Max power in? Max power out? AC vs USB? Higher rated AC adapter?


#1

Hello there! I’ve had the 10 port usb hub for a while now and it’s been great. Now I’m looking to see how far it can go.

First off, if I know the power supply is rated at 5V and 2.5Amps. If I had a higher 5V power supply (say 3Amps), would it add more power to be distributed throughout the 10 ports (I understand the 500mA max per port)? Or would it even work? Or damage the product?

Can I use a usb male to power plug barrel cable to add/supply power from a USB port to the hub? I just got this: http://www.amazon.com/EasyAcc%C2%AE-1… , which has a max total output of 3.5A, amongst four ports, one port having a 2.1A out?

What is the max USB power in that the port can draw and distribute?

And what if I started playing around with Y cables to try and add current? Especially if it’s already acting as a data connection as well…

Thanks for the great support you guys!


#2

Also, specifically, I’m trying to use this with a Raspberry Pi + the USB power brick I mentioned above + many assorted USB devices. Power has 4 ports, one powers RPi, one (or more with Y cable?) powers the hub somehow, I don’t yet have a USB to AC barrel cable yet, may splice my own


#3

Does this hub “backpower” devices?

I believe this means, if you plug the data out of a device into the hub data in of the hub, it sends power back to the data source and can power it as well. Specifically, with the raspberry pi i hear this is dangerous. See the section on back powering here http://elinux.org/RPi_Hardware

Conversely, can the USB hub receive additional power from into one of its ports *other than* the data port/computer port (via a USB male to male cable…)?

At the moment, I’m trying the following set up:

I connect the 2.1Amp USB power port of my battery back to any usb port (other than the computer / data port) on the hub, and it lights up, which would suggest the hub can be powered from ports other than the data port. Is this safe? I’m connecting them via a USB Y cable that has three terminals: a (#1) usb mini male connected to a (#2) standard usb type A male via a thicker cable, and another (#3) usb type A male connected to that same other type A (#2) via a thinner cable. I’m connecting #3 into the power pack, and #2 into any port (other than data) on the hub (the mini male just dangles, I don’t have a male A to male A cable at the moment, surprisingly, lol).

Then I connect the RPi to the computer / data port and the light get’s a wee bit brighter. Ideally, I don’t want extra drain on the RPi, and i’d rather be just using the DC power with a USB connector cable out from another port on the hub. Note, when i plug the RPi in, it doesn’t power on (which might suggest the hub doesn’t back power?). What’s the difference of this setup? Is it safe? Is my Pi backpowered? I wish i knew more about electricity and had volt and ampere meters etc.

Sorry for all these questions, this thing just got deeper and deeper!


#4

Our product has not been tested with a higher power supply, but in theory it should be capable of delivering a maximum of 500mA per port, just not all at the same time. The question really turns into can it do that per port at the same time? To do so you would need a 5A power adapter. That’s double the stock power adapter. We have a newer version that comes with a 4A adapter, and the power circuitry is similar, most likely the answer is yes, but we don’t support it and doing so is at your own risk.

You could in theory try to push power in through one of the USB ports (back-power) and it would likely work, but that would be going against USB spec. This could damage the hub over time as additional power would not be regulated through the hubs power circuitry.

Back-powering would mean the hub powers the Pi through the Pi’s USB female USB A port with the Pi’s power cable disconnected. Is this happening for you?


#5