Bluetooth Communication Not Working with DC Power But Works With USB Power? I am running a HM-10 Bluetooth Low Energy (BLE) module to transmit serial data (using SoftwareSerial) from an analog sensor onboard my Arduino Uno to a serial terminal app on my Android phone. When I power the Arduino with a USB power bank, the data transmits flawlessly. 

When I tried to power the Arduino with a 9V battery through the DC power jack instead of USB power, the BLE module connects to my phone, but no data is transmitted when a serial connection is established.

Any ideas why this would be?
Take two 9 volt batteries with same specifications and connect it into the parallel by using this efficiency of current increases and it full fill the current requirement at the time of data transmission and for others modules u r using with the arduino.