The procedure to use different ECM parameters for Charging and Discharging in Fluent is the following: For Charging Parameters: 1) In the Battery Model panel, go to the Model Parameters tab 2) Select Data Type Table, set the correct reference capacity (the Ah of the cell used for HPPC test) 3) Click on Parameter Estimation 4) Load User’s HPPC Test Files, select the Charge files 5) Fit Parameters 6) Close Parameter Estimation panel 7) In the Battery Model panel, click on RS Table… 8) Click on Write… to save the Rs parameters for Charge to a file 9) Repeat for R1, R2, Voc, C1, C2 For Discharge parameters: 1) Click on Parameter Estimation 2) Load User’s HPPC Test Files, select the Discharge files 3) Fit Parameters 4) Close Parameter Estimation panel 5) Enable the “Use Different Coefficients for Charging and Discharging” 6) Click on Rs Table… in the Data Table for Charging frame 7) Click on Read… to load the previously saved Charging values 8) Repeat for R1, R2, Voc, C1, C2 Be sure to save the case file after the parameters are entered.