25 1.5V Charger project


This project is another version of portable travel charger that uses only a AA or AAA 1.5v battery.Electronic parts are minimal and this electronic project is very cheap and very easy to construct.

This is useful when you are going to picnics, camping or going to places where no electric power for you to charge your cellphones, ipod or mp3 players.

The circuit is composed of simple oscillator, a rectifier, and voltage regulator. The feedback winding F is composed 4 turns of #30 AWG magnetic wire and main winding P is composed of 8 turns of #24 AWG wire. The 5.1V zener diode and 470uF capacitor regulates the output voltage to ensure proper charging.

The windings are not critical,you can experiment using different number of turns. If ever the circuit don't have any output, try to reverse the winding connection.

The circuit below is my working prototype.
modification of parts are as follows:
1. 470uF capacitor replaced by 100uF/10V capacitor
2. 2200uF output capacitor is replaced by 100uF/50V capacitor
3. 9013 transistor replaced by 2N222A transistor
4. Feedback winding is 5 turns
5. Primary winding is 10 turns
working 1.5v charger 
Toroidal core used is recycled from defective CFL (compact fluorescent lamp).
The red wire which is much fewer turns is the feedback winding ( 5 turns in prototype) and the yellow wire which is around 10 turns is the primary winding.

How to connect the winding?
1. Short number 2 and 4 together and connect it to the positive part of 1.5V supply
2. Number 1 of the winding is connected to 50-ohm resistor.
3. Number 3 of the winding is connected to the collector of transistor.

But if you find no output or the circuit is not working (no oscillation in winding), try to reconnect the winding in this manner.
1. Short number 1 and 4 together and connect it to the positive part of 1.5V supply
2. Number 2 of the winding is connected to 50-ohm resistor.
3. Number 3 of the winding is connected to the collector of transistor.

core winding
Note: If you find out that circuit operation is a bit unstable (output fluctuation and sometimes very low output), try replacing the 50 ohms resistor with much higher value. Start from 1.2k-ohms down to 50 ohms.

25 comments:

  1. I can able to glow only an white LED using this ckt. but it cant charge mobile phone bat.
    what is the problem!
    is output current is very low?

    ReplyDelete
    Replies
    1. yes... in my case its charged and i used 9-0-9v transformer secondary side as inductor ..my mobile took around three times of actual charging time.

      Delete
  2. Nhivekar thank you for your concern,
    I will going to check entire charger circuit and confirm if there are any problems.
    Regarding the circuit, i had built it my self and tested with my old nokia 3310 cellphone and it works fine.

    during my construction, i encountered also similar problems.
    Possible causes are the ff:
    1. winding orientation of both feedback and primary winding, and

    2.too large value of output capacitor that prevents the circuit from oscillation.

    do not worry i will post any updates and improvements regarding
    this charger.

    ReplyDelete
  3. Nhivekar and readers good day!
    As i promised, i updated the charger circuit above and posted my modifications.
    I want to emphasize that this charger is practical only for emergency cases or for hobby purposes only. We can able to power up low battery (off) cellphone but we cant charged it fully.
    If you find that this charger is not charging your cellphone, try to replace the value of 50-ohm resistor with much lower value. about 27-ohm or even much lower to increase the current delivered to the output. But take note that this changes drains your 1.5V battery quickly.

    With your problem. I can safely say that the output current delivered by the charger is very much lower to the idle or charging current specified by your cellphone manufacturer. Replacing the resistor with much lower value may resolve the problem. thanks!

    ReplyDelete
  4. Hi Sir,
    This is kiran.what may be the operating voltage of 2n222a transistor. because out of 1.6v (fully recharged battery) operating voltage can't be used to charge the mobile,as transistor should get ON.
    1.6v minus operating voltage will be used for charging the mobile.Is it right.My second question can we use 9V battery with the same circuit which can provide 4 times more than 1.5v battery,but 1.5v batteries are AA rated,where as 9v batteries are not rated as AA will it work.pls provide me information .My mail id : kirankumar.biche@gmail.com

    ReplyDelete
  5. This comment has been removed by a blog administrator.

    ReplyDelete
  6. Colin Mitchell good day!
    I appreciate your suggestion, actually you can use any general purpose diode. Replacing 1n4004 by 1n4148 signal diode is a good choice since as what you have said that it is fast.

