Thanks. I have studied required things, gathered information, I get to know how these electronics components works practically. … The resistores in this circuit, I presume all 1/4W… or is there one or more that isn't? The 10K preset associated with the above IC is set as per the battery voltage which needs to be charged. If the V-in of LM 338 is 35volt, is there any damage to LM 3915 ?regardsKanta. I would recommend you to build it as per the lat diagram explained in the following article: https://homemade-circuits.com/2015/12/lm317-with-outboard-current-boost.html. I am using the circuit no 2. the circuit with BC 547 replced the SCR which is in this link:https://homemade-circuits.com/2013/08/3v-45v-6v-9v-12v-24v-automatic-battery.html. first try to make a design fulfilling a single feature, could be the auto cut off feature and once you succeed with it then you could move ahead with the additional ones. Can i just prototype it using breadboard also ? After referring to the diagram I should be able to provide you with my opinion. Here, the adapter is your 10V supply source.the shown battery(+)(-) goes to the input of LM338.D2 anode disconnects from the shown points and connects directly with the batery(+).The output goes to the GG input supply port. Cut off battery charger Open in Editor. My question now is, instead of connecting the charger externally, can i transfer the charger inside the inverter’s frame and then connect the charger’s output directly to the battery terminal inside the inverter’s frame? 3. i am having littlebit knowledge of electronics. The input voltage supply is from 3-27 V and the current is also variable for different batteries to charge 2. i want to ask you which resistance is required to glow an led by a 4v battery having volts b/w 3.6 to 4.2 v otherwise when volts going low than 3.5 the led will off.please sir reply answer of my question.thanks a lot in advanceShow less. You can connect the 1.5V supply across pin#5 and ground. Then, we will turn the potentiometer of the adj pin of LM317 to set the cut-off voltage (ie. By doing this, the charging process is started.4. It will do, it's only for stabilizing the LED illumination, nothing more. The ideal transformer would be a 12V 10 amps which will become 16V 10 amp after rectification. Input 12v 2amp DC , battery 12v 7ah , need to connect WiFi modem for uninterrupted supply , I request you to please let me know necessary modifications . By the way why don't you opt for an opamp based circuit? Can i use the first circuit with scr to do same function as the last? Depending on whether or not pin9 of the IC is connected to the positive, the LEDs may light up all together or only one at a time during the sequence. instead you can do it over a PCB by soldering for better results. Hi again, Swagatam , and thank for you feeback, a support joy you show me, I will share with you. When i checked the logo of the IC, i found the logo is different with the one i bought in singapore. 3.Reduce the value of R1 to 180 ohms. Where should the middle of the 10k preset in adj pin of lm338 be connected. The solar panel consists of solar cells each rated at 1.2 volts. I want to use the Voltage Ladder Camera Flasher circuit to turn on the LED. With the charger in operation (power on), We will put the cut off switch in the position to cut the connection between base of BC 547 and the LED collector of BC 557. However please note that all PNP device parameters must be measured with respect to the positive line , not the negative line….so for thee BC557 you should measure its base parameters with respect to its emitter which is associated with the relevant positive line. I am a novice in electronics, so here is the question? and is it auto cut-off? BC547 is also operating correctly, it's only LM338 which appears to be faulty. if the main power is not there then will be diverted to battery power. Hi Solomon, I have replied to this question which was asked under LM317 current boost article, Hello sir, pls i need a little modification for this circuit, i want to attach a buzer that will make an alarm when battery is low, pls help me to modify it. I don’t really know if the schematic you recomanded me is better, and if so, please explain me why. hence i need the circuit above mentioned battery checker. cause isn’t the voltage regulator outputting a voltage higher than 12V? And also…i bridged collector of 557 (there is 1.7V when it's closed) with the gate without LED and resistor, but when 557 is