High efficiency solar panel - Spring 2013

The old panel i just posted in the low power solar thread is 15/24 or 63%. i'm sure there is some variation given all the innovation going on to improve panels so quickly, even if the underlying junction technology has certain basic properties.

Either way that paper is really good regarding variations in Mpp. In particular the edge case about full sun with high panel temp then a cloud, this is where I have seen max variation from Vmpp spec as well.

Jim

That's not a spec! Somebody just copied Voc incorrectly. Some critical thinking is needed!

My Kyrocera panel for example has Voc = 21.9, Vpm = 17.6, and a calculated k = 0.803

Sal

HiTech wrote:
Many of them including the outlier (at 92% - the last one down) are on this page: http://spsolarstation.com/solar-panels-eng.htm

Good paper BTW.

Voc Vmpp Difference Percent
21.6 17.2 4.4 0.796296296
21.6 17.39 4.21 0.805092593
21.96 17.86 4.1 0.813296903
22.6 18.2 4.4 0.805309735
19.8 18.18 1.62 0.918181818
34 28.3 5.7 0.832352941

Close as I am doing right now. Many of them including the outlier (at 92% - the last one down) are on this page: http://spsolarstation.com/solar-panels-eng.htm

Jim

Good paper BTW.

How are we supposed to verify your homework?

To answer your questions
k_mpp ~ 0.8

HiTech wrote:

Salvo wrote:
What happened to posting panel type & data?

You know you are adding a variable - you didn't ask for type LOL.

Jim

Salvo wrote:
What happened to posting panel type & data?

Lol you want me to get out the PC *again*? The IPad is so much more compatible with backyard camping and an adult beverage on a holiday.

;)

I didn't record type but I still have the pages open where I scraped the data into excel. Tried for a variety of sizes and types. You know you are adding a variable - you didn't ask for type LOL.

Jim

What happened to posting panel type & data?

Looking around, for quite a few Vmpp is around 80% of Voc so I see your point Salvo, but there is wide variation, up to 92% just in my sample size of 8. So my question not really answered unless that is considered close enough?

Why Voc instead of Vmpp? Maybe to use just a single parameter for Vmax of the series panels into the comtroller, and approximate Vmpp matching that's "good enough"?

Jim

Clearly they are correlated. But that tightly?

Jim

Some homework for you. Make a table, consisting of Voc and Vmpp specs from say 10 different panels. Calculate Vmpp / Voc for each one. Show results.

Sal

HiTech wrote:
Wintersun why Voc vs. matching Vmpp?

Jim

Wintersun why Voc vs. matching Vmpp?

Jim