Outback Power Systems GS4048A Operators Manual - Manual (Page 33)

Operation
900-0161-01-00 Rev A 31
NOTE: The Float timer begins running any time the battery voltage exceeds the Float Voltage set
point. This usually means that it begins running during the Bulk stage, once the battery voltage rises
above that level. Often the timer will expire before the bulk and absorption stages are complete. If
this happens, the charger will not enter Float but will go directly to Silent. The charger only spends
time in Float stage if the timer is still running.
Time limit: Float Time setting. The charger will go Silent once the timer has expired (if another stage
is not still in progress.) The Float timer is reset to its maximum amount whenever the batteries
decrease to the
Re-Float Voltage setting.
To skip this step: Setting Float Time to 24/7 will cause the charger remain in Float continuously so
that the Float timer no longer applies. (The charger also skips Bulk, Absorption, and Silent.) However,
the charger can initiate a single three-stage charge if the criteria are met, after which it will return to
continuous Float again.
Silent
Following the expiration of the Float timer, the unit enters (or re-enters) the Silent stage. The unit
remains connected to the AC source, but the charger is inactive.
The unit will continue cycling between Float and Silent for as long as the AC source is present.
New Charging Cycle
If the AC source is lost or disconnected, the unit will return to inverting mode if enabled. The battery
voltage will begin to decrease due to loads or natural loss. When the AC source is restored, the
inverter will return to the charging cycle.
Re-Bulk
If the battery voltage decreases due to discharge, the inverter will restart the cycle as soon as the AC
source is available, beginning at Bulk stage.
Voltage Used: Re-Bulk Voltage setting. The default set point is 49.6 Vdc.
If the batteries do not decrease to the Re-Bulk point, the charger will not enter the Bulk stage and will
return to its previous stage.
Absorption Timer
Time limit: Absorb Time setting. The charger will not necessarily run through its full duration, as this
setting is not a required minimum period for Absorption. It is only a maximum limit. The duration of
Absorption is equal to the amount of time the battery voltage was less than the
Re-Bulk Voltage
setting, up to the maximum limit.
If the Absorption timer expired on the previous cycle, it is not reset afterward and retains a “remaining
run time” of zero. Whenever the battery voltage decreases to Re-Bulk or lower, the Absorption timer
will begin gaining time. For as long as the batteries remain below this voltage, the Absorption timer
will gain an equal amount of time. This controls the duration of the Absorption stage. The intent was
to avoid a “blind” cycle that operates regardless of conditions. The charger avoids maintaining the
batteries at high voltages for excessive or unnecessary time.
The Absorption timer continues this operation even if the charger is still on. For example, if the
charger is in Float stage and there is a significant battery drain, the charger may not be able to
maintain the batteries at the Float voltage. Once the batteries fall below the Re-Bulk point, the
Absorption timer will begin accumulating time. (However, the accumulation will be minor, as this will
also cause the charger to re-enter the Bulk stage.)