What can I power off a USB port ?

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What voltage and how much current can I get out of a USB port?

--
Al Dykes
-----------
adykes at p a n i x . c o m
 

henry

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I think its 12vdc at 55 amps

H

"Al Dykes" <adykes@panix.com> wrote in message
news:c8dgmv$r76$1@panix3.panix.com...
> What voltage and how much current can I get out of a USB port?
>
> --
> Al Dykes
> -----------
> adykes at p a n i x . c o m
 
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Henry wrote:

> I think its 12vdc at 55 amps


So that makes what... 660 Watts output for a single USB port?
Care to cite your source?


-WD
 
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Will Dormann <wdormann@yahoo.com.invalid> writes:
>Henry wrote:
>> I think its 12vdc at 55 amps

>So that makes what... 660 Watts output for a single USB port?
>Care to cite your source?

www.usb.org/developers/docs/ has usb_20.zip which is about as
readable as any other standard. Digging through that it appears
that the standard may allow different devices to supply different
amounts of current. The voltages are to be between 4.4 and 5.25
volts for devices that provide between, the minimum of, 8ma and
100ma. Above 100ma you must meet USB 2.0 specs and keep the
voltage between 4.75 and 5.25 volts.

So the 12 volt claim is out of line BUT if you were to carefully
read between the lines it MIGHT be possible to build and get
certified a USB 2.0 device that supplied 55 amps! :)
 

morgan

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> Re: What can I power off a USB port ?


I have just powered up one of these from my USB port, albeit USB 2 and not
1.1.

http://tinyurl.com/2q5za

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Regards


Morgan

Hard Drive noise a problem....?

www.flyinglizard.freeserve.co.uk
 
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"Morgan" wrote:
>
> Hard Drive noise a problem....?
>
> www.flyinglizard.freeserve.co.uk

Hehe, good stuff (but ditch the left side frame so us normals don't have to horizontally scroll the
thumbnails).

Jon
 

alex

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Should be something here to help (as usual google finds a lot of pages....)

http://www.usb.org/developers/docs/







"Henry" <dj@124btinternet.com> wrote in message
news:c8dhjq$be6$1@hercules.btinternet.com...
>I think its 12vdc at 55 amps
>
> H
>
> "Al Dykes" <adykes@panix.com> wrote in message
> news:c8dgmv$r76$1@panix3.panix.com...
>> What voltage and how much current can I get out of a USB port?
>>
>> --
>> Al Dykes
>> -----------
>> adykes at p a n i x . c o m
>
>
 

henry

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yes, Worcester.......

H

"Will Dormann" <wdormann@yahoo.com.invalid> wrote in message
news:6nsqc.31673$sA.9092@fe2.columbus.rr.com...
> Henry wrote:
>
> > I think its 12vdc at 55 amps
>
>
> So that makes what... 660 Watts output for a single USB port?
> Care to cite your source?
>
>
> -WD
 
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On 18 May 2004 13:21:35 -0400, adykes@panix.com (Al Dykes) wrote:

>What voltage and how much current can I get out of a USB port?

5V, 500mA max for all devices combined, per port-pair.
 
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kony wrote:
> On 18 May 2004 13:21:35 -0400, adykes@panix.com (Al Dykes) wrote:
>
>
>>What voltage and how much current can I get out of a USB port?
>
>
> 5V, 500mA max for all devices combined, per port-pair.
>
>
I guess that means the super mobile MP3 system that I built for my car,
in it's trunk (boot), cannot continue to repower the car battery,
whenever the alternator fails?

Gee, I though I had 'sorta' invented the PERPETUAL ENGINE MACHINE!
 
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On Wed, 19 May 2004 13:02:53 +0100, Conor <conor_turton@hotmail.com>
wrote:

>In article <c8dhjq$be6$1@hercules.btinternet.com>, dj@124btinternet.com
>says...
>> I think its 12vdc at 55 amps
>
>ROFLMAO..55 amps..

I don't know what the problem is, I jump a dead car battery off my USB
port.

pat - pat(underscore)blank(at)hotmail(dot)com
 
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Wow, then the USB 2.0 device will be able to back-power
the host!!! :)

Don Taylor wrote:
>
> ... it MIGHT be possible to build and get
> certified a USB 2.0 device that supplied 55 amps! :)