REV110619
SimpliPhi Power, Inc. | 3100 Camino Del Sol | Oxnard, CA 93030, USA | (805) 640-6700 | info@simpliphipower.com |
SimpliPhiPower.com
| 30 |
AccESS Sol-Ark-12K-22.8 kWh Solar PV Array Sizing
The Sol-Ark-12K
’s built-in MPPT charge controller specifications are:
•
Quantity of built-in MPPT charge controllers per Sol-Ark-8K = 2
o
Quantity of PV ports per MPPT charge controller = 2
o
Total quantity of PV ports per Sol-Ark-8K = 4
•
MPPT charge controller starting voltage = 175V
DC
•
Maximum DC Voltage input per MPPT charge controller = 500V
DC
•
MPPT charge controller voltage range = 150-425V
DC
•
Maximm I
SC
current input per MPPT charge controller = 33A
•
Maximum operating current input per MPPT charge controller = 20A
•
Maximum battery charging current per Sol-Ark-12K = 185A
•
Maximum solar PV per MPPT charge controller = 8,000 Watts
•
Maximum total connected solar PV per Sol-Ark-8K = 16,500 Watts
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.
To properly configure solar PV modules to the Sol-
Ark’s built-in charge controllers:
1.
Due to the charge controller’s starting voltage of
175V
DC
, calculate the minimum number of solar
panel modules needed to meet this target voltage
at the module’s maximum power voltage (V
MP
).
In this example, consider the Canadian Solar KuPower CS3K-300 solar PV module with a V
MP
of
32.5V
at Standard Test Conditions (STC).
•
Six
modules in series are required to meet the charge controller’s minimum MPPT
tracking voltage requirement: 175V ÷ 32.5V = 5.4 (round up to the next whole number).
2.
The charge controller’s maximum DC voltage input is
500V
DC
. Temperature affects the solar PV
module’s voltage output: voltage increases as temperature decreases. To calculate the maximum
number of solar panel modules in series per PV string, consider the module’s open circuit voltage
(V
OC
) rating, temperature coefficient and lowest expected temperature at the installation site.
In this example, the KuPower 300W module has a V
OC
of
39.3V
at STC, a STC temperature of
25°C
, and a V
OC
temperature coefficient of
-0.29%/°C
.
To calculate the solar module’s V
OC
in an extreme low temperature condition of, say, -10°C:
𝑉
𝑂𝐶−𝑀𝐴𝑋
= 𝑉
𝑂𝐶
× {1 + [(𝑇𝑒𝑚𝑝
𝐿𝑂𝑊
− 𝑇𝑒𝑚𝑝
𝑆𝑇𝐶
) × (𝑉
𝑂𝐶
𝑇𝑒𝑚𝑝𝐶𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡)]}
𝑉
𝑂𝐶−𝑀𝐴𝑋
= 39.3𝑉
𝑂𝐶
× {1 + [(−10℃ − 25℃) × (−0.29% ℃
⁄ )]}
Remember to convert the percentage value given as the V
OC
temperature coefficient to a decimal.
𝑉
𝑂𝐶−𝑀𝐴𝑋
= 39.3𝑉 × {1 + [(−10℃ − 25℃) × (−0.0029 ℃
⁄ )]}
𝑉
𝑂𝐶−𝑀𝐴𝑋
= 39.3𝑉 × {1 + [(−35℃) × (
−0.0029
℃
)]}
𝑉
𝑂𝐶−𝑀𝐴𝑋
= 39.3𝑉 × {1 + [(0.1015)]}
𝑉
𝑂𝐶−𝑀𝐴𝑋
= 39.3𝑉 × 1.1015
𝑉
𝑂𝐶−𝑀𝐴𝑋
= 𝟒𝟑. 𝟑𝑽
•
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
