On a sunny day without clouds and direct sunlight, the power range of a 400W solar panel is between 320–350W (this data is obtained under the conditions of irradiance of 800–900W/m2 and the panel surface at 50°C (122°F)). The nominal data of the solar panel is obtained by testing under the conditions of AM1.5, meteorological conditions of 1000W/m2, and panel surface temperature of 25°C (77°F). A power close to the nominal value can usually be reached at midday on a sunny day in winter.