Raspberry Pi Forums

I need a powered hub to connect devices to the Pi.

I also need a hub that does not attempt to be bus powered if the power to the hub is lost, since that will cause the Pi to switch of due to lack of power.

Can anyone suggest a suitable hub please?

Regards,
Stephen

http://shop.pimoroni.com/products/pihub

http://www.belkin.com/uk/p/P-F5U234/


http://elinux.org/RPi_Powered_USB_Hubs

fruitoftheloom wrote:http://shop.pimoroni.com/products/pihub

Will run from bus-power in the absence of a power brick

Not what I want.

http://www.belkin.com/uk/p/P-F5U234/

May do the trick, does anyone have one of these they can do a test with to see what happens when the power to the hub is removed?

http://elinux.org/RPi_Powered_USB_Hubs

This is a good list, but it doesn't answer the question I have directly.

I'm trying to avoid a trial and error loop purchasing and then testing USB hubs.

This one looks like it will do the trick though:
http://thepihut.com/products/7-port-usb ... spberry-pi

Steve

SteveMilner wrote:

fruitoftheloom wrote:http://shop.pimoroni.com/products/pihub

Will run from bus-power in the absence of a power brick

Not what I want.

yes it is
you run that and power the RPI from it - it will not back power your RPi and will provide all the umph you need - get a decent PSU with it

RaTTuS wrote:

SteveMilner wrote:

fruitoftheloom wrote:http://shop.pimoroni.com/products/pihub

Will run from bus-power in the absence of a power brick

Not what I want.

yes it is
you run that and power the RPI from it - it will not back power your RPi and will provide all the umph you need - get a decent PSU with it

Sadly it isn't.

Firstly I do not want to supply power to the Pi from the hub. I have an adequate power supply solution for the Pi.

If the hub looses power it will switch to bus powered mode. At that point the Pi can't supply enough current to the hub and peripherals, so it will freeze/shut down.

I have an in car application and the Pi is using a battery backup board (UPiS). When the ignition is switched off the UPiS board signals the Pi so that it can shutdown cleanly.

I can't battery back up the Hub so when the ignition switches off the hub you suggest will switch to Bus Powered mode and the current drawn will shut down the Pi instantly risking file system corruption.

I need a hub that will only work with external power.

Steve

Cut the red wire in the cable between your RPi and the hub.

DougieLawson wrote:Cut the red wire in the cable between your RPi and the hub.

I tried that with my existing hub. It seemed like the obvious answer.

I could have buggered the cable up of course, but once I did that the Hub & the Pi weren't talking at all.

Regards,
Stephen

Cut the red lead from the Hub to the RPi then it cannot back / bus power - this works for all hubs
but it may be cleaner to have the hub in the circuit behind the ignition switch, as you will not be wanting a PSU for th hub,
what have you got plugged into the hub to need more power anyway ?

It's a media server solution.

A hard drive is the main current source.

It also needs to be transportable since I need it move into other cars or my caravan.

I don't really want the hub constantly fed with power from the car thought. It will probably flatten the car battery within a few days.

Just had confirmation from the PiHut that this:
http://thepihut.com/products/7-port-usb ... spberry-pi

Is exactly what I need.

Happy days.

Steve

SteveMilner wrote: Just had confirmation from the PiHut that this:
http://thepihut.com/products/7-port-usb ... spberry-pi

Is exactly what I need.

Happy Days

Sadly the days were not so happy when I tested this on Saturday.

I pulled the power out of the hub and the Pi then attempted to provide power to the hub & peripherals. This was too much for the Pi and it switched off

However, this time cutting the red wire between the Pi & the hub solved the problem (It didn't work with my old hub though)

Steve

RaTTuS wrote:Cut the red lead from the Hub to the RPi then it cannot back / bus power - this works for all hubs
but it may be cleaner to have the hub in the circuit behind the ignition switch, as you will not be wanting a PSU for th hub,
what have you got plugged into the hub to need more power anyway ?

Actually my first hub I tested this resulted in the PI not recognising any USB devices at all were attached. The hub seemed to need the +ve supply from the Pi to work - even though it was externally powered.