Powering Rasberry Pi3 + 2.5" USB3 HDD with the same PSU?

[XC-3730C]

I want to put a Raspberry Pi3 PCB and a 2.5" USB 3.0 Hard Drive in a game system shell (either a PlayStation 1 or PS2) together as a file server, but I would like to power them both with the same power supply. What are my options?

[MaxK1]

You will need a power supply that can deliver it's full rated current at 5V. (IMHO "wall warts" and phone chargers just aren't good enough). So,
what you need to do is estimate the max current both the pi and HDD can draw and look for supply that can deliver that much or more. Use short, fat cables from the PSU. What you don't want is a power supply that "browns out" and drops below 4.75V - Some USB devices get a bit wonky and reset when that happens. Personally, I wouldn't be comfortable with less than a 3A supply.

[pcmanbob]

My pi3B and USB2 2.5" HD work perfectly well using the official raspberry pi 2.5A PSU with a keyboard and mouse also attached, I see no reason your USB3 HD should not work with the same PSU

https://thepihut.com/products/official- ... aspberrypi

[HawaiianPi]

I want to put a Raspberry Pi3 PCB and a 2.5" USB 3.0 Hard Drive in a game system shell (either a PlayStation 1 or PS2) together as a file server, but I would like to power them both with the same power supply. What are my options?

A Raspberry Pi3B can supply up to 1.2A from its USB ports (total), so it should be able to power just about any portable USB hard drive as long as your other USB devices aren't too power hungry. I have used a variety portable USB hard drives on my Pi3 and they've all worked. I've even managed to successfully spin up and mount TWO portable hard drives, but I could only access one at a time (trying to access both at once would result in one of them disconnecting).

Note that the Pi3B USB ports are only USB 2.0, so you will not get full performance out of the USB 3.0 HDD, and also, USB 3.0 ports can supply up to 900mA, so USB 3.0 hard drives can be more power hungry than USB 2.0 drives (which are designed to run on only 500mA). As long as everything you have connected to the Pi3 USB ports does not exceed 1.2A (1200mA) it should work.

... Personally, I wouldn't be comfortable with less than a 3A supply.

Depends on whether or not you are powering the HDD from the Pi USB ports, or independently.

You can't pull more than 2.6A total through a Pi3, or more than 1.2A total from all the USB ports combined, so a 2.5A supply is about the max you can realistically use as a PSU powering the Pi and its USB peripherals. A higher current PSU will work, but it won't give you any more power you can actually use. Now if the PSU is powering the HDD separately from the Pi3, then the extra current might be useful.

[MaxK1]

OP was asking about powering both - he didn't say if he was expecting the pi to supply power to the drive....

[HawaiianPi]

OP was asking about powering both - he didn't say if he was expecting the pi to supply power to the drive....

He didn't say he was powering the drive separately either, and powering a portable HDD from the USB port of the computer it's connected to is the normal/typical configuration.

[MaxK1]

Whatever... It probably isn't normal to power a USB 3 device through the pi.

[N00biPi]

Would this ( https://www.modmypi.com/blog/boost-usb-current ) work to allow the usb3 drive to work on the single Pi power supply?
I'm actually in a similar situation where I want to run (on a pi2 modelB) in a car where there is only a single 12V outlet, and I have a 2.0A usb adapter. If I can get away with not using a powered hub, or inverter, it would be ideal.

[pcmanbob]

I can tell you now you will not run a pi3B and a USB HD off of 2A USB adapter.

I tried running my pi3B and a USB2 HD off of 2A power supply had the low volt warning flash constantly, would only work with 2.5A official power supply so I would suggest you will need a good quality 12v to 5v buck converter able to handle 2.5A but you might be better with one that can handle 3A.