AC Coupling Guide

Figure 4AC-coupled system with external contactor
Sizing
The XW Pro can be connected in various configurations from just a single unit to multiple
units in parallel, or in a three-phase configuration. Regardless of the system configuration
however, the maximum continuous allowable rating of AC-coupled PV inverter(s) is the
lesser of:
n 125% of maximum allowable charge power of the battery (calculated as rated
continuous charge current times rated charge voltage).
n 125% of continuous rating of XW Pro inverter(s).
For example, if battery inverter is rated for 6.8 kW of continuous power at 40°C and
battery pack is rated for 3.75 kW at 40°C, then the PV inverter must be no more than
125% of lesser of two which is 4.68 kW at 40°C.
In three phase configurations utilizing XW Pro battery inverters, it is recommended to use
three-phase PV inverters, such as the Schneider Electric CL series, in order to provide
balanced power on the three phases.
AC Coupling with a Generator
NOTICE
RISK OF DAMAGE TO THE GENERATOR OR PV INVERTER
In an AC-coupled system, never connect a generator to the AC2 (GEN) port of XW Pro
without an interlocked contactor to prevent parallel operation of the generator and PV
inverters. XW Pro will not be able to regulate power being pushed by PV inverters into the
AC2 (GEN) port and may backfeed AC power into the generator.
Failure to follow these instructions can result in equipment damage.
While running a generator in an AC-coupled system, the generator provides AC power to
XW Pro and PV inverters. The PV inverter detects this (it recognizes the generator as
Planning and Installation XW Pro AC Coupling Solutions Guide
990-6421 This manual is intended for use by qualified personnel 13