best low light performance

I think that's on the original graph from Unisolar. The mc-Si BP panel is top for both, for a given size panel. 13.5% of roughly 5000w at 1000 lux. 12% of 500w at 100 lux. At 50 lux all the top 5 panels (including Unisolar) would put out about the same - 8% of 250w. If I am reading the scales properly.



Jim

I read this thread until I got dizzy and fell out of my chair. I didn't understand a great deal of it with regard to my perception of panel area versus lumens of irradiation. So I went and got my dunce cap and slipped it on.

Supposedly this makes me immune to snide snickers to my basic questions.

Say you have three panels five feet by three feet.
(Don't take my word for it I only saw three types here there may be more)

Fifteen square feet. That's what each panel is going to occupy.
I don't want to hear about "There ain't no such thing as a five by three panel!" That is not the point!

Irradiate all three panels with say 1000 lux
Which panel is going to produce the most WATTS?

Irradiate all three panels with 100 lux
Which panel is going to produce the most WATTS?

I'm preparing a KICK ME stickum for my hind end just in case.

Been there, done that.

6% superior in low light.

Really, nothing to toot your horn about.

Sal

bdosborn wrote:

The question that no one has answered is how superior is it in low light?
Bruce

That's the question indeed. Mine were really cheap but the price seems to have gone up.

It's also about real world performance. Real world low light situations are not just full spectrum light at some percent intensity. The spectrum is different at dawn vs noon vs shade as well. And there is a whole pipeline of new products announced weekly with improved performance. Somehow I only ever hear about a few actually making it into volume production though.

I think if I were going crazy, I would do as some here have suggested and put a Unisolar on my east facing side, one on my west facing side, and fill my roof with whatever I could best pack up there that is available in current production. I would have a very long solar day making productive amps.

I don't need that at all, but that's one dream.

Jim

HiTech wrote:


This is pretty compelling proof for the superior low light performance of UniSolars to me.

The question that no one has answered is how superior is it in low light? Lets assume that it's 50% more efficient at a 200w/m2 illumination level. A 124w panel would be gathering an amp at that level versus 0.5 amp for a SI based pane of the same wattage. Would you really buy what are now expensive panels without a warranty for an extra 0.5 amps? Or would you buy twice as many SI based panels for all that now available roof space, have the same output in low light, be covered by a warranty and have even more output in full sun? I bet the cost difference would be minimal as the Unisolars are getting expensive.

Bruce

LOL I actually considered following the roof line a foot down the curve of the nose on mine. I would get some bonus angling into the sun on my typical spot. I have 136W but I decided not to put them end to end! They make better racing stripes in long, thin places.

Jim

HiTech wrote:

...
This is the data from the previous picture, remapped for a 100w panel of each type. As we go left the light level gets lower, and UniSolar outperforms the others by a larger margin.

Jim

The Unisolar is a no go for me. To get the 130W I now have in a 32x43" space, I would need to start at the back bumper, up the wall, across the roof and down to the tongue! :)

HTH;
John

I think I am just not explaining it well. Time for a picture that will do better than my narrative.

But we will need to start calling BFL's pictures "pretty graphs" after my attempt.



This is the data from the previous picture, remapped for a 100w panel of each type. As we go left the light level gets lower, and UniSolar outperforms the others by a larger margin.

Jim

Must be above my head then cause I don't see that at all.

Our first concern is roof real estate and can we get the Watts we want.

I had a HF 45W kit that was 1sq meter and I replaced it with a 130W panel 32x42". About the same size but I would expect to get more Watts from the 130W even in the shade.

Plus the HF kit weighed 30lbs and the 130W panel is 20lbs.

HTH;
John