

 

[Loay Odeh]

Hello! Thank you @DIYrich for the help. The inverter has been installed and all is working well. It produced approximately 70 kWh today.
One last question: I noticed that instantaneous production reached around 10.8 kW (AC). The inverter has a rated AC output power of 10,000 W, and a Max AC output apparent power of 11, 000 VA. Is it okay that the production sometimes exceeds the rated AC output power (it was above 10 kW for around 3 hours) , or can this cause issues with the inverter, such as overheating and component degradation?

 

[DIYrich]

Hello! Thank you @DIYrich for the help. The inverter has been installed and all is working well. It produced approximately 70 kWh today.
One last question: I noticed that instantaneous production reached around 10.8 kW (AC). The inverter has a rated AC output power of 10,000 W, and a Max AC output apparent power of 11, 000 VA. Is it okay that the production sometimes exceeds the rated AC output power (it was above 10 kW for around 3 hours) , or can this cause issues with the inverter, such as overheating and component degradation?

The inverter is fine. It will "take" whatever power it can use. Any excess will be left behind. Some conversion losses and Inverter usage are normal, so DC will exceed AC.