®
Accessories
T emperature Sensors
BCD20024 Rev. AA, 03-Sep-2008 Page 1 of 3 www.power-one.com
Table of Content s Page Page
Description
Power-One offers a wide range of battery charger systems
consisting of adapted power supplies and appropriate
temperature sensors. The (lead-acid) batteries are
charged according to the battery temperature and the
properties of the battery cells. When the battery is fully
charged, it is maintained at the float charge voltage, which
represents the optimum point for maximum available
energy and optimum life expectancy of the battery. It is
essential to place the sensor as close to the battery as
possible thus sensing the battery temperature.
The most suited sensor model is defined mainly by three
parameters: The nominal battery voltage (e.g., 24 V or 48
V), the temperature coefficient of the cells (e.g., –3.0 mV/
K), and the nominal floating charge voltage per cell at
20 °C (e.g., 2.27 V/cell). The latter two are specified in the
data sheet of the battery.
The temperature sensors K can be used with all Power-
One converters with the standard R input. This input
allows the control of the output voltage, see fig. 1. The
open R input exhibits a source voltage of 2.5 V with a
source resistor of 4 kΩ.
The sensor can directly be connected to the R input and is
powered from the battery voltage, as shown in fig. 2. The
sensor supersedes the internal voltage control circuit of
the converter and adjusts the output voltage exactly to what
is needed for the battery.
Note: Some converters exhibit a current droop characteristic
to ease the operation in parallel connection. If the temperature
sensor K is connected to the R-input, it cancels the droop
characteristic and impedes current sharing. We recommend
the use of converters with true current sharing (option T).
Different models of battery sensors are available
depending on the battery specifications. Table 1 gives an
overview of available sensors.
Note: Other types for different cell voltages, temperature
coefficients, and cable lengths are available on request.
For example, if the application uses a 48 V battery
consisting of 24 cells of 2.27 V, a temperature coefficient
of –3.0 mV/K, and 2 m cable length, the sensor type
S-KSMH48-2.27-30-2 should be selected.
Fig. 3 shows the charge voltage depending on the
temperature and the battery type. If the sensor is
Description ..................................................................... 1
Fail Safe Operation......................................................... 2
Converters with DC Input ............................................... 3
Mechanical Dimensions ................................................ 3
Temperature Sensors for the T Series ..........................3
®
Accessories
T emperature Sensors
BCD20024 Rev. AA, 03-Sep-2008 Page 2 of 3 www.power-one.com
R
Vo+
Vo-
4 kΩV
ref
= 2.5 V
Control
circuit
L
N
Sensor002
R
safe
Power
supply Load
–
+
Input Vo–
R
Temperature sensor
ϑ
03099d
Battery
Vo+
+
R
Vo+
Vo-
4 kΩV
ref
= 2.5 V
Control
circuit
L
N
Sensor002
R
safe
2.10
2.15
2.20
2.25
2.30
2.35
2.40
2.45
Cell voltage [V]
–20 –10 0 10 20 30 40 50 °C
06123b
V
C
= 2.27 V, –3 mV/K V
C
= 2.27 V, –3.5 mV/K
V
C
= 2.23 V, –3 mV/K V
C
= 2.23 V, –3.5 mV/K
V
o safe
V
o max
Fig. 1
Block diagram of Power-One converters suited to
be controled by a battery sensor.
Fig. 3
Float charge voltage versus temperature for different
temperature coefficients.
Fig. 2
Block diagram of the sensor.
Table 1: Sensors for converters with standard R input
Battery Sensor Cell Cell temp. Cable
voltage type voltage
coefficient
length
nom. [V] [V] [mV/K] [m]
12 S-KSMH12-2.27-30-2 2.27 –3.0 2
24 S-KSMH24-2.27-30-2 2.27 –3.0 2
24 S-KSMH24-2.27-35-2 2.27 –3.5 2
24 S-KSMH24-2.31-35-0 2.31 –3.5 4.5
24 S-KSMH24-2.35-35-2 2.35 –3.5 2
48 S-KSMH48-2.27-30-2 2.27 –3.0 2
48 S-KSMH48-2-27-35-2 2.27 –3.5 2
Fail Safe Operation
To prevent batteries from overcharging but still maintain a
minimum charging in case of interruption of the sensor
signal cable to the power supply, Power-One offers
converters with a special nominal output voltage setting;
see table 2. These converters differ from the respective
standard models in the nominal output voltage and output
current settings. Without the sensor connected to the R
pin, the output voltage is set to Vo safe, which is higher than
the nominal battery voltage such avoiding discharging the
battery, but still lower than the theoretically needed float
Fig. 5
Connection of Rsafe, if standard converter models are
used.
