5.0
Operation
50
GenStar MPPT
51
Float Exit Time-out Voltage Threshold
Figure 5-4. Float Exit Time-out Voltage Charging Profile
Preset Charging Profiles
After entering Float stage, the controller will only exit Float if the battery voltage remains below
Float Exit Time-out Voltage
for sixty cumulative minutes. In Figure 5-4 above, a system load turns
on at 3:30 hrs when the controller is in Float stage, runs for one hour, and turns off at 4:30 hrs. The
load current draw is larger than the charge current, causing battery voltage to drop below the shared
Float Exit Time-out Voltage
of 12.6 for lead-acid, or 13.3 for Lithium, for sixty minutes. After the
load runs for sixty minutes, the time-out causes the controller to return to Bulk charging, and then
Absorption stage again. In this example, a load runs continuously for sixty min. However, because
the Float exit timer is cumulative, multiple momentary load events that pull the battery voltage
below Float voltage for a combined sixty minutes duration, will also force an exit from the Float
stage.
Custom Charging
The float exit time-out and voltage can also be custom programmed.
1:00
2:00
3:00
4:00
5:00
6:00
Float Exit V
L-A = 12.6V
Lith. = 13.3V
Voltage
Bulk
Float
Absorption
Absorption
60 mins.
below Float
Exit Voltage
Time (hrs)
Bulk
Float Cancel Voltage
Figure
5.5.
Float
Cancel
Charging Profile
For Lead-acid presets, the battery bank discharges below 12.0 volts (24.0 volts @ 24 V) the
previous night, Float charging stage will be cancelled for the next charge cycle. Figure 5-5 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 canceled.
Float
cancel voltage is disabled for Lithium presets (6-8).
Equalization Time-out
Figure 5.6. Equalize Time-out Charging Profile
1:00
2:00
3:00
4:00
5:00
6:00
12.0 V
Bulk
Absorption
Float Cancel Voltage
time (hrs)
Float cancelled this charge cycle
1:00
2:00
3:00
4:00
5:00
6:00
Absorp. V
Bulk
Float
Equalize
Equalize timeout
time (hrs)
Equalize V
