Powered USB hub as USB charger?

[rivan]

I've got a powered USB hub I'd like to use as a multi-device charger.

When it's not plugged in to a (powered up) computer however, it doesn't send power to the USB devices attached.

Any way to make it do that?

 

[heymrdj]

Not really, it's controller chip apparently is set to not enable the port until the host and device have completed a handshake. I have a 15$ Rosewill powered hub that will charge without having the computer on/connected.

I guess when you say you have a powered hub, it does connect to the wall outlet correct?

 

[corkyg]

Short answer, yes.

A powered hub can always be connected to A/C - but, in general, the port LEDs only light up when connected to a computer and a device. That is as Heymrdj states.

There are however, ways to do what you want to do. This is but one example:

http://news.cnet.com/8301-17938_105-9788412-1.html

And a good video after the gamer's commercial.

http://cnettv.cnet.com/use-your-usb-hub-gadget-charger/9742-1_53-50003408.html

it is possible that not all hubs can do this. Apparently the one you have can't. But, are you sure? Have you used a VOM to check the port outputs when not connected to the computer? As I said above, they just may not be lit up.

 

[rivan]

Not really, it's controller chip apparently is set to not enable the port until the host and device have completed a handshake. I have a 15$ Rosewill powered hub that will charge without having the computer on/connected.

I guess when you say you have a powered hub, it does connect to the wall outlet correct?

Yes.

Short answer, yes.

<snip>

it is possible that not all hubs can do this. Apparently the one you have can't. But, are you sure? Have you used a VOM to check the port outputs when not connected to the computer? As I said above, they just may not be lit up.

I have not used a meter on the ports; I only tested my phone, with it's normal USB charging cable. Neither the hub light nor the phone's battery status changed.

Interestingly, one of the stories linked (here) says that happened on one of his devices, yet the battery meter climbed anyway.

I guess I'll break out the meter - I just assumed I could trust my phone to tell me it was getting power.

 

[rivan]

Confirmed last night - no voltage out until the hub is attached to a powered up computer.

I wonder - is making the hub think it's connected as simple as grounding one of the wires? Any of the EEs around here knowledgeable about USB?

 

[fatpat268]

You could try this:
http://event.asus.com/mb/2010/ai_charger/

It's for iDevices, but it's possible it might work for other stuff. You don't need an asus mobo either...

 

[DesiPower]

I have a belkin active hub built into my comp desk, i charge cell phones MP3 player and GPS on it all the time, works even when comp is shut off. I think its your hub. It must be special, any cheap hub should work.

 

[corkyg]

Yep! Not all hubs are the same. As I recall, the video above used Belkin.