The red arrow points to the side of the “74” diode that comes right off the micro USB connector. With 5.00 volt input, downstream of the diode measured 4.72 V with the Edison idling. This voltage drop is expected due to the forward bias diode voltage drop.
Under 100% of one core CPU load measured 4.98 V on the USB side, and 4.66 V on the Edison side of this diode while powering from the USB port on the Verbatim 97928. The minuscule apparent 20mV voltage drop on the battery/USB side of the diode is likely to come from ohmic losses in the USB connector and cable.
Intel Edison alkaline battery life estimate is based on:
- Intel Edison measured power consumption
- assuming 2000 mAh for an AA battery
We estimate 10-12 hours of battery life on four AA alkaline batteries assuming continuous 100% CPU of one of the two CPU cores (other core idle). Normally the Edison will be mostly resting, drawing perhaps 100 mW.
Thus with mixed use, I might expect up to 4-5 days of continuous mixed use operation on 4xAA batteries for the Intel Edison.