Portable solar panels

[julesa]

Does anyone have any experience using copper-indium-gallium-selenide solar panels? I'm in an area where it's usually overcast. The sales literature says this technology significantly outperforms traditional silicon crystal solar panels when not in direct sunlight, and it's light and portable. But I have no idea how much it outperforms traditional solar cells in overcast conditions, and I'm not sure how many panels I'd have to buy to get an 800Wh charge for my bike on an overcast day, while I'm sitting in the office.

In direct sunlight, two should be enough... but a silicon crystal panel's output will drop 90% in overcast conditions, which means this idea could quickly get expensive, heavy, and impractical, even if the CIGS panels double silicon crystal low light performance... Can anyone guesstimate how much CIGS output would drop in an overcast environment?
http://store.altenergystore.com/Sol...rtable-Power-Pack-Black/p4337/?source=froogle

 

[pwbset]

Ooo... solar panel pron! Let me know what you learn as I'm also in a relatively cloudy area, but was thinking how cool it would be to slap a few panels on the garage roof for any "end of the world" type scenarios where I could at least still charge my ebike and cruise around checking town for signs of life.

 

[John in CR]

Can anyone guesstimate how much CIGS output would drop in an overcast environment?

Solar panels while it's overcast...Is this a trick question? Unless you have deep pockets and want to do it just because you can, then I assure you pursuing this battery charger is a waste of time.

 

[julesa]

Well, I wouldn't ONLY be using it for the e-bike application. I do more camping in the summer and I can usually count on sunshine for at least a couple months out of the year. And like I said, CIGS cells are more efficient than silicon crystal in overcast conditions. But I'm wondering what the real output drop is. 80%? 60%?

I haven't found any specifics yet. All I found was more solar pr0n:
http://www.powerfilmsolar.com/products/military/armytents/index.htm

 

[julesa]

Well, I wouldn't ONLY be using it for the e-bike application. I do more camping in the summer and I can usually count on sunshine for at least a couple months out of the year. And like I said, CIGS cells are more efficient than silicon crystal in overcast conditions. But I'm wondering what the real output drop is. 80%? 60%?

I haven't found any specifics yet. All I found was more solar pr0n:
http://www.powerfilmsolar.com/products/military/armytents/index.htm

I e-mailed powerfilmsolar.com with the same question... I'll post the response here.

 

[TylerDurden]

Also check the specs on unisolar films and firstsolar modules, they are similar in design (amorphous).

 

[monster]

i think the payback on solar cells is too long -both environmental and finacial. they may be gurunteed for a long time but i would probably acidentially breake them well before then. it could be a net co2 looser if they turn into a comercialy throw away item.

windpower -you can fix motors.
can you fix solar cells?

 

[TylerDurden]

Amorphous are less fragile and function even if penetrated (by bullet or similar), with lower output.

As for long ROI, that changes as production increases and prices drop. Institutional investment is seeking returns in perpetuity, so solar leasing is an emerging trend.

 

[paultrafalgar]

I remember someone posting in this forum who had a solar charging station for his bike (4 to 8 panels?). I think he had a recumbent. I remember seeing this photo of him standing in front of the bike and recharging station. He had a very competent setup. He used only solar to charge and did trips up hill and down dale.
Does this jog anyone's memory?

You aren't going to get enough juice in a cloudy climate to take the panels with you. There is a guy from NZ (or Australia) who is touring the world on a trike with very big trailer plastered with solar panel. Even he has to use grid recharging to get along.

 

[monster]

just switch to a green tarif on your house. or buy the panels get them grid connected on a feed in tariff so that they can pay for them self while your not using them.

 

[julesa]

You aren't going to get enough juice in a cloudy climate to take the panels with you. There is a guy from NZ (or Australia) who is touring the world on a trike with very big trailer plastered with solar panel. Even he has to use grid recharging to get along.

