Temperature Derating Calculator

Calculate power output reduction due to high cell temperatures.

Nameplate rating at 25C
Typically -0.30% to -0.45% for silicon panels
From panel datasheet (typically 42-48C)

Cell Temperature Formula

Cell Temp = Ambient + (NOCT - 20) x (Irradiance / 800)
Power Loss = Temp Coeff x (Cell Temp - 25)

Temperature Coefficient by Tech

Technology Pmax Coeff Heat Tolerance
HJT/IBC-0.26 to -0.30%Excellent
Mono PERC-0.34 to -0.38%Good
Polycrystalline-0.40 to -0.45%Moderate
Thin Film-0.20 to -0.25%Best