USB Multiple Port Hub

[SGOS]

Here's a little doo dad I noticed on Amazon:
https://www.amazon.com/Sabrent-4-Port-Individual-Switches-HB-UM43/dp/B00JX1ZS5O/ref=pd_bxgy_147_2?ie=UTF8&refRID=B88Z6PJ6B6BCNMJYEY84

It also comes as a 7 port hub.  I currently use a different hub without the convenient switches and I hook it up to different drives, some which also require a an external power supply that plugs into a 15 amp power source.  I find the drives that derive their power entirely through the USB connection are more convenient because I only have to make one connection, and I like to disconnect the drives when not in use, which is most of the time.

I like the ability to switch off the drives without having to fiddle with even just one USB plug, so you may see the advantage here.  But here's my main question:  Is there an advantage to having a drive with an additional power source with a clunky adapter that plugs into an outlet and often takes up so much space that it covers an adjacent power outlet on my power bar?  This hub comes with or without the capability of switching off both the USB and the 15amp power source, and I'd probably buy that option, because my 8TB external drives come with the extra power adapter.  But what is the reason for the additional power adapter?  Is that better than a drive (or a hub) than gets all its power through the USB connection?

[SGOS]

I'm not sure this hub switches off the power adapter as well as the USB connection.  So I might need to remove the power adapter manually every time I switch off the drive anyway.  That's not a real big problem, because the power adapter plug is easier to manipulate into the drives.  So I guess the question would be "Is a hub with an extra power supply better than a hub that doesn't use external power?"

[PopeyesPappy]

According to your link max power the hub can supply to all connected devices is 900 mA. It says to use the drive's external power source.

For a stable connection, the devices connected to the 4-Port USB 3.0 Hub must not exceed a combined current of 5 volts 900 mAh. External hard-drives should be connected to an external power source. This 4-Port USB 3.0 Hub will not charge an iPad (it will only sync).

I'd also be careful about using the switches on the hub to disconnect connected drives. You are going to to want to do a software shutdown of a connected drive before hitting the switch anyway or risk corrupting the drive.

[SGOS]

I'd also be careful about using the switches on the hub to disconnect connected drives. You are going to to want to do a software shutdown of a connected drive before hitting the switch anyway or risk corrupting the drive.

Good point.  I always do a software shutdown, and I'll need to keep doing it.  The convenience of the switches could tempt one into an easy peasy press of the button before remembering to do the software.

[Munch]

I brought one of these for my TV, can fit loads of movies on it with 4 sticks.



It still amazes me sometimes, how years ago I'd own loads of VHS tapes, both brought movies and recorded off tv, a wall of programs, shows, movies and documentaries.
Now I have a larger library of films, tv and *other* material, all in one tiny space.

[widdershins]

I don't see powered hubs very often these days, but they used to be very common when the USB power standard was a lot lower.  I couldn't imagine the need for 15 amps on USB.

The reason for a powered hub is that a single USB port can only provide so much power.  Since you are going from 1 to 4 ports it is now capable of providing as little as 1/4 of that power depending on how much each device is drawing.

There is an important difference between voltage and amperage that most people don't know.  When a voltage is listed on a supply (not applicable in this case), that is the voltage the supply puts out.  It must match the voltage needed by whatever you are plugging it.  When an amperage is listed on a supply, however, that is only what it is rated for and has no bearing on what it actually puts out.  It's the amperage listed on the device which decides the amperage actually used.  If you have a 1 amp power supply and plug in something that draws 2 amps either the safety circuitry on the device will shut it down or, more likely, it will provide you with the right amount of power for a very short time before burning out.

USB, I am pretty sure, does have some power limiting standards to prevent the "burning out" part from happening.  Back in the old days when USB was new I do remember seeing devices that simply wouldn't power up on some ports or unpowered hubs which wouldn't power up some devices.  I have not actually seen this issue for years, but I suppose it's likely still a concern when you're using a hub, especially if you're using external hard drives which require power to run a motor.

So to determine whether you need the powered or unpowered version you need to know how much power your devices draw.  If they're just flash drives you're unlikely to run into a situation where you'll be writing to all of them simultaneously (the biggest power draw), so it's probably not going to be an issue.  If it's mouse dongle, probably even less draw.  If it's USB powered external hard drives, I would guess those draw a little more.  If the devices are older they probably draw more power.  You also have to take into account how much each of the LEDs in the device use in power, which could be up to 20ma each (according to a quick search), but is probably less.

Finally I would assume that even the powered hub will work without the power cord so long as the USB port you're plugging into can provide enough power.  I know that is the case at least for some models, but not necessarily every model.  So if you're not sure, get the powered version, see if it woks without being powered and, if you ever need the extra power, add the clunky cord (if it works without being powered).  Or if you have extra money and REALLY don't want another cord, get the unpowered version and see if it works for your intended purpose.  If not, use all lower-powered devices on it to save your other ports for the higher-powered devices.

