Edited by pappajoes at Mon Apr 6, 2015 01:53 |
USB power on the BPi is quite strong and much better than on the Raspi.
However, i obviously managed to fry my BPi by overloading the USB ports. I had a 4port hub (nonpowered) connected to each port. One of them had a bluetooth dongle and a wifi adaptor (used for hostapd) connected. The second had a usb audio adapter, a multibay card reader and my Galaxy Tab 1st gen for internet access.
While this has worked many hours before i took the box to a party. Guests could use it to upload pictures from phones and cameras. to the internal 2.5 SATA hard drive. Within minutes of people connecting their phones to the box, wifi became so unstable, noone could connect anymore. in a desperate effort i tried power cycling. Turned out that GPIO aren't working properly anymore. USB power output has strong fluctuations which confuse devices. I can still use USB devices when connecting to a powered hub.
Overall load on both usb ports combined never exceeded 1.5A, that's for sure.
The damage done however is permanent. Though the unit smells burned, there's nothing to be seen on the board itself.
So let my experience be a word of warning. You should use powered hubs whenever feasible. Any help or hint how to possibly fix my BPi even if it involves changing parts or fine soldering is much appreciated.
To power the setup i used a 5.2V supply capable of 3A continuous load, with up to 4A peak.
I'd like to conclude that you should probably worry more about not overloading the ports than underpowering your BPi.
But there's a catch to uskng powered hubs: Some manufacturers decided to save a few cents by replacing the mandatory diode for preventing backpowering the host with a simple wire. In my experience this causes a lot of trouble by itself, so trying another hub may fix usb related issues. If you're unafraid of soldering and don't want to buy a new hub,, try cutting the wire or replacing with a proper schottky type diode(at least 10V 1A).