Wireless Mobile Battery Charger Circuit

Emerging technologies are making our life simpler these days. With the introduction of mobile phones, life has changed rapidly. This is a dream of radio engineering. Mobile phones merged land line telephone systems. These days, many advancements in the mobile phones were introduced.

These advancements provide many services such as text, internet etc. But although there are many advancements in the technology, we still rely on the wired battery chargers. Each phone will have its own designed battery charger. Thus the battery chargers are required to carry everywhere to keep the battery backup. Now just think of a battery charger that charges your mobile automatically. When you sit for tea and place your mobile on the table, it simply charges your mobile. This article explains a simple wireless battery charger circuit that charges your mobile when placed near the transmitter. This circuit may be used as wireless power transfer circuit, wireless mobile charger circuit, wireless battery charger circuit, etc.

Also get an idea about How to Design a USB Mobile Charger Circuit?

Wireless Battery Charger Circuit Principle:

This circuit mainly works on the principle of mutual inductance. Power is transferred from transmitter to the receiver wirelessly based on the principle of “inductive coupling”.

Inductance is the property of the conductor, in which the current flowing in a conductor induces a voltage or electromotive force in it or in another nearby conductor. There are two types inductance. 1) Self inductance, 2)Mutual Inductance.

“Mutual inductance” is the phenomena in which, when a current carrying conductor is placed near another conductor voltage is induced in that conductor. This is because, as the current is flowing in the conductor, a magnetic flux is induced in it. This induced magnetic flux links with another conductor and this flux induces voltage in the second conductor. Thus two conductors are said to be inductively coupled.

Wireless Power Transfer Circuit Diagram:

Wireless Power Transfer Circuit Diagram
Wireless Mobile Charger Circuit Diagram

DIY Project Kit: Wireless Power Transfer »

Wireless Mobile Charger Circuit Design: 

Wireless battery charger circuit design is very simple and easy. These circuits require only resistors, capacitors, diodes, Voltage regulator, copper coils and Transformer.

In our Wireless battery charger, we use two circuits. The first circuit is transmitter circuit used to produce voltage wirelessly. The transmitter circuit consists of DC source, oscillator circuit and a transmitter coil. oscillator circuit consists of two n channel MOSFETS  IRF 540 , 4148 diodes. When the DC power is given to the oscillator, current starts flowing through the two coils L1, L2 and drain terminal of the transistor. At the same time some voltage is appeared at the gate terminals of the transistors. One of the transistors is in on state while the other is in off state. Thus voltage at drain of transistor which is in off state raises and it fall through the tank circuit made of 6.8nf capacitors and transmitter coil of 0.674. Thus operating frequency is determined by using formula F=1/[2π√(LC)].

In the second circuit that is receiver circuit consists of receiver coil, rectifier circuit and regulator. When the receiver coil is placed at a distance near the inductor Ac power is induced in the coil. This is rectified by the rectifier circuit and is regulated to DC 5v using 7805 regulator. The rectifier circuit consists of 1n4007 diode and capacitor of 6.8nf. The output of regulator is connected to the battery.

NOTE: Also get an idea about the Battery Level Indicator Project Circuit and its Working

How to operate this Wireless Power Transfer Circuit?

  • Initially, connect the circuit as shown in the circuit diagram.
  • Switch on the supply.
  • Connect the battery charger at the output of the circuit.
  • Place the receiver coil near the transmitter coil .
  • You can observe the charging of battery.

Wireless Battery Charger Circuit Advantages:

  • Usage of separate charger is eliminated.
  • Phone can be charged anywhere and anytime.
  • It does not require wire for charging.
  • Easier than plug into power cable. 

Wireless Power Transfer Circuit Applications:

  • Wireless chargers can be used to charge mobiles, camera batteries, Bluetooth headsets etc.
  • This can also be used in applications like car battery charger with little modification. Go to Simple Car Battery Charger Circuit post for more information.
  • This can also be used in medical devices.

Limitations of the Circuit: 

  • Power is somewhat wasted due to mutual induction.
  • It will work for very short distances only. If you want to use it for long distances, then the number of inductor turns should be high.

[Also Read:Adjustable timer Circuit With Relay Output]

131 Responses

      1. Does the turns of copper wire affect the o/p of the circuit?? If so what is the ratio of o/p and turns of copper wire

  1. How can I make 1mh coil? Is there should be same size in master and slave coil? If not then how many round have to give?

  2. Please help me.
    How can I make 1mh coil? Is there should be same size in master and slave coil? If not then how many round have to give?