closed, these 1.7V drops to 0.4V so the gate can not close. however, when i touched the Ry which is current control resistor, it is very hot. the collector LED of BC557 must light up….because when the B557 is ON, current from the 3915 LED rail will enter the emitter of the BC557, come out from the collector, pass through the LED, enter the base of the BC547 and reach the ground through the emitter of the BC547…this must illuminate the LED. yes the LM31915 will continue to monitor since it is directly connected with the battery supply, you can use any SCR, but BT151 is rated at over 1 amp which is not required, it just needs to be 100mA, hello sir i have got a tip142 rated at 100v collector current current ic 10amp. Se my new diagram (with a fan speed controller (LM358) to a fan mounted at LM338 cool radiator ribs)): https://drive.google.com/file/d/1BcWFbQ4H9nvMQs__i-Ixc0oCYdoVJD96/view?usp=sharing. Check the voltage at the preset slider pin, while adjusting the preset as this voltage rises the sequence should shift from pin#1 LED towards pin#10 LEd and vice versa. I will manufacture the circuit, and hopely it will work. 1. Alternatively if you you are interested in making the circuit respond with all batteries from 3V to 12V then you may adjust the LM3915 preset such that the last LED barely illuminates at 14.4V. Now, i suspended all the making proses, until i get the new genuine IC. Apply a relatively higher DC potential at the input of the IC LM338, may be a 9V or a 12V input. The transistor is hot, but the LM317 is normal warm. Read 6v Battery Charger With Auto Cut Off Circuit Diagram PDF on our digital library. Best regards, Mihai. I read somewhere that when you’re charging a battery the voltage should be higher than than the battery voltage. I am afraid that should not happen, with pin9 connected to the positive supply should produce a sequentially increasing or decreasing bar graph type illumination on the LEDs in response to a varying voltage at pin5….this can be confirmed by adjusting the pin5 preset…, just move the 10k preset clock/anticlockwise at pin#5 and check whether this happens or not…. LED connected at pin#10 is the last LED. I was planing to charge 4 NiMh AA cells.The connection of the base of BC557 is to the A or K of the LED's?Can I use a 12V power supply in this circuit? ground indicates the common negative supply line, yes it should be connected to the negative point of the bridge rectifier. I also saw another website saying that R4 should be 100ohm and another saying it should be 2.2ohm otherwise theres a 5v drop over R4 but why even have R4? I noticed that pin 3 of IC is connected to V-in of LM 338. regards I meant as inverter having battery input wires, red and black out from the inverter’s frame, if now i want to charge the battery of the inverter, i must connect the battery through external charger. I'm a total noob though, so I have a few questions: 1. Note LED1, marked with a red circle, cut off voltage at measured charging voltage, 27.5 volts in my project, is this connected to the correct side, inverted / not inverted side of Op amp.? I have found a Step up converter, max 15A in / 440 watts, where I have to convert 12 volt voltage in the vehicle up to approximately 27 volts which is applied over the LM338K input (TO3 ver.) Daniel,did you make the circuit as it is shown in the diagram, with the start button or did you do any other modifications?The DC input to the circuit should be 14V DC and the connections to the relay should also be exactly done, and the input current should be rated at 1/10th of the batteryAlso did you follow all the instructions mentioned in the article? The circuit uses a 12 volt solar panel and a variable voltage regulator IC LM 317. This battery charger circuit provides the Automatic cut off the facility when the battery gets fully charged. To overcome this problem, i then connected the 7805 to the output voltage of 7815. ..BC557 and the BC547 together form a latch circuit, make sure this latch is working….so that the collector LED of the BC557 holds and latches-on once its triggered. Beacuse in other circuits, i've seen this to be marked with a small curve in the place of the crossing… (for not connected wires)For example the gate is connected with cut off LED in the one side, and in the other with 33uF + 1K + cathode, right…?Thanks! Notify me via e-mail if anyone answers my comment. Hi Muhammad, even a single of these cells cannot be charged using a cell phone charger at normal speed because