© 2017 Sensata Technologies
34
Operation
3.2
Battery Temperature Sensor Operation
The plug-in Battery Temperature Sensor (BTS) is used to determine
the battery temperature around the batteries. This information allows
the multi-stage battery charger to automatically adjust the battery
charge voltages for optimum charging performance and longer
battery life.
When the BTS is installed, if the temperature around the BTS is below
77°F (25°C) the absorb and
fl
oat charge voltage increases. If the
temperature around the BTS is higher than 77°F (25°C), the absorb
and
fl
oat charge voltage decreases. See Figure 3-2
to determine how
much the charge voltage changes (increases or decreases) as the
temperature reading of the BTS changes. For example, the nominal
absorb charge voltage for a
fl
ooded battery at 77°F (25°C) is 14.6
VDC. If the battery temperature is 95°F (35°C), the absorb charge
voltage would decrease to 14.3 VDC (14.6 VDC - 0.3 change).
If the temperature sensor is NOT installed, the charge voltages will
not be compensated and the battery will maintain the charge it had
at a temperature of 77°F (25°C). The life of the batteries may be
reduced if they are subjected to large temperature changes when
the BTS is not installed.
Info:
When the BTS is connected, the battery charger
uses a value of -5mV/°C/Cell from 0-50°C to change the
charge voltage based on temperature.
Temperature reading from BTS
Temperature Compensation using BTS
0C
32F
5C
41F
10C
50F
45C
113F
30C
86F
40C
104F
35C
95F
25C
77F
20C
68F
15C
59F
50C
122F
C
h
a
n
g
e
to b
a
tte
ry
c
h
a
rg
in
g
v
o
lt
ag
e
no BTS
connected
-0.15V
-0.3V
-0.45V
-0.6V
-0.75V
12VDC units
+0.75V
+0.6V
+0.45V
+0.3V
+0.15V
No Change
Figure 3-2, BTS Temperature to Charge Voltage Change
