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Make this Solar Powered Fence Charger Circuit

Make this Solar Powered Fence Charger Circuit

A Fence charger or energizer is an equipment which is used for charging(electrifying) a fence or a boundary in order to protect the inside premise from human or animal interventions.

Since these boundaries are mostly of large fields and parks, are normally away from the main cities, and powering them through some renewable option becomes more suitable than from utility grids which may become difficult to acquire in such remote areas.

The circuit of a solar electric fence charger explained here does not depend on traditional power source for operating, rather gets it 24/7 from a self sustained solar power conversion set up.The circuit is very simple to understand.

The fence charger circuit is basically a switching circuit which involves a few diodes and a high voltage capacitor.

How the Circuits Works

The diodes are used for rectifying the AC from a small step up transformer so that it gets stored inside the high voltage capacitor.

When this voltage reaches a particular threshold, the SCR fires and discharges the entire stored voltage inside the capacitor.

The above discharging of the capacitor is done or rather dumped inside the primary section of an automobile ignition coil.

The sudden dumping of the above high voltage inside the ignition coils primary, steps up the surge into several thousands of volts into the secondary winding of the ignition coil.

This stepped up voltage is used for energizing the fences or the boundaries appropriately.

However the above operations requires an AC input at the levels of around 100 to 220volts.

This voltage is generated by suitably processing the input DC from a solar panel set up.

The voltage from the solar panel is first controlled to a suitable level and then it's used for operating a triggering circuit.

The triggering circuit consists of a IC 555 oscillator which switches the voltage obtained from the solar panel controller into the transformers input, so that the output from the transformer generates the required 220V AC for powering the ignition circuit.

The solar panel output also charges a small 12V/7AH battery so that the power can be used after dusk, when sun energy is not available.

The above circuit can be powered through the following solar panel current controlled battery charger circuit:

For complete explanation of the circuit please refer this solar voltage regulator circuit.

 Fence Charger using a Stand-alone Inverter

Video clip showing the working details of the fence charger circuit. The video basically highlights the strength of the sparks generated by the CDI coil and how effectively this can be used when integrated with a farm fence.


About the Author

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials. If you have any circuit related query, you may interact through comments, I'll be most happy to help!

96 thoughts on “Make this Solar Powered Fence Charger Circuit”

  1. I wholeheartily thank you that you are doing a great job.
    I have a problem that I want secure 2km agriculture farm but this circuit cover only 100 meter.
    What machine parts will I change that cover such a ( 2km ) large area?

    • You are most welcome!,
      for increasing the range, I think you only have to upgrade the ignition coil specs…you can try a car ignition coil instead of the shown motorcycle coil

  2. Hi sir your site is very good n I already used many circuit that I used in my farm n now I’m goin for this bcos after Diwali we are going to grow chilly so I need to fence it, it is 4 Acer of land .

    1st . Is One circuit is sufficient for fencing 4 acre and what guage wire I have to use ???

    2nd what is the voltage of bt151 and tip 122 , 1uf capacitor voltage


    • Thank you Sidhesh, I am glad you are enjoying my circuits,

      Regarding the distance, I am not sure how much one ignition coil would be able to handle, you will have to check and verify this through a practical testing.

      BT151 is rated at over 300V, TIP122C at 100V, the IC 555 1uF capacitor should be 25V, the one attached with the SCR should be 1uF/400V PPC

        • I’ve used capacitor at scr 105/400v and base resistor for transistor tip122 is 180 ohms , when I checked input volt for transformar I’m getting 9.5 volt and out 11volt and transform is getting hot

      • Hi sir I have done that circuit on PCB
        But I’m not getting sparks , I have used normal transformer, input 230v n out put 12v , 300 ma when I connected this I get output 11volt only n no sparks at ignition coil n transform er is getting hot n even tip122

        • Hi Sidhesh, make sure the IC 555 is oscillating, to confirm replace the 1uF capacitor with 10uF or higher, check whether the red LED is flashing or not, it should flash rapidly.

