The 12V/24V in product titles (ex. 100W 12V Monocrystalline Solar panel) does not refer to the actual voltage (Voc or Vmp) of the solar panels, but rather to the voltage of the solar system or energy storage system to which the panel is best suited.
The voltage of the solar panel must be higher than the solar system voltage.
The performance of a solar panel may be hindered for many reasons. Most commonly environmental conditions, such as indirect sunlight, temperature rise, cloudy sky, and dirt and stain build up on the top glass, which can lead to a lower efficiency.
Yes, it will. Made of high-quality materials, this Renogy solar panel still works during cloudy weather conditions. But please note that the power conversion is not as high as on sunny days.