Oh, by the way, good call on disconnecting drives when they're not in use.  Modern encryption viruses will encrypt files on all external devices they find too.

[SGOS]

I don't see powered hubs very often these days, but they used to be very common when the USB power standard was a lot lower.  I couldn't imagine the need for 15 amps on USB.

The reason for a powered hub is that a single USB port can only provide so much power.  Since you are going from 1 to 4 ports it is now capable of providing as little as 1/4 of that power depending on how much each device is drawing.

There is an important difference between voltage and amperage that most people don't know.  When a voltage is listed on a supply (not applicable in this case), that is the voltage the supply puts out.  It must match the voltage needed by whatever you are plugging it.  When an amperage is listed on a supply, however, that is only what it is rated for and has no bearing on what it actually puts out.  It's the amperage listed on the device which decides the amperage actually used.  If you have a 1 amp power supply and plug in something that draws 2 amps either the safety circuitry on the device will shut it down or, more likely, it will provide you with the right amount of power for a very short time before burning out.

USB, I am pretty sure, does have some power limiting standards to prevent the "burning out" part from happening.  Back in the old days when USB was new I do remember seeing devices that simply wouldn't power up on some ports or unpowered hubs which wouldn't power up some devices.  I have not actually seen this issue for years, but I suppose it's likely still a concern when you're using a hub, especially if you're using external hard drives which require power to run a motor.

So to determine whether you need the powered or unpowered version you need to know how much power your devices draw.  If they're just flash drives you're unlikely to run into a situation where you'll be writing to all of them simultaneously (the biggest power draw), so it's probably not going to be an issue.  If it's mouse dongle, probably even less draw.  If it's USB powered external hard drives, I would guess those draw a little more.  If the devices are older they probably draw more power.  You also have to take into account how much each of the LEDs in the device use in power, which could be up to 20ma each (according to a quick search), but is probably less.

Finally I would assume that even the powered hub will work without the power cord so long as the USB port you're plugging into can provide enough power.  I know that is the case at least for some models, but not necessarily every model.  So if you're not sure, get the powered version, see if it woks without being powered and, if you ever need the extra power, add the clunky cord (if it works without being powered).  Or if you have extra money and REALLY don't want another cord, get the unpowered version and see if it works for your intended purpose.  If not, use all lower-powered devices on it to save your other ports for the higher-powered devices.

Oh, by the way, good call on disconnecting drives when they're not in use.  Modern encryption viruses will encrypt files on all external devices they find too.

What I meant about 15 amps is that the power cord plugs into a wall socket of a 15 amp circuit.  I think the clunky thing on the plug is a transformer that would reduce the amperage and voltage down to a level suitable for computer components.  While I can wire a house, I don't necessarily know what happens with electricity when it gets to a device.  I only know what I need to know to get it to the wall socket.  After that, it all becomes mysterious, so I really don't know.

[PopeyesPappy]

What I meant about 15 amps is that the power cord plugs into a wall socket of a 15 amp circuit.  I think the clunky thing on the plug is a transformer that would reduce the amperage and voltage down to a level suitable for computer components.  While I can wire a house, I don't necessarily know what happens with electricity when it gets to a device.  I only know what I need to know to get it to the wall socket.  After that, it all becomes mysterious, so I really don't know.

In that case this bears repeating.

For a stable connection, the devices connected to the 4-Port USB 3.0 Hub must not exceed a combined current of 5 volts 900 mAh. External hard-drives should be connected to an external power source. This 4-Port USB 3.0 Hub will not charge an iPad (it will only sync).

With that hub you are only going to have a total of .9 amps available to power all devices connected to it. Some new drives are very power efficient. Some aren't. For example:

1) SanDisk Extreme SSD 240GB - 5 vdc; 1.6A
2) Mushkin Chronos SSD 240GB - 5 vdc; 0.8A
3) WD Scorpio Blue 500GB - 5 vdc; 0.55A
4) WD Scorpio Black 500GB - 5 vdc; 0.55A

With those drives you should be able to run any one of WD's or the Mushkin off the hub alone but not two of them at the same time. The SanDisk draws too much power and would require an external power supply no matter what. What you can do depends on what you have...

[Johan]

Is that better than a drive (or a hub) than gets all its power through the USB connection?

In my opinion, yes in most cases. I am not a fan of spinning hard drives that can only get power via USB. Solid state drives are different. But if it actually has to spin a disk and move heads, it really should have its own power source IMO. While its true the USB can provide enough amps to get the job done, in most cases, its only just enough. Meaning you end up pushing the limits of what USB was meant to do as far as providing power goes.