          The output of the trafo must generate pulsating 220V in response to this oscillations, also make sure you have connected the TIP122 correctly, and it is not faulty…replace the 100 ohm at TIP122 base with a 10K

          • Thank you very much sir , Ur great ,

            Sir here instead of 2n3055 u mentioned tip31c is it same or different? Cos I have 2n3055

            • You are welcome Sidhesh, you can use 2N3055 also, no problem with that… since the current is low for this circuit I preferred using smaller transistors like TIP31,,,,

        • Hi sir thanks for reply, I already check tip is connected prprly , facing tip towards us first pin is base( is comin from pin 3 of 555 through 10k resistor ) ,2nd pin collector ( goin to transform 12v side ) , 3rd pin is emmitir ( is connected to output of transformar 230v side , which is negative to CDI coil) tip 122 is getting very hot , pulsing rate is ok since very fast led is blinking , I’m getting output to 12v only from transformar ,

          Pls help me sir , if you have any other circuit which give even 10kv also it’s ok

          • Sidhesh, remove everything from the transformer secondary and first confirm whether the transformer is generating 220V or not.

            connect a 1N4007 diode across collector/emitter of tip122, anode to emitter, cathode to collector, this is supposed to be already present internally for the transistor but just for extra safety I am recommending this.

            now connect a 10 watt bulb across the 220V side of the transformer and check whether it is glowing or not…

            the supply voltage should be around 12V 2 amp to the 555 circuit.

            add a heatsink to TIP122 to keep it cool.

            the concept is too simple, if the 12V primary of the transformer is pulsated with a 12V Dc, the secondary 220V side will accordingly pulsate and generate 220V DC, through magnetic induction.

            • this circuit was designed by me for auto-rickshaws and has been thoroughly tested, it worked immediately for me…

          • Hi sir I have done as u said but nothing change , but when I’m disconnect transformar tip is not getting heated up it remain cool I think there might be ptblom with the transform r ,

            On transfrmr it is written as
            I/p: ac 240v 50hz
            I/p : 12v 300ma
            Eng EI-350343

            Or should I change the tranform r

          • Or is the differenct step up transformation

            Or can I try with other invertor circuit of 45w output by giving input from the same circuit of urs only in place of transformar and rest as it is

          • Hi sir , I have completed the simple invertor circuit n it’s working , I have connected 10watt bulb n it’s glowing , it’s working fine , but my main concern is for fencing , pls tell now what should I do next

            • Hi Sidhesh, you can now build the CDI stage and configure it with the output of the inverter, for pulsing the SCR stage you will need a separate IC 555 astable circuit whose pin#3 will need to be configured with the SCr gate via a 1K resistor, and make sure to connect all the grounds together, you must connect the CdI ground, IC 555 power supply ground together, thi power supply can also be used for powering the inverter. If possible I’ll draw the design and update in the article…

          • Hi sir it will be great if you could explain with the daigram , (now don’t have to use tip 122 ?)

            Last part of scr , capacitor , n 100ohm resistor will remain same or change ???

            N what if i connect output of if 555 to the input of invertor circuit

            • Sidhesh, the IC 555 will be required only to trigger the SCR, the inverter circuit can work independently, and will not require the IC 555 assistance…TIP122 will also be not required now.

              I’ll try to update the design soon…

  3. 20,000 v is dangerous for human. So, what should be the output voltage, ehich will not affect human and can be use as fencing for animals.?

    • In the above circuits, if you use a DC source with lower current then the 2kv will be not dangerous, it will produce a nasty shock but won't kill anybody…

      That said, it's responsibility to make sure that the calculations are done correctly…

    • use 12V 2 amp as the input, this will make the 2kv very weak in current and not so harmful.. however it's your responsibility to check the results appropriately

  4. 20,000 v is dangerous for human. So, what should be the output voltage, ehich will not affect human and can be use as fencing for animals.?

    • 2kv can be dangerous to animals and humans only if it's accompanied with some higher current.

      In the above circuits, if you use a DC source with lower current then the 2kv will be not so dangerous, it will produce a nasty shock but won't kill anybody…

      That said, it's responsibility to make sure that the calculations are done correctly…

  5. Hi. Is there any way to electrify a fence with a 12v source using a common ground?

    I often want to park in bear country and in some areas they regularly open vehicles like tin foil wrapped burritos causing hundreds of thousands of dollars in damage annually. To use this circuit I would have to disconnect the battery's negative terminal which is time consuming and a pain in the ass.

    The van wouldn't shock anyone (or any animal) until the paint was scraped off, so I would have no qualms about using a high watt circuit to deter bears in the process of destroying my vehicle.

    • Hi, you can use the circuit which is explained in the above article.

