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    This Outdoor LED Solar Garden Lights project is a hobby circuit of an automatic garden light using a LDR and 6V/5W solar panel. During day time, the internal rechargeable 6 Volt SLA battery receives charging current from the connected solar panel through polariy protection diode D9 and current limiting resistor R10. If ambient light is normal, transistor T1 is reverse biased by IC1 (LM555).

    LED Solar Lights Circuit Schematic

    outdoor garden solar lights circuit schematic

    Here IC1 is wired as a medium current inverting line driver, switched by an encapsulated light detector (10mm LDR). Multi-turn trimpot P1 sets the detection sensitivity. When ambient light dims,transistor T1 turns on to drive the white LED string (D1-D8). Now this lamp load at the output of T1 energises. Resistors R1-R8 limits the operating current of the LEDs. When the ambient light level restores, circuit returns to its idle state and light(s) switched off by the circuit.

    Assemble the Outdoor Solar Lights circuit on a general purpose PCB and enclose the whole assembly in a transparent plastic box. Drill suitable holes on the top of the encloure to mount the mini solar panel (SP1) and the light sensor (LDR), and in front for fitting power switch (S1) and the sensitivity controller (P1).

    Fix the battery inside the cabinet using a double-sided glue tape/pad. Finally, the LDR should not be mounted to receive direct sunlight. It must be mounted at the top of the enclosure, pointing to the sky say southwards. This circuit is very simple. So interested and experienced hobbyists can alter/modify the whole circuit as per their own ideas without any difficulty (Just try a 6V relay with T1 to drive more number of LED strings)

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    33 Responses to "Outdoor Garden Solar Lights Circuit"

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    1. Hi Sir, i am currently working on a solar garden light project. I need a charge controller circuit to power some 6 LEDs of 20mA, 1.9V. Also i need to protect my 12V battery from
      overcharge. Can this circuit meet all my requirements? If not what modifications can be done to meet my requirements? Could you also guide me on how to calculate the solar panel sizing for my project please?

      Thank You Very Much

      • T.K.Hareendran says: on August 23, 2010 at 5:58 am

        You can use this circuit with some modifications.First of all change the values of LED current limiting resistors (here R1-R8),resistor R9 and resistor R10.If you wish to add a charge controller to your 12V solar panel circuit then remove R1 and add a shunt type charge regulator in place.Search for such circuits in this website.I will try to publish a 12V garden light circuit with enhanced features in near future.

      • Thank you for your fast reply.Can i use this circuit to replace a charge controller circuit? I just need to make sure that the circuit will not overcharge my 12V battery and also able to power my 6 LEDs without destroying them. It is going to be charged by a solar panel . Could you provide me with the correct values as this is the first time i am working on electronic projects.

        Thank You Very Much.

      • T.K.Hareendran says: on August 27, 2010 at 5:04 pm

        I am happy to note the overwhelming response that my circuit has drawn!Now I am developing a 12V solid-state Solar LED garden light for the sake of all interested visitors.I hope,I can submit the same within 6 days.Pls wait….

    2. Jayanta dutta says: on August 24, 2010 at 6:50 pm

      Sir, i am student of electronics and telecommunication engineering in final year. So i make a new project.please help me for project.
      I choose the your project of the solar system.
      Please send me full circuit diagram or value of total component of solar system.

      • T.K.Hareendran says: on August 27, 2010 at 4:51 pm

        Dear Jayanta,

        Sorry for the delay!

        I think you can easily modify my circuit to suit your needs.Just add a proper solar charge regulator to enhance its reliability. I regret,I can’t understand the line ” Please send me full circuit diagram or value of total component of solar system”.Pls feel free to write me again with your specific needs.Thanks.

    3. Hi i just have problems reading the components values. For R1-R8- 100E, E here is resistance(OHM), LDR 10MM( what it means by 10mm here?)

      Thank You

      • T.K.Hareendran says: on August 27, 2010 at 4:45 pm

        E means Ohm. 10mm means the physical diamension of the LDR ie 10mm round.Please note that you can use any under/over size-preferably a hermetically sealed ,I mean water proof casing,without any problem.

    4. Hi Sir, if i do not want the light to turn on automatically, i can just remove the LDR? The wiring is still the same with pin 2 of LM555 timer connected to ground?

      Thank You

      • T.K.Hareendran says: on August 27, 2010 at 4:56 pm

        If you are not interested in automatic switching,you can omit near 90% of components in my circuit including IC 555!However,I still prefer the auto mode to save power.In my design,the LEDs lights up only when pin 2 of 555 is held at a positive potential (not in ground level).Pls refer 555IC data sheets to know more about its working.

