Homemade BMS - Balanced LiPo Charger Multiple Cells and Current Limit
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- เผยแพร่เมื่อ 10 พ.ค. 2024
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🔥Today we test some circuits for a homemade BMS to charge, protect and balance our battery pack. We add current limit, balance mode for more than 2S packs and stop the charging process at 4.2V for each cell.
🔀LINKS
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Tutorial Website: electronoobs.com/eng_circuitos...
Schematic 1S: electronoobs.com/images/Circui...
Schematic 3S: electronoobs.com/images/Circui...
Other Posts: • Balancing unit (BMS) f...
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00:00 Intro
02:00 Why we need BMS?
03:19 How Balanced Charger Works
04:42 1S Circuit
07:25 1S Test
09:37 3S Circuit
11:17 3S Test
12:36 Thank you
Like share and subscribe to motivate me. Thank you
#BMS
#charger
#homemade - วิทยาศาสตร์และเทคโนโลยี
This project made me rethink my setup with an Adafruit solar charger. For my timemachine project to run longer using an Arduino Pro at 3.3v. I placed two Lipo Batteries in Parallel to have the same output of 3.7v with a larger running time or capacity when the sun was gone. I noticed the second battery drained more than the second battery once I place them in a commercial charger. Seeing your animations and showing single and multiple charging methods I now feel better about learning what are my mistakes. Thank You for sharing and keeping up on all the great content. Not everything is applicable but as makers we must learn from each other to share our project. Awesome overview and great tips. You are always setting the bar higher and higher for all makers.
Probably one of the best videos I've ever saw with explanation of BMS!
Thank you!
I understood it well. Thanks for the simple explanation and animations. Loved it. ❤️
I read A LOT of explanations about BMS and to really understand it well, this is really the best. I let it rest overnight, asked myself questions, and looked at it again. Really, very very very best explanation out here!!
I've watched quit a few of your videos and I just decided to subscribe. I've seen a lot of the things you make that might come in handy in the future.
Great Video! I've been subscribed for the longest of time, but every now and then, you just publish more and more explanatory and informational videos that go briefly into the problems were are trying to solve step by step, stage by stage. Thank you so much! 6/5 Starts
What an easiest way to explain the difficult concepts. Amazing.
True, this is honestly why i stopped electric builds years ago
I had to build this circuit.
Good working . Thanks a lot for your sharing of experience.
I've watched a few bms videos before this. I have to compliment on how well you explain how this works and how to build your own. You are very underrated and deserve more recognition. 5 stars!
Thank you very much!
Very informative content. Dispelled many confusions. Thanks.
Faz tempo que estava procurando um circuito como esse. Muito bom. Interessantes explicações. Congratulações!
excellent ! concise ,informative and articulate !
What an awesome circuit and I actually have all the components except the battery box but I could just print one
Excellent! Bravo bravo, great presentation!!
Amigo, que buen proyecto!!!! muchas gracias!!!! saludos desde Argentina GENIO
This electrical Circuit explanations are very good an unique on youtube, you can make much more of that.
And the way you do it, is very good, starting with the simplest case and after explaining it you explain more.
In other books, videos etc. they always start with the most difficult case as example :D
I also find didaktich very good when you ask questions.
So, for example, "What would happen if I didn't connect this capacitor"? Then the viewer has to think about why the component is connected at all.
Often, a circuit is only explained as "here comes a transistor, and behind it a resistor",
but it is not explained "why" and what would happen if this component was not connected.
I find this most important to really understand why the circuit contains the corresponding components.
Thank you! I will take a look over other circuits as well!
This is awesome sir. Is it possible to build such a circuit with 12v batteries in mind and how would the components change accordingly? Thank you.
Thanks. Built a 5S version and works well.
Error: The output of R2, R1, R10 voltage divider at 5:00 is supposed to feed into the Ref pin of the TL431 with Anode to negative and cathode to the BD140. If you just swap the AN/REF labelled pins on the schematic you should be right.
bro have you tested your circuit please tell me it'll be a great help
So the reference pin of tl431 must be between R1 and R2 resistor?
Yeah bro, I also saw there is a mistake, after i fix that issue it almost works fine, but i recommend others to use 22k and 1k resistors for that voltage divider connected to tl 431 ref pin cause the ref input voltage is higher when you use two of 20k resistors.
