© 2010 Magnum Energy, Inc.
3.0 Operation
31
Battery Temperature Sensor Operation
-
The plug-in Battery Tem-
perature 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 opti-
mum 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 15
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.
-0.75
-0.6
-0.45
-0.3
-0.15
0
0.15
0.3
0.45
0.6
0.75
0
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
4 5
5 0
Tem perature reading from BTS
T em p eratu re C o m p en satio n u sin g B T S
0C
32F
5C
41F
10C
50F
45C
113F
30C
86F
40C
104F
35C
95F
25C
77F
20C
68F
15C
59F
50C
122F
C
ha
ng
e to
b
a
tte
ry
c
h
ar
g
in
g
v
o
lta
g
e
no B TS
c onnec ted
12 V D C units
+0.75 V
+0.6 V
+0.45 V
+0.3 V
+0.15 V
N o C hange
-0.15V
-0 .3V
-0.45V
-0 .6V
-0.75V
Figure 16, BTS Temperature to Charge Voltage Change
