Keith wrote: > > For comparison, 50mW is what you can collect with a 10% > > efficient, 1 inch square solar cell on a sunny day, or > > a 10 inch square cell on a darkly cloudy day. > On Tue, Jun 09, 2009 at 03:23:57PM -0700, Daniel Johnson wrote: > Do you mean 10 square inches, or 10 inches, by 10 inches (100 square inches)?
100 square inches, or (10 inches) squared . Light levels on a full sunny day are about 100,000 lux, on a dark cloudy day about 1000 lux, average indoor home lighting about 100 lux, a full moon about 1 lux, and a clear moonless starlit night about 0.001 lux. The eye is wonderfully logarithmic, power from solar cells not so much. So a solar cell producing 5W (for a full access point) on a dark cloudy day would be about 100 inches on a side. On a moonless starlit night, you would need a light collecting area 800 feet on a side. Solar cells leak, so at some point you can't collect enough light to overcome the leakage. A lot of energy collection schemes fail when you do the numbers. Energy is a quantitative, not a qualitative, game. Keith -- Keith Lofstrom [email protected] Voice (503)-520-1993 KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon" Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs --~--~---------~--~----~------------~-------~--~----~ The Personal Telco Project - http://www.personaltelco.net/ Donate to PTP: http://www.personaltelco.net/donate Archives: http://news.gmane.org/gmane.network.wireless.portland.general/ Etiquette: http://www.personaltelco.net/index.cgi/MailingListEtiquette List information: http://lists.personaltelco.net To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] -~----------~----~----~----~------~----~------~--~---
