16 | SAMLEX AMERICA INC.
The value of the Bulk Charge Current "
I
o" depends upon the total
Ampere Hour (Ah) capacity of the battery or bank of batteries. A battery
should never be charged at very high charging current as very high rate
of charging will not return the full 100 percent capacity as the Gassing
voltage rises with higher charging current. As a general Rule of Thumb,
the Bulk Charging Current "
I
o" should be limited to 10% of the Ah
capacity of the battery. Higher charging current may be used if permitted
by the battery manufacturer.
The Bulk Charge Current "
I
o" can be programmed with the help of the
“Setting Menu” (SCREEN 6, page 41) as follows:
Parameter
12v version
24v version
Programmable
Range
Default
Programmable
Range
Default
Bulk
Charging
Current,
I
o
10 to 80A
(Steps of 10A)
10A
10 to 70A
(Steps of 10A)
10A
i
InFo
Please note that if an external charging source is
also used to charge the batteries at the same time
in parallel with the internal AC charger of the unit,
the charging current of the internal AC charger will
be controlled so that the total charging current of
the external charger and the internal charger is = the
programmed charging current.
For example, if the programmed charging current is say 60A and the
charging current of the external charger is 30A, the internal AC charger
will output only 30A (Programmed setting of 60A – external charging
current of 30A = 30A). Similarly, if the programmed setting is say 30A
and the external charger is 50A, the internal AC charger will not provide
any charging.
When the unit enters the AC bypass Mode, it starts working as a battery
charger and the charger will run at full programmed Bulk Charge Current
until the charger reaches the programmed Boost voltage.
As part of the Adaptive Charging Algorithm, a software timer will
measure the time taken from the instant the unit enters the AC Bypass
Mode till the instant the battery voltage reaches 0.3v below the
programmed Boost voltage, then registers this time as Bulk Charge Time
To and computes the Absorption Time T1 as 10 times the Bulk Charge
Time To in the internal “T1 Timer” i.e. T1 = To x 10. The “T1 Timer” is
used to determine the time the charging will take place in the next Boost
(Absorption) Stage.
boost (Absorption) Stage
During the Boost (Absorption) Stage, the charging voltage is held
constant near the Gassing voltage to ensure that the battery is further
charged to the full capacity without overcharging. The Boost (Absorption)
Stage restores the remaining 25% of the battery’s charge. The time the
charger remains in the Boost (Absorption) Stage is proportional to the
depth of discharge of the battery. When the battery is more discharged,
it will take longer time in the Bulk Charge Stage to reach the Gassing
voltage. As a part of the Adaptive Charging Algorithm, the “T1 Timer”
(explained above) computes the time the charging takes place in this
stage.
•
The “T1 Timer” has minimum time of 1 hour and a
maximum time of 12 hours.
•
When the T1 Timer runs out, the charger will enter the next
Float Stage.
•
The desired Boost (Absorption) voltage can be programmed
through the “Settings Menu” (SCREEN 4, page 41) as follows:
SECTION 4 |
battery Charging in
G4 Series
15
14
13
12
11
10
Char
ger V
oltage
, VDC
TIME
To
T1
10 Days
CURRENT (%) of S
et Bulk
Char
ge C
ur
ren
t Io
100%
60%
0%
BULK
BOOST
FLOAT
Voltage Curve
Current Curve
LEGEND
V
Boost
- 0.3V
Note 1:
The voltage curve
shows the voltage output of
charger. The intrinsic battery
voltage may be different and
will be proportional to the
state of charge.
Note 2:
The graph is for 12V
version. For 24V version,
double the voltages.
I
o
Fig. 4.1. Charging Curve for Normal 3 Stage Charging