each of the cells will require an optimal rate of 2 amps, that means together all the 4 would require around 8 amp current. From now on, the current is disconnected when the battery is charged. The project is the NiMH battery charger circuit with automatic cutoff when fully charged. It will be difficult for me to troubleshoot because I have no idea what kind of fault may be hiding in your prototype. Part 2: DIY Universal Battery Charger Circuit with Variable Auto Cut-off. Now each pinout of the IC corresponding to the relevant LED would sequence at the rate of 14.4/10 = 1.4V, therefore for a 6V battery the full charge LED pinout would be 7/1.4 = 5, meaning the 5th LED illuminated would indicate that the connected 6V battery is now fully charge. In this tutorial, we are making a simple transistor based solar battery charger with auto cut off function. Just before the IC or other place you have figured? Can you help me? Here is a simple but effective battery charger circuit using IC LM 317.The circuit can be used to charge 12Vlead acid batteries.The circuit is very simple and can be easily assembled on a general purpose PCB. What is actual value of the capacitor(2.2) above the battery?? I have already explained elaborately regarding the connection of the 10K resistor or the base of BC557 with LM3915 pinouts, please read the article in detail and build it only if you have understood the circuit well, otherwise you may fail to succeed. Hi sir, does it mean that I need to set the 2 potentiometers per voltage level to activate the auto off function. Now my question is, i want the output to be 5A, can i limit the 6.5A with a resistor using ohms law? And then it is getting autocut but still is showing 0.8 -1.0 amp. can you please design it for me…internet have so many designs but anything have not a circuit of both charging and discharging in one design.. all have one charging circuit and another design for led driver. https://homemade-circuits.com/2012/07/make-6v-4ah-automatic-battery-charger.html. Connect heat sink with voltage regulator LM317 to avoid thermal runaway. Sir suppose I want to charge a 12 v battery so which pin of LM 3915 should be connected to 10k (to the selected ic pinout ), first feed 14.4V supply and set the IC3915 preset such that the 10th LED just lights up at this voltage. so please do not force higher voltage across it, it will only damage the battery in the process. When the battery charge reaches 13.66 or 13.7 volts, rotate the resistor with a screwdriver slowly until the green light turns on. LM338 can deliver 5A max, how can I connect 2pcs LM338 in parallel that can provide up to 10A charging current and drastically reduce the charging time? May i repeat the problem now is, the cut off beepper sounds but the cut off led remains off when the relevant pin of 3915 get activated.RegardsKanta. A 0.01 uF bypass ceramics disc capacitor is connected from collector to ground. I am trying to charge 3V batteries with automatic cutoff but trying to do it reasonably fast, Hi, you can replace 1N4007 diode in series with the battery positive with an emitter follower stage. You can opt for some other simpler circuit for charging the battery and use the LM3915 separately for getting the indications…. Pls correct me if wrong. Hello sir, i have a little problem with this circuit, LM338 is not available in my area, i have another alternative which you will help me comfirm and modify. And what do you mean by saying "opt", optimise? Thanks sir this is the most helpful site I ever visited and you are the most helpful person i know till now . i think this is a pretty cool website im glad i stumbled opon it , ok my question ,wich i will have many more on other projects later on , but for now i was wondering ,i am disabled and dont have much money but i do have a pile of electronic equip of variouse brands and type ,is there cirtain items that may have the same parts you listed that i could break into and reuse i am very resourcefull and i love to make tools and such from old electronic equip. I guess R4 is there to limit the charging current. The transistor BC557 remains switched OFF as long as the last LED in the array which may be selected for the full charge indication is not illuminated. What do u say sir? This circuit will give adjustable DC supply output and charges battery ranges from 6 volt to 12 Volt. since each pinout for a 12V battery would correspond to 1.2V, two of them would enable 2.4V difference, so last two pins will mean the