40 Mobile Cell phone Charger project

Cell phone charging is a problem when you are away from home or where main source is not available. A fully charged phone may last its battery up to 3 to 8 hours depending how it is used. When you are out for picnics, camping, and or having adventure with your cell phone battery empty, you cannot receive calls, take pictures or listen to music, thus a simple and portable mobile charger is a need.
A good charger has an output of 4V DC to 8V DC and a current capacity of 100mA up to 500mA.With this charger capacity, standard 3.7V at 850mA battery can be charged up to 2 hours to 4 hours.
In this project, the charger can deliver a current up to 240mA which can fully charge a cell phone in about 3.5 hours. For the charger to be portable and handy, the electronic parts are minimal and powered only by a single 9V battery with only 3 to 5 cheap parts.
charger schematic
Part List:
9V battery (preferably chargeable)
Light Emitting Diode (LED) - any color yellow, red, or orange
R1 - 2 kilo-ohms resistor or use 1k when not charging
R2 - 220 ohm resistor
D1 - 1N4001 diode or similar
Q1 - 2N2222, 9013 or similar NPN transistor,
 wires and charger jack.

The use of LED and 220 ohm resistor is to provide output indicator of the charger.1N4001 diode protects the cell phone battery from draining its charge. Transistor and 2k resistor limits the charging current to 250mA max.

Improved and simplified charger
improved charger
What this charger do is deliver a constant current to your cellphone and its  input supply can be extended form 9V up to 12V.
Part list:
LED - yellow or orange color LED
R2 - 560 ohms 1/2W
Transistor - 2N2222 , 9013 or similar NPN transistor, wires, charger jack
R1- value is dependent on maximum charging current.
    - 5 ohms for 300mA
    - 3.3 ohms for 450mA , and
    - 3 ohms for 500mA

Feel free to replace any parts with any of the same specification. Build it and enjoy.

Note: If you have problem with the charging using version 1 charger replace 2K resistor to 1K and remove the LED and 220 ohms resistor. If you are planning to build a more "all purpose type charger" which is cheap and can charge different battery voltages with different charging current, try universal charger circuit.


40 comments:

  1. Hi,
    I tried doing this but it is showing an indication as charging but my battery in the mobile is not charged.

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  2. Sir/maam good day!
    Thank you for posting your problem.
    Assuming that your battery is about 3.7V,the charger can deliver up to 250mA current to your cellphone.
    But if ever your cellphone requires a specific current to charge, just change the value of 2K using resistor between these values.

    1K for 400mA
    3.9K for 100mA

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  3. Hi sir will 9v dc battery can charge a mobile for 5 times (full charges)

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  4. hi!, we have encountered a "not charging" indicator on our mobile phones..what's the best solution for it? thanks|!

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  5. Good day to all!
    About the question if we can charge our cellphone up to five times, the answer is possible if you are using high energy capacity batteries such as lead acid. but if you are using the type of battery that used in wireless microphone, it will never fully charge your cellphone even once.
    If you are trying to determine on how many times a 9V battery can fully charge your cellphone, just use this approximation.Assuming that our charger is about 50% efficient.

    no.of charging =(rating of 9V battery)/(rating of cellphone battery)

    note :
    Lead acid is rated in AH while cell battery is in mAH
    AH = 1000mAH

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  6. Not charging indication in phone could be the current delivered is either over or below the required current that is specified by the manufacturer.(Usually specified in the casing of your designated charger)
    just replace the value of 2K resistor of any values from 1K to 3.9K.
    But if it doesn't charge your phone the way you expect feel free to ask for a design and specs you wanted, so I can design and test it for you.. Or our other readers can help you.
    I recommend NOT using this charger if you have a good one, or if it is not in emergency cases.
    Build and try it at your own risk, coz i built it and tried it with my phone, with RISK.
    thnks.

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    Replies
    1. A good way to handle this is to use 4.7k variable resistor and adjust between 1k and 3.9k.

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  7. i'd like to have a 5 to 5.3v output and 500 to 550 mah...thanks

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  8. Sir,
    I tried the experiment that is mobile cell phone charger project but just it indicating the led is glowing but when i place in the cell phone charging point it is not indicating as that it is getting charged so how could i get it.

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  9. Sushma good day!
    I assume that the phone you are using requires higher current to start charging. I recommend replacing the 2K resistor with a much lower value such as 1K or 1.2K, and try to remove the 220 resistor and the LED. It might solve your problem. I got the same problem using my other phone and doing this modification fixes the problem.

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  10. how would the components change if i use a 6 V battery instead of a 9V one
    by shyamal

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  11. hi i want to use 6v battery instead of a 9v one what things should be changed

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  12. hi i want to use 6v battery instead of a 9v one what things should be changed

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  13. If you are planning to use 6v battery, just remove the diode 1N4001 and the 220 ohm resistor and the LED. Replace the 2K resistor with 120ohms.

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  14. I built your circuit and it connected to the nokia 5130 phone. phone showing charging, but after one hour phone off and it’s fully discharge. What is the reason for that?

