A 60-watt solar panel can generate between 240 to 360 watt-hours of electricity in a day, depending on factors such as sunlight hours and geographic location. This translates to approximately 0. Output changes a bit based on the model of the panel and the maker. One finds around 250 watts at the bottom limit up to 450 watts at the. Estimate daily, monthly, and yearly solar energy output (kWh) based on panel wattage, quantity, sunlight hours, and efficiency factors. Losses come from inverter efficiency, wiring, temperature, and dirt. This estimate depends mainly on four key factors:. A PV Watt Calculator is a tool that estimates the amount of electricity (in kilowatt-hours, kWh) your solar power system will generate based on: System Size (kW): The total capacity of your solar panels.