Introduction: USB Cell Phone Charger Hack! (With Video)

Here is an EZ to make, no frills, USB Charger for your cell phone. Great for anyone on the go. Add it to your "mobile goodies". Just in case. Video to follow...

Step 1: What You Need

Picture of What You Need

1. Standard USB Cable
2. 12v Cell phone car adapter
3. Wire Strippers
4. Solder
5. Shrink Tubing
6. Voltmeter

Step 2: Instructions

Picture of Instructions

1.Cut off the end of the USB cable that does not plug into the computer.

2. Strip the wires. You should have four wires. Red, black, green and white.

Step 3: Instructions (cont)

Picture of Instructions (cont)

3. Cut off the end of the 12v Car adapter that plugs into the car leaving the end that plugs into the phone.

4. Strip the ends. You should have 2 wires.

Step 4: Instructions (cont)

Picture of Instructions (cont)

5. Slip on shrink tubing now! If you forget, you have to unsolder like I have done before and kicked myself.

6. Plug the USB cable into your PC. Check the wires for voltage. You should have 4.9-5 volts on one of the wires. Usually red. Black will be the ground. Unplug from your PC

7. Check continuity and solder the red from the AC adapter to the red on the USB cable and the ground to ground.

8. Add a piece of electrical tape to your solder connections to keep them from making contact

9. Heat up the shrink tubing.

10. Plug in both ends and voila! You've made it!

Step 5: Here Is the Video! Enjoy!


sugotech (author)2012-03-05

its nice post, i have also do it but not with it i have done it with charging lite.

Bus213 (author)2009-06-08

Could please someone explain me why it does not work with nokia 6061? I did "exactly" as in the instructables, but as others I receive the message "NOT CHARGING". I know that my wall charger output is 5.7V 800mA and the battery requires 3.7V. So what is different?

martzsam (author)Bus2132010-10-16

I realize this question is really old, but it's because some phones won't charge unless the feel a small charge from the wires that carry information.

serith (author)2009-11-27

 I did something similar; I took an old ipod connector cable, cut it, found the positive and negative wires and hooked the end with the connector cable to a 6v 4AA battery pack, and took it down a half a volt via resister.

I then strapped it to the back of my ancient (really, it's a dinosaur) ipod. If I have time I will post pics.

Crail (author)2009-10-28

agh cheater! you have only two!

but really, what do I do if I find 7 wires instead?

Tropicana (author)2008-10-07

Works perfectly fine on my Samsung SCH-N370 Battery doesn't even get hot.

ddvniek (author)Tropicana2009-10-17

So it worked on your Samsung phone. I have a Samsung GT-S5233A (Star). Do you think this will work on my phone? On my cellphone charger it said that the output is 4.75V.

vptony (author)2009-06-12

this didnt work for me my wall charger is 5v my usb cable has red green black and blue wires and my phone plug red and white and red to red and white to black dont work phone shuts off compleatly and wont turn back on unless i unplug it? any ideas?

Smokedasphalt (author)2009-05-29

What is the value of the current??

Mr_Christopher (author)2009-03-09

For those who had mismatching colors when splicing cables, just remember that the main goal is to connect positive to positive, and negative to negative. In my experience messing around with stuff like this, I have observed that common colors for power wires in electronic cables (in order of common use) are: Positive: Red, White, Green Negative: Black, Gray, Blue Note that for USB, the standard would dictate there be four cables: Red, Black, White, and Green. White and Green in that case are for data, and Red and Black are Positive and Negative, respectively. So, for example, if you have one cable with Red and White wires, and another with Red and Black, connect Red to Red and White to Black. This should work ok, but if you get no response, switch them around and try again; the voltage is low, and unlikely to cause damage.

JussyfOgs (author)2008-11-28

on your phone charger somewhere there is the specifications of the charger, I don't know about all of them but the Nokia charger uses 5 volts. so just check your wall charger first.

Fommy_usa (author)2008-11-04

Two types of chargers are wall chargers to plug into the wall and car chargers to plug into your car's cigarette lighter.
g1 accessories

sumasbrod (author)2008-09-22

Nice thing, but not working with my nokia 5140 — just saying "not charging"...i wonder why it is so, because 220v charger provides less curent than USB...but working OK with 3310! )))

lathmos (author)2008-08-20

cool instructable, but my phone uses a standard usb cable to charge, so I can skip all but step 1 :)

Head Wound (author)2008-07-29

Kipkay, I liked your USB charger project, I took the basics of your charger and adapted it to apply to other hand held electronics.

sardines454 (author)2007-06-21

help needed, ok, i got the usb cable and was able to strip one end, when i put the black and red wires on a small motor it turns, then when i stripped my phone charger i found a red and white cable, red on red and black on white didn't work. anyone know why?

Head Wound (author)sardines4542008-07-29

As in the video Kipkay tested the wires with a volt meter, not all cables use the same coloring. Try using a volt meter for checking polarity, current and continuity. Also it does not hurt to double check your connections you just soldered.

Yerboogieman (author)sardines4542008-02-24

use black to black, red to red

Derin (author)Yerboogieman2008-06-25

no he is trying to say he had red and white cables on the phone charger

andrew101 (author)sardines4542007-07-29

whats your phone voltage?

sardines454 (author)andrew1012007-07-30

my wall charger says 5.7v and the battery in my phone say 3.7v

andrew101 (author)sardines4542007-07-30

hmm thats strange since your charger is 5.7 it should work does it still work with the wall adapter?

