How much current does the arduino uno need? Keep in mind that none of the voltage pins will be used ( 5V nor 3.3V ), except for 3 pins for data. All other electronics will have their own power supply.
The Arduino Uno R3 quiescent current is more like the 60 to 80 mA total power LED draws Lefty mentioned. About 10 - 20 mA each for the processors (328 and 16U) about 10 mA of various bias currents and 5 to 10 mA for the regulator does add up to more than 5 to 20 mA total.Bob
20ma is a good estimate, probably towards the upper end. 5ma is about right.If you consume materially more than that, there likely is something wrong.
About 10 - 20 mA each for the processors (328 and 16U)