    5. amit kumar says: on August 28, 2010 at 2:34 pm

      sir,i m interested in doing this project so plz help me by providing components required & total cost of this project.also provide me its circuit dig.thanks

      • T.K.Hareendran says: on August 28, 2010 at 4:07 pm

        Pls go throuh the sch.diagram&description again to clear your doubts.The described version is very economical .

    6. Hi Sir, could you explain to me how the diode and the resistor works to avoid the battery from overcharging? I am sorry as i am new to electronics project.

      Thank You

    7. Hi sir, i am currently bussy on my project ‘NIGHT ACTIVATED ALARM SYSTEM’ .I need to use the automatic switching part of your circuit to triger the PIC16F84A during the night,i also want to display something on my LCD.Is it possiple for the output voltage of LM555 to trigger the PIC?

    8. Francis Gubangco says: on October 2, 2010 at 7:25 am

      Hi Sir,
      I am a student of electronics engineering, I am really very interested in doing circuits that may help to protect our environment from global global warming. A solar panel is a very good one that’s why when I saw your circuit i found it very useful for my solar panel at home, it is exactly a 10 Watts solar panel. I wish you could send me some of your circuits that uses solar panels. Thank you very much… and God Bless You More.

    9. hi..
      im a final year student in northumbia university. i have chosen this project as my final year project. can u send me the full curcuit diagram for this project? can u send me the full report of this project..pls….. thank you.

    10. Hello sir!
      i would like to know more detail about the workings of the solar panel and the battery, how long does it need to charge the battery and how to protect my battery from over charge?

    11. Hello Sir,
      In your Circuit diagram in T1 where to connect the 6v Relay.is it T1 in Emiter/Base/Collector? plz send relay the connection in this diagram.

    12. Navi Teja says: on July 31, 2011 at 11:04 am

      Sir I am Navi Teja sudying B.Tech final year(E.C.E).As part of our project I am undertaking your Outdoor Garden Solar Light System as I found it very interesting.So please if a you can kindly assist me in doing this project I would be very thankful to you.If you can provide me the PCB layout and components list I would like to begin this project next week.So kindly consider my request and help me out.

    13. The resistors in serie with the LEDs will dissipate 40 mWatt each. It is more power efficient to limit dissipation by.

      1) using 2 LEDs in serie
      2) let the LEDs light with a 200 Hz current.
      3) using a current controlled circuit based on switching technology as used in switching power supplies.

      Disadvantage of no. 2 is it complicated schematic.

    14. hi sir…

      can u give more information about the solar panel. thanks.

    15. pl. issue me 5w led solar light cercuit

      and 2nd,
      issue single wt.led cercuit using 5252 f/1004

      thank u

    16. This Circuit is 100% working… I m doing a project on this circuit…
      U can also follow the link below for Solar Controller:


    17. SIDDHARTH says: on January 28, 2012 at 4:59 pm

      Hi SIR,

      i am electronics gagets enthusiast and i want to make a garden solar automatic light with charge controller for overcharge and battery discharge protection supplied by a 9 volts or 12 volts battery..please sir can you help to make this circuit by sending me a circuit diagram along with necessary components to my email ID : siddharthkonwar1@sify.com

    18. Seems to use a lot of power as there is only a single LED in the string.

      Adding two LEd’s in the string and reducing the resistor value would increase the battery life by 40%

    19. Hi all! Can somebody tell me what is the purpose of this resistance R10 – 15ohm / 10W

      • “During day time, the internal rechargeable 6 Volt SLA battery receives charging current from the connected solar panel through polariy protection diode D9 and current limiting resistor R10″

    20. I am attempting to learn electronics on my own. Can someone explain how an IC that is known to be a timer can function as a “medium current inverting line driver”, whatever that is? I have looked at the data sheet and do not understand this usage.
      Thank you,

      • Jim Keith Jim Keith says: on November 13, 2012 at 3:44 am

        There are many ways to apply some IC’s and that can be confusing to the novice. I do not agree with Mr. Hareendran’s description: “line driver,” so you may put that to rest. A line driver usually drives a data transmission line, and this is clearly not the case here–I suppose the 555 could perform that function under certain conditions, but I had never thought of doing so and I have never seen it.

        What I have done with the 555 is to use it as a schmitt trigger inverter driver as Mr. Hareendran has done here. This is undocumented as are many 555 applications. When the input voltage gets above 2/3 Vcc the output goes low, and when it goes below 1/3 Vcc the output goes high. Output drive capacity is capable of driving R9, a 220Ω base current limiting resistor.

      • Thank you for your prompt answer.

    21. how to arrange the circute on breadboard sir

    22. Datt Nanaware says: on February 7, 2014 at 11:01 pm

      dear sir please send mi 6v/13.5Ah Battery ,176 Nos Super Flux Led,solar street Light simple Dusk to Dawn circiut Diagram Pz Sir.
      I am wait for your Replay.

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