-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
7.2 kw system generates only 4 kw
- Thread starter Arun Kumar
- Start date
Thanks. It is split on different sides on my roof facing different angles. There are no shade blocking the panels.
@SVDNN and @bruce4000 have pointed you in the right direction.
I would add when looking at numbers, on a daily basis it is likely to be highest near the summer solstice (June 21) and lowest on the winter solstice (Dec 21). So don't associate hottest days with most solar production. It is length and intensity of the sun that matters, not temperature. In fact, high temperature can decrease solar panel efficiency as the panels get hotter during the dog days of summer.
Also, as far as what your system should produce, check your contract and look at the annual production guarantee.
BTW, how many kWh does your system produce per day now. And what does the curve look like? Starting early, rising fast, and dropping late in the day will give maximum area under the curve.
I would add when looking at numbers, on a daily basis it is likely to be highest near the summer solstice (June 21) and lowest on the winter solstice (Dec 21). So don't associate hottest days with most solar production. It is length and intensity of the sun that matters, not temperature. In fact, high temperature can decrease solar panel efficiency as the panels get hotter during the dog days of summer.
Also, as far as what your system should produce, check your contract and look at the annual production guarantee.
BTW, how many kWh does your system produce per day now. And what does the curve look like? Starting early, rising fast, and dropping late in the day will give maximum area under the curve.
Last edited:
One big mistake that many people seem to make when they buy solar / PV systems, is assuming some variation of "I bought a system that was size X, so I will see X max production during the day" (I bought a 7.2 kW sized pv system, why is my max production not 7.2kW?").
It doesnt work that way, as systems are sold by PV panel size but you are generally limited by the inverter, and / or the angle of the panels and sun etc.
You didnt provide nearly enough information for us to know for sure, but what we do know for sure is:
1. a 7.2 kW system wont peak at 7.2 kW by the way most PV systems are designed.
2. Its much more accurate to pay attention to total production over weeks, instead of looking at, or being concerned with daily production unless you have something to compare it to, like last years daily numbers in the same install.
I am going to guess that your system is fine, but you can model it using something like pvwatts, but absent any other information, and knowing the above, its highly (highly) likely that your system is working properly.
My 30kw system will max out at 22.7kw. Part of that is the 2 inverters limits. Plus shading, north panels, etc.
My 10 kW system is not inverter limited and faces two planes - WSW and SSW - on different inverters. Peak production on an ideal day (cool breeze and summer sun) can occasionally produce 10 kW - but that is transient and not sustained. I have seen 11.1 a couple of times with "cloud fringing" when the panels have cooled with a passing cloud and as the could passes, there is enough additive effect of the bent light from the cloud edge along with direct light that the system momentarily gets to near the theoretical max output. Max sustained output (greater than 5 minutes duration) is about 7.5 kW.
Best to follow using a kWHrs per day and annualized output. Peak output data is essentially entertainment...
Best to follow using a kWHrs per day and annualized output. Peak output data is essentially entertainment...
Similar threads
