inverter and heatwave

Alnat1

Found this -

Solar panels are power tested at 25C, so the temperature coefficient percentage illustrates the change in efficiency as it goes up or down by a degree. For example if the temperature coefficient of a particular type of panel is -0.5%, then for every 10C rise, the panels maximum power will reduce by 0.5%.

So on a hot day, when panel temperatures may reach 45C, a panel with a temperature coefficient of -0.5% would result in a maximum power output reduction of 10%. Conversely, if it was a sunny winter’s morning, the panels will actually be more efficient.

Skintsaver

This could explain why my installation of 2 and 4 panels facing over east west. At 8am. I'm seeing 500w from 2 panels at 3pm I see 1100w from 4 (poss the other 2) and now at 6pm when the sun looks the same as it. Does 8am but facing the 4 panels I'm getting just 400w. Could be a heat thing colder in the mornings hot afternoons and evenings. Is there a way I can test my panels? 

QrizB

Skintsaver said:

Could be a heat thing colder in the mornings hot afternoons and evenings.

Yes, that's probsbly it.

Is there a way I can test my panels? 

If you can wait, we'll probably get a spell in April or May 2023 with sunshine but cooler temperatures.

It's possible in September or October, too.

Spies

My panels STC is 25c they are rated at 390w under these conditions,  under NOCT at 48c I only get 294w from each panel and appears I lose 0.25% for each kelvin over that (why they mix units I don't know!).

Edit: just released an increase of 1 kevlin is equal to 1c increase. 

jimjames

Noticed my inverter was showing as 69C over weekend, tried cooling it with compressed air which dropped about 10C. It's outside so I guess one in a loft would get even hotter