Firms Develop Solar Powered LED Street Lamps

Posted 04/02/2010 at 6:04am | by Paul Lilly

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It took three firms working together to jointly develop an LED street lamp that doesn't require electricity from the grid, instead drawing energy from the sun.

Dubbed "Super CaLeCS Toki," the street lamp generates power by using photovoltaic (PV) cells and then stores the electricity in an electric double layer capacitor (EDLC) made by Nippon Chemi-Con. The EDLC contains 240 cells with a winding structure, a rated voltage of 2.5V, and a capacitance of 2,300F. By combining the capacitor with PV cells, the company claims the street lamp can stay lit for 14 continuous hours.

Stanley Electric provided the LED unit, which is comprised of two LED lamps with a power consumption of 15W. The company also tapped into technology used for automotive headlights to enhance the weather resistant nature of the LED unit.

And a third company, Tamura, contributed a newly-developed voltage control scheme called "maximum-efficiency tracking algorithm." Tamura says its power supply controller can charge the capacitor in about two hours in clear weather conditions, or six hours in rainy or overcast skies.