battery getting cut off at 14V, and restarting at 14 – 2.4 = 11.6V. By upgrading the above-shown scheme, or you mean to use some other scheme? I need your help. 1.Increase the value of R3 to 33K. Thank you Mr.T.Andersson, I appreciate your interest and curiosity regarding the concepts explained above. The only difference is i put some cooling cream in this charger unit and the cream is touching the Adj and V-in pins while there is none in the PSU. yes that will do, the setting up procedure is explained in the article, please go through it thoroughly, Noted sir, thank u so much for your patience and clear explanation !! Siri want to make a light, with rechargeable battery, battery charging keep plug in with over charging breaker. The circuit is a 6V LM317 voltage and current control battery charger circuit which generates a regulated 6V DC output. A bypass 10uF/50V tantalum capacitor is connected from ADJ pin of LM317 to ground.12. you can use the LM317 with an outboard transistor. SET the preset to get a precise 14.8V cut. [1] "Do not connect the battery initially and also keep the SCR gate disconnected from the BC557 network. My need for charging is: During long driving hours, during holiday periods, in my vehicle my wheelchair can be fully charged. I read on the internet that for a Ni-Mh accumulator, the voltage across it is not a precise indicator of it’s state of charge, or the circut doesn’t works by this method? Sir I have designed the circuit and am facing a few problems…please may I get your contact details. After the previous automatic battery charger circuit, I was not satisfied. I dont know what is causing this. That is, outside the circuit could not drop out of power. And another question, i found on the internet the next schematic: https://www.shdesigns.org/pdf/lionchg2.pdf I built it and charged the accumulator at the preset voltage of 11.2 V, but i stopped the charging process manually when the voltage across it reached 10.1 V. I would like the charging to stop automaticly, but what would be the preset voltage? Frequency Modulation reaches several meters to kilo meter with low …, This LDR switch relay circuit eliminates the physical contact with …, Here we added sound with visual output, yes the LED …, In some case we need temperature dependent output or temperature …, Emergency lights are very crucial in some situations, the traditional …, In this circuit LM3914 bar graph decoder IC used for …, Battery charger circuit diagram with auto cut-off. the positions are clearly shown in the diagram…. Is there any effect for higher or lower voltage zener diode in the circuit? Hi again…I remade the circuit again, and i designed it the same way as it is in the circuit scheme, so the pot under LM338 is adjusting the output voltage, but the diodes are ALL DEAD, (no matter if there is connection between pin#3 and pin#9 for graph bar mode) and the pot undr LM3915 is doing nothing…Can i ask you to chek the connection lines – this is the pic i uploaded in some web site for uploading photos: s22.postimg.org/rdai1fw5t/20150828_112454.jpg. can i use this circuit to charge a 4v lead acid battery. The circuit can be used for charging 1.5V, 3V, 6V, 9V, 12V, 15V, 18V, 21V and 24V batteries, in fact any voltage that may lie between 1 and 24V. I would use technical form 3, For an automatic ON / OFF function. Does it make any difference charging 6 AAs linked in series rather than a single battery?2. I try prototyping the 6V,12V,24V battery charger circuit as u suggested. when the LED illuminates at the relevant pin of the IC which is connected with the base of the BC557, the BC557 base receives a low signal which forces it to conduct. Hello Mihai, I think your battery full charge level is 8.4V, and the printed value is 7.4V (3.7 + 3.7 = 7.4)….So make sure your battery does not charge over 8.4V, otherwise it can get damaged. Thanks. im daniel Ok sir thank you advice now i received your message.How to make a High Current 100 to 200 Amp Automatic Lead Acid Battery Charger Mr,Swagatam i like your good work you been doing so far i do like your project.my firs quotation is this 12v battery charger circuit i build it but when i power the the circuit relay switch correctly but the problem is out put is 11v and if i calibrate 10k preset to left side it switch on the relay and it give 11v out put if i calibrate to right side it switch off the relay and give me 13v out put why sir any help? please reply sir,denoyjohn@gmail.com. After that, we set the charger output