Solar switch not cooperating with LED light strip

Discussion in 'The Projects Forum' started by Rehan Iqbal, Jul 28, 2018.

  1. Rehan Iqbal

    Thread Starter New Member

    Jul 27, 2018
    4
    0
    Hey guys,
    I have been attempting to recreate a solar light (Those little outdoor garden lights) but on a much larger scale. I have attached a photo of the diagram that I was basing this off of. I have also attempted to use an LDR, but that would force me to use a relay, which I would prefer not to use. I am primarily attempting to use the solar panel as a darkness detector so that the light strip will turn on when it turns dark.
    The Led Light Strip is 12v
    and the Battery is 9v
    The reason being is that I don't need the LED at full brightness.
    Please tell me what I should change, or if I should use a different diagram.
    Regards,
    Rehan Iqbal
    use-solar-panel-as-a-light-detector.jpg
     
  2. Rehan Iqbal

    Thread Starter New Member

    Jul 27, 2018
    4
    0
    Edit:
    The current problem is that the LEDs wont turn off
     
  3. Audioguru

    Expert

    Dec 20, 2007
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    You do not say the solar panel's voltage when it is lighted. It must produce a high enough voltage to turn off the transistor.
     
  4. Rehan Iqbal

    Thread Starter New Member

    Jul 27, 2018
    4
    0
    sorry, but the solar panel was 3v, should I use a 12v panel, or is there any way to get around it?
     
  5. Audioguru

    Expert

    Dec 20, 2007
    10,975
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    First you showed a 12V battery then you said it was actually 9V. Then why are you asking about using a 12V solar panel?
    The diode allows the solar panel to charge, over charge or explode the battery if there is nothing to limit the voltage and current.
     
  6. Rehan Iqbal

    Thread Starter New Member

    Jul 27, 2018
    4
    0
    Sorry for the confusion, but I meant a 9v solar panel, the reason for is that I wanted to use a solar panel as opposed to an LDR is because an LDR would have me use a relay switch.
     
  7. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    2,305
    Why? A transistor should be adequate as a simple switch; but a second transistor might be an advantage to provide the circuit with hysteresis.
     
  8. LesJones

    Well-Known Member

    Jan 8, 2017
    2,052
    605
    Also there is a good chance that a LED strip designed for 12 volts will not light at all with 9 volts. Tell us how many LEDs are in series and the value of the current limmiting resistor in each group on the LED strip. Also what colour are the LEDs. This is because different colour LEDs have different forward voltages.

    Les.
     
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