Solar panels receive their ratings under specific testing conditions known as "Standard Testing Conditions" or "STCs". These conditions serve as the industry standard for evaluating solar panels, making it easier to compare panels accurately. Solar panels come with two Current (or Amperage) ratings that are measured in Amps: 1. The Maximum Power Current, or Imp for short. 2. And the. Solar panels are classified by their nominal voltages (e.g., 12 Volts or 24 Volts), but these voltages are only used as a reference for designing. The Wattage rating of a solar panel is the most fundamental rating, representing the maximum power output of the solar panel under ideal conditions. You'll often see it referred to as “Rated Power”, “Maximum Power”, or “Pmax”, and it's measured in watts or kilowatts peak.
