USB Hub that can power RPI and extras


14 posts
by doveman » Mon Nov 05, 2012 3:51 pm
I'm planning to build a RasbpMC that will need a Remote dongle, Keyboard dongle, USB stick for booting/running (as well as SD, apparently it can be a lot faster, depending on the stick of course), socket for plugging in another USB stick for quick access to media that's not on the server and probably some other stuff I've forgotten, so that's 4+ USB sockets.

So I'll need a Hub and it seems to make sense to use a powered one and have that supply power to the Pi, either backpowered from the Hub's input port, or if that doesn't supply sufficient current, with another cable from the hub to the Pi's other USB port. I'd probably need a powered hub anyway, so this avoids the need for two PSUs.

So I probably need a 5-port hub minimum. I'm not sure how much current the PSU would need to be able to supply but I'm not planning to connect any USB-powered HDD to it, so I don't imagine the dongles and a couple of USB sticks will need that much on top of the Pi's 1A.

So has anyone found any suitable hubs that work with Remote, Keyboard and maybe Wi-Fi dongles connected and also work when USB sticks are plugged in, with a suitable PSU? It doesn't matter if the hub doesn't come with a (suitable) PSU, providing there's a suitable one that can be easily purchased that is compatible with the hub.
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by doveman » Mon Nov 05, 2012 4:30 pm
Ah, I stumbled across the Wiki which lists some powered hubs that have worked.

It looks like I'd need 2.5A+ to power my peripherals and the Pi. I guess an option is to make a splitter box, with a socket to plug the hub's PSU into and then split it so it goes into the hub and the Pi independently, which will avoid any issues with current limiting USB ports or the hub cutting power to the ports under certain conditions.
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by notarat » Mon Nov 05, 2012 4:39 pm
My Manhattan MondoHub is due to arrive today, so that will likely be my recommended hub.

Of course, it's a little overkill....lol. I like overkill, though.
Image
Ports
Transfer speeds: 1.5 / 12 / 480 Mbps / 5 Gbps
(1) upstream plug, Standard-A
(24) downstream ports, USB 2.0 Standard-A
(4) downstream ports, USB 3.0 Standard-A
(1) 5 V DC port
Up to 500 mA power, all ports

Physical
Dimensions: 23 (h) x 229 (w) x 112 (d) mm; .9 (h) x 9 (w) x 4.4 (d) in.
Weight: 354 g (12.5 oz.)
USB Standard-A to Standard-B cable, 75 cm (30 in.)
Housing: plastic
LED power indicator

Power Adapter
cUL, FCC
Input: 100 - 240 V, 50/60 Hz; 1.6A, maximum
Output: 5 V / 4 A Cable: 1.2 m (6 ft.)
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by doveman » Mon Nov 05, 2012 5:18 pm
Damn, I don't know about overkill but it's definitely over-budget ;)

I'm planning on building at least two RPIs for family and they'll both need hubs and as I'm paying for everything the idea is to keep the cost down by eliminating unnecessary components :D
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by penguintutor » Mon Nov 05, 2012 5:20 pm
It looks like I'd need 2.5A+ to power my peripherals and the Pi


I wouldn't have thought so by the devices listed. 1A should be sufficient; perhaps 1.5A to be on the safe side if you may add wireless networking later.

The 1A that users recommend for a Power supply (actual spec's recommend minimum 700mA) is for the Pi and typical peripherals connected to the USB. Typically the Pi will run at less than 450mA including Ethernet (USB peripherals are what take it higher).

USB memory sticks are likely to be less than 100mA - this is an old report, so storage sizes are potentially bigger these days (thought not an indication of needing more power), but still gives an indication of power
http://darts.cse.nd.edu/papers/OBrien08PAP.pdf

Remote control IR receiver current is going to be very small.

Wireless keyboard can have a significant draw, but that's the only thing you list that will be putting a large load on the hub.

Note wireless network adapters can have a significant draw as well if you decide to connect one of those.



Back-feeding is not part of the USB standard so will not work with a compliant HUB (back feeding can be problematic on the earlier Pis).

