No Stupid Questions @lemmy.world Xero @lemmy.world 11 mo. ago

Will there be power issues if I plug an unpowered USB hub into a powered on or vice versa?

I have two Orico USB hubs, the powered one has four 3.0 ports, and the unpowered one has one 3.0 port and five 2.0 ports. If I plug the powered hub into the pc then chain the unpowered one into it, will the unpowered hub run into power issues if I plug high-power-consuming devices into it? And does it make any difference if I switch the hubs order?

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will the unpowered hub run into power issues if I plug high-power-consuming devices into it?

Yes, since it's limited by how much power it can draw from the other hub, and would have a limit on how much power the unpowered hub can pass to its own ports.

And does it make any difference if I switch the hubs order?

Yes. Putting the powered hub second means that it doesn't need to pull power through the unpowered hub, and it should be fine right be used as normal.
- edit: I didn't understand what a 'powered' hub was and I read it as a hub that could transfer high amounts of power. I've left my original comment below for context
  
  Putting the powered hub second means that it doesn't need to pull power through the unpowered hub, and it should be fine right be used as normal.
  
  ~~I might be misunderstanding, but wouldn't this still be a problem?~~ I was misunderstanding
  
  Computer |-unpowered hub |-powered hub |-power hungry device
  
  it would need something like
  
  Computer |-powered hub |-power hungry device |-unpowered hub |-low power devices
  
  Why would the first be a problem? The powered hub doesn't get the power from the power hungry device from the unpowered up, does it?
  
  Just plug the lower power device in the unpowered or powered hub from the first example. You're just adding a hub for no reason.
How high is the consumption of the devices? Probably better to invest in multiple powered hubs for this use case. Not that it couldn’t work, but you’re certainly increasing the odds of intermittent and damned difficult to troubleshoot problems by doing it as you described.
What happened when you tried it?
- the only high power consumption devices I have is one RGB keyboard and two USB drives so I can't really test it, but I'm curious about what happens if I plug a bunch of high-powered stuffs into it though
Read all their electrical specs carefully!

Usually, powered hubs can provide only what is needed to fulfill the (old) USB standard of 5V, 1A, which is only a little snack for today's hungry devices.

But if the powered hub is actually much stronger than the standard of 5V, 1A, then the powerless hub may burn out.

That's why today's (much stronger) chargers are no hubs anymore.
- That is not how devices like this work; plugging a 5V 3A device into a 5V 1A port means you can only pull 1A. Going beyond that will either trip a fuse on the board or cause the port to shut off, or potentially keep working with diminished voltage.
  
  If it is USB PD or QC then the devices may negotiate a higher voltage, but for standard hubs like these it's most likely to just use a USB A port and 5V.
  
  Eta: a powered hub will also take its power externally from an adapter which can supply much more current, so its draw from the unpowered hub is minimal. In the opposite order, the unpowered hub could max out the current on the powered hub and as long as the port is protected everything should be fine.Theoretically a decent hub would be fused and not allow drawing enough current to damage anything.
  
  Going beyond that will either trip a fuse on the board
  
  I have seen dead hubs, but I have never seen one with such fuses.
Interesting question!

If I'm not mistaken, charging works by the voltage potential difference of the connected devices. Think of a wall outlet, having the highest voltage in your house probably, vs a phone out of charge with effectively 0 voltage. The high potential will move towards the low potential, pushing power to the low voltage device.

The mechanism requires a specific difference in voltage to work. Most electronics have very lower voltages, relatively speaking. So for your idea to work, you'll need to find a device that doesn't require a high voltage difference, and either a series of connected and fully charged devices or an electronic with high voltage. I think it doesn't exist because they won't be functional or unsafe if they do, but I'm not sure as I'm not as expert. I just took university electricity classes so there's a good Chance I'm wrong.

I hope an expert answers though because I'm curious now too!

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