voltage using potentiometer of the adj pin of LM317 ( this will be 7.3V), we then connect a discharged battery, and we turn on the cut-off switch (to connect the base of BC 547 to the LED collector of BC 557). It’s my pleasure Habtanu, please keep up the good work! 8. I miss the first number.ThanksRegard,Kanta. But sir can i use 4.7 mf instead of 2.2 mf . Hi Solomon, the ideal charging rate for any lead acid battery is 1/10th of its Ah level, but this not entirely critical, if you are using 6.5Ah that’s only marginally more, so no problem you can go ahead with 6.5Ah and still charge your battery safely. Goodluck Sambath kumar. And the charging imput for this type of accumulator? I.e (7.3 + 6.4 )/2 = 6.85 which is about 6.9V. Required fields are marked *. use the middle pin and the any one of the outer pins, leave the outer pin unconnected…, how to create a emergency light over charging breaker. Change the value of R4 to 22 0hms 3 or 5 watt. yes you can do that, no need to isolate the battery from the inverter, just make sure the inverter is not turned ON while the battery is charging, or until the battery is fully charged. Last Updated on July 15, 2019 by Swagatam 285 Comments. I planned to attach a beepper to indicate the cut off of the charging using IC 555 beepper with buzzer circuit, may i know how to put this into the charger circuit? zener model is not important, the voltage rating and watts are the only things that matters. once again it take it's own time to discharge fully. In the future, I will try to learn more from your experiments. Yes you can salvage most of the passive parts except the ICs. But, the series resistor (at the ground) for over current control is 0.167 ohm 6W (i connected 3 pieces of 0.5 ohm 2w by parallel) and this is very hot. current on ammeter. I am planning to make a detector device for sensing the water pipe in the wall so as we will not drill the wall with the water pipe in it. sir,i have 1 w Led and 4 v 0.8 ah battery.what i want is a light on a battery so that if there is no ac to charge battery light works for atleast 2 hrs. but then there is base to emitter drop as well as some drop across base resistor, R3…. 3v, 4.5v, 6v, 9v, 12v, 24v, Automatic Battery Charger Circuit with Indicator | Homemade Circuit Projects An all-in-one automatic voltage battery charger circuit is discussed in the following post; the circuit can be modified in many different ways as per individual requirements and applications. For this you may incorporate the following design: 1.bp.blogspot.com/-I2zlapFq6RM/UML_NxUJy2I/AAAAAAAAB3w/27ZLDjK9C9g/s1600/simple%20modem%20UPS%20circuit.png. It uses an Adjustable voltage regulator so that 6 volt and 12 volt batteries can be charged. The solar panel consists of solar cells each rated at 1.2 volts. And in this state the transistor will be in the activated mode…while with zero volt across its base/emtter it will be switched OFF. Hi chandrashekhar, you can use the second last concept from this article: https://www.homemade-circuits.com/usb-automatic-li-ion-battery-charger/, use 12V as the input instead of the shown 5V, and set the preset for the desired level cut off. This 12v battery charger circuit with Auto cut provides the Automatic cut off facility when the battery get fully charged. Aditya, yes that’s right, the external voltage should drop to the discharge level of the battery and this data must reach pin5 of the IC through the potential divider network…make sure the source current is significantly lower than the battery Ah value. I think you should use the following circuit for your battery: you can use 50% current rate for the charging, meaning at 150 mAh if you want a fast charging, but lower than this will be safer, so probabaly 100 mA will be OK. Set Rx to = 0.6 / 0.1 = 6 ohm, 1/4 watt. ion battery, that voltage is correct for the standby battery its range is from 13.6 to 13.8, usually 13.5 to 13.8 with room temperature. Sir I’m from the Indian naval academy and its difficult for me to access the internet..i request you to please share your contact details. The heart of the circuit is IC LM 317 … You have a nice calculation technique for the LM3915, as follows: “Alternatively, if you are interested in getting the circuit to respond with all batteries from 3V to 12V, you can adjust the LM3915 preset so that the last LED light barely lights up at 14.4 V. Now each pinout of IC corresponding to the current LED sequence at a speed of 14.4 / 10 = 1.4V, therefore for a 6V battery the LED pinout with full charge would be 7 / 1.4 = 5, which means that the fifth LED will indicate that the connected 6V battery is now fully charged. As per our directory, this eBook is listed as 6BCWACOCDPDF-174, actually introduced on 21 Jan, 2021 and then take about 2,737 KB data The IC spoiled. 