Ok, so here's the problem: I want to build a RPi 4 machine for gaming. From what I've read, if I want to attach a 2.5" HDD via usb 3.0 to the Pi 4, it will have to be powered somehow, since the Pi won't be able to power it - at least, not reliably. Now, I'm aware there are several options for this: Y-shaped USB 3.0 cable, powered Sata to USB 3.0 adapters, powered USB hubs, etc. All of these are fine, but they require that 2 power supplies be connected at all times.

I would like to build a case for all this, with a single power supply, for convenience and portability, since I'll probably be lending it a lot to my fiancee.

How can I go about it?

I've been thinking about using a powered hub of some kind and installing it within the case, but I don't know if this is feasible: I've read there are sometimes problems with this kind of hubs, "backpowering", USB-C implementation, etc. I also know NOTHING about electricity, so I actually don't know what "5.1V / 3.0A DC output" means, for instance. In general, I'm not aware of what adapters or options I can use or not.

That's about it. Any help or insight is highly appreciated. Cheers.

2 Answers 2


I don't know where you heard that the Rpi-4 can't power a 2.5 inch USB-3 hard drive "reliably". I have one RPI-4 running a 2 TB WD Elements 2.5 inch portable hard drive, and another one with a 1 TB Toshiba Canvio drive. Both of these drives are this type:

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If you run a Rpi-4 with the recommended official power supply you have 3 amps available. The board takes around 0.6 amps, and can supply a maximum of 1.2 amps to all of the USB ports combined. These external disks take less than 1 amp. My Toshiba is listed as 0.9 amp max (when starting to spin) and around 0.5 or less when running.

You might run into problems with 2 drives, but running one of these drives is a perfectly normal thing to do. I have one Rpi-4 set up as a NAS and the other is a DLNA server and I expect them to be reliable.

Don't use some no-name "charger" type power supply. Use a robust one, preferably the official PSU.

Raspberry Pi power information

  • Are you sure about this? Does this apply only to external disks or does it apply to other types of 2.5" HDDs (specifically notebook HDDs)? Another thing: what happens when I add other peripherals like gamepads, keyboards, mouse or, even, a second HDDs? Commented Aug 21, 2019 at 17:34
  • I am sure that portable hard drives like this one and this one work fine with an Rpi-4. If you mean using a 2.5 inch notebook drive with a USB-to-SATA adapter you may have problems, not power related, which have an entire thread (and fix) on the Raspberry Pi Org forums here. As I said, you can take 1.2 amps (or 1200 milliamps) total from the USB ports. Commented Aug 21, 2019 at 17:58
  • So with a heavier load, or more devices, use a powered hub, or a hard drive or enclosure with its own power supply. Much as I like Stack Exchange, the raspberrypi.org forum is much better because it is all about the Raspberry Pi. Here it is raspberrypi.org/forums/index.php Commented Aug 21, 2019 at 18:01
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    Would the downvoter like to be brave and say what was wrong with my answer? Commented Aug 21, 2019 at 21:42

If you want to go the really cheap route, you can buy a 2-USB power adapter from Dollarama (or whatever dollar store you have that has minor consumer electronic stuff).

There is one particular dollar-store specialty (I see it around a lot) that is very compact, one USB slot is 5v 1.0 amp, and the other is 5v 2.4 amp. The 2.4 amp USB would do fine powering the rpi, and the 1 amp would do fine for the external drive.

That's pretty much how I run my pis with external devices that require a bit more juice than the pi alone can provide.

  • Thanks for taking the time. It seems like a very good solution, but I have some follow up questions, if you don't mind: (1) Are you talking about dual USB port chargers, or is an adapter another thing entirely? If different, what's the difference? (2) Doesn't the RPi 4 need 5.1V / 3.0A? (I'm assuming the "3.0A" is amps? Sorry I don't know much about electricity) Does the -0.1V / -0.6A make a difference? Commented Aug 21, 2019 at 0:04
  • Actually I said 2.4 because that's the previous rpi charger standard. I looked at mine, and it's 3A on the powerful slot as you have noticed from others, but still only 1A on the weak one. Sorry about the confusion. They look like slightly larger iphone chargers, but with 2 usb slots - one which is only 1A and the other being 3. The intent is charging the phone/tablet/?? and a keyboard at the same time. Keyboards and mice (so far) never need more than 1A. Same goes for USB drives like Passports, etc. unless they have 2 usb inputs. But I haven't seen anything like that in more than a decade. Commented Aug 21, 2019 at 3:15
  • Ok. I'll explore this option further. I found something that might actually fit the bill: Dual QC3 charger PA-T16 - Thoughts? Commented Aug 21, 2019 at 4:04
  • The one you linked to is actually 2 ports pushing 1.5A each, so that's not going to do what you are asking. Here is one that is actually specified for Raspberry pi. As a bonus, both ports are spec'd at 3A: picclick.com/…, I realize that one is microusb, but at least from this one, you can see what it is you should look for. Commented Aug 22, 2019 at 16:02

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