I also found that out after struggling setting the TL431. Good observation
Hi, would you be so kind as to share the corrected plan, with the values of each component, thanks
Nice build! I am looking to build a BMS for a huge build with 1000 or more 18650s I have on hand. This circuit does have quite a few important limitations though:
No under voltage protection
No over temperature protection
No over current protection.
The DIY project could be massively improved with the use of a low power microcontroller for each cell monitoring the voltage and using galvanically isolated (optocouplers) in a token ring or CAN network to transmit data back to a more powerful MCU that manages the series string.
Active balancing is harder for sure. I have one idea involving using lots of gate drive transformers and implementing small basic forward converters for each cell to dump energy into a shared AC square wave bus, but have yet to get it to work right in LTspice.
This is the CHARGING "half" of a BMS. This does not have the LOAD "half" of a BMS ( load over-current & under-voltage ). He made that very clear at the beginning of the video.
Look at Adam Welch's channel th-cam.com/users/AdamWelchUKvideos and search for 'diyBMS'.
Mmm.. LM317 old school, that always works and is tested for decades.. 👍
431 references is used even in cheap BMS modules for batteries and ultracap's from China..
Great video!
Finally another great video to watch
Thank you. May the force be with you :)
Excelente proyecto! Muchas gracias desde Cuba
Good 1. Thanks for sharing the knowledge.
Nice video! What benefit is there to using this circuit over just putting the diodes in parallel with the battery?
Nice project! The point you dont need to use 2 LM317 to limit U and I. I faced to this case as well. There is a scheme that allows to do this with one LM317. The scheme is mentioned as Load Regulation in the datasheet. Anв as usuall you need to use addшtional transistor for hight current.
Awesome content,
Thanks bro :)
Sam 🎵✌🏻
Hi good video I always enjoy your content and learn about electronics, thanks for share
Thank you for the circuit explanation
This is great explanation!
Great tutorial. Thank you
This project is very good!
THANKS THANKS THANKS A LOT FOR THE WONDERFUL EXPLAINATION
Very interesting again!
Hola buenas, muy buena idea y video, quisiera saber si puedo utilizar el LM336 en lugar del TL431 y que modificación tendría que hacer?Desde ya muchas gracias!
The best one ❤️😃
Excellent BMS explanation, congrats!. I only have NPN transistors, how will the circuit be? Thanks a lot.
Nice for understanding the concept of charging but there are very low-cost chips to the same thing with much more effencency.
right
But they all charge to 4.2v, which is sub-optimal for battery life. This circuit is great for battery packs you don’t use much, and would otherwise just zero out eventually
Your intro is great.
hey great vid mad props. can this that lead battery charger?
Very educative!
Really enjoyed the explanation. Thanks. Love to see a more efficient example (for minimal heat dissipation).
BTW: has anyone seen a protection, balancing and charging solution for four 3.7V 500mAh LiPo batteries in "parallel" and in circuit? Protection, balancing and charging, without removing the batteries. Every battery management IC manufacturer offers 1S and multiple series solutions, in circuit and out, but I can't find one offering an "in parallel in circuit" solution. What gives?
Thank you so much mate :)
Thanks so much for this video Sir.
Please I am working with a 5s battery setup, what are the changes I will have to make for an efficient charging.
now need one with thermo control! gj!
It's really good.
If i want charge 5 cell. What i change in this circuit
I am sorry if this was mentioned before but the datasheet for LM317 has an application specifically for battery charger. You can put the current limiting resistor at the output before the voltage divider that sets the output voltage... and since the current limiter will be pretty much >2 orders of magnitude less than the resistors in the divider, it shouldn't affect the output voltage. You save 1 LM317 this way :)
Great Idea ! Or use a Buck Converter with adjustable voltage and current regulation built-in
Can you elaborate on this?
@@SocialPerspective101 on what? I don't think links are accepted in YT comments (unless they're made to your own video) ... but I can try if you tell me which part you want me to elaborate on.
