In this electronics project, a zener diode based circuit will be designed to protect a battery from over discharging. The discussed over discharge protection circuit for 12v battery consists of a voltage divider which is responsible for stepping down the input voltage and reduce to narrow range where arduino can read the voltage. BSLBATT’s... What is the Best Battery for Cold Weather? 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? Published by The purpose of connecting the diode in this manner is to operate it in reverse biased condition. In order to protect the batteries from over discharging, I have to know, when is the battery discharged. I like to power my electronic projects with two nickel metal hydride batteries in series. When relay gets de-energized then the polarity of the relay gets reversed and a back current will flow from the coil, this may damage the circuit. On full charging, the terminal voltage reaches a peak value which is an indication of 100 percent charging. You can typically find this chip on TP4056breakout boards (Lithium ion charger chip). Resistance R2 and R3 are connected to the collector of both the transistors and resistance R4 is connected in serises with the LED. This will activate the relay and the load will disconnect from the battery and LED circuit connected at the NO pin of the relay will start getting the supply and LED will start glowing, indicating the over-discharging of the battery. $10.73. This module can protect battery from burnout during charging or discharging. 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. But in this state, the Q1 is not fully ON as the base to emitter voltage till now does not reach to 0.65 V. This leakage current will be zero when the battery voltage is below 5.9 V but to cut off the battery at 6.2 V, another stage of switching transistor with  transistor Q2 is used to get an accurate cut in voltage of 6.2 V. The transistor Q2 gives low voltage indication and also disconnect the load from the battery when the battery voltage is below 6.2 V. Therefore transistor Q2 will start conducting and the voltage at the collector to emitter of transistor Q2 is almost zero since all the current drains to the ground. It is important that the relay voltage rating should be less than the cut-off voltage of the battery. This pack is *highly unlikely* to have any over OR under discharge protection. As the battery is attached to an electronics device and it starts discharging, its terminal voltage starts dropping. China H... For “BSLBATT” (Best Solution Lithium Battery), the world leader in lithium batter... Add: No.08, 12 / F, Unit 2, Zhongxin City Times, No.3, Jiangbei Civilization First Road, Huizhou, China, Address: No.08, 12 / F, Unit 2, Zhongxin City Times, No.3, Jiangbei Civilization First Road, Huizhou, China. Free shipping . BATTERY PROTECTION IC WITH DISCHARGE CONTROL FUNCTION FOR 1-CELL PACK Rev.1.3_03 S-8250A Series 3 Product Name Structure 1. $11.95. Brand New. The over-discharge protection monitors the cell voltage, turning off the output when the voltage drops below a preset “off” threshold. The percentage or level of charging of a battery is therefore estimated by its terminal voltage. I also have fitted a BMV712, smart battery sense and a 65 amp Smart Battery Protect. Overcharge protection - the module will safely charge your battery to 4.2V; Overcurrent and short-circuit protection - the module will cut the output from the battery if the discharge rate exceeds 3A or if a short-circuit condition occurs; Soft-start protection limits inrush current But practically it is observed that although zener diode should not conduct current below 6.2 V but it conducts some current (in microamperes) which flow from its cathode to anode, this current is the leakage current of the Zener. Welcome to Wisdom Industrial Power Co., Ltd. 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. Thanks in advance. It is 80 ohms for just being on the safe side. 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 purpose of these resistances is just to limit the current from the transistor and the LED. Even protection circuit is added on lithium batteries, users should avoid over charge and over discharge during the use of lithium batteries. 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. To protect the load and battery from over-discharging, we will build a protection circuit for 12V batteries. A current limiting resistor is connected in series with the LED to avoid any damage to the LED by excessive voltage. In this project, the zener diode used has 6.2 V/250 mW rating. They also disconnect the battery in an over-voltage situation, so protecting sensitive electronic appliances from damage resulting from faulty alternators or chargers. $11.29. 