Monday, January 30, 2012

Just Another DIY 12v DC Charger

As Seen On Hack A Day 


In the following video it shows the steps that I took for making an alternative means of charging my ASUS Transformer TF101 after the power supply seemed to give out on me. The following charger was built from spare parts laying around the house so out of pocket cost to me was $0.00

    Nothing fancy just a simple mod by replacing the stock barrel connector from a spare 12v power supply to a USB connector, but never the less a fast a simple solution to a problem that I did not have the time or money to pick up a new one from ASUS. Yes Putting it in the freezer did correct the issue with the stock charger but now I have no need to worry with this little mod.

DO NOT Plug In USB Drives Or Other Devices Not Rated For 12v Into Power Supplies USB Port

For those without a high speed connection or who just still can't figure out what exactly it was that I did here are a few shots of the simple build

First part was finding a proper power source. As stated in the video when ever working with replacing an electronic component like a power supply for a device you should try to get an exact match if not super close. For me I used a spare 12v power supply from what was either a printer supply or other peripheral supply.  

 With the power ratings being close enough for me I proceeded to cut the barrel connector at the end of the power supply off. After stripping back some of the plastic shielding containing the positive and negative wire I stripped them back a little to allow for connection to the PCB board that whould house my 12v USB port. The USB port was taken off a older P3 motherboard that was laying around in the scrap pile. The best way to desolder on of these factory connections is a heat gun...bottom line they drop right out within 30 seconds of some circular heat gun motion to the area of the component your want to remove and saves on some desoldering braid

After soldering the USB port that I extracted to the PCB board I proceeded to hook up the 12v positive connection to pin 1 on the USB port which is normally a 5v connection and left ground on pin 4 where it should be.

A very important note on proper polarity as seen below. Notice that when the positive lead (red ) and negative (black) coming from the multimeter show just 12.17v while in the other picture with the blue arrow pointing to the negative symbol on the multimeter shows revered polarity as the multimeter leads are reversed. This is a MUST for making sure you have the proper wires attached to the correct places as not all wires are color coded black and red TRUST your multimeter not just wire colors.

After making sure things matched up properly I proceeded to tuck my wires back with a zip tie to the PCB board and place everything in a general hardware store piece of heat shrink tubing to protect against accidental electrical shock and protect my connections.


More then a handful of messages have shown up in my email box , direct message on Twitter , and Youtube. I have answered more then a handful here as your questions might be one of them

Q. See that's what you get for not buying an iPad2
A. Yes , your right cause an Apple product has never had a general hardware connection issue in the history of the tablet, smart phone, MP3 player era. By that thinking then I should dump Windows cause it can get a virus and malware.

Q. Why a USB port and not just get a USB to barrel connector?
A. The whole point of why I had to put this together was at the time I need to charge it and didn't have the time nor money to find a USB to barrel connector to charge it.

Q. What's does the freezer trick do and does it work?
A. Nothing more then allow the internal thermal fuse to cool off and reset to allow for charging. 30 minutes in the freezer will do the trick in a zip lock bag to prevent moisture from getting in the internal components. 15 minutes out of the freezer and you should be fine to try charging your device. 

Q. How many times have you had to freezer your power supply.
A. For me personally I have only had to do it once and has worked fine since the first day I tried freezing it. 

Q. Why not just charge it through your computer...duh?
A. Cause unless you have a USB connection on your PC that gives off 12v instead of 5v then it will only charge at 5V which does nothing for a charge. Maybe if I left it on and hooked up all night it might but why charge at 5v when the device can handle charging at 12v and it's charger outputs 12v.

No comments:

Post a Comment