Raspberry Pi B+ USB Power: Difference between revisions

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It seems that the Raspberry Pi B+ by default is not configured to power a 2.5 inch self powering USB hard disk.  By default it seems that the USB ports on the B+ only allow USB power for about 400mA.  A USB hard disks uses 600mA at a minimum.
The Raspberry Pi B+ and the Raspberry Pi 2 B+ by default is not configured to power a 2.5 inch self powering USB hard disk.  By default the USB ports on the B+ and 2 B+ only allow USB power for about 400mA.  A USB hard disks uses 600mA at a minimum.


To increase the USB power to 1.2 amps
To increase the USB power to 1.2 amps
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I believe this changes the gpio pin 38 value from 0 to 1 which opens a second resistor in parallel allowing for higher amperage over USB.
I believe this changes the gpio pin 38 value from 0 to 1 which opens a second resistor in parallel allowing for higher amperage over USB.
'''NOTE''': A Raspberry Pi 3 uses 1.2 amps by default on the USB ports and does not require this setting.


[[Category : Raspberry Pi]]
[[Category : Raspberry Pi]]

Latest revision as of 09:54, 20 August 2016

The Raspberry Pi B+ and the Raspberry Pi 2 B+ by default is not configured to power a 2.5 inch self powering USB hard disk. By default the USB ports on the B+ and 2 B+ only allow USB power for about 400mA. A USB hard disks uses 600mA at a minimum.

To increase the USB power to 1.2 amps

vi /boot/config.txt

add the line

max_usb_current=1

I believe this changes the gpio pin 38 value from 0 to 1 which opens a second resistor in parallel allowing for higher amperage over USB.

NOTE: A Raspberry Pi 3 uses 1.2 amps by default on the USB ports and does not require this setting.