1

I just got a WD MyPassport external drive, that is solely powered via USB (there are no other plugs).

I have seen in various places that a powered USB port is suggested for the RPi, but I can't quite tell if that is referring to powering the Pi itself, or if you buy a powered USB strip, and plug that in to the Pi and then plug the External Drive to the power strip. And then leave the Pi itself powered by MicroUSB to the wall plug.

If I do need a powered USB, what specification do I need to look for? There are tons online, but only via amazon comments can I check if the RPi works with these -- and again there, I think people are referring to powering the Pi itself from the strip - not peripherals like HDD/Keyboard/etc. Would this work, or this Amazon one?

From what I understand, I don't need it to Backpower since I'm using the designed MicroUSB port to power the pi. Yes?

Thanks for any clarification on this!

Seamus
  • 23,558
  • 5
  • 42
  • 83
BruceWayne
  • 197
  • 1
  • 1
  • 10

1 Answers1

3

I have a RPi 3B+ (among others), and I have used them successfully for long periods of time with WDPassport drives plugged directly into a RPi USB port (i.e. not in a powered hub). However, the WDPassport units I use are compatible with USB 2.0 only, and not USB 3.0.

Your question contains a link to a WDPassport device that is compatible with USB 3.0 and USB 2.0. To my thinking, there's nothing to be gained by using a USB 3.0 device with a Raspberry Pi because the USB ports on RPi are USB 2.0. Further, this article suggests that USB 3.0 may use more power, but of course it doesn't have to do so. Also, it's not clear what it means for the device's power requirements when that device is declared to be compatible with both USB 2.0 and 3.0.

I've tried to find power specs for the WDPassport several times over the years, but I've been unable to find any specifications published by the manufacturer. Consequently, I'm unclear as to whether or not your chosen model of WDPassport will need a powered hub to operate properly with the RPi.

Due to this uncertainty, my answer is this:

Use USB 2.0 only devices with the RPi whenever possible

If that's not possible, and you can't be certain you won't exceed RPi's power capacity (600 mA), then a powered USB hub is the safe bet. Note that it is possible to up that limit to 1.2 A, but your mains-connected supply must be capable.

Seamus
  • 23,558
  • 5
  • 42
  • 83