User manual

37TriStar MPPT Operator’s Manual
Absorption Extension
Figure 4-3. Absorption extension charging profi le.
If battery voltage discharges below 12.50 Volts (25.00 Volts @ 24 V, 50 Volts @ 48 V) the previ-
ous night, Absorption charging will be extended on the next charge cycle as shown in fi gure 4-3
above. 30 minutes will be added to the normal Absorption duration.
Float Timeout
Figure 4-4. Float exit timeout charging profi le
After entering Float stage, the controller will only exit Float if the battery voltage remains below
Float voltage for 30 cumulative minutes. In fi gure 4-4, a system load turns on at 4:30 hrs when
the controller is in Float stage, runs for 1/2 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 30 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 30 min. However, because the Float
exit timer is cumulative, multiple momentary load events that pull the battery voltage below Float
voltage for a combined 30 minutes duration will also force an exit from Float stage.