Hi there,
I need to measure the internal impedance of some Lead Acid and LiFePO4 batteries as a measure of their State of Health. Does anyone have any specifics of using the ‘Two Tier’ method where you use two different current levels for two different periods of time as in the graphic? Also what resistor and rating are required to do this? I have also added a proposed circuit to do the measurement so any advice on it would be appreciated including if I need to do some calculations with the resistors in parallel.
Thank you

