Hello,
According to mobile center system requirements published by HPE (I have entered the link below), every mobile device connected to Mobile Center requires 900mA - 1.5A per port, depending on the device. To optimize power consumption and provide better utilization of USB ports, we recommend using a USB hub with an independent power supply that can sustain power consumption.
HPE recommends using a plugable USB 2.0, 7 Port High speed port hub with charging 60W power adapter and BC 1.2 charging.
http://mobilecenterhelp.saas.hpe.com/docs/en/1.51/mobilecenter_help/Content/Before_starting_installation.htm#Connector
I hope this answers your question.