Morningstar PS-30 Manual

Operation
ProStar Operator’s Manual
41
40
4.0
Float Cancel voltage
Figure 4.4. Float Cancellation Charging Profile
If the battery bank discharges below 12.10 Volts (24.20
Volts @ 24V) the previous night, Float charging stage
will be cancelled for the next charge cycle. Figure 4-4
above, illustrates this concept. At 0:00 hrs (dawn),
battery voltage is below the Float Cancel threshold
voltage. The diagram shows where Float stage would
have occurred if Float was not cancelled.
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 4-3. 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 4-3, a
system load turns on at 4:00 hrs when the control-
ler 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 minutes. 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 minutes.
However, because the Float exit timer is cumulative,
multiple momentary load events that pull the battery
voltage below Float voltage for a combined 60 min-
utes duration will also force an exit from Float stage.