voltage controlled switch

Discussion in 'The Projects Forum' started by Northtexasengineer, Apr 3, 2010.

  1. Northtexasengineer

    Thread Starter New Member

    Apr 3, 2010
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    I need some help buiding voltage controlled switch of solar panel of trucks battery charger. I have come up with schematic, but i have hard time figuring up what to use as control switch. The solar panel must continually provide power to batteries so our controlled switched should be able to turn on and off.

    Oussou!
     
  2. Northtexasengineer

    Thread Starter New Member

    Apr 3, 2010
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    I know I can use Op-Amplifier as comparator, but I'm not sure if PNP will be good as controller because we need 250Am.
     
  3. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    It will help if you post your schematic.

    Ken
     
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  4. Northtexasengineer

    Thread Starter New Member

    Apr 3, 2010
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    I mean i have some idea that using LM311 as comparator will work as industry standard, but i'm not sure what to use as controller! My schematic is nothing more than Op-Am
    Any idea Ken?
    Thank you!
     
    Last edited: Apr 3, 2010
  5. SgtWookie

    Expert

    Jul 17, 2007
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    So, what is it exactly that you want to do?

    Disconnect the solar panel when there isn't enough sunlight to charge the battery?

    Disconnect/dump the solar panel when the battery is charged enough?
     
  6. Northtexasengineer

    Thread Starter New Member

    Apr 3, 2010
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    I want to switch off the solar panel when battery is fully charge. The controlled switch must also be able to be turn on when battery is idle at night time.
    Thank you!
     
  7. SgtWookie

    Expert

    Jul 17, 2007
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    OK. Usually the way that is handled is either the charge voltage is "clamped" to a certain level, the panel is altogether disconnected from the battery, and/or the solar panel output is "dumped" to ground.

    I don't understand what you are attempting to convey.
     
  8. Northtexasengineer

    Thread Starter New Member

    Apr 3, 2010
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    I want a solar to be swicth off when there isn't enough sunlight to charge battery.
    Thank you
    Oussou!
     
  9. SgtWookie

    Expert

    Jul 17, 2007
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    OK.

    What is the maximum voltage and current rating of the solar panel? This needs to be known.
     
  10. Markd77

    Senior Member

    Sep 7, 2009
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    In the simplest system a diode is used so that current doesn't flow back through the cell at night. You lose 0.7V but it's nice and easy.
     
  11. Northtexasengineer

    Thread Starter New Member

    Apr 3, 2010
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    The maximum voltage is 18 given solar panel can hardly goes beyon that and the maximum current is 250Am.

    Thank you!
     
  12. retched

    AAC Fanatic!

    Dec 5, 2009
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    Did you mean 250mA? If not, Ive gotta get me some of your panels.
     
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