0

I want to run an external HDD on a Pi (currently a first-generation model, I might replace it with a Pi 3 in the future). The drive has no extra power supply apart from its USB port.

Just plugging the drive into the Pi will not work, as the Pi cannot supply enough power. It does work, however, if I insert a powered USB hub.

This led me to the question: can I get rid of the Pi’s power supply, and just plug the power port of the Pi into another downlink port of the hub, having the hub power both the Pi and the drive? That way, I would need just one power supply for everything.

I have tried plugging the Pi into the hub (i.e. hub downlink to Pi power), without the drive connected, and the Pi boots up and works. To complete the setup, I would then connect the hub’s uplink port into one of the Pi’s USB ports, and plug the drive into the hub. Will this work, or should I anticipate problems (other than the hub supplying insufficient power to the Pi)?

1
  • 1
    @user68186 I am aware that the MicroUSB port is power only, and would use it only to draw power from the hub. For data, I would hook up the uplink port of the hub to one of the Pi’s USB peripheral ports.
    – user149408
    Mar 4 at 23:22

1 Answer 1

1

I have taken the risk and in the meantime set up two Pis as described above:

+------------------------------+
|            USB hub           |
+--(uplink)---(port)---(port)--+
     |          |         |
     |          |         |
     |          |         |
+--(USB)----(power)--+   +----+
|         Pi         |   | HD |
+--------------------+   +----+
  • Pi 1: first generation, with a USB hub purchased recently (2022).
  • Pi 2: 3rd generation, with a USB hub purchased prior to 2011.

So far, everything seems to work, nothing got fried. Both Pis boot up and can access the hard disk. Pi 1 has been running for a couple of weeks now, Pi 2 was modified just a few minutes ago. So the Pi does not seem to have any issues with a double connection to the hub.

YMMV depending on how much power the Pi draws vs. how much power the hub can supply. However, since I got this to work with two different hubs and a 3rd-gen Pi (which are more power-hungry than the earlier ones), I would say the odds are in your favor.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.