@@VrumsAdventures current limiter will be > 2 orders magnitude... I did not get this part
@@SocialPerspective101 I believe it's easier to try and link you to the application. The LM317 datasheet has at chapter 9.3.6 the battery charger application I am talking about. There's the voltage divider that sets the CV part and the series current limiting resistor (Rs) that will set the max value for the charging current to your CC desired value. The CC part will not really be CC, but the current being drawn will not drop significantly during this time (it will drop with (Vbat - 1.25)/R1 and Vbat increases as the battery is charged). The CV part will stop the battery voltage from rising above the desired (usually 4.2V) value. Rs is more than 2 orders of magnitude (or 100 times) less than R1 or R2... and as such it will not significantly decrease the desired output voltage set by the divider (R1 and R2). If it's close to R1 and R2 than you're either limiting the current a lot or wasting it through the voltage divider... or both and you're setting yourself up for a hard calculation and less than optimal result.
I hope this is more clear :)
Sir, we thank you very much for this beautiful and very detailed explanation. Can this board organize the balanced charging of three poles of lithium batteries of 150 amps or more? And if not, what will be the shape of the diagram that I can make with her board, please explain and help.
Thank you so much for this. What about for Parallel cells?
Super video! Thanks
Thank you. I have benefited from your explanation, but I have a question: why 4 diodes and not one?
Best explanation
Good teacher! Please I need the full picture and diagram for two or more cells.
The explanation is perfect!
Thanks
God bless you
Thankyou so much❤️❤️❤️❤️
Awesome 😘
ThanQ excellent explanation 👍
Nice Video.
So can I suggest a video that you can make.
Can you make a DIY Ossliscope. Or how to measure waves at least with an Arduino. Thanks!!!!
this looks interesting, can we replace the BJT with P-ch mosfet?
also is the ref pin supposed to connect to negative of batt or its just a error on the diagram?
Hi sir very good video and explanation I understood whole video except 1 part and that is why you have connected 5 resistors of 10 ohms in series ?? [PLZ REPLAY 🙏 ]
Great video!!
Great video my friend👉❤️
nice presentation
thanks, one question, would this work if one mix cells with different ah ???, and please stay healthy !!! and continue with your work in lithium battery cells !!!
Amazing !!!!
Un sub mas te felecito lo estaba buscando gracias Dios te bendiga
Spot on
Really impressive. Explanation was awesome and so easy to understand but I have a small question because I am new to these stuff. Question is about 4 diodes, why would we use 4 diodes and the purpose of it? I really want to know. Thanks. Good luck with your future work. ❤️👍💪
The diode servers as the load connected to the battery
@@nanfwangdabiring1520 So what if actual load is connected to the 3 batteries in series? Do we still need the diodes?
Keep inspiring more..bro
Excellent bro .what a valuable circuit. Like it .
what can you recommend for it to work on 48 volts system 200 ah life04 battery with balancing current up to 6 amps? thanks and great video.
Thank you very much
Can you also use it to charge a battery pack (5p connection)? So not each one individually but all together.
I bought a Daly BMS a long time ago and I can't say I'm happy with it cause it makes one battery go over voltage I got lifepo4 will your BMS work for me . I'm using the batteries for a solar system on my house
Hey, is there any possibility to add a fuel gauge to the circuit , so that I can check the remaining charge in the battery ? like through a seven segment display ??
I know that keysight dmm is over a decade old but it's timeless. I love it. It must be 4.5 digit is it?
what you're doing is really cool, but can you modify the factory-made BMS to add a full charge led
How can you put in parallel to the battery a 4.2 V voltage regulator if the transistor closes at 4.2V?
You are Legend Legend 🥰🥰💝💝
awesome
Thanks so much for the idea.
Have we seen how the upper threshold is limited (4.2 V), but haven't we seen how the lower threshold is limited (3.2 V) ?
Do you know a place where you can buy parts for a BMS ? I would buy too!
Very nice video
Maybe you could improve by using an opamp to compare total output voltage to input and cut the charge
Please design a protection circuit similar to this that instead shows an led for low voltage and powers the device off as the cells reach a critically low voltage
I have constructed this circuit and i have found just a few issues, but the circuit does work pretty good.
