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Solar cell phone charger

  1. Sep 19, 2009 #1
    I'm planning on making a simple solar powered cell phone charger for a demonstration speech in my gen-ed speech class because it seemed like it would be fun at least. The best solar panel I could find for cheap has an output of 6v and 50 mA. My cell phone charger has an output of 5.0v and 700 mA.

    Now my question is do I need to use a resistor to lower the voltage of the solar panel, and if I do I assume the output current will be even lower, and will it even cause the cell phone to say it is charging? I imagine it would take forever but as long as it says its charging thats good enough. I could probably afford another one and hook them up in parallel if you think that would help.

    Also, out of curiosity, if you used 4 AA batteries in serial to get 6v, would you need to use a resistor to get it to 5v and, if you did, what would be the output current afterwards?

    Thank you for your help!
  2. jcsd
  3. Sep 19, 2009 #2


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    Using a resistor is tricky because it depends on the resistence of the phone charger circuit
    You are probably OK feeding it 6V - but a fixed 5v output regualtor is very easy to use.
  4. Sep 20, 2009 #3
    Im sure you can find a better solar cell in an electronics store with at least 500 mA.
  5. Sep 20, 2009 #4
    50mA is really low. If you decide to use the one you're already looking at then just put a diode in series with it to drop the voltage down to about 5.6ish volts and it should work fine.
  6. Jun 24, 2011 #5
    sir can i see your circuit design...so that i have a reference about solar panel design cicuit for my thesis.
  7. Jun 29, 2011 #6


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