Why are solar panels ineffective with LED produced light?

[aceO07]

I noticed last month that solar panels don't generate electricity when LED light is shined on it. However, it will work when an incandescent bulb shines light on it.

The 2 light sources are 1. Maglite 2AA, 2. INova XO.
The Maglite has an incandescent and causes the solar panel to do it's thing.
The INova XO has a Luxeon LED bulb and does not make the solar panel work.

The Luxeon LED is much much brighter than the Maglite. Infact it's about as bright as a Maglite 2D.

The only observable difference is that the LED light is white whereas the incandescent light is yellow/orange.

Can someone explain this one to me?

 

[Jon855]

The solar panels depends on a specific Sprectrum of Light to powers it up. Seems that the material used to light up the LEDs aren't in that band of Spectrum.

 

[aceO07]

Are there solar panels that do work with LED light?

 

[CycloWizard]

Originally posted by: aceO07
Are there solar panels that do work with LED light?

Why would there be? If you think about it, an LED is always powered electrically. Therefore, there is some inefficiency in it - you will never get as much energy out of it as you put in (though for LEDs, it's probably pretty close). Solar panels are also inefficient. Making a solar panel to capture the LED's output energy is simply converting electrical energy to less electrical energy.

 

[NoToRiOuS1]

my logic...and feel free to flame if its not logical...is that white light is technically comprised of all different wavelenghts in the visible spectrum...take for example a rainbow or a prism...it break up light(lets say sunlight for ex) and shows us the Red Orange Yellow Green Blue Indigo Violet so if a solar cell works from the sun...then it should...technically work from an LED since there is some sort of light eminating from the bulb...but then again...the thing could be that the solar cell that you have is sensitive only to certain wavelenghts and perhaps the LED isn't eminating those wavelengths from itself. run the LED through a prism and the regular maglite through a prism...let us know if there are any difference in the color patterns...that might help you out...hope this helps!! post your results if you are able to do this...id be interested in knowing if any of this ranting of mine is true or just plain BS

 

[CycloWizard]

Originally posted by: faboloso112
my logic...and feel free to flame if its not logical...is that white light is technically comprised of all different wavelenghts in the visible spectrum...take for example a rainbow or a prism...it break up light(lets say sunlight for ex) and shows us the Red Orange Yellow Green Blue Indigo Violet so if a solar cell works from the sun...then it should...technically work from an LED since there is some sort of light eminating from the bulb...but then again...the thing could be that the solar cell that you have is sensitive only to certain wavelenghts and perhaps the LED isn't eminating those wavelengths from itself. run the LED through a prism and the regular maglite through a prism...let us know if there are any difference in the color patterns...that might help you out...hope this helps!! post your results if you are able to do this...id be interested in knowing if any of this ranting of mine is true or just plain BS

You're generally on the right track. However, most of the energy coming from the sun is in the form of non-visible rays. Thus, a white LED, even if it produces all the visible wavelengths, will not necessarily be giving off the energy at the same wavelengths that the solar cell can use. The visible spectrum is actually a very small part of the overall spectrum electromagnetic radiation. I'm guessing that solar cells are more focused on absorbing higher-energy waves, such as those in the ultraviolet region of the spectrum. The energy in the waves is proportional to the wavelength, so this would be a much more efficient way to go about it.

 

[DrPizza]

Pretty good explanation here: http://www.howstuffworks.com/solar-cell.htm

 

[Leper Messiah]

Originally posted by: aceO07
I noticed last month that solar panels don't generate electricity when LED light is shined on it. However, it will work when an incandescent bulb shines light on it.

The 2 light sources are 1. Maglite 2AA, 2. INova XO.
The Maglite has an incandescent and causes the solar panel to do it's thing.
The INova XO has a Luxeon LED bulb and does not make the solar panel work.

The Luxeon LED is much much brighter than the Maglite. Infact it's about as bright as a Maglite 2D.

The only observable difference is that the LED light is white whereas the incandescent light is yellow/orange.

Can someone explain this one to me?

I believe that incadansent (i can't spell) lightbulbs are broad spectrum, and LEDs operate on a very narrow spectrum (which is why they take less energy). the photopics in the Solar panel don't work on that frequecny.

 

[severtki]

There are further ranges of white light even within the visible spectrum. For example, to grow plants under a light, you need a wide-spectrum flourescent (plant/aquarium type), not just regular flourescent. The same with different "colors" of incandescent lights.