Solis start-up issue at sunrise

[Finnish_solar]

Hi everyone.

Firt, the setup is 12x380W panels, and VOC is ~450V.
Inverter is Solis S5-GR3P6K, a 6kW 3phase grid tie inverter, installed at Helsinki Finland.

Currently there is an issue always, when the day starts sunny, that the inverter does not "kick in" as should in the morning.

Presented are 2 different graphs, one of them on a cloudy day, and you can see that it starts steadily generate from the sunrise.

The other picture, is a completely sunny day, and you can see that the system is not starting to generate with a steady pace, but "jumps" at one point into full production.

Any ideas? Any help would be appreciated. Otherwise the system is working fine, and no issues observed.

 

[Solar Guppy]

You having partial shading in the AM, that's what you are seeing in the sunny day image. In cloudy days, the sunlight is more even / dispersed so the effect of shading is diminished somewhat.

 

[Finnish_solar]

Thank you for the reply!

I am just wondering that the partial shading takes so much out in such rapid step.
This can also be seen in the log of DC voltage, that when inverter "kicks in" on the sunny day picture, the VOC drops and current goes up, while on cloudy day, the VOC start the day already at "load level" and continues to draw current steadily at peak the whole day.

Same rapid movement does not occur in the afternoon though, when we start to get partial shading from the oaks, which is similar as in the morning.

 

[DarthAdder]

My panels have two sections which operate in series, if one half of a single panel is shaded in a whole string of panels hooked up in series, then the output drops. So yes a partial shading, of one half of one panel, will knock out all your panels if hooked up in series.
As I have an old house with large chimney stack (8 fireplaces) I have put in four strings, so one quarter has morning shading and another afternoon shading.

 

[SeaGal]

@DarthAdder Welcome! Your upcoming project sounds interesting - keep us updated