      It's a common ground circuit but for electrifying the van body a separate battery will need to be used, or if the existing battery is used then its negative wire will need to be first disconnected from the van chassis, and then electrified through the high tension cable

  6. If we use resistor as current sensor than defenetly we have to use in series.so current pass through this resistance.but problem is current is not passing through resistor because current is passed through air by spark beetween two terminal of resistance.so resistance is not comes in picture.to overcome this problem i make three 100ohm 1watt resistance in series and put relay parallel across resistance.and i sucsess that relay is operating but on time is not more.and also spark is reduce so it is not used in large area.

    • the current limiting resistor should be used on the DC side tat is in series with the battery positive not on the high voltage side, and I am not sure to which circuit you are referring to??

  7. But sir at higher voltage resistor is bypaas using spark and if we connect bc 547 at parrallel to the resistor then gap beetween two pin is small then spark gap so it is spark beetween two pin and its burnout.

  8. Hello Sir,
    is there a way to easily monitor if the fence is working correctly (let's say I have multiple fences at home and have to check these daily) ?
    1) fence is not broken (some kind of DC sensor at the end of fence?)
    2) fence is somehow connected to ground (grass, bushes)
    Could You provide a PCB or any help would be appreciated…

  9. Hi sir,
    1) is output of 555 timer used to apply gate pulse to SCR?
    2) why have you connected output of 555 to transformer?
    3) can we use tl 494 instead of 555 timer?

  10. When I apply power to the circuit the tip122 locks on and just buzzes I know if I leave it powered it will burn the tip122 out what could be the cause I have double triple checked the work and cannot find the problem. any suggestions would be greatly appreciated.

    • that's not possible, if the IC555 works correctly, it's ought to oscillate the TIP122 and the transformer accordingly at the set frequency.

      Increase the base resistor of the TIP1222 to 10K and the check the response.

      if the trafo is an iron core type, then make sure the frequency does not exceed 100 to 200Hz…I think might be crucial to keep the TIP122 and the trfao cool

  11. Does the 12 v Battery used to power the fencer circuit have to be 7AH or will any 12 v battery work? will a car battery damage anything?

  12. In the schematic P1 calls for a 1M potentiometer. later it is referred to as a 27K preset. Did you change it to a resistor?

    • I don't remember actually, but that may be possible, I might have changed the 27k to a 1M… because a 27K preset will generate a much higher range of frequency than the 1M preset which might not be suitable for the associated iron core transformer.

  13. Hi Swagtam this is Suhas. Your circuit looks good.
    Currently Im building this but dont know how to check output high voltage and current ??? Please suggest.

    Also send your you-tube video link for this project.Thanks.

    • Hi Suhas, if you are asking regarding the solar panel measurements, it may simply done by connecting your multimter (in DC V range) prods directly across the solar panel terminals under peak sunshine, this will show you the voltage specs (open circuit voltage) of the panel, for measuring current you need to follow the same procedure again, but by keeping the meter in the DC ampere range…the reading will show you the amp spec of the panel (short circuit current)

      I'll wait for the video and pics if possible…thanks!

  14. hello sir
    thanks for putting circuit.i am student of engineering and my project is solar fence guard.
    in first stage i use step up transformer 12v/230v and charge capacitor.in next stage i discharge capacitor in output transformer.required output transformer is 230/10 kv but i dont know current rating of 230/10kv transformer.please suggest me the current rating of 230/10kv transformer.and what is its frequency.

  15. Hy i have used bc 547 and when ckt start uts burn any idea also still i have not connected the ugnitiin coil in this

  16. thank u swagatam bhai ,
    but i m facing 1 more problem that i can't get ic LM338 and scr BT151 so can u suggest me any other equivalent ic & scr … so i can get it…!

    • Hi Kalpesh, I am afraid there's no other reliable alternative for these two devices, because the specifications of these parts are unique and ideally suited to the proposed application, so I won't recommend any other equivalent because they could burn and get damaged overtime

  17. and in second ckt… battery charger ckt what is the value of R1, R2(p1),R3,R4 .
    THOUGH SOME OF THEM U HAVE PROVIDED. and transistor is also BT151 in second ckt…?

  18. hello… swagatam.
    in ckt what is the value of capacitor just below the scr 1.
    and value of capacor at pin 5 in IC 555 is .01 uf…?

  19. yes it's possible by adjusting the 22K resistor, make the 22k resistor variable, this will allow you to select any desired pulse timing.

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