Owner's Guide

Charge Controlling
Conext MPPT 80 600
The Conext MPPT 80 600 charge controller regulates the PV array current at an
appropriate level for 24 or 48 V batteries. It can produce up to 80 amps of charging current
for both 2400 watts at 30 V or 4800 watts at 60 V.
Conext MPPT 100 600
The Conext MPPT 100 600 charge controller regulates the PV array current at an
appropriate level for 24 or 48 V batteries. It can produce up to 100 amps of charging
current for both 3000 watts at 30 V or 6000 watts at 60 V.
Configurations
The charge controller can be configured to use a two-stage (no float) or three- stage
charging algorithm. The charging algorithm helps to ensure that the battery is optimally
charged with the available amount of solar energy.
Three-Stage Battery Charging
The three-stage battery charging process results in more efficient charging compared to
on-off relay type or constant voltage solid-state regulators. The final float stage reduces
battery gassing, minimizes electrolyte loss, and ensures complete battery recharging.
Battery voltage and current vary during the three-stage charging process, as shown in
Figure 2 on page 24.
Bulk Stage
During the bulk stage, the charge controller operates in constant current mode, delivering
the maximum current to the batteries (the maximum current depends on the available
solar energy). Once the battery voltage reaches the absorption voltage setting, the
charge controller transitions to the absorption stage.
Absorption Stage
During the absorption stage, the charge controller operates in constant voltage mode and
the charging current falls gradually as the amp hours are returned to the battery. The
voltage limit used for the first 60 minutes of this stage is the bulk voltage setting. The
voltage limit used for the remaining time in this stage is the absorption voltage setting.
The default settings make the bulk voltage setting and the absorption voltage setting the
same for all battery types.
The default voltage limit settings (bulk and absorption) can be adjusted if the battery type
is set to Custom (see Configuring Battery Characteristics and Battery Charging on page
31). For flooded lead acid batteries only, you can use a custom charging scheme which
sets the bulk voltage higher than the absorption voltage. The result of this is a boost
voltage charge level that has been found to be beneficial for ensuring enough amp hours
are returned to the battery bank for off-grid installations. For detailed information on how
boost charging works and when it is recommended, see Using Boost Charging on page
86.
Conext MPPT 80 and Conext MPPT 100 Owner’s Guide Introduction
23 This document is for use by qualified personnel 990-6214