Solar production dips

[SicEmBears]

28CCE853-C327-413C-AA6B-FD4E42DC1FDA.jpeg

I’m getting these dips in performance I’ve spoken with my rep at solar edge and he says there is nothing to worry about it’s just a drop because there is too much energy in the grid so the panels shut down. Is that correct? Some days it’s a lot of production as it’ll drop to almost 0 for 15 min 3 or 4x a day

[SunEagle]

Inverters stop producing for a number of reasons concerning the grid. Sometimes it is a phasing , or a frequency, or voltage issue. There are probably other software controls to disconnect due to anti islanding requirements.

[bob-n]

This is a really wild guess, but that's what happens to my output when a cloud passes by. If a small portion of a panel gets shaded by a cloud or other shadow, output from that whole panel drops like a rock. That's because each panel consists of many individual cells connected in series. If one cell in a panel gets shaded, it stops producing current and acts like an open circuit, preventing other cells in that panel from providing current to the output. Here's a graphic illustration of this mechanism:

https://www.youtube.com/watch?v=JTDSPjDSrS8

[SicEmBears]

Naw it’s not clouds, bob. I wish it was that easy.

SunEagle what can I do to look to see if it’s something that is correctable?

[NewBostonConst]

Where are you located?

If you have a volt meter and can check the voltage and frequency pretty easily. Guessing there is a youtube video on how to do it.

Monitor and write it down throughout the day and if you can catch when it drops.

Then look up you inverter specs and see if they the voltage and frequency are within specs.

I could be that the wires are to small from your inverter to you house wiring causing the voltage at the inverter to go up (because it can't push the power back into the grid fast enough) and the inverter will then shutdown. Is this only happening at peak sun?

[SunEagle]

Naw it’s not clouds, bob. I wish it was that easy.

SunEagle what can I do to look to see if it’s something that is correctable?

One place I would look at are the error codes on your inverter. It should tell you why it stopped producing if there was a software shutdown.

Otherwise there are some pretty cool meters out there that will record all of the grid power functions and show you if they fall out of spec which can shut down the inverter.

[jflorey2]

I’m getting these dips in performance I’ve spoken with my rep at solar edge and he says there is nothing to worry about it’s just a drop because there is too much energy in the grid so the panels shut down. Is that correct?

In some (poor) installations, the voltage drop from the inverter to the grid is large enough that the inverters detect a voltage fault and shut down. Once they shut down the voltage drops and they start back up. This can also be caused by a high normal grid voltage, which is harder to correct. Sometimes you can correct that by going to even lower gauge wiring to reduce the voltage drop, sometimes you can adjust the high-limit trip point - and in extreme cases you can use an autotransformer to drop the voltage 10 volts so the inverters see a lower voltage.

[scrambler]

I went through a similar experience that I detailed in the thread below

https://www.solarpaneltalk.com/forum/solar-panels-for-home/solar-panel-installation/410935-strange-production-behavior

My drops were a lot deeper than yours, the inverter would drop down around 500W basically shutting down production and ramping up again.
I became sure of the issue when it happened during sunny clear sky days, but after thorough investigation i found out it was actually also happening during cloudy days, way beyond what could be explained by the cloud shade level, as I figured even with the level of clouds happening during the drops, the drops should not have been that deep. (have a look at my thread above and the graphs I created during various situations)

As my provider was not caring about it, I installed a line logger which did not reveal anything related to the drops. But in my case the breakthrough came when I set the inverter in a different operating mode. Mine is a hybrid inverter and the issue was happening in self supply mode. When I switched to Backup mode, the issue disappeared which confirmed it was an inverter issue.

After I sent my full report to the provider, he finally took things seriously and they are coming up with some firmware revision to test.

So don't listen to your provider brushing it off until you identify a clear cause. A lot of these guys seem very incline at brushing off their shortcomings and taking a "good enough" attitude which is quite frustrating when you spend that kind of money on a system....

Your first step is making sure it is not related to any shade (clouds or otherwise), once you have clear proof of that (like the issue happening during sunny clear sky days), you may be on your own to hunt and test.

[SicEmBears]

I’m a complete nube to all of this. I wouldn’t know how to look at what errors the inverters were throwing or how to put them into test mode. :/. More homework I guess.

[scrambler]

The first thing you should do is monitor and document
Keep a log of the exact weather every day, major electrical events like EV charging, AC running etc... then compare them with the graphs of these days, and see if you see a pattern. Do you see drops in Sunny perfectly clear sky days
What is the production like when you have specific level of clouds to know what is a normal power output for each type of cloud cover Dark grey , overcast grey, light white clouds....
Then review the graphs in light of the weather, and see if you notice any pattern.
Also look for hours for the drops, like if they happen often at the same time, you could have a major motor in the neighborhood coming up that spikes the grid power.

Ask your installer or manufacturer if error logging has been turned on on the inverter.
Ask them or search the documentation for what type of errors the Inverter detects. Normally they should detect any grid spikes of various kind like Voltage or frequency. If so you can ask if the reports show any.

You haven't specified the exact model of the inverter, that may help gather graphs from other users of the same inverter on this forum, and see if they also experience drops in the same circumstances as you do.

[solar pete]

Looks like clouds to me

[Mike90250]

Or could be a bad panel that heats up and a ribbon trace opens up, till it cools down and reconnects. Or any of the dozens of interconnects on the outside.