Does RPi B+ have high enough power output?

Question

I have just bought a RPi B+ and found it cannot power my WD My Passport 1TB USB3 drive. The drive just clicks rather than spins up.

I'm hoping that it is something I ma doing wrong. Do all the USB ports on the B+ provide the same power?

e14 Contributor · Accepted Answer

You will need to configure the Raspberry Pi B+ to output up to 1.2A via the USB ports. It is limited to 0.6A by default.

From: https://projects.drogon.net/testing-setting-the-usb-current-limiter-on-the-raspberry-pi-b/

"Additionally, it can also limit the total current drawn by the USB peripherals. This is 600mA by default, but can be increased to 1.2A via software.

...

The first way is via a new option in /boot/config.txt. Currently you can add:

safe_mode_gpio=4

but note that this will become:

max_usb_current=1

in subsequent updates. To do that requires a reboot of your Pi, however there is a 2nd way and that’s in software – because the actual switch is controlled via the Pi’s GPIO, we can do it from the command-line after the Pi has booted:

BCM_GPIO pin number 38 is the magic control pin.

Using the wiringPi gpio command, you can do the following:

gpio -g write 38 0 gpio -g mode 38 out