another perspective on comparing different brands of panels

[SolarCity]

Thanks for the info.

 

[tlsambo]

Apologies if I got your back up BiggsSolar, perhaps I was a little brash. However I do stand by my guns.

Worcester - we mainly install REC and they provide NOCT data, so too do Up Solar who we are considering at the moment (BiggSolar please feel free to think what you like about any ulterior motive).

Whilst NOCT gives an additional benchmark to compare modules it is ultimately still only a snapshot at 44 degrees and 800w/m2. What happens when the temperature is -15 and irradiance 500 w/m2 or conversely temperature 60 degrees and 1300 w/m2?

In addition to including the above, PV Sol may also include the manufactures temperature co efficient but this is just a temperature coefficient at 1000w/m2, it doesn’t really mean much in the real world.

The point I was making is that real world module performance is not easy to model on a computer. Especially when the raw module data is not independent – it’s derived from manufacturers data sheets. So why does everyone get hung up on a computer model?

I would have thought a far, far better way to decide which modules are worth installing is to look at outdoor field data, such as Photon International.

Those who rate Sanyo hybrids may find this data from Sheffield University interesting….

Microgeneration Data

Though admittedly a new study, it basically shows per kWp installed there is little or no difference between monos, polys and hybrids.

Clearly there is no better way of testing than putting all the panels in a field adding the same shading, changing their orientation annually, taking in to consideration on those annual figures the fact that the panels have now degraded a bit, also altering their pitch too, perhaps pitch & orientation could be changed on alternate years, then we could move the shading across the panels in an infinite number of different ways, move the whole installation a few miles east to that valley where they're not getting so much morning/evening sun, wiping away a few clouds to allow for the extra light due to the valley being in the rain shadow etc etc etc... We'll also have to check that we're being fair by using flash tested panels that give the exact output, i.e. 0%+/- tolerance.

What PV Sol does do is create a level playing field for all panels to perform on. None of our customers installations are exactly alike and we can see that different situations demand different panels. Our desire is to give our customers an informed choice and without going through the millenia of testing that we'd have to do with the field testing you suggest... it's the best information we have.

That's why we're raving about PV Sol!

- - - Updated - - -

oh I didn't mention that we'd have to do the exact same test with every different inverter on the market.......... I know there's a lot I've missed out but you get the picture.

 

[Eco Deal]

that was a long time to wait for a reply !

 

[Jaycee]

Could you add the Linuo 245w poly.....I think it may do very well !!!

 

[Blueflash]

This is our horse race, you might find it intersting. we quite like Yingli as module now! They are 250wp I think and installed at same time and same array.
http://i64.photobucket.com/albums/h197/artymike8/RACE.jpg

 

[Gavin A]

now that's a good idea. Are they all nominally the same rated output panels?

 

[Blueflash]

They are all 250's as long as I am aware. It has opened a few eyes and as a company we have switched module.

 

[SolarCity]

Very interesting. All installed in similar conditions?

 

[Blueflash]

All on same ground mount, so good aspect. The online software promotes data analysis with many ways to compare.

 

[jason121]

would the positive tolenece effect the indivual panel, some can be 255w when first installed

 

[Blueflash]

http://i64.photobucket.com/albums/h197/artymike8/wedaug8.jpg
http://i64.photobucket.com/albums/h197/artymike8/wedaug82.jpg

These are the graphs for today for our horse race. REC, Hyundai, Bisol, Sharp,Yingli, Suntec, Trina, Perlight, Sanyo.
I could give the log in details but my boss would kill me! lol

Blueflash

 

[SolarCity]

It's interesting to see that Sanyo perform so well early in the morning.

 

[yftam168]

I don't understand Sharp & Bisol drop so much at 1700.

 

[Worcester]

Just guessing - they may get a bit of late afternoon shadow first, as the others drop off very rapidly later, our own systems tend to give a very smooth tail off in the evening - any chance of a photo of the array?

 

[zoe]

Great - really interesting thread here and very useful table thanks..( i like your detailed guide also to each column

if you did want other real-time information or a perspective from other installation owners you could also check out a free pv monitoring site such as PV-Log. This is a social monitoring site..no hardware costs and free to use, make solar friends, showcase your installations etc.

I'm new here so also hi to everyone!