Reuse That Old Mobile Charger




Introduction: Reuse That Old Mobile Charger

About: Electronics hobbyist and a DIYer and i love doing this stuff.

Step 1: Introduction

Six months ago,i stumbled upon a site discussing about usb charging secrets,and it was really interesting and helpful ,for many of us got some few old mobile chargers.And it happened that i got few old standard mobile chargers hanging around.,tinkering for it to be useful again.The informations could be quite helpful for others ,And i want to share it here.
•or just donate and dispose old chargers to recyling box.

Step 2: Parts and Tools:

•an old mobile charger
•2* 100k resistor 
•1* 75k resistor
•female USB 
•perf board (optional)
•Soldering iron
•Soldering lead
•electrical tape or shrink tube
•Blade or wire stripper

Step 3: Steps

1.Make sure that the mobile charger your going to use is working properly(test it first).
2.Gather all the parts needed for the project.I used only salvaged resistors from an old cd player mobo for this project.
3.Now cut the cable wire's end of the charger to expose whats in it.(commonly you'll find 2 wires in old model chargers-consist of red and black only (+ and -)
4.Now test it using multimeter to check it's dc volt output.(usually its 5-5.2 vdc)
5.If you get the correct value of 5.2 vdc(my charger did) you're good to go.
6.Then proceed to make the dc voltage divider using the resistors mentioned in parts needed.
7.Follow the schematics showed in some parts of this ible and do the soldering job.
9.After you've done everything accordingly.Test it first using your multimeter.Don't test it directly on your iPhone or iPod.
10.After all the checking and testing the project.,wrapped it up using electrical tape or shrink tube.(i used both).
•Attached image here:
•You can use different values of resistors in this project ,but make sure to get the correct dc value needed to feed the 
Data + (= 2.06 vdc) and 
Data - (= 2.76 vdc)
•This project were meant to work for iPhones,iPod and other USB compliant devices.
•Resistor values in this project won't work for some brands like Samsung latest smartphones and others.
•If you want to make this kind of project for Samsung and other brands smartphones.,just try it for yourself or you may just refer to the infos showed in some parts of this ible,for the
dc values for Data+ and Data-

Step 4: How I Made

You can easily figured it out how simple it was made,as shown in images here.Just follow the schematics-which is quite simple to follow and basic know how to solder will be helpful.

•used and salvaged resistor were used in this project.

Step 5:

Step 6: Testing

First tested on multimeter,followed on iPod nano 2nd gen then for final test.,i tested it on iPhone.
Then wrapped it up with electrical tape.

Step 7: Source About USB's

•USB Charging "Past-Present-Future

Step 8:

Original configurations from source

Step 9: Result

The result eventually did it's purpose-Reusing my old mobile charger was achieved.Now i can use it for my old ipod nano that was given to me by my sister without the charger.Thanks for your time and hoping you enjoy reading this ible.,a heart would be highly appreciated.
God bless us all! :-)

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    6 years ago

    I tested it too,leaving Data + and Data - floating.,not connected to anything wont charge an iPhone or an iPod.,Seems like it does'nt do anything at all.
    Anyways.,actually i've seen this data lines configuration also from Ladyada mint boost project.,same configurations of resistors and same schematics used to feed those Data lines.,Anyways hoping you share what your project result would be.,and share it here if you figured out other resistors match to this kind of project.


    6 years ago

    You're welcome,you're right about other chargers that's labelled as 5vdc but with an output of 6.2 vdc & some has more than 6vdc as you mentioned.,that's why i said better to check your mobile charger first using multimeter.,if you found it with an output of 5-5.2 vdc-then you're good to go.,and if not you have to figure out what type of resistors are needed to feed those two data lines.and convert it to 5vdc
    Regarding the LM 7805,i tested it on my old Nokia AC4E mobile charger with 890mah output of 6.2vdc.,i did convert it 6.2 vdc to 5.2 vdc using LM7805 then used the original configuration of resistor to feed data+ and data - mentioned in this ible.,and successfully accepted on my ipod and charge it normally.Not sure what LM7805 datasheet you got.,but according to the datasheet i found.,(image and link here).,
    LM 7805 datasheet

    15, 12:41 AM.jpg

    6 years ago

    If you leave your + and - data pins floating (not connected to anything) wouldn't that just give the mA output that the power supply is rated for? I didn't think that those pins did anything in a wall wart situation. Please correct me if I am wrong, but I also heard somewhere years ago (one of those friend of a friend said situations) that if you just short across the data pins visible from the device that most devices enter a rapid charge state. Do you know if that's true?


    Reply 6 years ago

    Without knowing the technical details I can confirm that for the iphone 4 if the + and - data pins are not dealt with that there is no charging (tried with an old USB cable for iphone 4 to only connect the current ones, still need to test the short + and- for data, although I will do this with a damaged iphone...)


    6 years ago


    Thank you for this, I still need to test it but I believe it covers well 2 points that are not always covered in other DIY projects similar to this one:

    1: The iphone D+ D- point. I still need to figure out your info but I think I will manage :)

    2: The output voltage: Big point here that you cover with the test part to check voltage output. But I think it is important to point out to other readers why it is important to do this: Many chargers "say" that they are 5v but are 6v, 8.8V,... which then is not suitable for this project (and risk R.I.P. mobiles). I have had this with 3 chargers from Nokia and Siemens that said 5v and were not, two were 6v and the third 8.8

    Now, apparently one can still do something with the 8.8V one and use a lm7805 as indicated in other instructables (in my case I cannot test as the nokia that gives 8.8v is 350 mAmps which is not enough for this).

    On the other hand, the 6v ones, I have not found a workaround as the LM7805 needs minimum 7v input. Is it too obvious how to bring down 1v and still keep everything inside the charger?



    6 years ago


    15, 6:23 AM.jpg

    6 years ago


    15, 6:22 AM.jpg

    6 years ago

    Yes,if you leave both data
    pins floating and not connected to anything will just deliver it's output mah as it was rated for,But old chargers wont be recognized by iphone,ipod & ipad or any smartphones with chip design as what the forum called it "Digital Signature".,While a few mah dropped if you add resistors on those data pins connected to 5v line and ground.My charger here was rated 700mah with my configuration it delivers an output of 605mah to my iphone. And if you just shorted both those pins together,as the forum said it would be configured as standard.I have'nt tried it yet.
    •While the USB forum released a generic ‘signature’ standard, other manufacturers came up with their own signatures and in the end, there are at least six D+/D- signatures in the wild:
    D+ / D-
    2.0V/2.0V – low power (500mA)
    2.0V/2.7V – Apple iPhone (1000mA/5-watt)
    2.7V/2.0V – Apple iPad (2100mA/10-watt)
    2.7V/2.7V – 12-watt (2400mA, possibly used by Blackberry)
    D+/D- shorted together – USB-IF BC 1.2 standard
    1.2V/1.2V – Samsung devices
    •And you have to figure out what resistors value to meet this standards.Which were not revealed.
    •attached image here using my app while charging it using this project