Expert: Russ Kinner - 4/23/2005

Question
Hey!!!!! How do you make lights solarpowered?!?! I am in 5th
grade and we need this for our science fair project. It would be
great if you could e-mail me back!!!! Thank you sooo much!

DeDe

Answer
What is needed are Photovoltaic cells which convert solar (or other light sources) into electrical power.  Matching the cells to a light (voltage and current requirements) should allow you to make the bulb light.  

What you may want to look at also are LED (light emitting diodes) which are very much more efficient in converting electrical power into light.  Many traffic lights here in Arizona where I live are now LED to save power and last many more years than incandescent light bulbs.  They are a much better match to photo cells since the conversion of light energy to electrical power is very low.  I've seen figures of 6% conversion and many researchers are trying to raise that to a much higher value.  Here in the SW USA there is a lot of sun and a better photo cell would make a BIG difference in how much power we use.  We even have a “traffic light on a trailer” here with photo cells to charge batteries in the day and it runs all night.  This couldn't be done if they used regular light bulbs for the lights.  Since many areas of the country don't have as much sunlight as we do, it may not be possible for other places until the cells become more efficient.

I have listed several links for you to help you:

http://www.juliantrubin.com/solarprojects.html#cells
http://www.siliconsolar.com/solar_kits.htm
http://members.tripod.com/ngaston/photoc.html
http://flashlight.wowshopper.com/solar-power-table.htm
http://www.motherearthnews.com/renewable_energy/2003_August_September/A_Simple_S...
http://mses.united-engineering.net/solorBenefits.html

The first link above links to many reference pages of science fair projects and may give you enough information to construct your own experiment.

We are hosting the Intel International Science Fair here in Phoenix in mid-May.  You might want to see what experiments they have done.

http://www.intelisef2005.org/

I hope to see you at the ISEF in about 5 years.  Good Luck.

Russ Kinner