Solver and step size warning

I am not sure why I get these warnings when I am trying to run the model. I am having difficulty understanding the warnings and do not know how to fix them.

I have attached the model. These are the errors I get

Warning: The model name 'untitled' is shadowing another name in the MATLAB workspace or path. Type "which -all untitled" at the command line to find the other uses of this name. You should change the name of the model to avoid problems.

Warning: The solver chosen is not recommended if the model is stiff, which is typical for models containing Simscape components. These solvers are typically preferred for Simscape models: ode23t, ode15s or ode14x (fixed-step). To disable this diagnostic, change the explicit solver diagnostic setting on the Simscape panel of the model Configuration Parameters.

Warning: Using a default value of 0.2 for maximum step size. The simulation step size will be equal to or less than this value. You can disable this diagnostic by setting 'Automatic solver parameter selection' diagnostic to 'none' in the Diagnostics page of the configuration parameters dialog

[Md.]

Also, for 72 solar cells in series with each Voc = 0.6V, I am expecting a total of 43.2V as output whereas I only get 14.25V. What is going on?

Answer 1

[Azzi Abdelmalek]

Change the name of your simulink model, because there is another type of file, probably an m-file, named untitled.m