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Non-power USB hub experiences

B

bjdraw

macrumors 6502a
Original poster
Jan 24, 2008
605
17
Tampa FL
So far as much as I love the MBA, the solo USB port is proving to be a challenge. I picked up a Targus 4 port non-powered USB hub, but it's been hit or miss. (I also picked up a 7 port powered hub, which works great when not on the go)

My main USB accessories fighting for time in the slot is my iPhone, (thanks Apple for no BT sync) USB EV-DO modem, USB SD Card reader and finally a external 160GB hard drive.

They all obviously work fine plugged in by themselves and although the USB drive works fine with a single port USB cable when plugged directly into the MBA, but if I plug it into the hub I have to use the dual headed USB cable. The bad news is that I can't sync my iPhone while the hard drive is plugged in, which would come in handy to sync movies or TV shows off the drive.

The good news is that I can sync my iPhone and use the EV-DO at the same time, as well as use the EV-DO while the hard drive is plugged in.

Has anyone else had success with non-powered USB hubs and have any tips to share.
 
P

prominence

macrumors regular
Jan 31, 2008
175
4
I don't know if this answers your question, but at work I have to use the ethernet adapter, and I was considering buying a 4-port USB extension, but the Apple guy told me I would get an error, and that to use the ethernet adapter or superdrive, they would have to be plugged in directly.
 
eddx

eddx

macrumors regular
May 12, 2005
231
0
Manchester, UK
non-powered usb hubs have never worked well for me

usb memory cards / pen drives work and printers, general powered devices are all good.

The usb superdrive, bus powered hard drives, ipods, iphones, wacom tablets etc all need a powered usb hub in my experience, some of my older bus powered hard drives even struggle on powered usb hubs.

I would go for a Belkin 7 port powered usb hub (after four or five different hubs this was the only one that worked will all my devices at the same time and has a relatively small power brick).
 
B

bjdraw

macrumors 6502a
Original poster
Jan 24, 2008
605
17
Tampa FL
No doubt powered hubs are the way to go at the desk, but on the go, it just doesn't make sense.

It's good to see that others are having some success. I also have the ethernet adapter, I'll have to give it a try with the non-powered hub.
 
T

twynne

macrumors 6502a
Apr 21, 2006
805
45
London, UK
izibo said:
I have this Logitech which is on sale for $15 after rebate.

http://www.amazon.com/Logitech-Premium-4-Port-USB-Hub/dp/B000RZUV9S

It's sleek, small, and works GREAT. It can charge my iPhone, run the USB ethernet adapter and run my 4gb memory stick. I'm very happy I bought a non-powered hub!
Click to expand...

Hi,

Just wondering if that Logitech hub is powered, non-powered, or power-optional. The Logitech site doesn't list it as including a power adapter, but a couple of other sites do. :confused:

Failing that has anyone else found a good hub for the Air? I'd really like one that will work non-powered, but that includes a power adapter for those occasional devices that do.

Cheers,

Tom
 
T

twynne

macrumors 6502a
Apr 21, 2006
805
45
London, UK
Just wanted to update this thread to say I picked up a Belkin F5U217 that works non-powered but includes a power adapter for those times when it's needed. I've had great success with it so far - in fact this evening I had a USB stick, 3G modem (Huawei E220), and hard drive (WD Passport 320GB) all attached and fully working *without* the external power supply.

The hub is great for travel as it's small and light and has an integrated USB cable that folds away. My intention is just to keep this permanently connected to my 3G modem as that's what usually occupies the Air's USB port.

Incidentally it was £19.95 in John Lewis, but I'm sure you can find it cheaper online. Image below for reference.

THN1001_F5U217.gif


Cheers all,

Tom
 
Sesshi

Sesshi

macrumors G3
Jun 3, 2006
8,113
1
One Nation Under Gordon
Assuming that the Superdrive is the maximum load that the Air supports, we're looking at 5V @ 1500ma output for the Air's USB port. The standard for USB is 5V @ 500ma. So the Air in theory is capable of hosting three fully powered USB sockets.

Usually, any non-powered hub you plug into a USB port divides the 500ma current capacity between the devices it's plugged into (and would also take a small amount of current for itself to work). I suppose the hubs which incorporate protection to prevent it taking too much power from the host USB port when unpowered wouldn't work well with the Air. I can't say which do and which don't. And on hubs which don't limit the power it takes, whatever power the hub draws means that the total current available across the hub's sockets probably isn't going to add up to three full USB sockets. For example, the power supply for a typical powered 4-port USB hub is rated at 2500ma - you do the maths.

Basically, if (combined peak current requirement of all connected devices including hub) =< 1500ma, it should work.

So three heavy-duty USB devices from one unpowered hub is too much. As examples, a HDD would pretty much max out 500ma. So would something like an iPod or an EVDO modem. So trying to power all of them at once would probably be a tad ambitious. Two devices should work fine though, provided you have a hub that doesn't limit the maximum cumulative current draw at 500ma - and I suspect most hubs do for protection of the connected notebook.

Even if it does work, one thing I'm not sure about though is how far Apple has factored in sustained current draw of that level (i.e. how often they expected the Superdrive to be in regular burning use). My Apple experiences lead me to be cautious and to recommend not to constantly demand the 1500ma from the USB socket. I could be wrong of course, but I suspect I'll be proven right down the line.
 
T

twynne

macrumors 6502a
Apr 21, 2006
805
45
London, UK
Well I suspect the USB stick doesn't require much power, so the 3g modem and hard drive are probably well below 1500. Occupying the 4th port would probably put it over the max. In any case I'm just glad it works for my needs, and thought it might be useful for others looking for a hub for similar types of devices (to what I'm using). Any non-powered hub may be the same, but I think this one has quite a nice design for keeping in the bag with the Air.
 
digitalfx

digitalfx

macrumors 6502a
Jul 18, 2007
715
215
You cant power a 2.5" HD + Ipod at same time on any non powered hub...very disappointing.
 
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