Saltatory generation with Voltronic InfiniSolar v4 (3.6KW)

[Aleksey]

Hello.

I have inverter "Voltronic InfiniSolar v4" and quite new (one-year old) pv panels that can potentially generate 1kw. At first, everything was fine, at sunny day they indeed were able to produce ~800w constantly for several hours. But, recently I started to observe the following picture (today's example):

Today is a perfect sunny day with clear sky, no shadows over the panels.

As you can see, at first the Sun is going higher as well as the generation. But then, instead of going up to the maximum generation, it starts to chaotically jump up and down, so that one second it shows 500w, the next second it may be even 0w (!) and so on. All that results in a very poor average generation, so that I receive only ~100-150w in average from 1kw panels in a sunny day).

Another strange thing is that at cloudy days the chart is way "smoother":

I.e. although the generation is quite low, but there are no these chaotic "hops".

I'm pretty new and have no experience in that area, I have tried to search for similar situations over the internet, but with no luck.

What should I check? Where to start diagnosing the problem? What could be the reason?

Edited March 27 by Aleksey

[TaliaB]

25 minutes ago, Aleksey said:

Hello.

I have inverter "Voltronic InfiniSolar v4" and quite new (one-year old) pv panels that can potentially generate 1kw. At first, everything was fine, at sunny day they indeed were able to produce ~800w constantly for several hours. But, recently I started to observe the following picture (today's example):

Today is a perfect sunny day with clear sky, no shadows over the panels.

As you can see, at first the Sun is going higher as well as the generation. But then, instead of going up to the maximum generation, it starts to chaotically jump up and down, so that one second it shows 500w, the next second it may be even 0w (!) and so on. All that results in a very poor average generation, so that I receive only ~100-150w in average from 1kw panels in a sunny day).

Another strange thing is that at cloudy days the chart is way "smoother":

I.e. although the generation is quite low, but there are no these chaotic "hops".

I'm pretty new and have no experience in that area, I have tried to search for similar situations over the internet, but with no luck.

What should I check? Where to start diagnosing the problem? What could be the reason?

Good day @Aleksey we need more information about your solar array, panel specs, how is your panels connected series?and the tilt, orientation should you know. The startup voltage of the mppt is 110v. Remember we are moving towards winter that would influence the output.

[Aleksey]

@TaliaB

Sure. I have 10 panels, all of them connected sequentially.

Each panel has the following specs (I couldn't find specs in English, the below is a translation):

Power: 100 w
Type: Monocrystal 75x166 mm
Number of elements: 36 (3x12)
PV element: 9BB (9 bus bar)
Idle voltage: 24,25 V
Working voltage: 20,40 v
Short circuit current: 5,25 A
Working current: 4,90 a
Max voltage: 1000 V
Module efficiency:  19,23 %
Element efficiency: 21,30 %
Number of diodes: 1

The panels are looking at South, almost. They are sitting on the wall, so the tilt, I suppose, is 90 degrees.

Note that I'm located at the North hemisphere, therefore now it's Spring for me and I'm moving towards Summer  The Sun is already very hot, plus snow still covers everything, it reflects a lot of sunlight. When I'm standing near the panels, it's too hot and bright there, very hard to be there without sunglasses.
The inverter reports pv voltage is around 230 V:

Btw, when the inverter reports that the generation is 0w, at the same time the voltage is still as usual.

[TaliaB]

14 minutes ago, Aleksey said:

@TaliaB

Sure. I have 10 panels, all of them connected sequentially.

Each panel has the following specs (I couldn't find specs in English, the below is a translation):

Power: 100 w
Type: Monocrystal 75x166 mm
Number of elements: 36 (3x12)
PV element: 9BB (9 bus bar)
Idle voltage: 24,25 V
Working voltage: 20,40 v
Short circuit current: 5,25 A
Working current: 4,90 a
Max voltage: 1000 V
Module efficiency:  19,23 %
Element efficiency: 21,30 %
Number of diodes: 1

The panels are looking at South, almost. They are sitting on the wall, so the tilt, I suppose, is 90 degrees.

Note that I'm located at the North hemisphere, therefore now it's Spring for me and I'm moving towards Summer  The Sun is already very hot, plus snow still covers everything, it reflects a lot of sunlight. When I'm standing near the panels, it's too hot and bright there, very hard to be there without sunglasses.
The inverter reports pv voltage is around 230 V:

Btw, when the inverter reports that the generation is 0w, at the same time the voltage is still as usual.

What is the load on the inverter output and battery soc it looks like the mppt is throttling( reducing) the current. Do you have a pv graph of the current

Edited March 27 by TaliaB

[Aleksey]

@TaliaB, I think you gave me the explanation! Thanks!

Now, when you asked to look at both generation and consumption, everything becomes clear:

When (active power + charging power) is more than the generated power, the generation graph is "smooth", otherwise throttling happens, which, on the graph looks like chaotic hops.

I thought it's an issue with my pv or inverter, but everything is fine, only a lack of experience from my side. Thanks.

Edited March 27 by Aleksey

[TaliaB]

1 hour ago, Aleksey said:

@TaliaB, I think you gave me the explanation! Thanks!

Now, when you asked to look at both generation and consumption, everything becomes clear:

When (active power + charging power) is more than the generated power, the generation graph is "smooth", otherwise throttling happens, which, on the graph looks like chaotic hops.

I thought it's an issue with my pv or inverter, but everything is fine, only a lack of experience from my side. Thanks.

Glad i could be of help. Just for interest sake in which country do you live.

[Aleksey]

54 minutes ago, TaliaB said:

Glad i could be of help. Just for interest sake in which country do you live.

I've updated my location in the profile.

[Coulomb]

On 2024/03/27 at 8:22 PM, Aleksey said:

When (active power + charging power) is more than the generated power, the generation graph is "smooth", otherwise throttling happens, which, on the graph looks like chaotic hops.

It's possible that you have a firmware issue. I don't collect Infini firmware, but if you tell me your main (U1) firmware version, I can do a quick search to see if I can spot more recent firmware.

Those 100 W panels are unusual, at least here in the West.

The 90° inclination is also very unusual. This may be contributing to your issues. As the sun rises higher in the sky towards summer solstice, I assume that the panels will receive less and less direct sunlight. Presumably, you can't rely on reflection from snow in the middle of summer (but I'm not familiar with your climate).