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Power From USB WARNING !!

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lodger  
So having got my Bpi  set-up to replace my Rpi i unplug the Rpi which has been powered via USB since i got her,,I Plugged the Bpi in its place plugin a monitor in just to set up my wifi in her new home.....

The Bpi did not power up from the USB . so OK i thought i will plug her in to one of the Hubs spare ports and micro USB to the BPI power..

Great the moniter jumped in to life and the Bpi Started Booting......untill she started to smoke !!!!

So Now Bpi is dead..So please beware has anyone else tried power her from the USB........
How did powering her off the usb hub that ran my Rpi for over a year and is again running now, Make her unhappy and go pop !!

I will be replacing the Bpi this week i just dont want to smoke her again ...
diordna  
I powered the unit (actually two) from USB my notebook. It has been running for more than a day without trouble you describe.
There are two mini USB ports, I hope you used the correct port.

Xnyle  
He means power through a usb hub from one of the usb A ports; this way you only need one power supply for the hub and the pi

this is working fine on the rpi but not working on the bpi (in my case just nothing happened, no smoke either, but thanks for the warning)

lodger  
nothing happened with mine until i powered her up using the correct mini port..lol
She only started smoking when i had a powered usb hub and normal power supply connected at the same time..

agocs  
Same  happened to me just right now
My problem on the first place was that when I connected my USB HUB with a 2.5" HDD on it, the BPi almost immediately powered off. Tried many times. So I thought 2A from USB HUB is not enough?? My HDD has an Y cable, so I powered it with a separate USB adapter, also 2A. Small popping sound, small smoke, byebye BPi...
I don't think this should have happened with proper electricity... :-/ Ok, I'll buy a new BPi when I'll have money again, but then how to make my HDD work (which works properly on my RPi btw...)?

Reply 5# agocs

Let me get this straight...
-You had the BPi powered normally through the micro-usb connector.
-You then added a powered usb hub with an external 2A power supply(along with the above micro-usb supply)....BPi halts.
-You then add a third 2A adapter to power the usb hdd,with the hdd connected to the external usb hub(along with the two power sources listed above).... Bpi gives up the ghost....hmm.

Like the previous posters in this thread have discovered it is dangerous to use 2 power sources simultaneously.
When using an external powered usb hub we must make sure the hub does not back-power(it's usb connector connecting to the Bpi shouldn't have +5V from the external adapter).

I think the BPi should carry a leaflet or sth with this warning,else others may also wind up smoking their boards,more so because the RPi doesn't seem to have this problem(correct me if wrong) and many unsuspecting users switching from RPi to BPi would someday make this fatal mistake.
The forum should also have an appropriately titled "Sticky" regarding this issue.

As for circumventing the problem either use an external hub which is known not to backpower or modify the connector or stick a piece of insulating tape on the +5V pin of the hub's usb connector(the one connecting to the BPi).

Something like this may help to avoid "back-power" when an external usb hub is connected:
http://www.thebitbangtheory.com/ ... to-a-cheap-usb-hub/
http://pihub.blogspot.ca/2012/06 ... ly-and-powered.html

good...safest to cut off the 5V line.

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