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?

  • "9V battery" as in little wimpy PP3 that can't power ****? – Majenko May 30 '17 at 15:11
  • @Majenko yes, correct. Is the implication of your reply that the (brand new) battery is not powerful enough? If so I could try to source a battery box to attempt to get it running on AA batteries as a test. – AggroCrag May 30 '17 at 15:38
  • PP3 batteries are the laughing stock of the battery world. You want at least 6V of AA batteries for what you are doing - and if you value your battery life you want to bypass the Arduino's on-board regulators and use switching regulators instead. – Majenko May 30 '17 at 15:39
  • @Majenko thanks! I am putting the Arduino onboard a drone and it'll only need to work for 10 mins at a time; the biggest concern is weight and not battery time. But I will give it a try. – AggroCrag May 30 '17 at 15:50
  • In that case you would be better using Li-Ion batteries since they have a higher energy density for their size/weight. – Majenko May 30 '17 at 15:51

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.


A PP3 battery is not a suitable power source for an Arduino.

For battery powered operations I would recommend a set of AA batteries with between 6 and 8 volts (if you don't care about bulk) or a Li-Ion battery (or two) and a suitable buck or boost (depending on number of cells) regulator to bypass the inefficient linear regulators on the Arduino.


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