Derin (author)andrew1012008-06-25

it should work i have a nokia like that which works

Kipkay (author)sardines4542007-07-30

Then the phone has a built in regulator that will regulate the voltage going to the battery.

andrew101 (author)Kipkay2007-07-30

um that doesnt tell why its not working! his charger is 5.7 volts if it had a regulator it would just lowerthe voltage slightly usb is 4.9 volts it is fairly close so it should work just fine the voltage regulator wouldnt stop it form working in these conditions

sardines454 (author)andrew1012007-07-30

it is strange but once i plugged the usb charger in the phone restarted and refused to charge, luckily it was still under warranty so I got a free replacement!

furcino (author)2007-09-21

I do not know what you guys have for phones, but mine usually used about 3.7V or !!!LESS!!! (2 Boshs, 2 Erricsons, 2 Nokias, 1 Motorolla - I checked the voltage because of a project I made.)

Check the battery first! I certainly would not try this one out.

Head Wound (author)furcino2008-07-29

Yes most cell phone batteries are 3.6 to 3.7 volts but the voltage you want to look at is out much the out put is on your Charger/ adapter. Vast majority of cellphone chargers are approx 5 volts. Hence check your charger and not your batteries.

Derin (author)furcino2008-06-25

my battery is 6 volts


Redgerr (author)2008-07-20

lol, why there a cat in almoest all of your video's :) very ammusing :D

Waterpolo93 (author)2008-07-02

this was exactly wat i was about to do rite now i thought it up last nite while texting but now y beat me to it!

ferny121 (author)2008-06-10

you better belive this works. i tried it and it worked like a charm. great instructable.

ptfuzi (author)2008-05-03

i tried to do that..but in my phone it says "not charging" have you any idea what's wrong?i checked voltage too

arsim4ever (author)ptfuzi2008-06-06

same problem here. My wall charger voltage is 5.3v. My phone umm.. i dont know.. how to fix this? tq.

Kipkay (author)2007-07-30

Okay, the "thing" as you call it is a voltage adapter. It does indeed adapt or convert 110ac to 12vdc or 9vdc or whatever is specified on the adapter. Measure the output of the adapter and in my case it was higher than the voltage of the battery in the phone. MOST phones DO have circuitry that regulates the voltage going to the battery. That is how the phone knows the battery is charged or it would continue to charge until it exploded. Yes it will take longer to charge, but not that much longer and it won't matter since this is really only to be used as a backup charging source.

sardines454 (author)Kipkay2007-07-30

this did fry my phone and I had to order a new one! :(

Yerboogieman (author)sardines4542008-02-24

it is really hard to fry a cellphone

Darkshot (author)Yerboogieman2008-04-29

or try washing your cellphone..

Yerboogieman (author)Darkshot2008-04-30

that did it to my teachers phone

Derin (author)Yerboogieman2008-04-05

actually very easy just throw it in a pot of hot oil

Darkshot (author)sardines4542008-04-29

try ebay..i washed mine..and it only cost me $9 to get a new one on eBay :D

andrew101 (author)Kipkay2007-07-30

ok it wouldnt actually explode but it might leak and fry your phone and as for the backup charging source if you cut your only adaptor than it will be your primary source!!!!!!!!

newkiraj (author)2007-07-30

and that makes me and idiot how? sure, maybe phones that take 3V could fry w/ 5V but lots of phones take 5 or more and it wouldnt fry them. btw can u read? it says at the bottom of the comment box that "We have a "be nice" comment policy. Please be positive and constructive with your comments or risk being banned from our site." u could've just corrected me, rather than start name-calling and pointing out facts that are irrelevant to whether i am an idiot or not. xD lighten up

Darkshot (author)newkiraj2008-04-29


andrew101 (author)newkiraj2007-07-30

there i changed it. I have seen 2.5 volt phones b4 and if you hoocked this up it would fry the phone. I just think the guy who made this instructable should but a voltage regulator in it. and for phones that are higher put something in it that would raise the voltage like a batery

UrmiRaj14 (author)2008-04-12

Hi Kipkay i just want to say thanks thank so much for having this video. in my search for a usb-powered cell phone charger for my se k790i i came across this site and made it my weekend "wanna-try" And it works!! love this and def made my weekend :-D

miss.charlotte (author)2008-03-24

About a week ago I lost my cell phone wall charger at school and didn't have the cash to buy another. My bf gave me a car charger for my phone, but seeing as how I don't have a car, it didn't do me much good at home. I'm so glad I found this instructable! I took apart the car charger, usb cord, and twisted the wires and wrapped it up in some electrical tape. Wonderful! It definitely keeps my phone charged and much better than the car charger did! Yayy!!!

fred531 (author)2008-03-02

About the voltage issue: would it not just be easier to strip some wire close to the car charger while it's plugged in and measure that, so you can later use resistors to match?

Kent (author)2007-12-17

The charger voltage must be higher than the battery voltage, or you can't get current to flow into the battery. There is always some kind of regulator on Lithium Ion batteries. What voltage it can handle varies. Also, some phones, like recent Motorola types, use a mini-USB cable to charge, but not just any cable. It won't work with this hack. They put a resistor from pin 5 to ground, not for any electrical reason, but to act as a signal that this is a genuine overpriced charger. The circuit tests for the resistor, and will not use the charger if the resistor is not there. It will say, "Unauthorized charger". The value of the resistor varies with the model. You could get around this if you could get a mini USB plug to wire yourself, but they are hard to find.

Yerboogieman (author)Kent2008-02-24

i used an older phone that took 5v and charged it with straight 7.2 volts before but those razr phones are harder you have to take a 1k resistor and put it between the black and X wires on the mini usb

About This Instructable




Bio: Tinkerer, hackster and prankster. Hit me up on Facebook: Thanks for checking out my Instructables!
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