12V Battery Charging Controller Protection Board Module, Undervoltage Low Voltage Cut Off Automatic Switch Recovery Protection Controller Module United States Patent 6617069 . The circuit designed in this project has the following circuit sections –, 1) Zener Diode Circuit for detecting cut off terminal voltage of the battery, 2) Transistor circuit to operate the relay, 3) Diode circuit for back current protection, 4) LED indicator circuit for indication of battery discharge. The other case can be when the Terminal Voltage of Battery can be below 6.2 V. When the battery voltage drops down below 6.2 V then the zener diode will no longer remain in the conduction state. The inductor will discharge through this diode and this will prevent the other circuitry from any back current. The circuit includes an LED indicator section also which will light up the LED as the battery discharges below the limit and require recharging. |, “Is your battery protected when battery is over-charged or over-discharged?” Our customers usually asked this. When a battery is charged, its terminal voltage i.e. THE BEST LITHIUM BATTERY FOR SOLAR STREET LIGHTS BSLBATT Lithium is China’s Lithium battery m... Years ago, when an application required 36 volts, the best option was to connect three 12V bat... 48V Lithium-Ion Battery for Hybrid Power Solutions of Telecoms & Off-Grid Sites Now at a voltage below 6.2 V the transistor Q1 will conduct but it will not in its full saturation state. But in the experiment, resistance R1 is higher than 55 ohms. To safely utilize lithium-ion or lithium polymer batteries, they must be paired with protection circuitry capable of keeping them within their specified operating range. The Terminal Voltage of Battery can be above 6.2V- When the battery voltage is above 6.2 V then the cathode of the zener diode (D1) will be above 6.2 V. In this case, zener diode will breakdown and will start conducting from cathode to anode terminal (as shown in below image). MOSFET selection. Active 6 years, 3 months ago. Crt monitor clicking sound and image shrinking and expanding in loop, can someone help ? Features: 1. Digital Low Voltage Protector Disconnect Switch Over Discharge Protection Module for 12-36V Lead Acid Lithium Battery 4.4 out of 5 stars 221. Your email address will not be published. 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. Opens image gallery. 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. That is why the sales from BSLBATT usually ask our customers to tell us the application of their battery, the charge condition and discharge … 2,777 With the use of series resistance, zener can provide a regulated voltage at the output. 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. A complete battery-pack circuit, the bq77905 uses external FET switches for charge, discharge, and protection control. There are two Li-ion batteries connected in series so they have a total 6V end of discharge voltage. So to be on the safe side, the cut-off voltage can be taken 6.2 V and therefore, a zener of 6.2 V is used in the circuit. 12V batteries are widely used by makers in DIY projects, solar power supplies, etc. In this electronics project, a zener diode based circuit will be designed to protect a battery from over discharging. Over Discharge Discharging the battery will cause the cell voltage to drop. voltage between the anode and cathode of the battery increases. Discharging a lithium cell this low is stressful to the cell and reduces cell lifetime. When a battery is charged, its terminal voltage i.e. “Is your battery protected when battery is over-charged or over-discharged?” Our customers usually asked this. Viewed 2k times 3. On September 23, 2015 at 5:43am In this era of portable electronics devices, most of the electronics run on batteries. Thus the entire collector current gets a shorted path and current will start flowing from collector of Q1 to its emitter, finally to the ground. The transistors are used as high side switch in the circuit where two stages of transistors are operating as logical invertors. 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. Battery over-discharge protection . A good battery protection circuit will also provide over-discharge protection. Free shipping . A battery will have more capacity per charge if it is discharged all the way. Various battery chemistry require specific charging profiles to optimize performance and prevent safety issues during charge. Image not available. Required fields are marked *, Welcome to Wisdom industrial Power Co., Ltd. All rights reserved. When the zener diode is in non-conduction state and there is not sufficient voltage at the base of the transistor, the collector current is short-circuited to ground through emitter and collector voltage is dropped. So current in milli-amperes will start flowing from collector to emitter. AFAIK, for example, AW over-discharge protection will work with relatively high discharge current, but the trigger is set too low for a low amp application (where the voltage drop, under a light load, is minimal). Let's take a look at a popular protection board circuit in use on 18650 batteries, the Tenergy 23002 PCB with a … A battery stores the charge and then supply that charge to power up any electronics device. Customer Support and Superior Service. This degrades the recharge capability of the battery as well as its efficiency. The selection of zener series resistance must be chosen wisely so that it will not allow current more than the zener rating. When the two Li-ion batteries will be connected with the load then there can be two cases as follow –. The DW01A chip is a battery protection device for a single cell LithiumIon battery and it protects the cell from over and under charging,reverse connection and short circuit. All Rights Reserved. Since batteries do have nice price tags, it ultimately adds up the maintenance cost of any electronics device. 