I've encountered the following problem: when I connect 1 external usb hdd to my Pi, everything works fine. But when I connect second one with the same characteristics, both drives are not usable. I believe the problem is with drives' power consumption: each hard drive draws 1A from the USB port and as far as I understand raspberry pi3+ provides 1.2A to all the four usb-ports and this is maximum current available.

Is there a way to solve this problem (my current sata-USB cases DOES NOT have an external power supply, but if they had, would this help)? Ideally I'd like to connect four drives, but even two would be cool.

  • My answer to the following question might help: raspberrypi.stackexchange.com/questions/103784/…
    – tlfong01
    Jan 4, 2020 at 13:43
  • 4
    Use an external powered hub.
    – goldilocks
    Jan 4, 2020 at 16:43
  • yeap. usb-hub with external power supply does the trick, thanks. (I thougth those things were cheap but they are actually not. ~30 bucks for one)
    – Ivan
    Jan 5, 2020 at 12:14
  • Please make an answer for the solution and accept it after two days. Only this will finish the question and it will not pop up again and again for years.
    – Ingo
    Jan 6, 2020 at 8:14

1 Answer 1


I have solved the problem by connecting all the USB HDDs through the usb-hub with external power supply.

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