I was just perusing this thread and noticed ' R = I / E, so if the battery has a capacity of 2.1 Amps (a 2100 mAh battery), 2.1 / 3.6 = 0.5833 Ohms'. Ohms law is E=I * R, so R=E / I. Also, 50% battery capacity (the link suggests 25%) is 1.05 amps. If you want to measure the voltage at 50% then R...