Adding an External Power Supply to a Cheap USB Hub

248,530

109

75

Intro: Adding an External Power Supply to a Cheap USB Hub

One day I found myself in the need for a USB hub with an external 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:

You will also need the following skills:

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

For better quality pictures check out http://www.thebitbangtheory.com/2012/06/adding-an-external-power-supply-to-a-cheap-usb-hub/

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.

Step 2: Get a Connector and Solder It in Place

Luckily I had a connector that I had scavenged from some other device. I soldered the connector. In the case of your hub, if you soldered two wires, just solder the connector to the wires. Make sure you solder the VCC to the right pin of the connector.

Step 3: Cut the VCC Wire of the USB Cable

This is the last step of the hacking. Just look for the USB cable that connects the hub to the computer and cut the red wire (VCC), so that the computer will not be able to provide current to the USB hub. The USB hub will not be able to provide current to the USB port either.

Step 4: Test the Hub

All the hacking has been done by now. Get a regulated 5V power supply and plug it in the connector. If you hub has any "power on led"it should be emitting some light. That's a good sign. If everything is ok, plug the USB cable into the computer and check if the hub is recognized. In linux you can open a terminal and type "lsusb" to see if the hub recognized. If it is recognized, plu some device in it and test if it works.

Step 5: Put It in the Enclosure and You're Done!

If everything worked you can put the hub in its enclosure and you're done. Depending on the router that you have you may have to modify the enclosure to make the connector accessible. Hope it's useful for you :)

For a longer story about it and better quality pics check http://www.thebitbangtheory.com/2012/06/adding-an-external-power-supply-to-a-cheap-usb-hub/

3 People Made This Project!

Recommendations

  • Furniture Contest 2018

    Furniture Contest 2018
  • Metalworking Contest

    Metalworking Contest
  • Audio Contest 2018

    Audio Contest 2018

75 Discussions

0
None
Christian RobertA

7 months ago

Hi!
I read you instructions about this mod.
Im interest, why you cut the vcc which goes to the pc?
The instruction under No. 5 in your to-do list.

That makes no sense to cut the wire actually.
If you leave the vcc which is coming from the PC usb to the hub, and put an external 5v vcc to that wire and the two gnd wires are also connect in paralel, you will have a parallel connection, which will
cos in a higher capacity output of the hub.
Any explanation for the vcc cutting under No. 5?

3 replies
0
None
msaleiroChristian RobertA

Reply 5 months ago

You have to cut it in order to not have two competing power supplies (the PC and the external one). If you have two power supplies trying to feed the same circuit you may end up burning one of them.

0
None
Christian RobertAmsaleiro

Reply 5 months ago

Ok, I don't got the point, sorry.
If I understand you, than, you cant power a device from two separated battery which are in parallel or you can't power a device from two separated power adapters which are in parallel connected?

Where is the big-bang theory here?

0
None
msaleiroChristian RobertA

Reply 5 months ago

It depends on the battery technology e charge state. Consider for example two equal Li-Ion batteries. One of them (A) is fully charged at 4.2V and the other one (B) is discharged and has only 3.5V. In the moment you connect them in parallel there will be a sudden flow of energy from battery A to battery B until they reach balanced state, This sudden current is uncontrolled and can cause either battery to burn because of the amount of current involved. Of course, this depends on the battery technology. Some are more sensitive than others. When you think of power supplies the same happens. One may be providing 4.9V and the other 5.1V which means that the 5.1V power supply will be providing energy to the circuit and also into the other power supply which can result in damage to either one.

0
None
Poppo_Popporation

10 months ago

Hi, I try to do this instructables: the current runs at 100%, but the hub is no longer recognized by the pc. Can anyone explain to me why?

1 reply
0
None
msaleiroPoppo_Popporation

Reply 5 months ago

Maybe you damaged something in the process. Make sure the GND wire is connected and the D+ and D- wires are also ok.

0
None
msaleiroAOTN2000

Reply 5 months ago

You're welcome. Thanks for your appreciation.

0
None
morrisonsean711

Question 6 months ago

hey do you think it would be useful to solder a diode in series with the vcc input via usb red wire instead of cutting it so if voltage drop occured due to multiple devices etc, the pc could take up the slack?

1 more answer
0
None
msaleiromorrisonsean711

Answer 5 months ago

Could be useful in some cases but I'm not sure if it would help because the diode would impose a 0.7V drop between the PC USB and the actual USB hub circuit. With some devices it could work but with others could cause problems

0
None
AdrianI34

9 months ago

Hi. I have a 4 ports usb 2.0 hub and it has a power input connector. But I don't have the AC wall adapter! That's how I bought it, without the wall adapter. But now I want to use it with hard drives and they require more power! I found a power adapter with the right plug, BUT it is a 6v and 1000 mA.

My question is: can I use it with my usb hub? Will I have problems with the Hard Drives (as I have important stuff on it)? Is it to much power or too little? Or it is just fine to use it? Thanks so much for help! Great tutorial, by the way!

1 reply
0
None
morrisonsean711AdrianI34

Reply 6 months ago

if you have a multimeter, you can check to see how close it is,, ive seen power adapters that say 10v and are 14v. if the adapter is a solid 6 or a hair over no worry, there is a hack for that. for every diode that you run in series, you drop about .6 -.7v run a couple of them if you need to, remember that things are designed for almost 20 percent this way or that way as far as voltage goes so you would probably be fine throwing one diode in series with the power positive.

you can do that on the hub, or on the adapter wire itself. or use a usb phone charger and save yourself the hassle.

0
None
T FawazelulR

1 year ago

hat kind of power adapter can i use? can i use a power adapter from a
rc car charger? cuz it seems like the connector and the power adaptor
cord is plugabble.. but i dont brave enough to test it LOL xD

3 replies
0
None
msaleiroT FawazelulR

Reply 1 year ago

Hi. You need a power adapter that outputs 5V. If you get one with 5V 1A or 2A it will do.

0
None
AdrianI34msaleiro

Reply 9 months ago

Hi. I have a 4 ports usb 2.0 hub and it has a power input connector. But I don't have the AC wall adapter! That's how I bought it, without the wall adapter. But now I want to use it with hard drives and they require more power! I found a power adapter with the right plug, BUT it is a 6v and 1000 mA.

My question is: can I use it with my usb hub? Will I have problems with the Hard Drives (as I have important stuff on it)? Is it to much power or too little? Or it is just fine to use it? Thanks so much for help!

0
None
msaleiroAdrianI34

Reply 9 months ago

Hello. You should try to get one that says 5V. 6V might damage the devices.

0
None
RajaCellular

10 months ago

A unit load is defined as 100 mA in USB 2.0, and 150 mA in USB 3.0. A device may draw a maximum of 5 unit loads (500 mA) from a port in USB 2.0; 6 (900 mA) in USB 3.0. (source: https://en.wikipedia.org/wiki/USB#Power)

So, if you have more hubs, you'll need more current (ampere).
No need to increase the voltage, just the current.
Get these extra current from another power source, dont take it from your computer.

Good luck and be careful for playing with electrical current.

0
None
Atle SeppolaG

10 months ago

I'm planning on adding an external power supply to one of these units, but have to say I'm a bit short on how much current I can push into it. The hub has 4 ports, would it go crazy if I give it 5v 10A? Not an expert on this, but in my head that would be just fine since the connected units take what they need and nothing more? And will that current be divided by four all the time (2.5A on each port?), even when there's only one unit connected to the hub? Would be great with some extra information regarding this issue in an article like this. :-)

Or do I have to think like usb 3 = 900mAh x 4 = 3.6A, or is that only when power is coming through the usb-cable and not from an external source?

1 reply
0
None
msaleiroAtle SeppolaG

Reply 10 months ago

Hello. If the PCB traces can handle the 10A that will be no problem. The connected units will only take what they need and it will not be divided by 4 all the time (one unit can take 5A and other device 3A, other 2A and other 0A). The USB 3 power is the power from the USB ports on the computer. If you plug an external power source you can get much more, as long as the PCB traces and USB cables can handle the larger amount of current.

0
None
LizY5

1 year ago

i want to use a twelve foot telephone cable with this mod, cut off both ends of telephone cable solder a usb for pc on one side on the other end use your mod, i only will use data lines from pc usb port. usb cables are too bulky for my pc cams that are 12 foot away.