Inverter output
-
sivapari1989@gmail.com
- Posts: 2
- Joined: Sun Aug 11, 2024 8:16 am
I am planning to install 40kW U40 3phase string inverter with the installed capacity of 46.4kW panels. According to the data sheet Maximum output is 44kW. Will I get 44kW if the solar irradiance is almost closer to 1000W/m2 and no shadows in the site? Please educate me regarding this. because I have noted in 20kW inverter where the power curve is getting cutoff with 20kW.
-
Dave Foster
- Posts: 1148
- Joined: Thu Oct 13, 2022 7:21 pm
Quite a few other variables to consider, a solar panel is rated for max output (when brand new) when tested with 1000W/m3 but also a solar cell temperature of 25C and they often quote an output tolerance as well.
All that said, typically if the solar cell (surface) temperature is 25C and with direct sunlight with the sun overhead ('noon') the output will be approx what the panels are rated at.
With a brand new array, rated at 46.4kW you would expect it to produce that on a cool day with full sunshine (possibly even more), in summer when the ambient is hotter the panels will derate slightly for each degree C above the panels rating - in the UK I expect ~ 15% less than rating on a hot day, obviously in hotter climates that might be greater.
Your inverter will be rated at a maximum DC 'PV' input and a maximum AC output, it will not produce anymore than either of those limits and so the inverter will limit the MPPT 'clip' the output to match it's rating.
As already said, with increased temperature the panels derate and with age they slowly derate as well so it is good practice to have slightly more generation possible than your inverter can handle - some countries limit the max allowed, I think it's Australia that specs 30% max but a 10-15% over rating is more typical.
All that said, typically if the solar cell (surface) temperature is 25C and with direct sunlight with the sun overhead ('noon') the output will be approx what the panels are rated at.
With a brand new array, rated at 46.4kW you would expect it to produce that on a cool day with full sunshine (possibly even more), in summer when the ambient is hotter the panels will derate slightly for each degree C above the panels rating - in the UK I expect ~ 15% less than rating on a hot day, obviously in hotter climates that might be greater.
Your inverter will be rated at a maximum DC 'PV' input and a maximum AC output, it will not produce anymore than either of those limits and so the inverter will limit the MPPT 'clip' the output to match it's rating.
As already said, with increased temperature the panels derate and with age they slowly derate as well so it is good practice to have slightly more generation possible than your inverter can handle - some countries limit the max allowed, I think it's Australia that specs 30% max but a 10-15% over rating is more typical.