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. Discover over 476 of our best selection of 1 on AliExpress.com with top-selling 1 brands. Until the terminal voltage of the battery will be above cut off limit and the peak reverse voltage of the zener diode, the zener diode will remain in conduction state but as the terminal voltage will drop below cut off and the peak reverse voltage of the zener diode, it will go in off condition. 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. Assuming a .9V cut-off per cell, that'll mean a 7.2 cut-off voltage. voltage between the anode and cathode of the battery increases. Tacho feedback to 555 pwm motor speed control. You can determine if this is so by checking the voltage between the 3 wires - black to white should be 3.7 (nominal), and white to red should be the same -- assuming a "balanced" battery pack. The circuit is based on the working of zener diode. 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. 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. As internally the relay has an inductor coil this coil stores some charge when the relay gets activated or energized. 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. However, this is stressful on the battery and will reduce the lifetime of the battery. A major problem with the use of batteries is their over discharging and overcharging. If the terminal voltage of a battery goes below a lower threshold limit, the battery starts dying prematurely. Specifically, in this project, two Li-ion batteries connected in series will be taken as power supply unit. 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. Note that up to five cells can be monitored and balanced. Top Rated Seller Top Rated Seller. When the collector of the transistor Q2 will provide ground to one end of the relay then only, the relay will energize. Shop the top 25 most popular 1 at the best prices! Provide many protection functions against overcharge, over-discharge, short circuit and overcurrent. Once the charger enters constant voltage mode it is important to ensure the charge does not exceed the maximum level allowed to avoid exposing them to overcharge conditions as it can cause excessive internal temperature rise and lead to premature failure. Over Discharge Conditions Typical rechargeable lithium cells can safely operate down to 2.75V/cell. 2. Induction cooking etc. Fig. It is always recommended to follow cell manufacturer’s specific electrical parameters such as maximum discharge/charge current, operating Voltage, as well as operating temperature as they are some of crucial design elements to ensure battery safety, performance, and longevity. In the specification is written: … The use of batteries requires its own kind of precautions and handling. Consequently, a battery which has been over … So the base of transistor Q1 will start conducting and acts like a close circuit. Discharging a lithium cell this low is stressful to the cell and reduces cell lifetime. NiMH cells are cheaper and safer than lithium ion batteries (brand name vs brand name), and, like Li-ion batteries, can deliver a lot more current than alkaline cells. 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. Various considerations must be given prior to designing a device requiring rechargeable Lithium-ion batteries. Generally, almost all Li-ion battery chargers use a constant current/constant voltage charging algorithm. A good battery protection circuit will also provide over-discharge protection. A key element of a battery protection circuit are the MOSFETs used to switch the cell in and out of the circuit. 4) LED indicator circuit – The LED indicator circuit is connected at the NC point of the relay. The base of the transistor Q2 is connected to the collector of the transistor Q1. The over-discharge protection threshold also has an impact on capacity/charge and cell life. 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. The 10k pre-set resistor is used to calibrate the readings on arduino; these readings are used by arduino to trigger the relay, the calibration of this setup will be discussed … The output will typically turn back on once the cell voltage rises above a preset “on” threshold. Suitable for discharging protection of all kinds of batteries. Protects against, over-charge, over-discharge, short-circuiting, and potentially other things. As the base of Q1 transistor is connected to the anode of zener (as shown in below image). These issues are often ignored by the consumers too. Typical rechargeable lithium ion battery cells can safely operate down to 2.75V/cell. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media Privacy Policy | Advertising | About Us. However, when it comes to over-discharge protection the limits are set very low: 2.7V or 3V. Charge Controller For 12V Battery Over Discharge Under Voltage Protection. Both of these issues affect the life of a battery and cost the end user needlessly. Therefore a diode (D3) is used across the relay to prevent the circuit from the back current when the relay is de-energized.