STRING SIZING WITH TS4-L
TS4-L has a state of the art technology designed to reduce balance of system
costs by allowing longer strings. This can reduce the number of strings by up
to 30%, which directly correlates to a 30% reduction in
combiner boxes, wiring,
fuses, and hardware overhead costs, as well as reducing the labor
requirement for installation.
40
Traditional String Design:
Max.
string
V
OC
÷
Temp
corrected
V
OC
=
# of
modules
per string
TS4-L String Design:
Max.
string
V
OC
÷
Reduced
V
OC
=
# of
modules
per string
Verify maximum string length
according to inverter parameters
Inverter MPP
Voltage Max.
÷
Module
V
MP
=
# of
modules
per string
By inverter:
By code:
Example Calculation (based on a 260W module):
Max. V
OC
for code: 600V
V
MPP
range: 190-510V
Module V
OC
: 38.2V
Module V
MP
: 30.6V
Temp. Corrected V
OC
: 38.2 * 1.25 = 47.75V
Max. string: 600V ÷ 47.75V =
12 modules
Max. V
OC
for code: 600V
Inverter V
MPP
range: 190-510V
Reduced V
OC
:
35V
Module V
MP
: 30.6V
Temp. Corrected V
OC
: 35V * 1 = 35V
Max. string: 600V ÷ 35V =
17 modules
Verify string V
MP
limits by dividing inverter max MPP voltage range by the Smart Module's V
MP
.
From the example above: 510V ÷ 30.6V =
16 modules per string by inverter
In case of discrepancy between the code requirement and the inverter voltage
requirement pick the lower number of the two. Therefore, this example results in a maximum
of 16 panels per string, a
33% increase
in string power, with a corresponding reduction in
electrical BOS costs.
