Blog  /  DIY Electric Fence Charger: A Guide to Simple and Effective Construction

DIY Electric Fence Charger: A Guide to Simple and Effective Construction

About DIY Electric Fence Charger Setting out on new farm projects such as rearing livestock or growing some crops can be a challenge at first. Not only will you cater for the cost of the products/animals, but you will also need to consider their protection. Electric fence chargers offer more than the security you might need. And what is a better option than actually learning how to make one?

The DIY of the homemade fence charger in this article is less expensive, not to mention its effectiveness in keeping the tough-headed ‘beasts’ from having a sweet escape. Furthermore, you will have better chances at electric fence maintenance since the knowledge of the fence at every corner is at your fingertips. Then again, you can get the materials (electronic components) quickly or purchase them at a surprisingly low cost. 


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Why do I Need an Electric Fence Charger? 


Undoubtedly, there are many ways by which you can use the electric fence charger, especially for protection purposes. Let us take an instance whereby you have a larger agricultural field, and there is a need to keep invaders (animals or humans) away from it. Installing an electric fence is the surest way to provide safety to your crops. 

Besides, building it yourself makes the whole process cost-effective. Even better, you will have boundaries for animals (if that is your project plan) in a secure place, free from predators. 


goats behind an electrically charged fence

(goats behind an electrically charged fence). 


The electric fence will produce a painful electric shock when manipulated or touched physically. It is all thanks to its highly electrified voltage power. In that way, you can deter any intrusions across the restricted boundaries. 


Part List for DIY Electric Fence Charger 


When working on electric fence installations, these are the components you will need for the circuitry;

  • SCR = BT151
  • TR1 is 0-12V/3Amp (120 volts or 230 volts)
  • TR2 is 0-12V/1Amp (120 volts or 230 volts)
  • TRIAC = any 1 Amp/400V is applicable. For example, BT136
  • All diodes used are 1N4007
  • IC is 555
  • R4 is 1K, 1 Watt
  • R5 is 100 Ohms, 1 Watt
  • P1 is 27K preset
  • C4 is 105/400 PPC
  • Two-wheeler ignition coil used 


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The Circuit Diagram of the Electric Fence Charger 


Below is the circuit diagram of an electric fence charger. 

Circuit diagram of an electric fence charger. 


DIY Electric Fence Charger 


We are going to discuss the electric fence charger circuit.


  • First, the charger circuit is a pulse generator with high voltage that derives its power from an automobile ignition coil
  • Then, you can use an astable multivibrator to produce the optimum frequencies that will enable the ignition coil to function. In addition, a second astable will control the supply of pulses to the electric fence. 


In large agricultural areas 


For this part, you will need an electrically charged fence circuit with a steady production of voltage levels up to approximately 20,000 volts. Due to the volts, the death rate is also inarguably high. Luckily for the intruders, the intermittent periods of action of the pulses give enough time for them to come to a realization, recover, then step back from the fence. 

However, without the adequacy of the conductor in the fencing, you will experience leakages through sparking and airing. Consequently, it reduces the unit's effectiveness. 


Importance of automobile ignition coils here;


The designation of an ignition coil’s winding ratios creates a high voltage arc between two closely positioned electric conductors located in the ignition chamber. In other words, it acts as the step-up transformer that augments an input voltage applied from a primary winding to highly-elevated levels at the secondary winding/output. 


auto ignition coil

(auto ignition coil).


Caution; Carefully handle the ignition coil and circuit when powered. Improper handling sometimes can cause paralysis because the ignition coil, in particular, is lethal. 


How the circuit operates 


Four stages contribute to the circuit's working. They include;

  • A direct current location.
  • Stage of an intermediate 12V to 230V step-up.
  • Firing and voltage collector stage.
  • The stage of a highly high voltage booster. 




  1. First and foremost, the two step-down transformers, TR1 and TR2, have their secondary windings linked through the SCR2. Depending on the country's specification, you will find varied selections of the TR1 input in terms of the primary winding. Nonetheless, keep rating the TR2 at a standard 230V.
  2. The associated electronic components and the IC 555 make up a standard astable multivibrator stage. The secondary TR1 provides the supply voltage to the fence circuit.
  3. Then, you will use the astable multivibrator’s output for triggering the whole fencing system and the Triac BT136. It is often at a specific fixed intermittent rate according to P1 settings.
  4. When the circuit is on the switch ON periods, the Triac joins TR2’s secondary to the 12V AC from the TR1. In this way, a 230V potential immediately becomes accessible at the TR2’s other end.
  5. Next, you feed this voltage to the stage of voltage-firing comprising SCR1 (main active component), a resistor, capacitor C4, and a few diodes. 
  6. You then dump the SCR1’s fired voltage into the ignition coil primary winding. Here, it gets pulled to an immense 20,000V at the secondary winding. Far along, the fencing may suitably terminate the voltage.
  7. Finally, you will need to carefully apply the high voltage made by the fence charger across the whole fence. 




  • You should keep the two poles from the ignition coil 2 inches apart during their connection to the fence wiring.
  • The fence’s pillars should have non-conductors such as plastic insulators. Do not use metal or wood. Metal conducts electricity. On the other hand, wood can absorb moisture, giving a path to leakages in the circuit.


an agricultural electric fence with a plastic insulator

(an agricultural electric fence with a plastic insulator)


Transformer Specifications


  • First, use any iron-cored step-down transformer (500mA). It is frequently applied in the transformer version Alternating Current/Direct Current in power supply devices.
  • Evaluate the output crosswise the transformer output at the secondary winding level. For example, when you have 220 volts at the secondary level, you can gauge the work on the same stories.
  • You can heighten or step up the degree above using a connected diode and a capacitor charge pump set-up that resembles a Cockroft-Walton voltage multiplier system. The project arrangement will lift the 220-volt level to higher volts that you can compel to spark crossways in the charge pump circuit at the stipulated finishing terminal.
  • Also, you can wire up the above-end terminals that have high tension on the whole fence length you intend to guard against intruders. 
  • Separate the fence charge wires a small distance to prevent sparks from flying off even if there is no intrusion.





FAQs for DIY electric fence charger


I wanted to protect my beehives from bears. From the projects I have seen before, they use a car's old-style ignition coil. Is it strong enough to build a DC electric fence energizer?

We have tried out the concepts discussed in the article above and confirmed that the potent automotive ignition system. So powerful that it can keep even elephants away from your property. 

Which is the appropriate length of the space between the stakes? And how many meters of fence will the project energize?

Often, 3 meters is a considerable length for the stakes. As for the energized meters, the project will cover 20 meters of fence.

What if I want a more expansive area covered, say a fence of about 800 meters, which will be the best approach?

Eight hundred meters is pretty broad. Therefore, you'll need a system that works widely. For that, I would suggest a siren sound method. It becomes activated should any animal/intruder get near the fence. You can also operate each module separately and charge them from small individual solar panels. 


Grid sign

(Grid sign)




Even though electric fencing can be dangerous if mishandled, it still proves to be a helpful tool by which you can add extra security to your farm. Not only is the electric fence charger easy to build, but it is also cost-effective if you are on a budget. Still, if you need to clear any doubts, contact us. We are at your service. 



Special Offer: $1 for 5 PCB Assemblies!

One requirement only: Order must be placed using a company account.
Please email [email protected] for details.
Special Offer: $1 for 5 PCB Assemblies!