Create base powers off when launching turtlebot_bringup minimal.launch, how is this fixed?

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 In my lab we're using a create base turtlebot, and each time we try to run turtlebot_bringup minimal.launch the create base simply powers off.  Upon further inspection we discovered that it turns off after the handshake of the serial port communication. Is this a known bug? Does anyone have any idea how to fix this? We have two turtlebots with create bases and they both have the same problem. 

 We are able to run the turtlebots and leave them on for long periods of time, so the batteries are fine. It's only when we run the minimal.launch that they then power off. Any help is appreciated!