User Guide

Battery Inverter/PV Inverter Sizing
Because battery charge management through Frequency Shift is not instantaneous, the
power rating of AC coupled PV inverters must be sized taking into account the battery
charge power and the battery-based inverter ratings. Charging power is calculated as
minimum battery voltage times the recommended charging current. Regardless of the
system size, the maximum allowable rating of any AC Coupled PV inverter(s) is the lesser
of:
a. the maximum allowable charging power of the battery
b. 125% of the continuous charge power rating of the Conext XW+/SW inverters
Note:For the Conext XW+, the Max Chg Rate setting only regulates charge from the AC1
or AC2 port, but not the AC OUT port used for AC Coupling. This parameter cannot be used
to regulate or reduce the battery charge current from AC coupled PV inverters. Charge
regulation using Frequency Shift is initiated when the battery reaches the bulk voltage.
Therefore, it is critical that the battery is rated to accept charging from the full rated power of
AC coupled PV inverters during the bulk charge stage.
Always refer to the battery manufacturer for recommended charge settings to configure your
Conext XW+/SW. For specific settings of AC coupled PV inverters, refer to the PV inverter
manufacturer.
Lithium Ion (Li-ion) Battery Compatibility
NOTICE
RISK OF EQUIPMENT DAMAGE
n Always check your manufacturer's recommended applications. Not all Li-ion batteries may
be used in offgrid or backup power applications.
n Always follow PV and battery sizing guidelines.
n Ensure Li-ion batteries can accommodate the high inrush current from the initial
connection of battery-based inverters. A pre-charge circuit may be required. Conext XW+
has 26 mF capacitance and the Conext SW has 16 mF capacitance. Check with your
battery manufacturer to confirm compatibility.
Failure to follow these instructions can result in equipment damage.
NOTICE
RISK OF EQUIPMENT DAMAGE
n Check with your manufacturer to confirm the rated charge power of any Li-ion battery
packs connected in parallel. Due to possible variations in current sharing between parallel
connected battery packs, the rated charge power may not be proportionate to the number
of battery packs in parallel.
n Ensure that the rating of any AC coupled PV inverter is less than the rated charge power of
the Li-ion battery packs.
Failure to follow these instructions can result in equipment damage.
976-0240-01-01 Revision G This document is intended for use by qualified personnel 8
Conext XW+/SW Battery Inverters and PV Solutions Guide