Xantrex Technology XW POWER SYSTEM XW4024-120/240-60 - Manual (Page 78)

XW Solar Charge Controller Installation
4–2 975-0239-01-01
Installing the Charge Controller
This chapter describes installing the XW Solar Charge Controller with the XW Power
System, including the power distribution panel. For stand-alone installation, see the XW
Solar Charge Controller Owner’s Guide.
PV Array Requirements
Each Charge Controller must be connected to its own PV array. For optimum
performance, each individual array must be composed of the same type of solar panel,
with the same V
oc
and V
mp
specifications.
Array Size
For PV array sizing guidelines, use the XW Solar Charge Controller PV array sizing tool
accessible from www.xantrex.com/support.
Although the Solar Charge Controller can harvest a maximum of 3500 W, the PV array
size can be as large as 6720 W (based on 48 A × 140 Vdc = W).
Array Voltage
The maximum PV array voltage for XW Solar Charge Controller MPPT operation is
140 Vdc.
When calculating PV array size for the XW Solar Charge Controller, consider the
expected V
oc
of the array under all possible conditions. Panel voltage increases with
decreasing temperature. The array needs to be sized so that 150 Vdc does not occur, even
at the lowest expected panel temperature during open circuit. The panel manufacturer
provides a V
oc
rating per panel, but it is usually rated at 25 ° C (77 ° F).
Array Current
Panels rated up to 48 A at 25 ° C (77 ° F) are recommended to allow for increases in I
sc
at
low panel temperatures and at solar noon. Ensure that the I
sc
rating under all conditions
does not exceed 60 A. A factor of 1.25 is applied to the rated I
sc
at 25 °C (77 ° F) when the
panel is colder than -21 °C (70 ° F).
Important: The following information provides only general guidelines. The installation and
rated performance of your PV array is subject to inspection and approval by the authority having
jurisdiction.
CAUTION; Equipment Damage
The PV array voltage must never exceed 150 V
oc
(open circuit voltage) under
any conditions.
Important: The I
sc
(short circuit current) rating of the array must not exceed
the 60 A input current rating of the XW Solar Charge Controller at any time.