pvlib.singlediode.estimate_voc(photocurrent, saturation_current, nNsVth)[source]

Rough estimate of open circuit voltage useful for bounding searches for i of v when using singlediode().

  • photocurrent (numeric) – photo-generated current [A]

  • saturation_current (numeric) – diode reverse saturation current [A]

  • nNsVth (numeric) – product of thermal voltage Vth [V], diode ideality factor n, and number of series cells Ns


numeric – rough estimate of open circuit voltage [V]


Calculating the open circuit voltage, \(V_{oc}\), of an ideal device with infinite shunt resistance, \(R_{sh} \to \infty\), and zero series resistance, \(R_s = 0\), yields the following equation [1]. As an estimate of \(V_{oc}\) it is useful as an upper bound for the bisection method.

\[V_{oc, est}=n Ns V_{th} \log \left( \frac{I_L}{I_0} + 1 \right)\]

[1] http://www.pveducation.org/pvcdrom/open-circuit-voltage