  3. there is a Rectifier circuit.i think it was full wave rectifier but there is a no center tapping to the transformer and my doubt is the circuit given above is working or not.If it is correct then could you please send me the list of componets along with their values

  4. I did it all but even set the values of capacitor and resistor in oscillator ckt.
    in transmitter ckt, the output after v reg is as required 12 V but the output of osc circuit is 0

  5. yeah, the “oscillator” is connect via a single wire, that will surely work… together with the two diodes pointing in the same direction this will be a brilliant device to show how not to do things

  6. This circuit is not correct and will not work. It is incredibly irresponsible to post circuits like this, particularly that include a mains input. How about you review circuits before posting them?

    1. i done this project. but not working. my first mosfet getting heated. i dont know how many turns of transmitter reciever. and also diameter and length of transmitter and receiver. please help me

    2. Brother i also want to make itt as my project,If you show me complete circuit with pareter values as well as inductor turns and wire gauge it will be helpful for me.Please share.

    3. what is the value of resistor R3 and R5 in trasistor circuit?
      And how many turns we have to take for transistor and resistor to work properly???

    1. sir, i am a student who is willing to do this project with complete idea of it’s operation as well as design… so can you please give the design equations or the design procedure to get the resistor , capacitor and inductance values sir… it will be very much helpful for me sir… so please provide the requested information sir…
      thanking you..

  7. Hi,

    I want to design LED lights for my home when there is no power.Can you tell me the circuit diagram with material details.

    Secondly is there any led lights for home with the help of magnatic genrator.

    Thanks
    Narendra

  8. i have done the circuit connections yesterday and iam changed the value of inductors- 8.6uh as 10uh and 0.674uh as1uh and in the receiver circuit 1.235uh as 3uh. i give the power supply one of the mosfet is burst. please explain it.

  9. hello sir …………..
    i want to buy wireless mobile charger
    how to buys this project pls tell me
    my contact no. 8923701540

  10. hello sir
    i want to buy wireless mobile charger project
    give me some more information about this project
    my co. 8923701540 plsssssssssss help me

  11. i am going to do exactly this project on my final year but i have a qn regarding the last six capacitors.
    Is it a must to put them in series as many as they are or i can just add them and put a one capacitor with total capacitance.?

  12. For the Red LED in the circuit, is that an LED driver or just a regular LED? I am trying to do a SPICE simulation for this.

  13. Hi admiin,
    i want to make this circuit but i am not sure to make the transmitter coil with 0.674uH and inner diameter is 30mm. how must i turns?
    I also did not find inductor with 8.6uH values in my town. It can be change with any others, 10uH maybe?

  14. Can someone please help me urgently. I’ve been trying to do this project for a month now but whenever I test the transmitting circuit it is giving me short circuit.

  15. If i use 24 volts ac in input, integrated 683pf capacitor this circuit will work?How turns and what gauge of inductor wire?please reply me because its my project.

  16. Connect the battery charger at the output of the circuit what that mean and what type of battery charger used please explain how we can get the output?

  17. Can you please elaborate the “How to operate this Wireless Power Transfer Circuit?” part.
    How to use once the circuit is done?

  18. if we given power supply 0f 12v dc to my circuit with a change inductor values 10microh and tanker circuit with 1 microh my ir 540 mosfet get burned help us to find our output

  19. what will be the input of transmitter ckt and how?.. and also what should be turns of both the coils ..am also tried this ckt in multisim but its not working …help me pls

  20. how many turns needed for transmitter coil and how many turns needed for receiver coil and pls give a oscilator circuit with all values……pls soon

  21. how to calculate the value of inductor and other components, if the distance between transmitter and receiver has to increase

  22. I make this circuit but it not working so plz send
    How to make this project circuit plz send video in my email id…

  23. I built this circuit and had to calculate the component values to oscillate around 100KHz for best results. Interesting concept. Original charger takes approx. 1 hour. This one takes 2 hours to fully charge from fully depleted state. Thanks for a great idea! .Also you have an omission mistake in your receiver diagram – D3/D4 anodes must be connected to output negative, otherwise there will be no current flow and C2 will not charge!!

    1. Good catch Fred. I am an electrical engineering master’s student and am thinking about building this circuit for fun.

      That’s how you dummy proof circuits. Add a little mistake so that you are forced to understand what you are doing!

      1. Fred (or anyone who has implemented the circuit) kindly send me the component values that you used to implement the 100KHz circuit. Also, what did you use to protect the mosfets from blowing up?

    2. what is the distance of the transmitter and receiver coil in order to charge ? and what is the diameter of the wire used and the number of turns.?

  24. sir can please give me the value of the components used in it the values in the diagram is not clear enough. Also mention, how the circuit work i decide to do this as my project please help me

  25. Admin!u must should mention the input source how is it connected or used and the main thing is turns of coils and their gauge.i can’t find where is coil used or inductor ….Regardz

  26. how much range this work please answer me fast ..and kindly send me all documents related to this project…
    send me all documents via mail plz..

  27. i made this circuit on Proteus but it does’t transmit current from sender to receiver circuit,what’s the issue?
    i am waiting for your fast reply.

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