BeagleBone Black reboots periodically
I have seen similar issues with the beaglebone black. Below was my hardware and Software configuration.    


Hardware: Beaglebone Black A5C, 4D System LCD Display, USB cable, old 5V 0.8A cell phone charger re-purposed.  
Software: Angstrom with Embedded QT or Android 4.2.2 (Jelly Bean).  Ubuntu base host system


I found that the System was resetting when the system was powered using 5V USB power. The current capacity with 5V USB I believe is 500mA. The problem was common when running an Android Application. Also similar issues were occasionally observed when running Embedded QT base applications.  

Solution: Use a 5V external power supply with current capacity of 1A or 2A. In my case for small application the 5V 0.8A supply worked find. If I load the system I had to use the 5V USB power. I recommend using the 1A or 2A power supply. 

External Power Supply



Click on image for a larger version of the image.

Hope this solves your problem.



References:


Can not boot BeagleBone Black with 4D LCD touch screen using pre-built Android images
Boot android (TI-JB) on beaglebone black from SD card
4D 4.3” LCD CAPE Beagle Bone Black 4.3” LCD CAPE
BeagleBone Black Accessories