I have no experience of solar PV generation, so this is purely hearsay. However, it looks as if the benefits and drawbacks of having an inverter rated higher or lower than the array depend on several factors. I found an (admittedly American) article that explains this pretty clearly: Solar inverter oversizing vs. undersizing - Freedom Forever.

Though the explanation may be clear, what it means in your particular circumstances isn’t!

@Solarbob2024 As an electronics engineer what @Firedog is saying is correct but it shouldn't make a noticeable difference given the mismatch in solar array power and the rating of the inverter in your circumstances. Generally inverters work best (have the highest efficiency) at or near their rating. An inverter working below it's rating may be a few percent less efficient but this is less than the year to year variation so you wouldn't necessarily notice this.

I'm on other forums (like Speak EV) and people with solar have been saying that their output is significantly down this year due to the cooler, cloudier conditions so my guess would be that it is 2024 rather than changing the inverter that is causing your reduced output. If you have previous data and it persists over a number of years then it may be that the inverter is the cause. Different makes have different efficiencies but they are usually within a few percent of each other. Cheaper invertors could use thinner copper wire and use less efficient switching transistors to save money.

I hope that helps in some way

Peter

@Solarbob2024 Found a link for you about solar power for this year

In particular look at the energy chart a bit further down. Some months were really dismal.

https://www.renewsolar.co.uk/solar-tracking-and-mounting/solar-production-down-2024/

Peter

Hey @Solarbob2024, 

Hopefully the above posts from @Firedog and @Peter E are helpful in answering your question? If you have any follow up thoughts let us know and we’ll see how we can support!