Battery Deactivation Controlled by a Reed Sensor REED RELAYS REED SENSORS REED SWITCHES Introduction When an automobile is completed at the factory, it is ready to be driven. However, the vehicle may sit in a completion lot for several day or weeks awaiting transportation. The vehicle is then transported either by truck all over the country or even sent overseas on a ship. Once the vehicle arrives at its final destination it may sit for an extended period of time. The entire process could add up to several months for which the vehicle has been sitting idle prior to being sold. During that idle period, if the vehicle's battery was connected it would have undergone small leakage currents that exist in any car. These leakage currents would drain the battery, leaving the new owner with a car that won't start. MEDER designers working with automotive engineers have solved these leakage current issues by using a magnetic Reed Sensor. Figure 1. MK14 Sensor physical layout Features • The reed sensors reliably operate between 50˚C to 150˚C • Magnet and Reed Sensor are isolated and have no physical contact by typically having the Reed Sensor module mounted beneath the car windshield and the magnet is manually positioned over the module to accurately detect the magnet and deactivate the battery • The reed switch used in the Reed Sensor is hermetically sealed and is therefore not sensitive to rough, wet environments Figure 2. Connected battery showing small current leakage. • The magnet is not affected by its environment • Tens of millions of reliable operations • Surface mount and through hole packages available • Cylindrical hole and screw fastening mounting • Contacts dynamically tested Applications • Ideal for sensing remotely when the magnet is clearly separated from the reed sensor by nonferromagnetic material (glass, plastics, etc). Figure 3. Magnet is placed over the sensor module to deactivate the battery to prevent battery drain. MEDER’s Reed Sensor Modules Are Able To Control The Discharge Of An Automobile Battery Many automotive salesmen and auto dealers have been embarrassed when they have attempted to take potential customers for a test drive only to find that the vehicle of their dreams will not start. New cars that have sat around for months will experience small leakage currents that naturally exist in all cars causing their battery to drain. MEDER electronic Application MEDER electronic AG | Germany | tel.: +49(0)7731/8399-0 | Email: [email protected] MEDER electronic Inc. | USA | tel.: +1 508.295.0771 | Email: [email protected] Page 1 of 2 www.meder.com Battery Deactivation Controlled by a Reed Sensor REED RELAYS REED SENSORS REED SWITCHES MEDER designers working with the auto makers have solved this problem by using a magnet external to the car coupled with a reed sensor internally in the car. Here the dealer can activate and deactivate the reed sensor by using an external magnet from outside the car. Specifications Operate specs Min Max Units Must close distance 5 25 mm Must open distance 5 25 mm Hysteresis Load Characteristics Switching voltage Switching current Carry current Contact rating Static Static Contact resistance Dynamic contact resistance Breakdown voltage Operate time Release time Operate Temp Storage Temp Typical 50% Min Max Units 200 0.5 1.5 10 150 V Amps Amps Watts mΩ 200 mΩ 320 V 0.5 msec 0.1 msec -20 85/130 °C -35 85/130 °C MEDER has designed a reed sensor module that is mounted under the window of car. When the dealer brings a magnet near the sensor from outside the window, the sensor activates triggering an electronic switch that in turn can turn the battery circuitry on and off. In this manner the battery power is saved when it is really needed. An additional advantage with this approach is that when the vehicle is sold, the reed sensor module is removed and can be re-used by the automotive manufacturer by mounting it on another vehicle. MEDER’s reed sensor module is designed for ease of connecting and disconnecting its electrical leads. Consider some of the below options in cylindrical panel mount and rectangular screw flange mount for the battery deactivation sensor or other similar applications. Cylindrical Panel Mount Series Series MK03 MK03 Dimensions mm Dia 5.25 L 25.5 Illustration inches 0.207 1.004 MK14 MK14 Dia L 4 25.5 0.157 1.004 MK18 MK18 Dia L 5 17 0.197 0.669 MK20/1 MK20/1 Dia L 2.72 10 0.107 0.394 Rectangular Screw Flange Mount Series Series MK04 MK05 MK05 MK12 MK12 Dimensions mm W 13.9 H 5.9 L 23.0 W 19.6 H 6.1 L 23.2 W H L 14.9 6.9 32.0 Illustration inches 0.547 0.232 0.906 0.772 0.240 0.913 0.587 0.272 1.260 **Consult the factory for more options not listed above. ** MEDER electronic Application MEDER electronic AG | Germany | tel.: +49(0)7731/8399-0 | Email: [email protected] MEDER electronic Inc. | USA | tel.: +1 508.295.0771 | Email: [email protected] Page 2 of 2 www.meder.com