best low light performance

pianotuna wrote:
Hi Salvo,

Actually this thread is supposed to be about which is better in low light conditions. Poly or Mono. I'd appreciate your opinion (you have helped so many folks so often).

There is one report of Poly doing much better than mono in a side by side real life test.

I plan on populating the rest of my roof with either poly or mono panels. They are the same price, same size, and nearly identical wattage (5 watts difference on the rating). But it will be a flat install, so I want the best low light response possible, between poly and mono.

If you are seeking the best low light efficiency possible, what you want is the Sanyo hybrid, dubbed Heterojunction with Intrinsic Thin Layer (HIT). The highest conversion efficiency ranging from 15.3 to 16.4. Rated #1.
Sanyo's 190-watt module earned a 17.4 percent efficiency rating. Industry average is 12 percent.

Don't forget those DM145s that have extra high Voc and unusually low Isc for their Watts combo of I and V.

I would avoid those because I want the highest Isc I can get for the watts with my PWMs using 12v panels.

So there is more to all this than low light for how many amps you get from the same wattage using different design/Brand panels even if they are all Poly or all Mono.

I have no idea what would be better with MPPT-- they work differently to get their amps.

Hi Salvo,

Actually this thread is supposed to be about which is better in low light conditions. Poly or Mono. I'd appreciate your opinion (you have helped so many folks so often).

There is one report of Poly doing much better than mono in a side by side real life test.

I plan on populating the rest of my roof with either poly or mono panels. They are the same price, same size, and nearly identical wattage (5 watts difference on the rating). But it will be a flat install, so I want the best low light response possible, between poly and mono.

HiTech wrote:
Mine do the same.

Harold what do you have to back up your claim about efficiency beyond the standard test conditions of strong light? If we are talking efficiency, the relative efficiency from full sun to 50% or less light strength is what is interesting when discussing low light situations. Efficiency in full sunlight is interesting, but moot in low light discussions.

Jim

I have nothing other than the industry standard Tier rating, of which thin film is rated the lowest.
Do you have information to the contraty?

The Uni-Solar efficiency increases with decreasing irradiance. It may go from 6% @ 1000W/m^2 to 8% @ 200W/m^2.

The Kyrocera panel efficiency decreases with decreasing irradiance from 12% to 11.5% (1000 vs. 200W/m^2).

Still, the Uni-Solar efficiency is poor at low irradiance. There's a reason they're no longer produced.

http://www.flexenergydelsol.com/wp-content/themes/energy_del_sol/pdfs/uni-solar-flat-roof-data.pdf

Mine do the same.

Harold what do you have to back up your claim about efficiency beyond the standard test conditions of strong light? If we are talking efficiency, the relative efficiency from full sun to 50% or less light strength is what is interesting when discussing low light situations. Efficiency in full sunlight is interesting, but moot in low light discussions.

Jim

hi harold,

Did I say I was replacing the Unisolar panels?

Charging starts at 20 minutes after sun rise for me in June, on a non tilting install.

I have never monitored it. Suppose I could just post some figures and they should be accepted as fact.

I am still wanting to find anything suppoprting your claim of the superior low light capabilities of thin film. havent found any yet, only the opposite.

If your Unisolar thin film amorphous panels have such superior capabilities, why would you think about replacing them?
At your northern latitudes I would think your claim of low light power production would the most desirable. Anything else would a waste of time and money.

The difference is output per rated watt. Not output per unit area. Unisolars put out the largest fraction of their full light output in partial light that I have seen. The other rating is, I believe, output at max light density, per surface area; quite a different measure, having nothing to do with low light performance.

Jim

hi harold,

And how long after sunrise do the panels start producing amps?