In my computer tech days, I ended up replacing many fried USB circuits (or just adding new USB cards instead) because the user bought a USB powered external drive, and left it plugged in all the time. Works great for the first six months. Then the USB stuff stops working all together or worse, works most of the time, but not all. Always a bitch of a time diagnosing when it works right most of the time.

If you're plugging it in, transferring a few files, and then unplugging it, you can get by fine with USB powered drives. But like I said, I'm not a fan. Because you're still pushing the limits of what the specs can do and you're still making more heat than the hardware was designed to withstand long term.

[Baruch]

I brought one of these for my TV, can fit loads of movies on it with 4 sticks.



It still amazes me sometimes, how years ago I'd own loads of VHS tapes, both brought movies and recorded off tv, a wall of programs, shows, movies and documentaries.
Now I have a larger library of films, tv and *other* material, all in one tiny space.

And one Winter static spark off the carpet ... and its gone!

[Baruch]

Rule of thumb for electrical stuff in the US (115V).  Most wall sockets (the whole thing, not just one plug in a two plug outlet) are rated for 20A.  For example you could have a two plug outlet, and you could get away with putting in a 3-way lamp with a top rating of 150W ... but you couldn't run two of those lamps off the same outlet with both lamps on high.  But don't run more than 10A long term, leave some error room.  Electronics is rated short term for twice what the specs say ... that is why people tried double clocking their CPUs ... but that burns them out in the long run, particularly laptops that have no way to get rid of more than the rated heat output.

More on your high density solid state memories.  Back in the day, you wouldn't touch electronics without an electrostatic discharge wrist strap tied to ground.  And of course never when the power was on (you have to wait for those big power supply capacitors to discharge, particularly if you are wearing a wrist strap.  Now imagine you have a high density solid state memory that has the entire Library of Congress on it, and you have the only copy.  How confident are you that your careless handling of it, won't lead to disaster?

[Johan]

Rule of thumb for electrical stuff in the US (115V).  Most wall sockets (the whole thing, not just one plug in a two plug outlet) are rated for 20A.  For example you could have a two plug outlet, and you could get away with putting in a 3-way lamp with a top rating of 150W ... but you couldn't run two of those lamps off the same outlet with both lamps on high.  But don't run more than 10A long term, leave some error room.  Electronics is rated short term for twice what the specs say ... that is why people tried double clocking their CPUs ... but that burns them out in the long run, particularly laptops that have no way to get rid of more than the rated heat output.

'The fuck? The level of fail in this is almost epic. Go to any hardware store in the US and check which size breaker they stock in the greatest numbers and you find that to be 15 amps, not 20. Why? Because they sell more 15 amp than 20. Why? Because 15 amps is far and away the most common size you find in residential applications. Usually 20 for the kitchen outlets and possibly the garage. Generally 15 for all other outlets.

Now your lightbulb theory. A 15 amp breaker is capable of supplying 1800 watts of power without tripping or overloading the associated wiring and hardware assuming all is up to code, in good repair and correctly installed. Now if my math is correct, your 2 individual 150 watt light bulbs would draw somewhere in the neighborhood of exactly 300 watts. If a 300 watt load is tripping your 15 amp breaker, call an electrician immediately.

[SGOS]

In my opinion, yes in most cases. I am not a fan of spinning hard drives that can only get power via USB. Solid state drives are different. But if it actually has to spin a disk and move heads, it really should have its own power source IMO. While its true the USB can provide enough amps to get the job done, in most cases, its only just enough. Meaning you end up pushing the limits of what USB was meant to do as far as providing power goes.

In my computer tech days, I ended up replacing many fried USB circuits (or just adding new USB cards instead) because the user bought a USB powered external drive, and left it plugged in all the time. Works great for the first six months. Then the USB stuff stops working all together or worse, works most of the time, but not all. Always a bitch of a time diagnosing when it works right most of the time.

If you're plugging it in, transferring a few files, and then unplugging it, you can get by fine with USB powered drives. But like I said, I'm not a fan. Because you're still pushing the limits of what the specs can do and you're still making more heat than the hardware was designed to withstand long term.

Thanks, this is exactly the kind of thing I wanted to know.  In fact, I have left a USB powered external drive on for long periods of time.  Just a month ago, one of my computer's USB ports went dead.  That may have been the cause.  I will change my future behavior accordingly.

[SGOS]

Here's another nifty innovation I found while surfing Amazon.  While it's not a vital, it's clean and tidy.  It's a wall outlet with USB ports in addition to the 15 amp sockets.  They are too expensive to use for every outlet, but a couple of strategically placed wall outlets with this capability strikes me as useful, or maybe just tech "cool."

https://www.amazon.com/dp/B019WA4CKM?psc=1

[Hakurei Reimu]

Interesting how fakers always tip their hand eventually.