Panels will not produce enough

[sunshine_eggo]

Not sure if they are rated/approved for DC, I would not advise on using them. I used them as it was on a temporary setup and I didn't want to dig up the driveway again to install DC/solar wires. And yes, they are prone to oxidation so if anyone absolutely needs to use them, keep them indoors and protected from moisture.

To clarify, you no longer have those connectors or the solid wire in the system, correct?

I concluded you've gone from a temporary setup to a permanent setup more consistent with best practices.

 

[Tomthumb62]

What is the airspeed velocity of an unladen swallow?

And does trigonometry get involved in order to compare it to a laden one? (I've yet had the need to use trig...hoping this might be the moment...)

 

[iRomeo]

Too vague. what is your latitude/longitude?



Are all panels in a string facing exactly the same direction?



Need PV panel specs.



"Wiring" also includes any changes to the array configuration, i.e., did you change the number in series or in parallel?

Is this your first seasonal transition from summer to fall/winter?

Canadian Solar 375 Wp, CS3L-375MS, PERC, HiKu
They are the same 7 panels, connected in series. Previously there were organized in 1 row, now they are in 3/3/1 (will add 2 more panels soon)

I've had them for longer, but they were part of a pair of strings on a different invertor, so I can't use the historical data from last fall. But in spring they were producing >2kw and in summer, on a cold day or after rain, they would go over their rated power at 2.5kw

My only thought is that somehow (during transport maybe) the bypass diodes are activated on some of the panels. Being half-cut, only 1/2 of some of the panels work...

 

[iRomeo]

To clarify, you no longer have those connectors or the solid wire in the system, correct?

I concluded you've gone from a temporary setup to a permanent setup more consistent with best practices.

Yep. New location, same equipment, but new wires and new MC4s between panels and inverter.

 

[sunshine_eggo]

Canadian Solar 375 Wp, CS3L-375MS, PERC, HiKu
They are the same 7 panels, connected in series. Previously there were organized in 1 row, now they are in 3/3/1 (will add 2 more panels soon)

I've had them for longer, but they were part of a pair of strings on a different invertor, so I can't use the historical data from last fall. But in spring they were producing >2kw and in summer, on a cold day or after rain, they would go over their rated power at 2.5kw

My only thought is that somehow (during transport maybe) the bypass diodes are activated on some of the panels. Being half-cut, only 1/2 of some of the panels work...

I believe if you check Voc of each individual panel, failed bypass diodes will manifest by yielding reduced voltage readings.

 

[iRomeo]

I believe if you check Voc of each individual panel, failed bypass diodes will manifest by yielding reduced voltage readings.

Should be the other way around. So in case of partial shading, you're only producing 50% of the current, but 100% of the voltage.

 

[sunshine_eggo]

I meant to indicate shorted.

Checking a PV panel for open bypass diodes

Panels subjected to regular shading conditions are prone to have blown out open bypass diodes. Bypass diode can fail open or short but most often they get overheated and fail open. A shorted bypass diode is easy to detect as Voc of panel will be low due to the shorted bypass diode shorting...

diysolarforum.com

Should impact half cut the same.

If failed open, they will only impede performance if there is shading.

 

[Bad Randy]

And does trigonometry get involved in order to compare it to a laden one? (I've yet had the need to use trig...hoping this might be the moment...)

Bank angle and Moon phase may effect your results!

 

[timselectric]

My moon phase comes pretty late.
Unless I start drinking earlier.

 

[JRH]

Oh Lord , ???…you guys can be brutal sometimes.. ………….J.

 

[Nobodybusiness]

African or european?

I don’t know. Yaaaaaahhh

 

[Supervstech]

I don’t know. Yaaaaaahhh

Um, actually it's "What? I don't know that... Yaaahhhhh"

 

[Nobodybusiness]

Um, actually it's "What? I don't know that... Yaaahhhhh"

That’s right. Memory not what it used to be.

 

[Bad Randy]

My moon phase comes pretty late.
Unless I start drinking earlier.

Don't forget Reynolds number; Re = ρVL / μ.
The Wright brothers were wrong!