3) you can use the middle lead, and any one of the outer leads of the pot, the third one can be left open or unconnected. ThanksRegardsKanta, If the pot is getting warmer then that's a clear indication of a malfunctioning LM338, Hi Mr Swagatam,For your additonal information, the Cut off was wroking properly before the LM 338 got damaged.Regards,Kanta, Two days ago the 12V battery was charged completely, the final voltage of the charged battery reached 13Volt. I am making a circuit using a Arduino and a servo to lift a lid with mechanical arm. When i checked the voltage were as follows:On BC557:Pin Base was 4.3VPin Emmitter was 4.8Vpin collector was 3.1V, On BC 547:Pin Base was 0.6VPin collector was 13.6V. 2. An all-in-one automatic voltage battery charger circuit is discussed in the following post; the circuit can be modified in many different ways as per individual requirements and applications. what does ground mean in this circuit?? this might be caused by the damaged LM338 (non genuine IC) in the past. Please help me out sir I am just a 8 grade student and i had a bit knowledge of electronics but i am also a electronic hobbiest . My name is Goran,and i want to ask, up to what current can handle the charger circuit (for a long time charging)? But YES, sometime the LEFT MOST LED is flickering. 2. But in this state it becomes very hard to lit it up steadily, as on a little bit adjustment, the LED right of it goes on, n it goes off. Hello Goran, you can increase the base voltage of the BC547 by replacing the 3v zener with a 6V zener diode. Another question is about the method of detecting the charge state of the accumulator. https://circuits-diy.com/battery-charger-circuit-for-12v-6v-batteries Thank you Anderson, I appreciate your interest and efforts, however it seems the link you have sent was not set to the shared mode, and therefore it isn’t opening at my end. But Cut Off LED remains off for all other setting. pls send me a circuit diagram for Li Sorry for concerning you about this, but i want to make this circuit, and if you have any other ideas, i would be glad to hear them, so thank for the help! The IC has ten linearly incrementing output which sequence one after the other in response to a rising potential fed at its pin#5. and when ac light is there battery charge and it stop charging when fully charged. so where can i place it and which rating if am charging batts between 100Ah to 200Ah thanks. The instructions given below will help you to understand regarding how to quickly set up an opamp 741 battery charger circuit for an auto cut-off operation. here's my email for better comunication, mamdouh.mikail@gmail.com. Solomon, you can use LM3914 instead of LM3915. thanks. now wil i need to add a resistor. the best place to contact me is through the comments in my website, just as we are doing now. Hi Kanta, the circuit results indicate that except the LM338 stage rest all are working as proposed in the article, so that's better. I found such a connection, but it may indicate it would be difficult to fit into diagram # 3. https://1drv.ms/u/s!AizwNFNuGCzdtIxNDWUJJql4ORm_nw?e=nhn7wJ Do you have another better idea/solution to gain up charge current? That's it the circuit is all set now. How could i set the current to battery to 1/10 of capacity (28mA) ? The circuit what you are about to see is a smart battery charger based on ATMEGA8A with auto cut off.Different parameters are shown via a LCD during different charge states.Also the circuit will make sound via a buzzer upon charge completion. Do you have any ideas where is the problem? what exactly are you tying to make? Hello Goran, the maximum current output is 5amps, you can upgrade the IC LM338 for more current by following the steps explained in the following article: https://homemade-circuits.com/2015/07/designing-customized-battery-charger_13.html. The battery now stops receiving any voltage and thus it is inhibited from getting over charged. Hi Swagatam,Can I charge NiMh batteries with this charger? Replace the transistor base resistor with 10K Use a 16V input with 1 amp current. that will also provide you with an effective auto cut off…the above design can be a bit complex for any new comer.