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EN
PANELS OPERATING PRINCIPLES
GENERAL OPERATING PRINCIPLES
Photovoltaic panels are generators of current composed by cells that transform the solar energy into
electricity.
In presence of light, the panel provides its operating voltage (Vmp). This last almost does not vary (only
+/-5% in case of high temperature).
Its intensity (I) however, varies according to the light power (refer to
INSTANT PRODUCTION
section)
To charge a battery, t
he panel voltage must be higher than the battery’s, because most of solar charge
controllers on the market convert the voltage downwards.
INSTANT PRODUCTION
The peak power is given according to standardized test conditions (STC):sunshine of 1000W/m², cell
temperature of 25°C.
In actual use, panel temperature is 45°C (+/-2%), and maximal light power is 850W/m².
For example, a solar panel will have a maximum
instant production of a 80 to 90% of its peak
power in summer, and 40 to 50% in winter.
In Lille, these values would be from 60 to 70% in
summer and from 20 to 30% in winter.
DAILY PRODUCTION DISTRIBUTION
Solar production has a Gaussian
curve (bell curve).
In winter, 80% of the production
is made between 11am and 3pm,
against 50-60% in summer with
its longer daylight periods.
It
is
therefore
highly
recommended to avoid any
shadow on your solar panel
during this time slot, in order to
optimize its daily production.
Winter
Summer
Lille
(North)
200W/m²
700W/m²
Marseille
(South)
500W/m²
850W/m²
Production influence according to irradiance
Ex. 150W solar panel
Irradiance according to season
