14% Efficient - that has to do with the 'rated output' power and the typical lab test input of 1000 watts per square meter.
So if the panel is putting out 140 watts per square meter, it will be considered 14% efficient.
Some panels are a little more efficient in low light cloudy conditions, because they are more square feet for a given rating at 1000 w/square meter. But in clouds, where it might be only 500 watts per square meter, the flexible solar panels will collect a little more wattage than a polycrystalline panel.
So in cloudy conditions a 150 watt flexible panel might put out say 50 watts, the poly panels rated at 14% might only put out 40 watts under a cloudy condition at 500 watts per square meter.
I measured the watts per square meter in San Diego CO in Boulavard, and also in Lakeside close to 1 pm in January. At 3,800' elevation the W/M was close to 950, while in Lakeside about 45 minutes later it was only 860 W/M. This indicates that you are much more likely to get 1000 watts per meter at a higher elevation.
Also enhancing the solar panels is cold temperatures, wind helps a lot too! I mounted my panels about 1" above my roof, so that air can circulate below the panels, and keep them as cool as possible.
When the solar panel is not connected to 12 volt battery or load, nothing happens to the power that 'might have been' generated. .
Good luck!
Fred.
