USB charging port

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silverback
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USB charging port

Post by silverback »

Vague question coming up.
A friend has just bought a new desktop, an HP Pavilion All in One 27-XA0XXX.
The (Very inadequate) documentation says that one of the USB ports is 'a charging port'.
Friend claims that a USB Disk plugged into this port 'got quite hot'. She then tried it in another USB port and it didn't get hot.
I've never heard of a USB Charging port. Is there such a thing and, if so, can ordinary USB devices safely use that port without overheating?
I said it was vague. :smile:
Thanks
Silverback

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StuartR
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Re: USB charging port

Post by StuartR »

I think this might mean that this port still has power even when the laptop is shut down. So it can be used to charge an external device from the laptop battery when the laptop is not in use.
StuartR


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ChrisGreaves
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Re: USB charging port

Post by ChrisGreaves »

StuartR wrote:
22 Jul 2020, 07:00
...it can be used to charge an external device from the laptop battery when the laptop is not in use.
Ouch! So one is charging one battery from another battery, losing energy as all energy-transfers must, losing battery life in the laptop, too, I would think.
Most laptops have a "mains power" light blinking away, so I assume that although the Power-OFF button has been used, mains electricity is still available. And since the computer hardware can detect when a device is plugged in (else how would Windows know?), it seems strange that the wizards can't come up with a way to pipe that mains electricity "straight-through".
And yes, I recognize that the mains has to be stepped-down, rectified, condensed, resisted etc.

One other thing I don't like is the prospect of waking up dead from a house fire caused by an overheated device.

FWIW I plug my phone into the laptop late at night so that it charges while I listen to the last thirty minutes of music before bed, and so that it continues to charge the instant I turn the laptop ON first thing in the morning.

Cheers
Chris
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silverback
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Re: USB charging port

Post by silverback »

Don't know if it affects this erudite exchange of postings, but the device is a desktop, not a laptop.
Does that make a difference?
Silverback

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Leif
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Re: USB charging port

Post by Leif »

silverback wrote:
21 Jul 2020, 22:16
Vague question coming up.
A friend has just bought a new desktop, an HP Pavilion All in One 27-XA0XXX.
The (Very inadequate) documentation says that one of the USB ports is 'a charging port'.
Friend claims that a USB Disk plugged into this port 'got quite hot'. She then tried it in another USB port and it didn't get hot.
I've never heard of a USB Charging port. Is there such a thing and, if so, can ordinary USB devices safely use that port without overheating?
I said it was vague. :smile:
Thanks
Silverback
USB ports must adhere to a standard output voltage, nominally 5V. The output current available varies depending on the port specification.
A device connected to a USB port will endeavour to take whatever power (current) it requires, and if this exceeds what is available, the USB port should shut down.

Unless the USB port itself is faulty, the power requirements of a USB Disk drive are determined by it, not the port it is connected to. This should mean that if the USB device is getting hot, that is down to the power it is drawing, not what the USB port is delivering. My guess would be that the drive was getting hot because it was in use in the first port, and not in the second.

It may be easier to understand if you think of it like a mains circuit. You have a number of sockets in your house, some of which are protected by a 5A breaker, some by a 13A breaker. If you plug a 100W (approx 0.5A) lamp in to either, the maximum power it can take will be 100W, but it will depend on whether or not it is switched on. The lamp will/may get hot if it is switched on, but not if it is switched off.
Regardless of which socket it is plugged into, it will only draw 100W.
Leif.

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StuartR
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Re: USB charging port

Post by StuartR »

I can't find the article now, but I did read recently about a software attack that could cause a USB device to draw too much current and cause overheating. If I find the article again then I will post a link here.

Edited to add
FOUND IT. BadPower Vulnerability In Fast Chargers Might Make Phones Halt And Catch Fire
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Re: USB charging port

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ChrisGreaves
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Re: USB charging port

Post by ChrisGreaves »

Hi Stuart.
I watched the video and noted in the first ten seconds (and then at later points), a pixel-blurring of the area near the demonstrator's hands, especially as he was plugging in/out the cables - but not while the cable/devices were in place.
This pixel-blurring is similar to news agencies blurring people's faces.
Any idea why this blurring is done here?
Thanks
Chris
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StuartR
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Re: USB charging port

Post by StuartR »

I have no idea Chris. Maybe to hide information about what devices are vulnerable
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Re: USB charging port

Post by ChrisGreaves »

StuartR wrote:
23 Jul 2020, 09:06
I have no idea Chris. Maybe to hide information about what devices are vulnerable
Thanks Stuart.
Chris
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Re: USB charging port

Post by jonwallace »

You fiend Stuart, it took me half an hour to get off that site :hairout:
John

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StuartR
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Re: USB charging port

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jonwallace wrote:
23 Jul 2020, 14:42
You fiend Stuart, it took me half an hour to get off that site :hairout:
:laugh:
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ChrisGreaves
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Re: USB charging port

Post by ChrisGreaves »

jonwallace wrote:
23 Jul 2020, 14:42
You fiend Stuart, it took me half an hour to get off that site :hairout:
Well, Jon, if you had used 3.0 technology you would have been done in three minutes! :laugh: :rofl:
Cheers
Chris
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jonwallace
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Re: USB charging port

Post by jonwallace »

ChrisGreaves wrote:
23 Jul 2020, 15:23
jonwallace wrote:
23 Jul 2020, 14:42
You fiend Stuart, it took me half an hour to get off that site :hairout:
Well, Jon, if you had used 3.0 technology you would have been done in three minutes! :laugh: :rofl:
Cheers
Chris
I think I would actually need 3.0 capability fitted internally on my optic/brain interface to comprehend everything in 3 minutes :innocent:
John

“Always trust a microbiologist because they have the best chance of predicting when the world will end”
― Teddie O. Rahube