Generally, almost all Li-ion battery chargers use a constant current/constant voltage charging algorithm. Welcome to Wisdom Industrial Power Co., Ltd. Over Discharge Conditions Typical rechargeable lithium cells can safely operate down to 2.75V/cell. A battery stores the charge and then supply that charge to power up any electronics device. As the battery is attached to an electronics device and it starts discharging, its terminal voltage starts dropping. When the collector of the transistor Q2 will provide ground to one end of the relay then only, the relay will energize. Specifically, in this project, two Li-ion batteries connected in series will be taken as power supply unit. The series resistance of the zener diode can be calculated by the following equation –, Maximum Power dissipation of zener diode, Pz = 250mV, Maximum zener current, Iz can be calculated as follows. This module can protect battery from burnout during charging or discharging. These issues are often ignored by the consumers too. 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. Or does it somehow not drop any of the charging voltage and use the (3.2v) battery, and some little current, to protect the battery from over/under discharge? With the use of series resistance, zener can provide a regulated voltage at the output. If the terminal voltage of a battery goes below a lower threshold limit, the battery starts dying prematurely. Shop the top 25 most popular 1 at the best prices! Let’s check the details of the over-charge and over-discharge protection of lithium batteries. Image not available. In this electronics project, a power circuit is designed which will detect the lower threshold limit of the terminal voltage by the use of a suitable Zener diode and will cut off the battery connection with the load device by the use of a relay. As the base of the transistor Q2 is connected to the collector of Q1 but the potential at the collector of Q1 is almost zero because all the current has grounded, So the conduction of Q1 will ground the base of transistor Q2 and the transistor Q2 will be in the non-conducting state. However, when it comes to over-discharge protection the limits are set very low: 2.7V or 3V. 2020 popular 1 trends in Consumer Electronics, Electronic Components & Supplies, Tools, Home Improvement with 12v Battery Discharge Protection and 1. 12V Battery Charging Controller Protection Board Module, Undervoltage Low Voltage Cut Off Automatic Switch Recovery Protection Controller Module We will use a similar circuit, but change the resistance and make it … THE BEST LITHIUM BATTERY FOR SOLAR STREET LIGHTS Over-discharge Protection Battery Charge Controller 20A durable High quality. Arduino Battery Over-Discharge Protection (O-DP) Ask Question Asked 6 years, 3 months ago. 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. A zener diode when connected in reverse bias configuration and its cathode voltage is below its breakdown voltage then zener acts like an open circuit. Typical rechargeable lithium ion battery cells can safely operate down to 2.75V/cell. The selection of zener series resistance must be chosen wisely so that it will not allow current more than the zener rating. Main function of PCM, a. The circuit includes an LED indicator section also which will light up the LED as the battery discharges below the limit and require recharging. As the current at base of the transistor starts increasing it acts like a variable resistance, the value of this resistance starts decreasing as current increases. From the above practical observations, it is can be analyzed that the practical voltage at which the battery disconnects from the load is 6.27 V. Therefore the battery will cut off when the battery voltage of each Li-ion battery is at 3.15 V approximately. Free shipping . The purpose of connecting the diode in this manner is to operate it in reverse biased condition. That means the voltage difference between the collector to emitter of Q1 is very less but it has sufficient voltage which can drive the base of the transistor Q2. When the two Li-ion batteries will be connected with the load then there can be two cases as follow –. BSLBATT You can typically find this chip on TP4056breakout boards (Lithium ion charger chip). The most important faults that the batteries must be protected from are overvoltage, overcurrent, and over temperature conditions as these can place the batteries in a dangerously unstable state. Resistance R2 and R3 are connected to the collector of both the transistors and resistance R4 is connected in serises with the LED. Required fields are marked *, Welcome to Wisdom industrial Power Co., Ltd. All rights reserved. This XH-M609 battery over discharge protection module is a Power Supply Module/Battery Charger Control Module, With an Input Voltage: DC 7~80V, ST processing chip, stable performance, high integration and durable. For calculating R1 the Zener current has to be calculated by the following method. Lithium battery protection circuit, its function that protects rechargeable battery, sustains its safety and consistence during charge and discharge, plays a important part in the whole battery circuit, e.g. Customer Support and Superior Service. The base of the transistor Q2 is connected to the collector of the transistor Q1, so the collector voltage of the transistor Q1 will be switching the transistor Q2. United States Patent 6617069 . When the zener diode in conduction state and there is sufficient voltage at the base of the BC547 transistor, the collector voltage is drawn as it is. 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. Since batteries do have nice price tags, it ultimately adds up the maintenance cost of any electronics device. NiMH Battery Over-discharge Protection Circuit. BATTERY PROTECTION IC WITH DISCHARGE CONTROL FUNCTION FOR 1-CELL PACK Rev.1.3_03 S-8250A Series 3 Product Name Structure 1. For e.g. Battery guards prevent this excessive discharge by disconnecting the battery from loads in an under-voltage situation. 4) LED indicator circuit – The LED indicator circuit is connected at the NC point of the relay. The different voltage readings taken from the circuit are summarized in the following table –. But in the experiment, resistance R1 is higher than 55 ohms. Your email address will not be published. Picture Information. Various considerations must be given prior to designing a device requiring rechargeable Lithium-ion batteries. 3) Diode Circuit – A diode circuit is connected parallel to the relay coil for back current protection from the load device. MOSFET selection. |, “Is your battery protected when battery is over-charged or over-discharged?” Our customers usually asked this. The over-discharge protection threshold also has an impact on capacity/charge and cell life. In this electronics project, a zener diode based circuit will be designed to protect a battery from over discharging. Induction cooking etc. 1) Zener diode circuit – A zener diode is connected in series with the battery such that the cathode of the zener diode is connected to the anode of the battery and anode of the zener diode is connected with the base of the switching transistor. Dec 07,2018. A good battery protection circuit will also provide over-discharge protection. Therefore a diode (D3) is used across the relay to prevent the circuit from the back current when the relay is de-energized. 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. Digital Low Voltage Protector Disconnect Switch Over Discharge Protection Module for 12-36V Lead Acid Lithium Battery 4.4 out of 5 stars 221. It is 80 ohms for just being on the safe side. The leakage current from zener will also switch ON the Q1. When the transistor circuit switches the relay to NC point, the LED gets forward biased as the anode of the LED is connected to the NC point of relay and cathode is connected to ground. my question is about how I best protect my batteries from over discharge whilst using the inverter. Discharged all the way back current when the relay will energize some charge when the two batteries! Components & supplies, Tools, Home Improvement with 12v battery charging Controller protection Board Module, low! 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