Installation Guide

Configuring Advanced Settings
975-0638-01-01 Rev A 4–15
Battery Charger Functions
When AC power is available, the Conext SW can operate as a battery charger.
Different battery types and chemistries require different charging voltage levels.
Not charging batteries at the required levels can shorten battery life or damage
the batteries. The Conext SW is configured at the factory to work with the battery
types recommended for inverter applications. If the default settings do not work
for your specific installation, you can adjust the charge stage settings (as
recommended by the battery manufacturer) on the Custom (Battery) Settings
menu (see page 4–18).
Multi-Stage Charging Process
The charging cycle is a multi-stage process. Whenever qualified AC power is
present at the inverter’s input, it passes power through to the connected load and
begins charging the batteries.
Bulk Stage Bulk charge is the first stage in the charging process and provides the batteries
with a controlled, constant current. Once the battery voltage rises to the bulk
voltage threshold, the charger switches to the Absorption stage.
Absorption Stage Absorption charge is the second stage of battery charging and provides the
batteries with a controlled, constant voltage. During this stage, the current drawn
by the batteries slowly decreases. When this current falls below 2% of the battery
capacity, or when the configurable Absorb Time expires, the charger switches to
the Float or NoFloat stage, depending on the selected charge cycle.
IMPORTANT: This information is provided for guidance only. Variations in
battery chemistry and site-specific environmental considerations mean that you
should consult your system designer or battery manufacturer for specific
recommendations for appropriate battery voltage and current settings.
NOTE: If the AC input fails or drops below the lower VAC limit (as set in AC
Settings), the complete multi-stage charge cycle (Bulk, Absorption, Float/No
Float) restarts once the source AC returns to within tolerance condition. If the
batteries are already nearly full, the charge cycle will take little time to complete.
NOTE: If there are DC loads on the batteries, the charger’s current may never
decrease to a level to initiate the next stage of charging. In this case, the
charger would stay in absorption until the Absorb Time setting is reached.
To make sure the charger does not remain in absorption for too long, adjust
Absorb Time on the Charger Settings menu. The timer begins at the start of the
absorption stage and terminates absorption charging if the charge current does
not decrease to below 2% of the battery capacity before the Absorb Time
setting expires. The Absorb Time setting may be increased if the charge cycle
continually runs the full Absorb Time in the absence of DC loads. This is an
indication of too large a battery bank for the selected Absorb Time setting.
Also, the Absorption Time setting resets to its default value of 180 minutes when
the Battery Type is changed.
ConextSW-NA-OwnersGuide.book Page 15 Thursday, December 20, 2012 2:00 PM