Power second hard drive via GPIO on Pi 3
Would it be possible to power a second hard drive via the GPIO 5V pin? I would connect the 5V of the HDD only to the 5V of the GPIO. If I try to power both from USB they will not spin up.
Re: Power second hard drive via GPIO on Pi 3
If your PSU can't provide enough power to the USB ports it's not going to provide enough through the GPIO. Your best bet to get both working is by using a powered USB hub.
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davidcoton
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Re: Power second hard drive via GPIO on Pi 3
How much power does each drive need? How much can your PSU provide?
No definitive answer is possible within the above data, but my (semi-informed) guess is no, you will still be overloading the Pi's polyfuse and possibly the microUSB power socket. Even if these are OK, the USB cable will be passing so much current that even a normally good cable will drop too much voltage. I would recommend a separate PSU for one of the HDDs. A powered USB hub for both HDDs is also a possibility.
No definitive answer is possible within the above data, but my (semi-informed) guess is no, you will still be overloading the Pi's polyfuse and possibly the microUSB power socket. Even if these are OK, the USB cable will be passing so much current that even a normally good cable will drop too much voltage. I would recommend a separate PSU for one of the HDDs. A powered USB hub for both HDDs is also a possibility.
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Re: Power second hard drive via GPIO on Pi 3
The PSU can handle the current without problems. Using the 5V GPIO header would bypass the USB polyfuse. The Pi's polyfuse is rated 2.5A and should be able to handle two HDDs and the Pi, should it not?
Re: Power second hard drive via GPIO on Pi 3
To quote David...wackazong wrote:The Pi's polyfuse is rated 2.5A and should be able to handle two HDDs and the Pi, should it not?
davidcoton wrote:How much power does each drive need?
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davidcoton
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Re: Power second hard drive via GPIO on Pi 3
Using the 5V pin of the GPIO header to power an HDD does NOT bypass the polyfuse. If you use the GPIO header to power the Pi, that does bypass it.wackazong wrote:The PSU can handle the current without problems. Using the 5V GPIO header would bypass the USB polyfuse. The Pi's polyfuse is rated 2.5A and should be able to handle two HDDs and the Pi, should it not?
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Re: Power second hard drive via GPIO on Pi 3
Based on unscientific testing the 2.5" drive I have (1TB Pi drive) takes greater than 0.6A to spin up (won't work on the Pi2 unless the high usb power setting is put in). From My own and others experience the Pi3 can use 1.3A when running (particularly when running the cores at their full speed).wackazong wrote:The PSU can handle the current without problems. Using the 5V GPIO header would bypass the USB polyfuse. The Pi's polyfuse is rated 2.5A and should be able to handle two HDDs and the Pi, should it not?
0.6 + 0.6 + 1.3 = 2.5A and from my unscientific testing that's not enough.