UMAX090600 Version 1
Preliminary Documentation – May be Subject to Change
7-48
1.2.3.
Bulk Charge Stage
Bulk charge is the stage which restores the battery’s charge level in the shortest amount of time.
This is done by applying a high constant current level to the battery. The battery voltage will
continue to increase during the time the constant current is being applied to the battery. Once the
battery has charged enough during bulk charge its voltage will reach a certain level at which point
the operation will shift to Absorption Stage.
1.2.4.
Absorption Stage
This stage is used to bring the battery to one hundred percent capacity by applying a constant
voltage to the battery while it draws as much current as it needs to reach that full capacity.
1.2.5.
Maintaining Charge/Float Stage
Once the battery has reached full capacity, the profile will shift to the float stage which will maintain
the battery at full capacity by adjusting the duration of the constant voltage level.
1.2.6.
Battery Charger Configurable Setpoints
During initialization of the controller, the CAN-BC-LED will monitor the battery voltage and
determine which stage of profile shown in
Figure 1
the controller will engage. The points at which
the stages transition from one to the next are configurable by the user. This section will explain
how these points are interpreted by the controller.
When the battery is completely discharged, the stage that will be active will be the
Pre-charge
mode. At this stage, the controller will begin constant current mode at the current level entered in
Pre-Charge Stage Current Level.
This current level should be low enough as to prevent damage
to the battery. The battery will pre-charge at this constant current level while the CAN-BC-LED is
continuously monitoring the battery voltage. When the battery voltage has reached the level
Bulk
Charge Stage Voltage Threshold
the controller will then shift the
Bulk Charge
mode. Once in
Bulk Charge
mode, in the case the battery voltage drops lower than
Bulk Charge Stage Voltage
Threshold
minus
Voltage Hysteresis Value
the controller will shift to
Pre-charge
mode.
At
Bulk Charge
mode, the controller will increase its constant current level to
Bulk Charge Stage
Current Level
to charge the battery more rapidly
.
The controller will remain in this mode until the
battery voltage has reached
Absorption Stage Voltage Threshold.
When this transition to
Absorption Stage
occurs, the controller will shift to constant voltage so that
the battery is able to reach full charge capacity. To determine if the battery has reached its full
charge monitoring the sourced current is necessary. When the current sourced by the CAN-BC-
LED is less than
Float Stage Current Threshold
it is an indication that the battery is fully charged
and move to
Float Stage
mode.
Float Stage
is used in order to maintain the battery at full charge by adjusting its constant voltage
on time. The amplitude of this constant voltage level is determined by
Float Stage Voltage Level.
It is recommended that the battery is not connected to a load until it has been fully charged (in
Float Stage
mode). When the battery is connected to a load during
Float Stage
mode, the
