Full discharge test procedure
    - Connect power supply to Rpi
    - Use pijuice setup GUI to enter custom battery profile, for Li-po battery set cutoff
      voltage to somewhat below nominal for li-po 2850 is good value.
    - Charge battery to full level
    - Edit pijuice-soc-test.py script and enter c0 - nominal battery capacity value and
      Rload - resistor value attached to Vsys pin.
    - Run test with: python pijuice-soc-test.py
    - Wait until test completes, it can take hours
    - Test results are logged on screen and in log file: battery_soc_test.txt (before test
      rename or delete log file from previous test, otherwise log  will be appended)
    
Battery parameters derived from full discharge test can be written to pijuice with
pijuice_calib.py script to calibrte state of charge evaluation.
