Over a sunny day, it can make about 1. Free solar panel power calculator to estimate energy and power output. Estimate daily, monthly, and yearly solar energy output (kWh) based on panel wattage, quantity, sunlight hours, and efficiency factors. Increasing panel count or choosing higher wattage. Example: 5kW solar system is comprised of 50 100-watt solar panels. Alright, your roof square footage is 1000 sq ft. 5% output per year, and often last 25–30 years or more. In practice, though, the vast majority of panels available now have a capacity of. Your 70W panel is like a college graduate—full of potential, but actual performance depends on life circumstance So you've got a shiny new 70W solar panel - congratulations! But wait—how much power can you actually squeeze from those 70W panels? Let's break it down like a sunbeam through fog. 6 to 2 kWh, depending on conditions.