Temperature Sensors Accessories Melcher 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 Melcher converters fitted with the standard R-input. This input allows adjustment of the output voltage see fig. 1. The open R input ex hibits a source voltage of 2.5 V with a source resistor of 4 k. 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 feature (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 co efficients, 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 is S-KSMH48-2.27-30-2. Fig. 3 shows the charge voltage depending on the temperature and the battery type. If the sensor is disconnected, the converter output voltage is regulated to V . This voltage prevents the battery from o safe being overcharged even at high temperature. Overcharging a battery is dangerous and can cause the battery to explode. Table of Contents Description........................................................................................1 Mechanical Dimensions....................................................................3 Fail Safe Operation and Suitable Converters ................................2 Temperature Sensors for the T Series .............................................3 Converters with DC Input .................................................................3 belfuse.com/power-solutions BCD20022 Rev AJ, 05-Dec-2018Cassette Style Mating Connectors Accessories JM114 03099d Vo+ L Vo+ Power Load Vo Input supply R V = 2.5 V 4 k R ref + Control + logic N Temperature sensor Battery Vo- Fig. 1 Fig. 2 Block diagram of Melcher converters suited to be controlled Block diagram of the sensor. by a battery sensor. Cell voltage V Table 1: Sensors for converters with standard R input 06123c 2.45 Battery Sensor type Cell Cell temp. Cable 2.40 voltage voltage coefficient length V o max nom. V V mV/K m 2.35 12 S-KSMH12-2.27-30-2 2.27 3.0 2 2.30 12 S-KSMH12-2.27-35-2 2.27 3.5 2 2.25 24 S-KSMH24-2.27-30-2 2.27 3.0 2 24 S-KSMH24-2.27-35-2 2.27 3.5 2 2.20 24 S-KSMH24-2.31-35-0 2.31 3.5 4.5 V 2.15 o safe 24 S-KSMH24-2.31-35-2 2.31 3.5 2 2.10 24 S-KSMH24-2.35-35-2 2.35 3.5 2 20 10 0 10 20 30 40 50 C 48 S-KSMH48-2.27-30-2 2.27 3.0 2 V = 2.27 V, 3 mV/K V = 2.27 V, 3.5 mV/K C C V = 2.31 V, 3 mV/K V = 2.31 V, 3.5 mV/K C C 48 S-KSMH48-2-27-35-2 2.27 3.5 2 Fig. 3 Float charge voltage vs temp. for different temp. coefficients. Fail Safe Operation and Suitable Converters To prevent batteries from overcharging but still maintain a minimum charge in case of interruption of the cable from the sensor to the converter, we offer models with special nominal output voltage setting see table 2. These converters differ from the respective standard models in the nominal output voltage and output current setting. Without the sensor connected to the R-pin, the output voltage is set to V . This voltage is higher than the nominal battery voltage such avoiding discharging the battery, but still lower o safe than the theoretically needed float 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. Table 2: Special models for battery charging V V P = 50 W P = 70 W P = 100 W P = 150 W P = 250 W P = 280 W P = 375 W nom safe o o o o o o o P = 125 W P = 500 W V V o o 2 12 12.84 LM1781-9RG LH1781-2R LS4740-9ERG LK4740-9ERG LWN1140-6EM1G 3 LOK4140-2RLDG LWR1140-6EM1G CK1740-9RG 2 24 25.68 LM1782-7R LH1782-2R LS5740-9ERG LK5740-9ERG LKP5740-9ERG LKP5741-5ERG LXR1240-6M1G 3 LOK4240-2RLDG LWR1240-6EM1G CK2740-9RG LWN1240-6EM1G LXN1240-6M1G 36 38.52 LM1783-9RG LH1783-2R LWR1840-6EM1G LWN1840-6EM1G LXR1840-6EM1G XN1840-6EM1G 1, 2 1 1 1 48 51.36 LM1784-9RG LH1784-2R LS5740-9ERG LK5740-9ERG LKP5740-9ERG LKP5741-5ERG LXR1740-6M1G 1,3 LOK4740-2RLDG LWR1740-6EM1G CK2740-9RG LWN1740-6EM1G LXN1740-6M1G 60 64.2 LM1785-9RG LH1785-2R 1 Both outputs connected in series. 2 Not for new designs Similar models with DC input (DS/LS1740, DS/LS2740) are available as well. 3 DC input DK/LK1740 and DK/LK2740 are available as well. tech.support psbel.com belfuse.com/power-solutions BCD20022 Rev AJ, 05-Dec-2018 2018 Bel Power Solutions & Protection Page 2 of 10 +