It usually comes down to the quality of components used, particularly the stability of the power supply, on how well the hub will work. You should avoid cheaper hubs, although saying that I have a very old cheap hub that works fine.
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by penguintutor » Mon Nov 05, 2012 5:24 pm
Up to 500 mA power, all ports


Could be a problem if powering the Hub from the Pi - although most likely will still work.

My actual measurements indicate that the Pi stays under 500mA (without anything plugged into USB), but recommended minimum is 700mA.

Does it limit to 500mA - or is that just maximum guarantee?
May need to use one of those Y-cables to combine two USB outputs to one.
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by doveman » Mon Nov 05, 2012 5:35 pm
penguintutor wrote:
It looks like I'd need 2.5A+ to power my peripherals and the Pi


I wouldn't have thought so by the devices listed. 1A should be sufficient; perhaps 1.5A to be on the safe side if you may add wireless networking later.


OK, thanks. That should make it easier to find a suitable hub/PSU then :D

Yeah, I was just going by the stated 1A for the Pi plus looking at some of the listed working hubs and what ampage their PSUs were.
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by notarat » Mon Nov 05, 2012 6:47 pm
penguintutor wrote:
Up to 500 mA power, all ports


Could be a problem if powering the Hub from the Pi - although most likely will still work.

My actual measurements indicate that the Pi stays under 500mA (without anything plugged into USB), but recommended minimum is 700mA.

Does it limit to 500mA - or is that just maximum guarantee?
May need to use one of those Y-cables to combine two USB outputs to one.


The USB 3.0 ports support up to 900mA.
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by notarat » Mon Nov 05, 2012 9:11 pm
ALCON,

Here's the response from Manhatten (so everyone's aware)

Dear ________,
The hub has the ability to deliver a max of 4A. The 3.0 ports will receive 900ma when in use ( if their are 900ma still available) at the time of use.

Best regards,
Manhattan Computer Products
Technical Support
www.manhattan-support.com <http://www.manhattan-support.com>
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by penguintutor » Tue Nov 06, 2012 5:00 pm
That should definitely work then if it can supply 900mA.
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by notarat » Wed Nov 07, 2012 2:56 am
Here it is in all its "4x larger than my keyboard glory"

Image

It powers the Pi just fine. Each port has its own off/on switch, Each # lights up to let you know which port(s) is/are on (Blue LED)

I'm happy with it so now all I have to do is rip it all apart and completely remake the case similar to my other one so it holds the wall wart and keyboard and SD Cards
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by profharris » Tue Feb 12, 2013 10:21 pm
I had a 4-port powered hub attached to my Type 2 Raspberry Pi.
I recently purchased a small compact 7-port powered hub off eBay.
I'm powering the hub with a 5V 2.4A power supply. I'm powering the
Raspberry Pi from one of the powered USB ports. I also connected
the "host" cable from the powered USB hub to the bottom USB port
on the Raspberry Pi. Now for the surprise...

When I unplugged the micro-USB power cable from the Raspberry Pi
to swap it out for a shorter one... my Raspberry Pi stayed on!

I unplugged the powered USB hub from the wall (to power down my
Pi) then plugged it back in, my Raspberry Pi will power itself,
boot and run from power from the powered USB "host" cable, with
nothing plugged into the micro USB power port.

Is the normal? ... with this damage my Raspberry Pi?
-profharris
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by Rutishauser » Thu May 09, 2013 8:24 pm
It works the same way for me. When I connect the Pi to the usb hub, the red LED goes on. But the device does not boot. I am still not sure that the Pi can be powered from and connected to the same usb hub.
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by pjc123 » Thu May 09, 2013 10:40 pm
Here is the one I am using; it looks to meet all your requirements. The price is $19.99, but I don't know if that is also out of your price range. I chose this hub because I needed at least 5 ports, it has a 3 amp power supply, great reviews on Amazon (in particular by raspberry pi users), listed as working in the wiki, it is tiny (4.5"L X 3"W X 1"H), and most importantly it has a separate port that will not backfeed voltage into the pi (through the vertical USB ports). The hub easily powers the pi through the pi's micro-usb port (Well it should, considering all the peripherals are powered by the other hub ports!).

http://plugable.com/products/USB2-HUB-AG7

Here is a video of it attached to the pi:

http://plugable.com/2012/10/25/raspberr ... le-devices
My Project Website:
http://www.flaminghellmet.com/
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