Best solar panel to use in Northern Aus
Submitted: Monday, Dec 20, 2004 at 10:59
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Austravel
With all this talk of solar panels I like to find out what panel is the best from those people in the industry. I note from some of the posts that there are some readers that are or have been in the solar industry. So to them, which do you think is the better brand of panel and why??? Or what should I look for in a panel?? I've read a bit on BP, Unisolar and Kyocera. So far Kyocera sounds the best but similar to BP. But what is the real world advice for the best brand at around 80 watts and used remotely from the vehicle in Aus's hot summers etc.
Thanks
Reply By: Member - Jimbo (VIC) - Monday, Dec 20, 2004 at 23:20
Monday, Dec 20, 2004 at 23:20
Aus,
You have no doubt read my "Solar Test" posts.
Now I'm not going to get into a debate about what's best because I don't really know, I just went the Uni Solar after a lot of research.
What I do know is the conventional panels start to lose efficiency at over 25 C. Clearly printed on the back of the Kyocera 120 watt is that it produces 120 watts at 25 C and 87 watts at 40 C. Whether that refers to temp in the shade or the temp of the panel in the Sun, I'm not sure; perhaps a call to Kyocera would clear it up. Regardless, if you're planning to travel in Summer you're going to get a lot of days
well over 25 C and a conventional panel will not produce its quoted power.
The Uni Solar is a "Light Energy" panel and doesn't lose efficiency in the heat. Given that the Kyocera drops to 72.5% efficiency in the heat you could only expect 58 watts from an 80 watt panel, still not too bad. So on balance of cool, warm and hot days to will probably average similar to a Uni 64 watt and they are about the same price.
The Uni's are supposed to be more efficient in overcast and semi shaded positions. Also the Uni's are virtually indestructable and should you damage them, a bit of silicone fixes them.
Hope this helps in some way.
Cheers,
Jim.
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89668
Reply By: sav - Tuesday, Dec 21, 2004 at 00:38
Tuesday, Dec 21, 2004 at 00:38
Solar panel ratings are generated using a STC (Standard
Test Condition)
test.
This basically means that a panel is flashed with a controlled light source at 1000 W/m2, with the cell and air temperature at 25°C (68°F) and 0 m/s wind speed.
The flash is generated a xenon filled arc lamp. The output spectrum
of this lamp is as close to the spectrum of the sun as possible.
From my understanding, the flash duration is as short as 30ms - meaning the module has no chance of heating.
Crystalline solar cells can be anything between 15-30 degrees C. above ambient temperature in the real world.
If it is 25C. and sunny, cell temperatures of 40C. to 65C. are possible.
If a panel drops voltage and power by 0.4% per degree over 25C. (typical of most panels) -
well you can do the math (I' lazy).
The amorphous Uni-solar cells however don't follow this same pattern (although they aren't anywhere as efficient in terms of available power per m2.
It also shows that while the Uni-solar cells are relatively inefficient below cell temps of 25C. - this is rarely a problem in Aust.
BTW - after looking at this whole solar panel issue over the last few weeks, I still can't decide myself which type of cell is the better for my intended use...
Sav.
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89680
Follow Up By: Member - Jimbo (VIC) - Tuesday, Dec 21, 2004 at 01:09
Tuesday, Dec 21, 2004 at 01:09
Sav,
You're dead right about sizing. The Uni Solar 64 watt panel is similar in size to the Kyocera 120 watt. I've seen them side by side.
If space is a consideration go the conventional panel. For me it wasn't, I can fit it in the camper; I've got space to burn.
Cheers,
Jim
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