MPPT (Maximum Power Point Tracking) is a technique used to extract the maximum possible electrical power from solar panels under changing operating conditions. A solar panel’s output changes continuously with sunlight intensity, panel temperature, shading, panel orientation, and connected electrical load. An MPPT controller works by continuously adjusting the voltage and current drawn from a solar panel so that the panel produces its maximum available power. It uses active electronic tracking by keeping a close eye on the solar array's output. The controller determines the precise voltage and current combination that generates the most wattage (also known as the "maximum power point"), and translates that information into the ideal voltage and current for battery charging. 

Solar Panel Power = Voltage (V) x Current (I)

Common MPPT techniques:

• Perturb and observe: Slightly changes the operating voltage and checks whether power increases or decreases.
• Incremental conductance: Uses changes in voltage and current to determine the direction of the maximum-power point.
• Constant voltage: Maintains panel voltage near a predefined percentage of its open-circuit voltage.
• Advanced digital tracking: Uses adaptive control, fuzzy logic or predictive algorithms for rapidly changing conditions.

MPPT enhances solar-energy harvesting by boosting the usable output from the solar array, compensating for changing sunlight and temperature, improving battery-charging efficiency, allowing the solar-array voltage to differ from the battery or system-bus voltage, and maximizing the energy available to terrestrial and spacecraft electrical systems.

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