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  15. I built your circuit and it connected to the nokia 5130 phone. phone showing charging, but after one hour phone off and it’s fully discharge. What is the reason for that?

    Thank you for raising your concern!!
    Discharging of cellphone battery is theoretically not possible unless the 1N4001 diode is removed or defective.

    Suggestions:
    We suggest that replace the 1N4001 diode. The purpose of the diode by the way is to protect the cellphone battery from discharging.
    OPTIONAL
    You can replace the 2K resistor with much lower value such as 1K to get more charging current, thus much shorter charging time.
    Remove LED and 220 resistor for better efficiency.

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  16. I replaced 1N4001 diode and Removed LED and 220 resistor. After this changes phone showing charging but after 20 minutes phone is showing not charge and hearing battery low sound.

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  17. I replaced 1N4001 diode and Removed LED and 220 resistor. After this changes phone showing charging but after 20 minutes phone is showing not charge and hearing battery low sound.

    Try replacing 2K resistor with 1K and use higher capacity battery supply. Probably the battery power is consumed before your cellphone is charged. I want to remind you also that this charger is intended for emergency use only and not recommended to be used for longer period because of the following reasons:

    1. might not compatible with your phone and can cause damaged.
    2. expensive, since you are using battery as power supply.
    3. Circuit is designed also for emergency cases where your phone is dead (drained) and you need to open to read messages. Meaning we cant expect to charge our cellphone fully unless we got higher power capacity battery supply.

    I once used this circuit to charge my old Nokia 3310 and works fine. You can modify and use it.,ofc at your own risk.
    tnx!

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  18. Nirosh,
    what happen if I change 9013 transistor to 2n2222a transistor.

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  19. Nirosh,
    what happen if I change 9013 transistor to 2n2222a transistor.


    You can replace 9013 to any general purpose transistor such as 2n222a. Replacing it with any transistor is not a big issue and gives no or little difference to the charger performance.

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  20. Hi. I find your article very interesting. I've tried building this battery charger before, but my only component is the 12 volts car light bulb connected in series with the battery to act just like a resistor. The bulb just glows when the charger is connected to the phone. My lead acid battery drained faster because of this. But my phones are charging successfully. Later on, I got a nicer cellphone battery charger using a TIP transistor. The output is a regulated 5V, just like the USB output voltage. The current is limited to 150-500 mA range. Every phone that I connect to this charger charges without problems. I even connect it to other gadgets like a PSP, Discman, etc.

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  21. thanks akai1987.
    If you want a 12V to 5V regulated power supply you can use 7805 IC. it can deliver more than 1A at a regulated 5V.
    See USB charger and 12V to 5V regulator
    These circuit are more efficient, regulated, and you can assemble it using 1 electronic part, the 7805 IC

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  22. hello...do you have any idea how to construct mobile phone charger circuit that can cut off the supply automatically if the the battery phone already full...? please help me..

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  23. Cellphones have built in program or circuitry that automatically turn the charging off when battery is fully charged. I cant give you a charger circuit that automatically turns off the charging when battery is fully charged since we need to know the type of the battery.

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  24. excellent site.. sir i just use 6v 100ma solar panel but unable to charge a phone...

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  25. If your solar panel is rated 6V @ 100mA, i suggest just connect it directly to your mobile and just series 22 ohms resistor rated 1/2W and 1N4148 diode.
    The problem if you use this charger with your panel, it might not charge because the charger itself consumes power.
    Another cause of problem is the 100mA output current might be too low for the cellphone to charge.

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  26. sir i want to make a 4v mobile charger without transformer which component are needed please told thier value also

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  27. Use Improve and Simplified Charger
    R2-2k ohms 1/4W
    LED - red
    R1 - 5 ohms 1/2W
    Transistor -2N2222 or 9013

    But the supply source is from battery.

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  28. I want to built 1100mAh to 1500 mAh with 3.7 v and 4.9wh,
    can you advice me to how i can do so by using parts recd in India or in china.

    pl reply urgently

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  29. sir,
    which are the best cell phone charger
    available in india and not available in india keeping in mind its price & perfomance, which can able charge latest high end cell phones.

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  30. which is the positive and negative of mobile???

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  31. i have 2 lithium cells of laptop battery rating 3.6v 2200mah each can i charge my cell phone with them?

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  32. can i used a USB port instead?

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  33. Mahendra er.mkgautam@gmail.comSeptember 27, 2012 at 1:10 PM

    Thanks for your effort, Kindly tell me the requirement and circuit for an output of 5v 1.0A (regulated supply) as most of the current smartphones require using usb port, using rechargeable AA NiMH/NiCd batteries or 9V..

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  34. Thank you,
    The information you shared is very informative.

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  35. Please can i get project report of this charger.

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  36. A good charger has an output of 4V DC to mt5000 cd de mountek 8V DC and a current capacity of 100mA up to 500mA

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  37. sir how to connect this to my cellphone

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  38. can please explain ckt operation in detail..

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  39. please give me conclusion to this circuit and future scope

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