PT-100 Manual

Page 67
© 2017 Sensata Technologies
Operation
4.7 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, the controller will adjust the absorb and fl oat charge voltages according to
the temperature around the BTS. 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 4-12 to determine how
much the charge voltage changes (increases or decreases) depending on the temperature reading
of the BTS. For example, if the nominal absorb charge voltage on a 24-volt model is 29.2 VDC
at 77°F (25°C); if the battery temperature increased to 95°F (35°C), the absorb charge voltage
would decrease to 28.6 VDC (29.2 VDC), a - 0.6 VDC change.
If the temperature sensor is NOT installed, shorted or open, the PT controller only charges at a
temperature of 77°F (25°C). This may reduce the life of the batteries if they are subjected to large
temperature changes.
Info: When the BTS is connected, the PT controller uses a value of -5mV/°C/Cell from
-20°C to +54°C to change the charge voltage based on temperature.
Info: If the BTS cable is damaged and the wires are shorted, the display will indicate a
F05 (BTS Shorted Fault) message. If the BTS has been connected, and later the cable has
been cut or is disconnected, the controller displays a F16 (BTS Open Fault) message to
alerts the user that the BTS has been disconnected. In either situation, the PT controller
will no longer automatically adjust the charge voltage level based on temperature changes,
but will maintain the charge voltage level based on a temperature of 77°F (25°C).
Info: When a PT controller is networked to a Magnum inverter that has a BTS connected,
the inverter’s BTS is used to determine the PT controller’s temperature compensation.
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
-5C
23F
-10C
14F
-15C
5F
-20C
-4F
55C
131F
Change to battery charging voltage
+5.4V
+4.5V
+3.6V
+2.7V
+1.8V
+0.9V
-0.9V
-1.8V
-2.7V
-3.6V
Shorted, Open, or
No BTS connected
High Battery Temp Fault (55°C)
Recover from High Battery
Temp Fault (50°C)
0.0V
48-volt values shown
(For 12V values
÷ 4, for 24V values ÷ 2)
Figure 4-12, BTS Temperature to Charge Voltage Change