My battery was 280mAh battery, datasheet called for a standard of 58mA charge, or max charge of 280mA.. i chose 58mA.. estimated charge time ~ (280/58mA) = 4.8 hours
Because I have a power supply i figured I would skip the lm317 voltage regulation and simply use only one lm317 for CC and just use 4.2V from power supply for the input.. the issue with the lm317 in current mode is you can't use 4.2V input supply because the output will not provide CC at the given 4.2V output.. it states on datasheet of headroom around 3V or soo..
So i decided to use both lm317 for voltage and current.. like the circuit diagram shows but only CC comes first then Voltage regulation.. IMPORTANT you must have power supply 3 volts above battery level.. so for a 4.2V lipo i put a supply of 7.5V into the CC lm317 input and connected the output into the input of a lm317 in voltage mode.. with an output of 4.2V.. only needed 60mA.. P=(7.5-4.2V)(60mA)=200mW.. lm317 isn't even hot
I could have used only one lm317 in both constant voltage and current.. but would have been bigger headache in calculations because of output impedance
Also Iref into the tl431 is too low.. around 8mA is recommended.. for the voltage divider i used resistor values of 212.2 ohms for R1 and 313.5 ohms for R2.. this will provide more stable reference of exactly 4.2V
I monitored my batteries voltage and current throughout the whole charging process.. the current started at my selected max current limit of 60 mA.. the battery voltage slowly rised.. once i hit around 4.19V the current slowly slowed down to 0 amps.. then the transistor opened and the battery stopped charging.. so the circuit does provide CC charging and CV charging.. the closer the battery gets charged to the supply voltage then obviously a trickle charge to 0 amps will occur..
Overall was a great learning circuit.. learned alot about tl431 and also lm317...
idk, I'm gonna take another 5 year break of electronics
How about the scenario where max input voltage is limited to 14.7 volts?
Good job... But suppose I want to have the solar panel supply an the input voltage from 12 to 18v and want a 12 volts output
It's good. Not highly efficient but works in a jiffy.
Hi quality video ,have an idea for a 40 v battery pack
can I use a power resistor in replacement of the diodes as the load?
Really nice 🥰
❤️❤️❤️
I have a question.i have some lipo here that no matter how long they charge they never reach 4.20/4.25 volts. I was wondering how to make a circuit to show the battery is not charging properly. Maybe use some circuitry based on time lapse. Do you have a. Idea?
Just one more question: how to add a temperature control based?
Can we measure air core inductor(lower value for rf projects) by a cheap 15$ lcr meter(4070lcr meter)? Please answer me.
Nice video, thanks, like it :)
Высококачественные видео, у этого гениального парня! и почему то , так мало лайков? Ау люди проснитесь, ваш лайк - это уважение автору видео , за его труд.
How would you design a 144V battery BMS. Not sure you can simply add more batteries and listed components? Some of the components would require different component types to be able to work with potentially 185Vdc in a 120Vac standard system. Thanx again for your presentation. Learned lots from it.
Useful video👌👌👍🙏
Hi man do you think you can make a MPPT SOLAR CHARGER from a step down converter and a pwm solar regulator ? with a relay voltage protection you think you can do it ? so when is fully charged to stop conection from solar panel to stepdown module ? thank you i hope i hear from you. nice videos i watch them with pleasure.
Very understandable. Bit what aboit parallel battery configuration?
Suppose if I have connected 3 cells to get 12V and have a charging adapter of 5v. now I want them charge parallel so they could charge at all at once with the 5v adapter. is there any circuit that you can design that gives 12v output but charge cells with 5v without using multiple switches?
Nice explanation, but i was wonder how its possible in my case i make a 3s2p bms circuit? i'm having a lot of doubts about this topic, one of them is how i will make this kind of circuit and why only bms are sells with 3s, 4s, 5s options instead of 3s2p, 4s2p and soo on...
Hi, good stuff. But you make one mistake in your schematics. Current limit must go first, after that voltage regulation.
If voltage regulation have to give 4.2V, then you need to add another 2V for LM317, then you need to add another 1.25V + 2V, which means power supply must be at least 4.2 + 5.25 = 9.45V or more.
Can you please explain why the additional voltage is required?
all voltage regulators have a voltage drop ( eg. 0.7 V for SI semiconductor jonction ), for LM317 is safe to use Vin-Vout at least 3V so no way to use 5V for one lithium cell that requires 4.2V.
I ment Linear Voltage Regulator as LM317 is.