In this previous discussion on minimizing power consumption on the NRF51-Dongle, it says:
You are using evaluation kit or development kit and LEDs are connected on your board. Solution: Disconnect the LEDs or disable them in software. When using nRF51-DK or nRF51-Dongle, LEDs are not included in the current measurement.
However I don't see documentation anywhere on how to disable the 'system status' LED LD2 when it comes time to get serious about power measurement. Can you point me in the right direction?