best low light performance
Hi, Amorphous panels are clearly the best for low light performance--but are relatively speaking huge. Does any one know if Poly or Mono are better in low light?
Forum Discussion
bdosborn wrote:
Unisolar Efficiency by Bdosborn, on Flickr
Yes, Unisolar is more efficient at lower light levels. Unfortunately, efficiency decrease with increased irradiance so you actually have decreased unit output on sunny days. This doesn't address partial shading, angle to the sun or high heat conditions but I don't see much of a reason to go with Unisolar based on low light performance. The typical poly and mono panel is still going to outperform the unisolar, watt for watt, in low light conditions at STP.
From the link posted earlier:
Unisolar Linky
Bruce
Upon studying this, it actually proves that of the technologies listed on this chart, UniSolars have the best low light performance per watt (not per square meter) of any technology listed in the graph.
If you are comparing a 100w panel of each technology, you need to look at the 1000 irradiance w/square meter line and normalize there for the same wattage per panel. You shift all graphs so that they intersect this line at the same point. The standardized test point where the nominal panel wattage is defined, 1000. Now you have normalized to have a comparison for each technology in an equal wattage panel for each, rather than for a constant physical footprint for each panel.
As you move left on the curves in this shifted graph, the Unisolar is the only one where the power efficiency actually increases above that intersection point. The unisolar efficiency increases as light level drops. All the rest stay flat and then some start dropping off early, non linearly. The Unisolar drops off too but at a much lower light level and after climbing. When normalized so the panels being compared are all the same nominal watts, the UniSolar curve is the last to drop off and stays the highest from full power all the way to the left. In very low light, it actually achieves the same performance *per square meter* as the very best mono technology, and has more square meters per watt, so the output for the same wattage panel is significantly higher at lower light levels.
This is pretty compelling proof for the superior low light performance of UniSolars to me.
Jim