    ReplyDelete
  7. Hi Sir,pls reply me
    This is kiran.what may be the operating voltage of 2n222a transistor. because out of 1.6v (fully recharged battery) operating voltage can't be used to charge the mobile,as transistor should get ON.
    1.6v minus operating voltage will be used for charging the mobile.Is it right.My second question can we use 9V battery with the same circuit which can provide 4 times more than 1.5v battery,but 1.5v batteries are AA rated,where as 9v batteries are not rated as AA will it work.pls provide me information .My mail id : kirankumar.biche@gmail.com

    ReplyDelete
  8. kiran good day!!
    If you are asking if this 1.5V battery voltage is enough to operate the 2n222a transistor, the answer is yes.
    The circuit can increase the 1.5V input voltage to much higher voltage that is enough to charge a cellphone battery.
    how the circuit works:
    The primary and feedback coil helps the circuit to oscillate and at the same time acts as a step up transformer that converts 1.5V to much higher voltage which enough to drive the transistor and charge the cell battery.
    You can use any type of 1.5V up to 3V battery using the same diagram, but using 9V voltage(of any battery type ) input results to much higher output voltage that can damage your cellphone.(Assuming that zener diode accross the output fails).
    The idea is if you increase the input voltage, the output voltage also increases(assuming non of the parts fail).

    ReplyDelete
  9. hi
    which Toroidal core to use, is there any ready made core in market

    can u mail component with Toroidal core specification

    email:rahulsrahuls@yahoo.co.uk

    ReplyDelete
  10. Dear, from this charger I can only charge my Nokia 5130 and 2730 phones, but I can't charge my Nokia N1600. why is that?......(Nirosh)

    ReplyDelete
  11. Dear, from this charger I can only charge my Nokia 5130 and 2730 phones, but I can't charge my Nokia N1600. why is that?......(Nirosh)
    I never tried using this charger to the cellphone units you mentioned. It should work fine regardless of the phone type unless the said phone requires special charger. I recommend not using this charger if it is not charging properly. Ill post some updates later when i figure out the problem.
    tnx

    ReplyDelete
  12. I have found that when the Joule Thief circuit (with LED on the output) doesn't seem to want to work, but the LED flashes briefly when it is connected, the problem is that the resistor is _too_low_. I put a higher value resistor in and it usually cures the problem. The conventional Joule Thief uses a 1k resistor, but you may be able to go lower. There is a point where the circuit will start unreliably or not start at all. In that case, raise the resistor a bit and it should again start reliably. For a fresh 1.5V alkaline, I would say 680 or 470 ohms would be the minimum. I think 50 ohms is too low.

    ReplyDelete
  13. To Watson aName
    Thanks for your input, the other users may find your comment useful and can help them also in their future construction of the charger.
    We will note this one and add it to the project above so other readers can benefit

    ReplyDelete
  14. Replies
    1. I can't speak for this project, but the ones that I've built and blogged will run at voltages as low as 0.6V. But the lower the voltage, the more difficult it is to get enough current to do the job. If you're going to use a supply that is much lower than 1V, then you will have to use very high current transistors and do a lot of optimization to get the performance you need. See more of them in my rustybolt(.)info(/)wordpress(/) blog (remove the parens)

      Delete
  15. 2n222a OR 2N2222A I'll do with the 2N2222A because I did not find in internet this ytransistor:2N222a

    ReplyDelete
    Replies
    1. You can use the PN2222A, which is 1/4 the price. The 2N2222A has a metal can package, which is not needed. The PN2222A is electrically the same but in a plastic package. If you want a bit more power, use the BC337-25.

      Delete
  16. 5v1 zener FALS ! Neu position 2SC9013 C-E.

    ReplyDelete
  17. what Amperage can deliver that circuit ?

    ReplyDelete
    Replies
    1. I would guess less than 0.1 amp, maybe as low as 50 milliamps. But the battery current will be high and the rechargeable battery will not last long.

      Delete
  18. somebody has tested ? really charge ?? ... i knew current charge is very low
    i dont think is efficiency .....
    with 5 voltage the phone will display charging but baterry level may not increase

    exist a type 1AA bettery charge in shop but maybe can provide more Amps
    circuit based joule theif

    ReplyDelete
    Replies
    1. It will charge, but it will take longer. You can make two or three of them and connect them in parallel to the same plug. Two should charge faster, three even better.

      Delete
  19. sir what is the use of mobile battery uper electronic part

    ReplyDelete
    Replies
    1. You might try this blog post which features a YouTube video explaining a Joule Thief.
      rustybolt.info/wordpress/?p=1314

      Delete