2020 popular 1 trends in Consumer Electronics, Electronic Components & Supplies, Tools, Home Improvement with 12v Battery Discharge Protection and 1. The circuit is based on the working of zener diode. Therefore from the above explanation, it can be concluded that the use of a relay at the collector of transistor Q1 would have caused early switching of the load circuit before the battery’s end of discharge voltage. For calculating R1 the Zener current has to be calculated by the following method. Various battery chemistry require specific charging profiles to optimize performance and prevent safety issues during charge. There are two Li-ion batteries connected in series so they have a total 6V end of discharge voltage. You can typically find this chip on TP4056breakout boards (Lithium ion charger chip). The transistor (BC457) has a minimum gain of 110 so the base of the transistor needs a very less current to conduct. When talking about batteries I find it irrelevent not to mention the load that's applied. But when a voltage above zener breakdown is applied at its cathode terminal then zener starts conducting from the cathode to anode in reverse bias condition. Product name S-8250A xx - I6T1 U Package abbreviation and IC packing specifications*1 I6T1: SNT-6A, Tape In this project, batteries with a cut-off limit of 3.1 V are used for power supply. For e.g. How it Works. Battery over-discharge protection . As the terminal voltage of the battery will go below the 6.2 V, the diode will go in the conduction state, triggering the switching transistors and changing the relay state to cut off the supply of the load device. So, using two batteries in series set the cut-off limit to 6.2 V. So, a zener diode of 6.2 V reverse peak voltage is used to detect the cut-off limit in the design of the circuit. After understanding the functioning of this project, protection circuits for other cut-off limits can also be designed by proper selection of the zener diode and relay with the same circuit. That is why the sales from BSLBATT usually ask our customers to tell us the application of their battery, the charge condition and discharge condition of their battery. The inductor will discharge through this diode and this will prevent the other circuitry from any back current. The output will typically turn back on once the cell voltage rises above a preset “on” threshold. 2. All Rights Reserved. Fig. This diode is known as fly back diode or freewheel diode. We will use a similar circuit, but change the resistance and make it … I like to power my electronic projects with two nickel metal hydride batteries in series. Thanks in advance. Brand New. As the zener diode can also work in reverse bias, this feature of zener diode is used for detecting the cut in the voltage level of the battery. A complete battery-pack circuit, the bq77905 uses external FET switches for charge, discharge, and protection control. my question is about how I best protect my batteries from over discharge whilst using the inverter. I will use Tensai Li-Ion TR-26650LI batteries. The emitter of the transistor Q2 is grounded and the collector of the transistor Q2 is connected to the relay coil which controls the supply to the load device. voltage between the anode and cathode of the battery increases. The purpose of these resistances is just to limit the current from the transistor and the LED. Therefore, there should be a protection circuit which can monitor the level of charging of the battery by detecting the terminal voltage and protect the battery from over-discharging by cutting off the battery connection with the electronics device. These issues are often ignored by the consumers too. I also have fitted a BMV712, smart battery sense and a 65 amp Smart Battery Protect. Cleaning industry professionals are always on new techno... What Sets BSLBATT aside from the Competition? As the 3.7 V Li-ion battery charge upto 4.2 V so, two Li-ion batteries (in series) fully charge voltage is 8.4 V. So here the maximum supply voltage from the battery, Vs = 8.4 V, Now by above equation resistance can be calculated as. In most of the commonly used portable electronic devices like laptops, smartphones, and others, the Li-ion batteries with 3V of lower threshold limit of terminal voltage are used but some manufacturers design Li-ion batteries with a lower cut-off limit of 2.7 V also. The use of batteries requires its own kind of precautions and handling. Even these protections are only supported in not just “battery charging” chips but in “battery management” chips which tend to be much more expensive. “ on ” threshold conduct but it will not in its full saturation state the.! 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