What's the deal with 5W+ solar panel variants?

[BartonB]

I looked at a lot of spec sheets for panels when researching what to buy
And they all have a range, for example 590w-620w, with 5W jumps (590, 595,600...)
That's a lot of variants, and I don't get it
Why not just put two options - 590W and 620W
The price difference is negligible, the size is exactly the same, VOC difference is negligible...
What am I missing?

 

[WarmPepsi]

they're all made the same, but not all are "A" perfect. so if it's not 620, they can rate it as 610, 600, etc.

 

[BartonB]

they're all made the same, but not all are "A" perfect. so if it's not 620, they can rate it as 610, 600, etc.

Got it, so it's a manufactory thingy and quality grade
Still they can just say if they are not 620 they are 590 and be done with it

 

[WarmPepsi]

Got it, so it's a manufactory thingy and quality grade
Still they can just say if they are not 620 they are 590 and be done with it

Yep. Sometimes the lesser ones get a slight discount… or last dibs. Most of the best get bought and paid full price; the others are discounted and offered up.

 

[MikeInKingman]

Everyone also always forgets that the panel rating is a MINIMUM.
Unavoidable manufacturing issues cause variations in performance from cell to cell.
Panels get put in a Flash Box after construction and tested for output.
Panel makes 191w? It goes in the 190w pile.
Panel makes 194w? It goes in the 190w pile.
Panel makes 195w? It goes in the 195w pile.
Panel makes 199w? It goes in the 195w pile.
Jumps in "size" of 5 or 10 watts has been the norm for the 15 odd years I've been dealing with them.
Have Fun, Stay Safe.
Mike

 

[BartonB]

Yep. Sometimes the lesser ones get a slight discount… or last dibs. Most of the best get bought and paid full price; the others are discounted and offered up.

Discounted panels lets goooooooooooooo
Give me all those mutant deformed ugly premature panels 610 you've got mr. manufacturer

 

[BartonB]

Everyone also always forgets that the panel rating is a MINIMUM.
Unavoidable manufacturing issues cause variations in performance from cell to cell.
Panels get put in a Flash Box after construction and tested for output.
Panel makes 191w? It goes in the 190w pile.
Panel makes 194w? It goes in the 190w pile.
Panel makes 195w? It goes in the 195w pile.
Panel makes 199w? It goes in the 195w pile.
Jumps in "size" of 5 or 10 watts has been the norm for the 15 odd years I've been dealing with them.
Have Fun, Stay Safe.
Mike

I didn't forget, I just never knew ))

 

[45North]

Could also depend on the consumer protection & advertising laws of the local country: eg.
Yield of manufactured products will vary according to a normal statistical distribution.
Local law may require seller to meet claimed yield x percent of the time. To be sure of meeting claimed spec they could market product claiming a slightly lower number.

 

[Rocketman]

This is the same issue that used to (maybe still does) affect computers cpu chips. Intel would make a large wafer of cpu chips then when testing- some would run faster than others. So they sold those CPU’s in various speeds.

 

[wpns]

'Binning' happens with LEDs (and pretty much everything that varies in final result). Make a million of them, test them to see what you got, and throw them in the 'bin' for color, or output, or whatever.

If you look at resistor values, they are spaced out that way so you can sell every resistor you make, no matter what it's value is.

 

[MattiFin]

Tight binning is beneficial when you connect large number of panels in series.
Series connection is limited by the weakest panel, assuming that power limit comes from panel current and not voltage.
9 x 620W panels + 1x 600W panel could total to 6000W whereas 10x620W panels would give you "free" extra 200* watts.

*Real word numbers are probably bit more complicated and the difference could be somewhat larger or smaller due to how the operating curves slope and how well the MPPT controller can handle the situation.

 

[mciholas]

Panel makes 191w? It goes in the 190w pile.
Panel makes 194w? It goes in the 190w pile.
Panel makes 195w? It goes in the 195w pile.
Panel makes 199w? It goes in the 195w pile.

Not necessarily.

I ordered a pallet of 395 watt panels (CS6R-395MS-HL). The pallet came with a test card for all 30 units by serial number. They scored between 396 and 407 watts, thus 1 to 12 watts above rating. You can buy these in 5 watt increments none the less.

The grading is both how it tests and what orders they need to fill, so you may end up with panels that score more than 5 watts better than the rating.

Mike C.