Hello,

I got this error when I run my model,
Please, can any one help me to fix this error?     


 
 
    Equation 13 (size: 1) Ia[3] = Ia[2] + (Ir * (-1.0 + exp((Vc + 0.01711085220626408 * Ia[2]) / Vt_Ta)) + Ia[2] - Iph) / (-1.0 + (-0.01711085220626408) * Ir * exp((Vc + 0.01711085220626408 * Ia[2]) / Vt_Ta) / Vt_Ta) is not big enough to solve for enough variables.

thanks in advance for your answer