Uniteck UNIMPPT 60/15.24 Manual Del Usuario página 24

EN
ADVANTAGES OF MPPT VS PWM TECHNOLOGY (CONTINUED)
GAINS OF A MPPT OVER PWM
The voltage of a photovoltaic solar panel varies according to its temperature: its voltage decreases as the
temperature increases and vice versa. This normative value, called the temperature coefficient, is given
with a cell temperature of 25°C.
Example: with a panel that displays +/-0.34%/°C, we must correct the Vmp voltage by -0.34% per cell
degree above 25°C.
As shown in the example below, which highlights voltage variations due to temperature and voltage drops
due to the cable, a UNIMPPT charge regulator allows an APG (Average Production Gain) of 20% in
summer and up to 40% in winter.
In addition, it is noted that the more the battery is discharged and/or the panel voltage is high, the greater
the advantage of an MPPT over a PWM is.
Solar radiation
during the winter

Sunrise 9h
12h
End of charge 16h
Solar radiation
During the summer

Levé du jour 7h
10h
Fin de charge 14h
* Example MPPT efficiency 95%
24/59
100 W solar panel with a UNIMPPT regulator
Solar Panel
panel Voltage
temperature Vmp
5°C 20,0
19,9
19,8
19,7
19,6
15°C 19,5
Solar Panel
panel Voltage
temperature Vmp
30°C 18,4
17,2
17,2
16,6
16,3
70°C 16,0
-Voltage Voltage
drop due to battery
the cables charge
(5%)
19,0 12,2
18,9 12,5
18,8 13,0
18,7 13,5
18,6 14,0
18,5 14,6
-Voltage Voltage
drop due ti battery
the cables charge
(5%)
17,5 12,2
16,3 12,5
16,3 13,0
15,8 13,5
15,5 14,0
15,2 14,6
www.uniteck.fr
Theorical Theorical
Gain in gain in
value %
6,8 56%
6,4 51%
5,8 45%
5,2 39%
4,6 33%
3,9 27%
GPM Moyen
Theorical Theorical
Gain in gain in
value %
5,3 43%
3,8 31%
3,3 26%
2,3 17%
1,5 11%
0,6 4%
GPM Moyen
Gain
rectified
MPPT *
53%
49%
42%
37%
31%
26%
+ 40%
Gain
rectified
MPPT *
41%
29%
24%
16%
10%
4%
+ 20%