USB problem.

23 20748
No need to solder a cable, a bit of electrical tape inside the USB plug will work: Pin 1, "thick" side at the bottom:


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).

Sorry for double posting.
Just found the schematic of the BPi on the net:
Appears to be valid. If i'm right, the AXP209 may be the culprit as all power going to the GPIO 3.3V and USB ports is going through this chip. However the AXP209 datasheet is not so clear about the maximum current that can be drawn through the IPSOUT that powers said power rails. If i read them right, about 2.5A is the absolute maximum as long as the maximum power dissipation for the IC is not met. Can someone please have a closer look at it? AXP209 datasheet can be found here:

This product is so awesome. I have 3 kids with phones and tablets. Both me and my husband have smartphones, Nook, bluetooth speakers, and a variety of other things that are always needing to be charged. It seemed like every plug in my house was taken over by something needing to be charged. With my 10 port USB charger I can charge 10 things using one plug!! ... ?keywords=USB+Ports

You have to log in before you can reply Login | Sign Up

Points Rules