Epever ET4415BND User Manual page 9

Input power (P )= Output power (P )
PV Bat
Input voltage (V ) *input current (I ) =Battery voltage (V ) *battery current (I )
Mpp PV Bat Bat
Normally, the V is always higher than V , Due to the principle of
Mpp Bat
conservation of energy, the I is always higher than I . The greater the
Bat PV
discrepancy between V &V , the greater the discrepancy between I & I .
Mpp Bat, PV Bat
The greater the discrepancy between array and battery, the bigger reduction of
the conversion efficiency of the system, thus the controller's conversion
efficiency is particularly important in the PV system.
Figure 1-2 is the maximum power point curve, the shaded area is charging
range of traditional solar charge controller (PWM Charging Mode), it can
obviously diagnose that the MPPT mode can improve the usage of the solar
energy resource. According to our test, the MPPT controller can raise 20%-30%
efficiency compared to the PWM controller. (Value may be fluctuant due to the
influence of the ambient circumstance and energy loss.)
Figure 1-2 Maximum Power Point Curve
In actual application, as shading from cloud, tree and snow, the panel may
appear Multi-MPP, but in actually there is only one real Maximum Power Point.
As the below Figure 1-3 shows:
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