Fig. 4
Connection of a sensor to the standard R input
+–
Battery
Vo+
R
Vo–
Temperature
sensor
Sensor
cable
Sensor
wires
+
05174a
green
brown
white
Fuse
–
disconnected, the converter output voltage is regulated to
Vo safe. This voltage prevents the battery from being
overcharged even at high temperature. Overcharging a
battery is dangerous and can cause the battery to explode.
®
Accessories
T emperature Sensors
BCD20024 Rev. AA, 03-Sep-2008 Page 3 of 3 www.power-one.com
56 (2.2")L
L = 2 m (standard length)
other cable lengths on request
adhesive tape
26 (1.02")
9.8 (0.4")
09125a
NUCLEAR AND MEDICAL APPLICATIONS - Power-One products are not designed, intended for use in, or authorized for
use as critical components in life support systems, equipment used in hazardous environments, or nuclear control
systems without the express written consent of the respective divisional president of Power-One, Inc.
TECHNICAL REVISIONS - The appearance of products, including safety agency certifications pictured on labels, may
change depending on the date manufactured. Specifications are subject to change without notice.
Fig. 6
S-KSMH temperature sensor.
European
Projection
Table 2: Special models for battery charging
Vnom Vsafe Po = 50 W Po = 70 W Po = 100 W Po = 150 W Po = 250 W Po = 280 W Po = 375 W
[V] [V] Po = 125 W Po = 500 W
12 12.84 LM1781-7R LH1781-2R LS4740-7R2LK4740-7R
LWN1140-6EM1
LOK4140-2RLD
LWR1140-6EM1
CK17403
24 25.68 LM1782-7R LH1782-2R LS5740-7R2LK5740-7R LKP5740-6R LKP5741-5R LXR1240-6M1
LOK4240-2RLD
LWR1240-6EM1
CK27403
LWN1240-6EM1
LXN1240-6M1
36 38.52 LM1783-7R LH1783-2R LWR1840-6EM1 LWN1840-6EM1 LXR1840-6EM1
LXN1840-6EM1
48 51.36 LM1784-7R LH1784-2R LS5740-7R1 2 LK5740-7R1LKP5740-6R1LKP5741-5R1LXR1740-6M1
LOK4740-2RLD
LWR1740-6EM1
CK27401 3
LWN1740-6EM1
LXN1740-6M1
60 64.2 LM1785-7R LH1785-2R
1Both outputs connected in series.
2Similar models with DC input (DS/LS1740, DS/LS2740) are available as well.
3DC input; DK/LK1740, and DK/LK2740 are available as well.
charge voltage. As soon as the sensor is connected to the
R pin, the output voltage will be set to the correct value.
This is essential for best energy and battery life time.
Other Power-One converters may also be used for battery
charging controled by the temperature sensor. However,
the output voltage at low temperature might not be
reached. If the sensor is used only for decreasing the
output voltage, for instance, if using a 15 V power supply to
charge a 12 V battery, then disconecting the sensor
results in a dangerous situation. We recommend to add a
resistor between the R input and its reference, which
adjusts the output voltage with disconnected sensor to
Vo safe. This is shown in fig. 5.
Converters with DC Input
Most of the models listed in table 2 have an AC input.
However, there are applications requiring battery charging
from a DC source – sometimes even without electrical
isolation.
For this purpous, DC-DC converters of Q, P, M, S, or K
Series may be used, such as all switching regulators,
provided that they exhibit the standard R input.
For safe operation, we recommend to provide a resistor
Rsafe with the correct value (see fig. 5).
Mechanical Dimensions
All dimensions in mm.
Temperature Sensors for the T Series
T Series battery chargers exhibit a cell voltage selector
switch to set the required floating charge voltage directly at
the converter. A special temperature sensor T matches to
the T Series. All details are provided in the T Series data
sheet at Power-One's web site; see www.power-one.com.
