Xantrex Technology GT 2.5-DE - Manual (Page 27)

Planning the Installation
975-0253-01-01 2–7
Guidelines for Matching PV Array Size to Xantrex Grid Tie Solar Inverter Input
For determining the number of panels required in the PV string (panels connected
in series), you must ensure that the following three requirements are met:
1. To avoid damage to the inverter, ensure that the PV array output will never
exceed 600 Vdc under any conditions.
2. Do not exceed the maximum array short circuit-current rating marked on the
inverter.
3. To achieve maximum energy harvest from your array, ensure that the V
MP
(voltage at maximum power) does not drop below 195 Vdc or increase above
550 Vdc under most conditions.
Guidelines to help you meet these requirements:
• Consider the expected V
OC
of the string under all possible conditions. The
panel manufacturer provides a V
OC
rating per panel, but it is usually rated at
25 °C (77 °F). Ensure that the V
OC
rating at the coldest ambient temperature
does not exceed 600 V
OC
. Panel voltage increases in cold temperatures—the
panel manufacturer should be able to provide a coefficient of voltage increase
per degree.
• Panel voltage decreases in high temperatures. This will affect the panels’
V
MP
. Again, the manufacturer’s coefficient must be used with the highest
expected temperature to determine the minimum V
MP
.
Once you know the specifications of your panels, all these factors will help
determine the maximum and minimum number of panels that can be used.
Visit the Support page at www.xantrex.com to use an online PV array sizing tool.
Grounding Requirements
AC Grounding
AC grounding is governed by local codes. Consult the local utility for specific
grounding requirements.
DC Grounding
The GT Inverter is designed to work with ungrounded PV arrays.
WARNING: Shock hazard
The GT Inverter must be grounded by connection to a grounded permanent wiring system.