DCIR Pulse Test

by VladM

7 parts

Direct-current internal resistance (DCIR) is measured by loading a resting cell and dividing its voltage drop by the current. Here a clock closes S1 for 1s every 5s, connecting 0.3Ω to a cell modelled as a 3.3V source (its charge does not change in this demo), R0 20mΩ, and R1 15mΩ ∥ C1 33F. Press Run: a pulse every 5s of the circuit's time (every 1.6s on screen), and the graph keeps the last 25s. Real cells: these values are of the order of a small cylindrical cell; a 100Ah prismatic cell's R0 is nearer 1mΩ.