Solar cell linking / Charger ?

Discussion in 'The Projects Forum' started by badspell68, May 10, 2008.

  1. badspell68

    Thread Starter Member

    May 10, 2008
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    FYI I a complete newbie at electronics...

    I have 5 cells from lawn lamps and would like to link them all in a chain to make a charging device for some electronics. Can I link them in sequence or onto a running positive and negative wire or do I need some type of electronics?

    After linking them I would like to have it end in a standard cigarette lighter socket or plug, again can this happen or do I need something special?

    I put a voltmeter on one of the cells and, I think, it was registering at between less -then-one volt up to 4 volts depending on how much light it had . Is this possible?


    How would I keep the voltage from going to high and damaging the attached device?

    The cells seem to be very thin and laminated or glued on to a think piece of glass. What type are they?

    Thanks so much all!
     
  2. Audioguru

    New Member

    Dec 20, 2007
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    The solar cells in garden lights are too weak to do anything useful. The max output current is only about 50mA at noon in the Sahara desert with it pointing directly at the sun. The current is less at other places and times. Window glass reduces the current to about half.

    Their voltage depends on how much light and how much load current.

    Five in series would charge a little 9V Ni-MH battery in a couple of days of sunshine.
     
  3. badspell68

    Thread Starter Member

    May 10, 2008
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    What type of cells could I use?

    Are the cells really all that bad, I see all sorts of chargers being made on the maker and constructables web site?
     
  4. Audioguru

    New Member

    Dec 20, 2007
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    Many "Instructables" circuits are poorly designed.
     
  5. thingmaker3

    Retired Moderator

    May 16, 2005
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    I think we are starting at the wrong end.

    What are the requirements of the load? What type of battery do you wish to charge?
     
  6. badspell68

    Thread Starter Member

    May 10, 2008
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    Some cell phone batts, trickle charge my car, mp3 player and a bunch of AA batts at one time.
     
  7. Audioguru

    New Member

    Dec 20, 2007
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    Don't try to charge a lithium battery. It might catch on fire if the voltage is too high.

    The solar cells from garden lights are too weak to trickle charge a car battery.
    They would take months to charge 2500mAh AA Ni-MH cells.
     
  8. badspell68

    Thread Starter Member

    May 10, 2008
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    The solar cell was connected to a Nicad 1.2 volt. Could I use 4 solar cells to charge 4 of the Nicads?

    Can you suggest a type of cells I can use for other stuff?
     
  9. thingmaker3

    Retired Moderator

    May 16, 2005
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    Yes. Connect the photovoltaics in parallel to charge the NiCads in parallel. Connect the photovoltaics in series to charge the NiCads in series.


    Do you know the amp-hour rating of your 1.2V NiCads? Do you know the current and voltage requirements of "other stuff?"
     
  10. badspell68

    Thread Starter Member

    May 10, 2008
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    Could you define parallel and in-series so that I am sure I have it correct? I really not sure of any other information except that the NiCads are 1.2 volt.
     
  11. thingmaker3

    Retired Moderator

    May 16, 2005
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