Battery Temperature Sensor Operation; Figure 3-9, Bts Temperature To Charge Voltage Change - Magnum Energy MagnaSine Hybrid Mobile Series Owner's Manual

Operation
3.5

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 3-9 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) on a 24-volt
model is 29.2 VDC. If the battery temperature is 95°F (35°C), the absorb charge voltage would
decrease to 28.6 VDC (29.2 VDC - 0.6 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.
12VDC units
+0.75V
+0.6V
+0.45V
+0.3V
+0.15V
No Change
-0.15
-0.15V
-0.3V
-0.45
-0.45V
-0.6V
-0.75
-0.75V

Figure 3-9, BTS Temperature to Charge Voltage Change

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Temperature Compensation using BTS
0.75
0.6
0.45
0.3
0.15
0
-0.3
-0.6
0C 0 5C 5 10C 10 15C 15
32F 41F 50F 59F
Temperature reading from BTS
no BTS
connected
20C 20 25C 25 30C 30 35C 35 40C 40
68F 77F 86F 95F 104F
24VDC units
+1.5V
+1.2V
+0.9V
+0.6V
+0.3V
No Change
-0.3V
-0.6V
-0.9V
-1.2V
-1.5V
45C 45 50C 50
113F 122F
© 2013 Magnum Energy, Inc.