Discrepancy between nominal cell capacity and simulated capacity fade starting point

[OuadiiOuledboutaarija]

I'm encountering an issue with capacity fade simulation in PyBaMM. While my nominal cell capacity is set to 45 Ah, the capacity fade curve starts at approximately 1.8 Ah.

Additionally, I'd like to know if it's possible to plot the capacity fade against Full Equivalent Cycles (FEC) instead of cycle number.

here i'm attaching the voltage output and also the summary variables where the capacity is starting from 1.8 A.h instead of 45 A.h:

### Code:
import pandas as pd
import pybamm
import numpy as np
import matplotlib.pyplot as plt

Import drive cycle

drive_cycle = pd.read_csv(r"C:\Users\OO000009\Desktop-----.csv", comment="#", header=None).to_numpy()
drive_cycle[:, 1] = -drive_cycle[:, 1]

def create_experiment(num_cycles):
# Create drive cycle step using the current function
drive_cycle_step = pybamm.step.current(drive_cycle)

# Create cycling experiment
cycle_steps = [
    (drive_cycle_step, 
     "Rest for 0.5 hours")  # Add rest between cycles
] * num_cycles

return pybamm.Experiment(cycle_steps)

Set up model with degradation

model = pybamm.lithium_ion.DFN(
{
"cell geometry": "pouch",
"SEI": "interstitial-diffusion limited",
"SEI porosity change": "true",
"lithium plating": "partially reversible",
"calculate discharge energy": "true",
}
)

Parameter values

parameter_values = pybamm.ParameterValues("OKane2022")

Your parameter settings

parameter_values["Upper voltage cut-off [V]"] = 4.3
parameter_values["Lower voltage cut-off [V]"] = 2.5
parameter_values["Nominal cell capacity [A.h]"] = 45
parameter_values['Electrode height [m]'] = 0.104
parameter_values['Electrode width [m]'] = 0.35
parameter_values['Cell volume [m3]'] = 4.2498e-04
parameter_values['Number of electrodes connected in parallel to make a cell'] = 43

Create experiment with 2 cycles

experiment = create_experiment(num_cycles=15)

Solver settings

solver = pybamm.CasadiSolver(
mode="safe",
atol=1e-3,
rtol=1e-3
)

Create simulation

sim = pybamm.Simulation(
model,
parameter_values=parameter_values,
experiment=experiment,
solver=solver
)

try:
print("Starting simulation for 2 cycles...")
solution = sim.solve(initial_soc=0.27)
print("Simulation completed successfully!")

# Plot summary variables
pybamm.plot_summary_variables(solution)
plt.show()

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