Gert
Posts: 142
Joined: Wed Oct 24, 2012 10:19 pm

RPI 4 able to drive USB 3 laptop drive?

Wed Sep 11, 2019 6:41 pm

Hello All,

Seagate came out with 5T external laptop-size drive which would be nice to make a hobby-NAS. I've done this with a RPI3 and 1T drive but that required an extra powered USB hub.

Would the RPI 4 be able to power such a 5T drive on USB 3 without extra clutter of a hub?

Thanks
Gert

drgeoff
Posts: 9728
Joined: Wed Jan 25, 2012 6:39 pm

Re: RPI 4 able to drive USB 3 laptop drive?

Wed Sep 11, 2019 10:26 pm

AIUI a USB3 host port should be be able to supply at least 0.9A. Does the Seagate drive claim to be OK with a standard USB3 host?

A RPi4B connected to a genuine 3A PSU has up to 1.2A total available for devices taking power from its USB ports and/or GPIO header.

Gert
Posts: 142
Joined: Wed Oct 24, 2012 10:19 pm

Re: RPI 4 able to drive USB 3 laptop drive?

Thu Sep 12, 2019 1:43 am

That's my point.
drgeoff wrote:
Wed Sep 11, 2019 10:26 pm
AIUI a USB3 host port should be be able to supply at least 0.9A. Does the Seagate drive claim to be OK with a standard USB3 host?
Does the RPI adhere to the spec and funnel the proper 0.9A to the USB3 port? Anybody know?

Cheers,
Gert

User avatar
rpdom
Posts: 14976
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: RPI 4 able to drive USB 3 laptop drive?

Thu Sep 12, 2019 2:28 am

Gert wrote:
Thu Sep 12, 2019 1:43 am
Does the RPI adhere to the spec and funnel the proper 0.9A to the USB3 port?
Unless things have changed on the Pi4, all the power pins for the USB ports are connected together. That means you can take the full 1.2A from a single port.

Gert
Posts: 142
Joined: Wed Oct 24, 2012 10:19 pm

Re: RPI 4 able to drive USB 3 laptop drive?

Thu Sep 12, 2019 4:17 am

Sounds good, I will try.
Steady-state operation is surely OK. Power-up current spike might be an issue.
My remote hope is to have 2 USB3 laptop drives on the RPI4. Would be so coll if power-up could be staggered.
Cheers,
Gert

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