Solar panel output dropping during peak sun.

Where's the inverter situated? Attic, shed, internal to house? And no battery, right?

The way that the generated power is bouncing around the 2kW mark makes me think that it's interacting with some external factor. The drop was earlier yesterday than it was on the previous day too, interesting.

Just looking at my own inverter the times you start to see the drop is the time where the inverted internal temperature starts to climb.

I use a fan to dissipate the heat and find it works well.

Other much more knowledgeable posters here might know better the impact.

Yeah, so it also de-rates at 45C:

https://solar.huawei.com/en/products/SUN2000-3-4-5-6KTL-L1/specs/

-25 °C to +60 °C (Derated above 45 °C @ Rated output power)

I'm not sure of the de-rating value, maybe have the installer check with Huawei, but it's the likely cause here.

Hi,

I have a Huwawi inverter. I had a very similar problem over the last two months, as soon as the inverter started hitting max output it would drop. Each day there would be at least two drops and sometimes as many as 10 or 12. It would only happen on sunny days when i was exporting the vast majority of what was being produced. Below is an example of one day last week.

The ESB put a monitor on the meter and it was a grid issue. They switched the phase in my meter and everything is now running well and back to normal. Below is today's graph.

Maybe you should get the ESB to stick a monitor on your meter. I did notice on the APP that the grid was spiking above 253 and up to 255.7 on many occasions.

I talked to the ESB after they took off the meter that had been put on for two weeks, he had arrived to ask me to turn off my inverter and they would monitor it further for two days. He said that the reading for the grid voltage were consistently high and then they were spiking a various times during the day. He said that they would investigate the situation and get back to me, they arrived back two days ago and I was not there, he told my wife that he was changing the phase and they would leave the monitor on the meter and also monitor their output, I presume from the substation. he did not mention harmonics and I assumed from seeing my own spikes on the APP and what he said that the issue was a higher than normal voltage issue.

Looking at the graphs from Stephen013 and the issues he describes to me it looks like a similar problem but I could be totally wrong as I know nothing about the grid or the technical side of this. However getting a his voltage monitored could rule a high voltage issue in or out.

I had no email exchange of a technical nature.

Shouldn't the inverter be throwing out a alarm if its derating?