According to the Arduino Hardware Guide, page 18: Intel® Edison Boards — Intel® Edison Kit for Arduino* Hardware Guide, the Edison module operates at 200mA, and during Wi-Fi transmit bursts, the current could reach 600mA for milliseconds. In case of the Arduino Expansion Board, the sum of current could exceed 500mA. However, since you need the current drain under specific conditions, I recommend you to make a test to measure the current drained by the Arduino Expansion Board under such conditions. You can use an amperemeter to measure the total current drained by your board in the conditions you need.
Thanks Diego, I saw those values in the hardware guide but I also saw an idle power with radios off of ~15mW, or a little less than 5mA at 3.3 volts. In a quick test during boot, I measured from 50mA to 200 mA with short peaks above that which were probably due to the radios. That was with a lab grade DVM. I intend to do a dynamic measurement with a DC current probe and oscilloscope but wondered if Intel had done any additional characterization of the Edison since the hardware guide was published.
The active circuits of the Arduino breakout board when operating from a 3.3 volt supply instead of the external PS or USB power represents a rather low drain .. the ADC for example, only takes a couple of mA.
I'll post measurement results when I get far enough into the project.