norsac321
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Can my Raspberry Pi power a external hard drive?

Sun Feb 24, 2013 1:44 am

I was wondering if my power supply could power this external hard drive thought the USB port while the Raspberry Pi is on

Any help would be appreciated

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tonyhughes
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Re: Can my Raspberry Pi power a external hard drive?

Sun Feb 24, 2013 3:00 am

Generally not. The RPi USB power capability is average at best, and often regarded as poor.

You need to power your hard drive from an external source.

Commonly done with a decent powered USB hub, to power the Pi, and peripherals like hard drives.

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mahjongg
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Re: Can my Raspberry Pi power a external hard drive?

Sun Feb 24, 2013 3:05 am

the PI has a polyfuse rated at about 1.1A, for everything! As the PI itself can use about 400 to 500 mA (depending on what it is doing), and you want to be well below the tripping point of the polyfuse, this leaves only a few hundred milliamps for the USB port, not enough for something as power hungry as an USB hard-disk. Also most often the PSU used also cannot supply more than 700 to a 1000mA max.

norsac321
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Re: Can my Raspberry Pi power a external hard drive?

Sun Feb 24, 2013 4:23 am

mahjongg wrote:the PI has a polyfuse rated at about 1.1A, for everything! As the PI itself can use about 400 to 500 mA (depending on what it is doing), and you want to be well below the tripping point of the polyfuse, this leaves only a few hundred milliamps for the USB port, not enough for something as power hungry as an USB hard-disk. Also most often the PSU used also cannot supply more than 700 to a 1000mA max.
tonyhughes wrote:Generally not. The RPi USB power capability is average at best, and often regarded as poor.

You need to power your hard drive from an external source.

Commonly done with a decent powered USB hub, to power the Pi, and peripherals like hard drives.
Do you think this external hard drive work as it gets powered from a external source?

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mahjongg
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Re: Can my Raspberry Pi power a external hard drive?

Sun Feb 24, 2013 2:03 pm

yes an externally powered device should pose no power problems.

gelfling6
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Re: Can my Raspberry Pi power a external hard drive?

Thu Feb 28, 2013 11:50 pm

Externally powered, yes.. Directly off the Pi? Don't!! That fuse will blow!

There are some external 3.5+ drives, which are powered solely through the USB cable, I would plug them into a powered Hub, and running a cable from the Pi to the Hub's input.

Better safe, that sorry.

oliviervoutat
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Re: Can my Raspberry Pi power a external hard drive?

Wed Apr 03, 2013 8:37 am

If I use a Galaxy Tab 8.9 charger in my RaspBerry, could it work? (2A)

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tonyhughes
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Re: Can my Raspberry Pi power a external hard drive?

Wed Apr 03, 2013 9:26 am

No. You cant get more than the 1.1A polyfuse is rated for. The extra 0.9 doesnt get drawn.

mertresvag
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Re: Can my Raspberry Pi power a external hard drive?

Sun Apr 07, 2013 7:52 pm

I have a Transcend StoreJet 25M3 1 TB drive, I connected the signal cable and the power cable to one of my raspberries, and it worked. The device booted and it is stable. So my advice is to try it and see.
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