Bypass diode inside the junction box

AN3432

10/24

Doc ID 019041 Rev 1

Equation 8

Figure 7.

Maximum numbers of solar cells to bridge with bypass diode

diode is 24. This is the common setting used by module manufacturers.

2.3.2

ambient temperature with the maximum irradiance.

Equation 9

where dt% = average voltage dispersion, which depends on the panel manufacturer.

Most of the time, the junction box manufacturer is different from the solar panel

manufacturer. Then the junction box is not dedicated to one panel, but it could be used with

any solar panel power range up to 400 W.

(see Section 1.3.2). If the deviation tolerance dt% is 20% (average dispersion estimate

given in the literature) and 3 bypass diodes are used in the junction box, the reverse voltage

of each bypass diode is 43 V, then V = 45 V is selected.

junction boxes.

1

5

.

0

V

V

n

5

.

0

)

1

n

(

V

V

V

5

.

0

V

V

V

With

V

)

1

n

(

V

V

F

c

max

max

c

F

u

_

oc

c

s

u

_

oc

s

bypass

+

−

<

•

−

−

<

≈

<

•

−

−

=

V

V

F

Vbypass =VF

0.5V

0.5V

Vs

0.5V

Vocmax = Voc(Tjmin) · (1 + dt%)

VRRM >

Vocmax

nd