Maximum Power Point (MPP)
The maximum power point (MPP) is the combination of output voltage and current at which a solar PV cell or module produces its maximum electrical power under a given set of conditions (irradiance, temperature, and load). It represents the optimal operating point on the panel's current-voltage (I-V) curve.
The power (P = V × I) of a solar panel is not constant across all voltages — it varies with operating conditions and the connected load. The MPP is where V × I is maximized; operating above or below this voltage point results in less than maximum power extraction.
Maximum Power Point Tracking (MPPT)
Maximum Power Point Tracking (MPPT) is the electronic control technology built into solar inverters and charge controllers that continuously adjusts the electrical load to keep the panel operating at its MPP as conditions change throughout the day.
As the sun's angle changes, clouds pass, and panel temperature fluctuates, the MPP shifts. MPPT algorithms (most commonly Perturb and Observe, or Incremental Conductance) continuously sample the panel's output and make small adjustments to find and maintain the new MPP.
MPPT improves energy harvest by 10–40% compared to fixed-load operation, making it standard in all modern solar inverters.
Temperature and Irradiance Effects on MPP
- Higher irradiance: Increases current (Isc) proportionally; voltage (Voc) increases slightly. MPP power increases.
- Higher temperature: Reduces voltage significantly (temperature coefficient of voltage ≈ -0.3 to -0.4%/°C); current increases slightly. Net effect: MPP power decreases with higher temperature.
This is why hot climates, despite high irradiance, may not achieve proportionally higher production — temperature losses partially offset the irradiance advantage.