Chapter 4 _____________________________________________________________ Technical Data
VAISALA________________________________________________________________________ 17
Table 8
Voltage Selection Resistor Value vs. Charging
voltage (typ. @ +25
°
C) and Battery Type
Battery Type
Ubatt (Cell)
Charge Voltage
Ext. Resistor
Sealed Lead-acid
12 V (6 cells)
13.7 V
Not Connect
Flooded Lead-acid
12 V (6 cells)
14.0 V
154 k
Nickel-cadmium battery 12 V (10 cells) 14.4 V
68,1 k
Sealed Lead-acid
24 V (12 cells) 27.4 V
4,48 k
Flooded Lead-acid
24 V (12 cells) 28.0 V
4,32 k
Nickel-cadmium
24 V (20 cells) 28.8 V
4,07 k
Temperature Compensation NTC
An external temperature-sensing resistor (NTC) controls the
maximum charging voltage level. With the ambient temperature
rising, the temperature compensation circuit drops the charging
voltage level, and vice versa. The compensation coefficient is
−
20 mV/
°
C for 12 V systems and -40 mV/
°
C for 24 V systems.
The NTC resistor is connected between the terminals X3/4 and X3/5.
The optimum place for the NTC resistor is as close to the batteries as
possible, but if the batteries and QBR101 are enclosed in the same
space, the NTC resistor may be mounted straight to the X3 screw
terminals as well.
Recommended type for the NTC resistor is PHILIPS 2322 645 03103
(Vaisala code: 16253), with values 10 kohm at 25
°
C, 5 %, 0.1 W.