But I'm sure that guy goes more than 20 miles in a day... and he's almost certainly not using copper-indium-gallium-selenide flexible panels. At 60W output in a 2.6 pound portable, foldable package, that's doable in a sunny environment with only one or two units. Overcast, yeah, it's pretty unlikely that it's practical even if money wasn't a concern. But considering that it's a new technology, supposedly more efficient in overcast conditions, more efficient than amorphous silicon, I am interested in getting more details.

 

[julesa]

CRAP. The powerfilmsolar.com guys aren't usng CIGS panels - they're amorphous silicon. One of their resellers was claiming it was CIGS which got me all excited. Oh well. CIGS products should start hitting the market soon... Sorry.

 

[Mark_A_W]

Amorphous are less fragile and function even if penetrated (by bullet or similar), with lower output.

Crikey, you must live in a different world to me...

My solar panels (getting installed in 2 months or so), might get hit by hailstones....or even bits of Skylab (well, the ISS), but there is zero chance of them taking a bullet

 

[julesa]

The powerfilmsolar.com guys aren't usng CIGS panels - they're amorphous silicon.

Update: Global solar is selling portable panels that look just like the ones at powerfilmsolar.com, but they're using CIGS.

http://www.google.com/products?q=global+solar+p3-55&btnG=Search+Products&hl=en&show=dd

From what I read, the advantage CIGS has over silicon solar cells is output drops linearly as light levels drop. Silicon cells are much less efficient in lower light than in bright light. Irradiance levels on a typical sunny day will make a pretty bell curve, peaking around 1000W/m2 at noon. Overcast and cloudy conditions will typically bounce around 250-400W/m2 all day long, with occasional bursts well over 1000W/m2 on days with bright reflective clouds.

The current/voltage graph for the P3 unit has a peak output at about 20V (55W) at 1000W/m2, so if you're charging your batteries at more than 24V you would want to connect at least two of them in series anyway.

So if CIGS output is really linear with irradiance, then two of these units in series (about $850 each) should charge at around 30W in overcast conditions, and 100W in average sunny conditions. Folded size - 11 x 9 x 1.3 inches, 3.7 pounds each. That's doable for a lot of people, I would think. Unfortunately I'll need more than 270Wh on most overcast days, and I wouldn't want to carry around more than two of them on my bike, so I don't think I can justify the investment myself.

 

[Drunkskunk]

The technology is viable.
But better for a home charging station.


a better use of $$ and resourses, not to mention weight and space on the bike, is a home solar base station, either charging batteries for your own backup system, or conected to the grid earning you money, and charging the bike when its home, then using the weight savings of not having to carry the pannels with you to just increase the size of your battery for more range.

 

[michaelplogue]

Amorphous are less fragile and function even if penetrated (by bullet or similar), with lower output.

Crikey, you must live in a different world to me...

My solar panels (getting installed in 2 months or so), might get hit by hailstones....or even bits of Skylab (well, the ISS), but there is zero chance of them taking a bullet

Turks Wound At Least 23, Firing Guns in Air to Celebrate Soccer Win
International Herald Tribune / AP
21 June 2008

ANKARA, Turkey -- At least 23 people across Turkey were wounded by stray bullets following the firing of shots across the country to celebrate the win over Croatia in the European Championship quarterfinals. Governor Muammer Guler said Saturday that 11 people were accidentally shot in Istanbul, the country's largest city where all night festivities were the wildest. Twelve other people, including a 10-year-old girl an elderly woman, were wounded by ricocheting bullets in seven other cities, police said.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Celebratory Shooting, Stray Bullet Injury Require Urgent Action - Turkish MP
Today's Zaman (Istanbul)
27 June 2008

ANKARA -- A member of Parliament's Human Rights Commission has recommended that a parliamentary commission should be set up to address the problem of deaths and injuries caused by stray bullets fired into the air in celebration, a common problem in much of Turkey. Speaking to Today's Zaman, Democratic Society Party (DTP) Diyarbakir deputy Akin Birdal stressed that a cultural and social transformation was needed to prevent deaths...


This is where I'll be moving to in less than a year...... Almost like being in the "Wild West"...... :wink: