Is it possible to power a powered usb hub off of computer power supply?

[Popcorrin]

I was thinking about powering my usb hub from a 5v line of my power supply.  The hub requires 4 amps at 5 volts.  I couldn't think of any issues with this but I wanted to check to be sure.   

[Turnarcades]

If i's a USB 2.0 hub isn't it already drawing 5v from the USB port? Not sure if you'd be able to tap further power from the 5v line.

[whammoed]

I was thinking about powering my usb hub from a 5v line of my power supply.  The hub requires 4 amps at 5 volts.  I couldn't think of any issues with this but I wanted to check to be sure.   

I don't see why not if your power supply is rated for it (although most usb devices won't draw the entire 500 milliamps the port is capable of anyway)
Is it an 8 port hub?  Not sure why it would need 4 amps otherwise...

[Popcorrin]

I guess I shouldn't say it requires 4 amps, that's just what the original power transformer supplied.  It is a 7 port hub and I am going to be running a couple of led wiz's off of it along with a 5 more usb devices so it will be pulling some decent current.

[Franco B]

If you are running two LED WIZ's as well as 5 other devices from one USB port (via the 7 port hub) you will more than likely exceed the 500 mA.

All you need to do is feed the LED Wiz'z 5v from your PSU and they will take power from that which will free up the USBs power for the other devices.

[Popcorrin]

If you are running two LED WIZ's as well as 5 other devices from one USB port (via the 7 port hub) you will more than likely exceed the 500 mA.

All you need to do is feed the LED Wiz'z 5v from your PSU and they will take power from that which will free up the USBs power for the other devices.

I'll be running 5 volts from the ps to the led-wizs but I still want to run 5 volts to the powered usb hub just to be safe and to make sure all the devices get the power they need.

[Shieldwolf]

not to derail, but is there a ledwiz document for dummies and power?

[Teebor]

I was thinking about powering my usb hub from a 5v line of my power supply.  The hub requires 4 amps at 5 volts.  I couldn't think of any issues with this but I wanted to check to be sure.   

Yes you could do this, and it should work fine (assuming you get the wiring round the right way, not like I do sometimes hehe)

To answer the other questions, if you have a passive hub (draws its power from the usb port) you do not get the full 500ma delivered to each port on the hub, you get slightly less and this is enough to stop some devices working (usb hdd, dsl modems, etc)

Providing additional power through an external power source to an inlet jack as is available on self powered hubs you provide the full 500ma to each port and do not suffer the same problems.

Not so much a big a deal these days but it is handy, a few years back I think VIA had a chipset that if you tried to draw the full 500ma direct from the port the USB ports on the machine shutdown and would not start working again until you reboot.

[MrMojoZ]

My Xbox 360 wireless controller receiver won't work when I also have my G15 Keyboard plugged into my PC, a powered USB hub solves the problem. 

[vertygo]

Just thought of this thread when I came across this..

molex powered usb hub - $7.99 (SYBA)

Just in case anyone else was looking for it

[Popcorrin]

Just thought of this thread when I came across this..

molex powered usb hub - $7.99 (SYBA)

Just in case anyone else was looking for it

Where were you a week ago? 

That would have made things easier.   I was successful in splicing into a 5v line and powering my hub though.

[vertygo]

Haha sorry.. but honestly, I bet you feel much more accomplished splicing a wire than entering a credit card number

Plus, it always impresses the laaadies..

"Look Honey, I spliced this wire to the USB hub and it's powering up!"

"Oh snookums, that makes me want to tear your clothes off right now!"

or something like that (it's 2:30 AM, gimme a break)

Cheers!

[scotthh]

Not so much a big a deal these days but it is handy, a few years back I think VIA had a chipset that if you tried to draw the full 500ma direct from the port the USB ports on the machine shutdown and would not start working again until you reboot.
[/quote]

I have a monitor with a USB hub. When it's hooked up to a PIII that's now in an arcade cabinet, it draws enough power at start up that the machine can't POST. If I hook up the hub after the PC is booted, it runs.  I'm not sure if it's the hub that's broken or a weak power supply in the PC, but obviously I don't use that combo anymore.

[ark_ader]

My PSU powers the USB ports even when the main PC is powered off.

Would that be a better solution?

Also you get a 5v plugs to USB 1.1 when you buy an external drive.  I plugged one of these into my Belkin 4 port hub and it worked fine, well until I powered off the laptop.