Outback Power Systems GS3548E Operators Manual - Manual (Page 32)

Operation
30 900-0145-01-01 Rev A
period whenever the battery voltage decreases below this setting. (See page 31 for more information
on how the timer works.)
To skip this step: Setting Absorb Time to a very short duration will cause the charger to spend
minimal time in Absorption once the Bulk stage is complete. Setting
Absorb Time to zero will cause
the charger to skip both the Bulk and Absorption stages and proceed directly to Float. This may not
be desired if the intent is to skip Absorption but retain the Bulk stage.
Silent
This is not a charging stage, but a quiescent period between stages. The inverter remains on the AC
source, but the charger is inactive. It enters this condition upon completing a timed stage such as
Absorption, Float, or Equalize.
In Silent, the batteries are not in significant use by the inverter, but they are also not being charged.
The battery voltage will naturally decrease when not maintained by another means such as a
renewable source.
The term “Silent” is also used in an unrelated context regarding Power Save levels. See page 39.
Voltage Used: Re-Float Voltage setting. When the battery voltage decreases to this point, the
charger becomes active again. The default set point is 50.0 Vdc.
To skip this step: Setting Float Time to 24/7 will cause the charger remain in Float continuously so
that it does not proceed through the Silent, Bulk, Absorption, or Float timer steps.
Float Stage
This is the third stage of charging. It is sometimes known as maintenance charging. Float stage is
initially a constant-current stage. The initial DC current may be as high as the charger’s maximum
current, depending on conditions. This current is only sustained until the charger reaches the
Float
Voltage setting, after which the charger switches to constant-voltage operation.
Float stage balances the batteries’ tendency to self-discharge (as well as balancing the draw of any
other DC loads). It maintains the batteries at 100% of capacity.
Voltage Used: Float Voltage setting. The default set point is 54.4 Vdc. This setting is also used by
Offset when in this stage. (See page 35.) For the charger to work normally, this setting needs to be
higher than the
Re-Float Voltage setting.
Time limit: This can vary. If the duration of the Float Time setting is less than the total time of the
bulk and absorption stages, the charger will not enter Float and will go directly to Silent instead. See
Float Timer.
To skip this step: As noted, the charger will not enter Float if the Float Time setting is less than the
total bulk and absorption times. Decreasing the
Float Time setting to zero will cause the inverter to
enter Silent as soon as the absorption stage is complete. The inverter will perform neither the
constant-current nor the constant-voltage portions of Float.
Setting
Float Voltage equal to the Absorb Voltage level will cause the charger to proceed through
the normal three-stage cycle, but at a single voltage.
Float Timer
This is not a separate stage of charging. In Figure 4 on page 28, it is marked as a separate step to note
when the charger switches from constant-current to constant-voltage charging. When this occurs,
the current varies as needed to maintain the
Float Voltage, but typically drops to a low number.
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