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From: strong@tc.fluke.COM (Norm Strong)
Newsgroups: sci.electronics
Subject: Re: SOLAR CELLS WITH HIGHPWER TO AREA RATIO
Message-ID: <1991Jun26.172030.5685@tc.fluke.COM>
Date: 26 Jun 91 17:20:30 GMT
References: <17973@chaph.usc.edu>
Organization: John Fluke Mfg. Co., Inc., Everett, WA
Lines: 27

In article <17973@chaph.usc.edu> rajha@girtab.usc.edu (T.R. Rajha) writes:
}I am looking for a solar cell that can charge a NiCd battery in a
}device while the device is in its standby mode.
}
}There are a few important considerations:
}
}The device will be used mostly indoors. Therefore the solar cell 
}should be able to operate in the indoor ambient lighting including
}incandecent and fluorescent lights. 
}
}The solar cell should have a high power to area ratio.
}
}It should be able to deliver a charge of approx. 50 mA at 4 volts
}
}It should fit in area of approx. 60 sq. cm

Indoors it's impossible.  You're asking for 3.3mw/cm**2.  Since 
strong commercial lighting is only about 2mw/cm**2, even cells with 100%
efficiency would not give you the current you need.  The 5% typical
efficiency will fall way short of your goals.  

Outside in the noonday sun:  No problem.    

-- 

Norm Strong  (strong@tc.fluke.com)
2528 31st S.   Seattle WA 98144   USA