Rolls Battery - AGM Constant Current Charger (IUI); AGM Bulk Stage (Constant Current); AGM Termination (Constant Current); AGM Refresh Charge

7
AGM CONSTANT CURRENT CHARGER
–
IUI
A constant current charger may also be used. However, it is important to adhere to the
termination criteria mentioned below to minimize the chance of excessive over-charge.
See Figure 2 for the recommended constant current charge profile.
AGM BULK STAGE
The charger should deliver the initial current B until the voltage limit A is reached.
Absorption Stage – the charger should maintain the voltage A until the current
tapers to B.
AGM TERMINATION
If the charger can be programmed, the charge should terminate when the voltage stops
increasing over time. This is called a float termination. The charge should terminate
when the float is equal to 2.5mV/cell/hour. The charge time in the final phase should not
exceed 8 hours and the total charge time should not exceed 20 hours. The percentage
recharge should be between 105%-110%.
AGM REFRESH CHARGE
If Rolls AGM batteries are properly charged they should never require an equalizing
charge. If they were not properly charged and there is a decrease in capacity, recharge
the batteries and make sure they complete the entire charge cycle. If the batteries are
stored for extended periods of time, recharge them as follows
Charge
Voltage
(12V Battery)
Float
Voltage
(12V Battery)
Storage Temperature Refresh Charge Interval
Below 68°F (20°C) 9 Months
68°F (20°C) - 86°F (30°C) 6 Months
Higher than 86°F (30°C) 3 months
B=Bulk
A=Absorption
F=Float
2.55V 2.51V 2.47V 2.45V 2.43V 2.39V
2.38V 2.34V 2.30V 2.28V 2.26V 2.22V
15.30V 15.06V 14.82V 14.70V 14.58V 14.34V
14.25V 14.01V 13.77V 13.65V 13.53V 13.29V
30.60V 30.12V 29.64V 29.40V 29.16V 28.68V
28.50V 28.02V 27.54V 27.30V 27.06V 26.58V
61.20V 60.24V 59.28V 58.80V 58.32V 57.36V
57.00V 56.04V 55.08V 54.60V 54.12V 53.16V
32°F
(0°C)
50°F
(10°C)
68°F
(20°C)
77°F
(25°C)
86°F
(30°C)
104°F
(40°C)
Charge
Voltage
(2V Battery)
Float
Voltage
(2V Battery)
Charge
Voltage
(24V Battery)
Float
Voltage
(24V Battery)
Charge
Voltage
(48V Battery)
Float
Voltage
(48V Battery)
B=Bulk
F=Float
A=Absorption
1.75
0.00
0.20
0.15
0.10
0.25
0.05
0.30
0.35
2.07
2.03
2.00
1.98
1.86
2.00
2.40
2.30
2.20
2.50
2.10
2.60
2.70
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B = 0.25 x C20 (1max = 0.35 x C20)
A = 2.45V/Cell (+/- .05V/Cell)
Voltage varies with age
Termination: F= 2.5mV/Cell/hr
or 105-110% recharge
CHARGING TIME: <=16 HRS
CURRENT (X C20 RATE)
VOLTAGE PER CELL
Temperature: 25ºC (77ºF)
Temperature Coefcient: -4mV/ºC/cell (-2mV/ºF/cell)
1
2
=0.01 x C
20