46
Operation
Absorption Extension
1:00
2:00
3:00
4:00
5:00
6:00
50.00 V
Bulk
Extended
Absorption
Float
Absorption
Absorption Extension Voltage
time (hrs)
Figure 4-3. Absorption extension charging profile.
If battery voltage discharges below 50.00 Volts the previous night, Absorption charging will be
extended on the next charge cycle as shown in figure 4-3 above. 30 minutes will be added to the
normal Absorption duration.
Float Time-Out
1:00
2:00
3:00
4:00
5:00
6:00
Float V
Bulk
Float
Sub-
Float
Absorption
Absorption
60 mins.
below Float
time (hrs)
Bulk
Figure 4-4. Float exit time-out charging profile
After entering Float stage, the controller will only exit Float if the battery voltage remains below
Float voltage for 60 cumulative minutes. In figure 4-4, a system load turns on at 4:00 hrs when
the controller is in Float stage, runs for one hour, and turns off at 5:00 hrs. The load current draw
is larger than the charge current, causing battery voltage to drop below Float voltage for 60 min-
utes. After the load turns off, the controller returns to Bulk charging and then Absorption stage
once again. In this example, a load runs continuously for 60 min. However, because the Float
exit timer is cumulative, multiple momentary load events that pull the battery voltage below Float
voltage for a combined 60 minutes duration will also force an exit from the Float stage.
