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2020 Sensata Technologies
Page 39
Operation
3.4 Battery Temperature Sensor Operation
The plug-in Battery Temperature Sensor (BTS) is used to determine the battery’s temperature.
This information allows the multi-stage battery charger to automatically adjust the battery charge
voltages for optimum charging performance and longer battery life.
With a BTS installed, if the temperature around the BTS is below 77°F (25°C) the absorb and
fl
oat
charge voltage increases, and if the temperature around the BTS is higher than 77°F (25°C), the
absorb and
fl
oat charge voltage decreases. See Figure 3-10 to determine how much the charge
voltage changes (increases or decreases) depending on the temperature reading of the BTS. 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 automatically adjusted
because of temperature, but will be maintained 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
an
ge t
o
ba
tt
er
y c
h
ar
gi
n
g
vo
lt
ag
e
no BTS
connected
+0.75V
+0.6V
+0.45V
+0.3V
+0.15V
No Change
-0.15V
-0.3V
-0.45V
-0.6V
-0.75V
Figure 3-10, BTS Temperature to Charge Voltage Change
