Does backfeeding the pi allow me to draw more current than normal from the other free usb port?

Question

I've designed a PCB that does some I/O and powers the raspberry pi through one of the Pi's usb ports. I want to use the other free USB port for a wifi dongle.

Since I'm backfeeding power will the wifi dongle draw current directly from my board allowing the wifi dongle to draw more current than if I wasn't backfeeding--effectively turning the free usb port on the pi into the equivalent of a port on a powered usb hub.

Answer 1

Yes. The USB ports on the Pi are a direct connection to the +5V rail. How much current you can draw will depend on the device doing the backfeeding. This, of course, bypasses the polyfuse and negates the transient overvoltage protection.