External HDD and USB 3.0 Y-Cable

[luckyluca]

Hi,

I'd like to use an external usb3 2tb mypassport 5200rpm HDD as sole drive on my Pi400 for a large Retropie project.

I think having it running from the Pi400 alone is not enough ( I once noticed some ext4 errors on reboot, which perhaps is caused by the lack of power).

I was thinking of using a USB 3.0 Y cable cable (which I already own) to supply enough power to the external HDD:
https://www.amazon.co.uk/InLine%C2%AE-U ... B00NQHZBF8

Would it be ok to plug the power only usb-A end to a 5v 1a power adapter?

Alternatively, can I plug both USB-A ends to both the usb3 Pi400 ports instead to give the HDD more power?

Thanks

[davidcoton]

Hi,

I'd like to use an external usb3 2tb mypassport 5200rpm HDD as sole drive on my Pi400 for a large Retropie project.

I think having it running from the Pi400 alone is not enough ( I once noticed some ext4 errors on reboot, which perhaps is caused by the lack of power).

I was thinking of using a USB 3.0 Y cable cable (which I already own) to supply enough power to the external HDD:
https://www.amazon.co.uk/InLine%C2%AE-U ... B00NQHZBF8

Would it be ok to plug the power only usb-A end to a 5v 1a power adapter?

Alternatively, can I plug both USB-A ends to both the usb3 Pi400 ports instead to give the HDD more power?

Thanks

How much power/current does the HDD need? Are there any labels on it with these details?

It should be fine to use an external power supply -- although you may get problems with it back-powering the Pi.
Putting both USB-A into the Pi probably won't help, since the Pi's limit is shared between all ports, not per port.

[luckyluca]

thanks for the fast reply.

no, I couldn’t find anything online regarding power requirements.

reasons that I think the single usb3 port is not enough, is that the file system expansion failed the first run. It worked on second run. But on reboot I saw some ext4 errors in the log. I suppose caused by power?

I’m using the extra power supply now, what problem would I encounter if feeding more power into the pi400 through the usb ports?
is this a guaranteed issue with this cable?
asking because the cable going into the hdd is thicker, so I wonder of there really is a risk of it going into the pi400 instead. thanks again

08B03ED2-2C41-4EE1-BDD3-72829F1246C5.jpeg (78.61 KiB) Viewed 296 times

[davidcoton]

thanks for the fast reply.

no, I couldn’t find anything online regarding power requirements.

reasons that I think the single usb3 port is not enough, is that the file system expansion failed the first run. It worked on second run. But on reboot I saw some ext4 errors in the log. I suppose caused by power?

I’m using the extra power supply now, what problem would I encounter if feeding more power into the pi400 through the usb ports?
is this a guaranteed issue with this cable?
asking because the cable going into the hdd is thicker, so I wonder of there really is a risk of it going into the pi400 instead. thanks again

I agree, it does show the symptoms of a power shortage. Unfortunately, WD are shy about putting the power consumption in their data sheets.

The issue with extra power is that the Pi can get enough power leaking back through the USB connector to fool the PMIC, which in turn prevents the Pi from rebooting properly. To avoid that:

• The external PSU must provide enough power for the drive by itself, ⁣ and
• The USB-3 connection must be disconnected from the 5V connection from PSU to HD.

I am not sure the first is true, and I am fairly sure the second is not.

Side note: the thickness of the parts of the USB cable is because the connection from USB-2 to USB-3 is power only, while the other cable has power and a full set of USB-3 data connections.

[thagrol]

A follow up question or two:

1. What are you using to power the 400?
2. What else do you have connected to the 400? By USB and by the GPIO header.

If you're using the official PSU and have nothing other than the HDD, monitor and mouse connected, to hit power problems the HDD would need to be drawing more than 1A (allowing 100mA each for the mouse and the built in USB keyboard).

In theory, a USB 3.0 device shouldn't draw more than 900mA and a USB 2 device more than 500mA so if WD havbe stuck to those limits...

An inexpensive* USB power meter that goes betwenn host and drive may give you some indication if WD does not.

*: how inexpensive depends on which you are and hwere you buy from.

[luckyluca]

I use the original pi power adapter, and have a logitech 2.4ghz dongle for the wireless keyboard, and hdd only.

I also use bluetooth controllers, rj45, no wi-fi.

I run a usb3 ssd for two years perfectly before swapping for the larger 2tb hdd.
Just having issues with the hdd.

The y cable seem to help, no more recognisable errors. But I’m now worried if it could cause other issues to the health of the pi400 as you pointed out.

Thanks for looking.