I want to power a Pi model B from a powered USB hub.
I got surprised that the Pi powers on with only the USB attached. A little search in the forums confirmed me that it is a working solution.
I measured the voltage between TP1 and TP2 and it says 4.25 V. (my experience says it's quite low making the Pi unstable)
If I also connect the microUSB to the hub the voltage jumps to 4.90 V.
Is it safe, from an electronic point of view, to have the Pi powered from two sources?? Can this damage the hardware in some way?
The hub is a Belkin F5U701 with a power adapter that outputs 5V with 2.5A.