When we are discussing solar panels for man portable off-grid Communications, there are really only three choices. Despite the paid-for-promotion YT videos, we can easily cut through the brouhaha
Polycrystalline cells are almost always found in rigid panel form. They’re not as efficient as monocrystalline panels, require a larger surface area to produce the same amount of energy, and lose efficiency as temperatures increase. On the surface they appear cost-effective, what are too heavy and bulky for the portable operator in the field.
Monocrystallines are also found in both semi-flexible and rigid form factor. These are more efficient than polycrystalline, and produce the same amount of energy, while having a smaller surface area. They can also be lighter and more portable them polycrystalline panels in their semi-flexible form factor. By far these are the most “cost-effective” if you don’t need to carry them on your back.
Polycrystalline and monocrystalline need to be pointed almost directly at the sun to be effective. Both polycrystalline and monocrystallines suffer from partial shading or shadows from clouds, tress, leaves, … They also lose efficiency in increasing summer temperatures. One thing they do well (depending on your perspective), is “save your money”, kind of. The buy-in price is usually quite attractive. In the case of monocrystalline in a semi-flexible form factor, these are usually the bridge before taking the step into amorphous solar panels, they are lighter than polycrystalline panels come and less expensive than amorphous panels.
Before we get to amorphous panels, let me tell you how annoyed I become when I see these videos slamming amorphous panels for being so costly. I get that, they are costly in comparison to polycrystalline or monocrystalline panels. However, in my experience, the panel is no use to me if it’s not charging my batteries in the field. If I continuously need to point the panels at the sun, move them out of the Shadows of the trees and leaves, or deal with not having them produce any energy at all because it happens to be cloudy, they’re not really a good deal (for me). Of course if I were still living in sunny Southern California, Western Sahara, or Yuma Arizona, we have the benefit of few trees and lots of sun, that’s another matter. In the real world we have clouds, trees,… Our camping spots are usually located near sources of fresh water (under trees), and I’m often traveling on foot. Am I really going to try to save a buck, in exchange for 25 to 30 extra pounds of mono-, polycrystalline gear loadout!? Only if I’m on foot, or have a limited wake budget.
Some would say amorphous panels are the most efficient solar technology available to the public today. Yes, they do require twice as much surface area to produce the same amount of energy, but they produce that energy in a wider range of conditions, and at a fraction of the weight. They’ll continue producing energy when it’s cloudy, when they’re partially shaded by trees and leaves, … They are also flexible! Not semi-flexible, semi-rigid or any other bogus marketing names used to trick you into buying fakes. Amorphous panels are also lighter in weight and more portable than monocrystalline or polycrystalline panels producing the same amount of energy. They can also withstand the summer heat, where mono or polycrystalline panels lose efficiency in the same ambient temperatures.
Finally, amorphous panels absorb a wider spectrum of visible light, giving them a head-up, over mono or polycrystalline panels. In a direct comparison with mono or polycrystalline panels, amorphous cells outperform them in low light conditions. For the portable operator, this translates into charging batteries far earlier, and continuing to charge them later in the day, than operators using mono or polycrystalline panels. The achilles heel is their cost.
Read more about the advantages of amorphous silicon panels
Consider this question. One operator has a 120w monocrystalline or polycrystalline panel out in the field on a partly cloudy day. Another operator has a 60 watt amorphous panel out in the field at the same location. They’re both trying to power a 12 amp hour Bioenno battery during field day. If you don’t touch those panels throughout the day, which one will produce more energy from sunrise to sunset?
Alright I’ll stop poking fun. The point is we shouldn’t be making these videos claiming something is better than the other, because they’re not. They each have buses and minuses come on Fort amorphous panels, cost is the problem. Still, solar panels are like tools, and we choose the right tool for the job. Certainly there are the Makita quality of tools, and there’s also the bottom shelf from Harbor Freight. The trick to using the right tool for the job is understanding the capabilities of the tool we’re trying to deploy, and what we’d like to do with it. Just because some good-looking YouTuber with the nice smile and a good set of teeth tells you something is better, doesn’t really mean it is. That’s why we do the research for ourselves.
Without any doubt amorphous panels are exponentially better suited for the field radio operator, but that comes with a much higher price. If I didn’t have the budget for amorphous panels, I would try to find semi-flexible diy monocrystalline solar panel kit, until I had the budget for amorphous.
Food for thought.