My 3B+ boots from a Western Digital Blue SSD. The nameplate under the SSD indicates 1.6A at 5V so, I am really puzzled how it works at all off a USB port with no external power.

My WD Blue is wired in just like this stock photo:

enter image description here

The SSD is configured with Nextcloud: how will I know if the SSD should have its own power supply and not be powered by the pi's USB port?

If I can ssh into the rPi / SSD: can I conclude that it has adequate power (current)?

  • If the power supply for the Pi meets the stated requirements (i.e. what Raspberry Pi foundation recommends), then it should work - though, I've never used WD SSD's so YMMV Commented Nov 8, 2023 at 1:34
  • The Pi USB is rated at 1.2A; use at your own risk.
    – Milliways
    Commented Nov 8, 2023 at 4:21

2 Answers 2


I have a number of Pi's running with the WD Green SSD pictured and have few if any issues with them. However slightly more power hungry SSDs are marginal and for reliability use a powered hub.

  • Do you have separate power supply for the SSD? The photo is a stock photo. I am using Blue western Digital.
    – gatorback
    Commented Nov 8, 2023 at 16:28
  • I don't for the green ones but I think you will need a powered usb hub for the blue WDs as they can require more current.
    – Bra1n
    Commented Nov 8, 2023 at 17:01
  • Also the bigger the SSD capacity the more current it consumes. The current consumption varies with the operations the SSD is performing so whilst it may boot and run OK there will likely be times when higher current is required and the OS ends up crashing. i have experienced this occasional unreliability with other SSDs and a powered hub cures it every time.
    – Bra1n
    Commented Nov 8, 2023 at 17:09
  • Thank you for insight. I plan to add a separate power supply to the SSD. Q1) Are there any other power-supply symptoms other than an OS crash? Q2 Does the nameplate of your WD-Green indicate less than 1.6 Amperes at 5V?
    – gatorback
    Commented Nov 8, 2023 at 19:53
  • 1
    The only one easily accessible is a 240GB WD Green SSD which states 5v at 1 amp, however this operates through a powered hub for reliability (used to crash around once per month). My numerous128GB WD Green SSDs have proved to be reliable without additional PSUs
    – Bra1n
    Commented Nov 9, 2023 at 7:23

If you are using a USB power port for powering up your Pi, then YES, it is a issue. Use power input through GPIO, and use precisely 5,1 - 5,15V.

  • I like the idea of powering the pi and the SSD through GPIO pins. Assume the SSD works on 1.6A, how much current is needed for the pi? 2.4A seems to be more than necessary. would 3A total do the job? What is the max current (i.e. limit) that can be put through the GPIO power pins?
    – gatorback
    Commented Nov 24, 2023 at 19:20
  • 1
    As far as i know, Pi4 will pull as much as needed, but will limit the USB current IF TOO HIGH. So it does not matter how much you will put into PI. But as far as i know, i was using 5A modules to run many PIs, so i guess a 2.5-3A power supply would be OK. Commented Nov 28, 2023 at 14:20

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