Windy Nation Xantrex C Series Multifunction DC Controller - Manual (Page 25)

Operating Modes
975-0004-01-02 Rev D 5
Bulk Stage
During this stage, the batteries are charged at the bulk voltage
setting and maximum current output of the DC source. When
the battery voltage reaches the bulk voltage setting, the
controller activates the next stage (absorption).
Absorption Stage
During this stage, the voltage of the battery is held at the bulk
voltage setting until an internal timer has accumulated one
hour. Current gradually declines as the battery capacity is
reached.
Float Stage
During this stage, the voltage of the battery is held at the float
voltage setting. Full current can be provided to the loads
connected to the battery during the float stage from the PV
array. When battery voltage drops below the float setting for
a cumulative period of one hour, a new bulk cycle will be
triggered.
Figure 1-2 3-stage Battery Charging Process
Bulk Stage Floa t Stage
DC Voltage
DC Current Constant Current Reducing Current Reduced Current
B ulk Vol ts Setti ng
Float V olts Setti ng
Time
Max Amps
Absorpti on Time
Charging
Started
Increasing Vol tage Constant Vol tage Reduced Vol tage
0 amps
0 vol ts
Absorption Stage