Operation
36
900-0167-01-00 Rev A
Time limit:
Absorb Time
setting. The charger does not necessarily run through its full duration if it
retained time from a previous charge cycle. The timer counts down from the inception of the
Absorption stage until it reaches zero. The time remaining can be viewed in the system display.
The Absorption timer does not reset to its maximum amount, or to zero, when AC power is
disconnected or reconnected. It only goes to zero if the timer runs out during the Absorption stage, or
if an external STOP BULK command is sent. In all other cases it retains any remaining time.
Absorb Time
is reset to its maximum amount whenever the battery voltage decreases to the
Re-Bulk
Voltage
setting. The reset occurs immediately, regardless of the time spent below this voltage.
To skip this step:
Setting
Absorb Time
to a very short duration causes 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 the constant-current
Refloat stage. 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 47.
Voltage Used:
Re-Float Voltage
setting. When the battery voltage decreases to this point, the
charger becomes active again.
Default Set Point
(nominal voltage): 12.5 Vdc (12-volt), 25.0 Vdc (24-volt), 50.0 Vdc (48-volt)
To skip this step:
Setting
Float Time
to
24/7
makes 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
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. This setting is also used by Offset when in this stage. (See page
42.) For the charger to work normally, this setting needs to be higher than the
Re-Float Voltage
setting.
Default Set Point
(nominal voltage): 13.6 Vdc (12-volt), 27.2 Vdc (24-volt), 54.4 Vdc (48-volt)
The charger may perform two functions during Float. Both are called
Float
in the system display.
They are defined here as Refloat and Float.
Refloat
Refloat is a constant-current function. The initial DC current may be as high as the charger’s maximum
current, depending on conditions. This stage is similar to Bulk, except that the charger uses the
Float
Voltage
setting as noted above. The charger delivers current until the batteries reach this value.
Float
Float is a constant-voltage function. The current varies as needed to maintain
Float Voltage
, but
typically drops to a low number. This stage is similar to Absorption, except that the voltage is different.
