Adding an external power supply to a cheap USB hub

One day I found myself in the need for a USB hub with an eternal power supply but when I went to a shop I verified they can be quite more expensive than the ones that don’t ha\ve external power supply. No big deal, “I’ll just by a cheap one and add the external power supply”, I thought. And that’s what I did! After all I just had to add a wire on VCC, another on GND and cut the VDD wire of the USB cable that connects to the computer.. So, I went to a shop and bought the cheaper USB2.0 USB hub that I found and took it home for some small hacking.
This instructables has only 7 steps:

1. Inspect the USB hub for signs of upgrades
2. Open the enclosure
3. Locate the GND and VCC traces and solder a wire to each one of them.
4. Solder a connector to the wires.
5. Cut the VCC (red) wire of the USB cable that connects the hub to the computer.
6. If necessary, modify the enclosure to make the connector for the power supply accessible.
7. Close the enclosure

For this instructable you will need the following tools:

• Precision screwdriver set
• Side cutters
• Soldering iron
• Solder
• Digital multimeter

You will also need the following skills:

• Basic circuit analysis skills (continuity testing, voltage measuring)

For better quality pictures check out http://thebitbangtheory.blogspot.pt/2012/06/adding-external-power-supply-to-cheap.html

Step 1: Inspect the USB hub, open it, and inspect it again

A good inspection of the device may make everything a lot easier than expected. The USB hub that I used had the shape of a 4-pointed star and in one of the corners there was the USB cable. However, I noticed that on another corner of the enclosure there was just a small hole. “Weird! Why is this hole here?”, I thought. I opened the case and right next to that unexpected hole, there were three holes in the PCB without any component inserted on them. I started to guess that those holes in the PCB and the hole in the enclosure were to solder the connector for an external power supply. I used my multimeters’ sound probe to verify if my suspicion was correct and fortunately it was!  Two of the holes were on a GND trace and the another one was on the VCC trace.
Probably there are two versions of the same USB hub being the only difference the presence or the absence of the external power supply connector. I guess it’s a lot cheaper for companies to manufacture a big amount of a single printed circuit board than to order smaller amounts of two different boards

If your USB hub doesn't already have holes for the connector, look for the USB cable and find the VCC(red wire) and GND(black wire) tracks. Solder a wire to each one of them. If it is a single sided board you can even drill some holes in the tracks to solder the wires or a connector.

Comments

[R167]

Thank you. I knew the basics, just wanted a confirmation of what someone else has done. I need to hack a usb multiplexer for my pi which just can't supply enough power for a wireless keyboard/mouse combo and wifi adapter. Now I just need to find a 5v regulator and a barrel plug and I will finally be able to use the pi without sacrificing internet or keyboard.

[portablesounds]

Is there any chance of interference from the power cables or are those cables just for power?

[msaleiro]

The power cables are only used for power. Noise may come from power cables if you use a very noisy power supply. That's why I recommend using a 5V regulated power supply

[Khochora ALEX]

hi..can i use a 5v battery ?

[msaleiro]

You can only use a battery if you add a 5V voltage regulator at the output of the battery. Otherwise it will not work since the battery voltage will change along time.

[Khochora ALEX]

My computer can not read my usb sticks. It's because it can not give enough power to the usb sticks. Will this work ?

[msaleiro]

Hi! I find it very strange that the computer cannot provide enough power for a USB stick. Try connecting some other device to see if it works ok. It seems to me that you have some problem in the USB controller of your computer. You should try connecting other devices to your USB ports and try your USB sticks on other computers. If it's really a power issue (but I seriously doubt it is), yes, this will fix it.

[Flosbert]

Amazing idea. So why couldn't I just tap power into a normal usb extension cable? For example to power a device on the Raspberry pi where you might need a powered hub but not necessarily more ports.

[msaleiro]

Yes, it would work as long as ou have a good quality 5V regulated power supply :) I've seen somewhere that some guy, after some circuit inspection and research, made a direct connection from the power input of the RasPi to the USB ports in order to directly power them. If you search for it on google I'm sure you'll be able to find it :)

[m1s73r]

Hello, I tried your instructable, the LED of my USB hub is glowing, but when I insert my USB stick and have the Hub connected to my PC nothing happens... The LED of the USB just keeps blinking... I tried different USB Sticks but still nothing. Is there something I did wrong? I even double checked I cut the red wire...

I'm using 4.5 Volt, but do 0.5 Volt really make a difference?

[msaleiro]

Hi! Yes, 0,5V can make big difference in USB. you should really get a 5V regulated power supply

[m1s73r]

Hello, I tried your instructable, the LED of my USB hub is glowing, but when I insert my USB stick and have the Hub connected to my PC nothing happens... The LED of the USB just keeps blinking... I tried different USB Sticks but still nothing. Is there something I did wrong? I even double checked I cut the red wire...

I'm using 4.5 Volt, but do 0.5 Volt really make a difference?