8.16 kW DC Solar Panels but never generating more 6.5kW

[fatcatXK]

Hi,

I had Tesla 8.16 kW DC Solar Panels installed in June 2020 but they never generate more 6.5kW even after cleaning the panels...Across entire year, 6.5kW is the maximum generated power which is typically around noon to 1pm. I'm trying to understand whether getting 8.16 kW is realistic. I have a family member that installed a 4.8 and is getting 4.8.

The inverter installed is a solaredge SE7600H - USOOOBSU4 that maxes out at 7.6kW. Wanted to check here on whether this would be a cause as to why I'm not getting the maximum possible. My panels face south on the roof and has very clear and direct access to the sun across the whole day. Nothing obstructing.

I have a total of 24 Hanwa panels.

Thank you!!!

 

[wwhitney]

I'm curious @wwhitney what is your reasoning behind that statement?

That is the result of a simple model that inactive panels absorb all of the sun's power and convert it to heat; that active panels convert 80% of the sun's power to heat, and 20% to electricity; and that rate of cooling is proportional to the temperature rise from ambient (true for conduction and convection, not true for radiative heat transfer).

At equilibrium the rate of heat gain must match the rate of heat loss. So the temperature rise of the active panels should be 80% of the temperature rise of the inactive panel. The observed delta of 5C should be 20% of the temperature rise of the inactive panel, so the active panels should have 20C temperature rise, the inactive panel 25C temperature rise.

That's just an approximation but should be in the ballpark.

Cheers, Wayne

 

[ptdusn]

I happen to have a (crappy) infrared camera and a rooftop solar array with one panel that’s out due to a dead microinverter, so I went ahead a took some photos.

At midday on a sunny day the “dead” panel was approximately 5C/9F hotter than the adjacent panels.

I imagine a cheap handheld IR thermometer (the kind that looks like a little gun) could also be used to identify similar temperature disparities.

View attachment 942746

If you know the brand and part number of the microinverter, (i.e IQ7), you can get one inexpensively and replace it, if your solar installer won't honor a warranty

 

[jsmay311]

If you know the brand and part number of the microinverter, (i.e IQ7), you can get one inexpensively and replace it, if your solar installer won't honor a warranty

I already got the replacement microinverter (M250) from Enphase under warranty. The original solar installer is out of business, and getting another solar installer to come out to install it in will cost several hundred dollars, so I'm waiting until an upcoming reroofing job to replace it then.

 

[charlesj]

I already got the replacement microinverter (M250) from Enphase under warranty. The original solar installer is out of business, and getting another solar installer to come out to install it in will cost several hundred dollars, so I'm waiting until an upcoming reroofing job to replace it then.

If you were next door to me, I would help you.
I had to replace one a couple of years ago under warranty.

 

[ptdusn]

I already got the replacement microinverter (M250) from Enphase under warranty. The original solar installer is out of business, and getting another solar installer to come out to install it in will cost several hundred dollars, so I'm waiting until an upcoming reroofing job to replace it then.

It's really not that difficult to replace. Just lift the panel, detach the old and install the new.

 

[charlesj]

It's really not that difficult to replace. Just lift the panel, detach the old and install the new.

He would need those tools that will help with the disconnect. You need to place and tie down the panel to replace inverter. Two can do it much easier.
I did it by myself. Not fun.
He may not like climbing on roofs.

 

[jsmay311]

He would need those tools that will help with the disconnect. You need to place and tie down the panel to replace inverter. Two can do it much easier.
I did it by myself. Not fun.
He may not like climbing on roofs.

Climbing on roofs… no problem. That’s how I got those IR photos.

Special tools that I don’t have, removing panels, etc., is not worth the hassle when I’m likely getting my whole array taken down in a few months anyway, all for just a few dollars per month of electricity in the meantime.