Implement different string's length on the same MPPT (only one MPPT)

[hcapdevi]

Hello,

I am testing different inverter on the same project to make a choice.

I am testing an inverter from the brand Kaco with only one MPPT.

I don’t know how to, or if it is even possible, to create a system with different string’s length on a same MPPT. Since I only have one MPPT I can’t use the multi mppt function.

Kaco is telling me that the mismatching losses of such a configuration (different number of modules in parallel string on a single mppt), is balanced with the better efficiency), but I would like to see that myself on PVsyst.

Does anyone can help me?

[Lazare Fesnien]

Hi,

The only way is to re-define your inverter as 2-MPPT inputs, and define one sub-array per kind of modules.

By the way the mismatch between strings of different but close voltages is completely negligible.

You can have a look on our tool "Detailed Losses > Module quality – LID – Mismatch > String voltage mismatch, strings study".

And on the Help "Project design > Array and system losses > Array mismatch losses".