REV110619
SimpliPhi Power, Inc. | 3100 Camino Del Sol | Oxnard, CA 93030, USA | (805) 640-6700 | info@simpliphipower.com |
SimpliPhiPower.com
| 29 |
•
Eleven
modules is the maximum allowable number of modules in series to prevent the
solar PV string from exceeding the charge controller’s maximum voltage input rating even
in the coldest weather conditions at the installation site: 500V ÷ 43.3V = 11.6 (round
down to the next whole number).
o
Eleven modules in series at the KuPower 30
0W module’s V
MP
rating of 32.5V at
STC also equates to 357.5
V, well within the charge controller’s 150-425V
DC
maximum power point tracking range.
3.
The charge controller’s maximum short circuit current (I
SC
) input rating is
20A
DC
. Temperature
also slightly affects the solar PV module
’s current output: current increases as temperature
increases. However, because the temperature coefficient is negligible, it is acceptable to simply
use the module’s I
SC
rating at STC for the following calculation.
To calculate the maximum number of solar PV strings per charge controller in this example,
consider the KuPower 300W
module’s I
SC
at STC:
9.82A
.
•
Two
solar PV strings is the maximum allowable number of strings per charge controller:
20A ÷ 9.82A = 2.04 (round down to the next whole number).
o
T
wo solar PV strings in parallel at the KuPower 300W module’s I
MP
rating of
9.24A also equates to
18.48A
at STC. This is slightly greater than the charge
controller’s operating current input limit of 18A. However, the charge controller is
capable of limiting its input current; no damage to the equipment will occur.
Based on calculations #2 and #3 above, a maximum two parallel strings of eleven KuPower 300W
modules in series can be wired to each of the Sol-Ark-
8K’s two charge controllers.
4. The charge controller can be paired with a maximum 6,000 Watts of solar PV Wattage.
In this example, the KuPower 300W module has a Maximum Power (P
MAX
) rating of
300W
at
STC.
•
20
modules is the maximum allowable number of modules that can be paired per charge
controller: 6,000W ÷ 300W = 20 (round down to the next whole number when the
calculation results in a fraction).
5. The Sol-Ark-8K (with two built-in charge controllers) can be paired with a maximum 11,000 Watts
of solar PV Wattage.
In this example, the KuPower 300W module has a Maximum Power (P
MAX
) rating of
300W
at
STC.
•
36
modules is the maximum allowable number of modules that can be paired per Sol-
Ark-8K: 11,000W ÷ 300W = 36.7 (round down to the next whole number).
Although calculations #2 and #3 above dictate that a maximum two parallel strings of eleven KuPower
300W modules can be wired to each of the Sol-Ark-
8K’s two charge controllers, the maximum power
ratings outlined in calculations #4 and #5 above suggest further module reduction.
Two parallel strings of nine
KuPower 300W modules in series per charge controller would reduce the
total number of connected solar PV modules to match the Sol-Ark-
8K’s overall maximum limit (36, as
found in consideration #5).
Again, wiring two parallel strings of eleven KuPower 300W modules in series to the Sol-Ark-8K will not
damage it, but while the panels are producing their fully rated power, much of that solar PV power will not
be utilized.
CAUTION
:
It is critical that the solar PV string’s voltage does not exceed 500V
OC
; voltage greater
than 550V
DC
will damage the Sol-Ark equipment.
