Homemade BMS - Balanced LiPo Charger Multiple Cells and Current Limit

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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

[@tom95076]

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.

[@Undermada]

Probably one of the best videos I've ever saw with explanation of BMS! Thank you!

[@ShivamKumar-rp8kr]

I understood it well. Thanks for the simple explanation and animations. Loved it. ❤️

[@JohanDegraeveAanscharius]

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!!

[@DrJALAGHARI]

What an easiest way to explain the difficult concepts. Amazing.

[@Eduardo_Espinoza]

True, this is honestly why i stopped electric builds years ago

[@ELECTRONOOBS]

Arduino Course LEVEL 2 (Spanish): bit.ly/2ZNWgqy Follow me on FACEBOOK for more: facebook.com/Electronoobs Help me on Patreon: www.patreon.com/ELECTRONOOBS

[@len8752]

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

[@jackwilliams2010]

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!

[@ELECTRONOOBS]

Thank you very much!

[@stevenA44]

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.

[@officializm4171]

Very informative content. Dispelled many confusions. Thanks.

[@maungmaungtint8572]

I had to build this circuit. Good working . Thanks a lot for your sharing of experience.

[@mickeyfilmer5551]

excellent ! concise ,informative and articulate !

[@ricardosanchez1638]

Excellent! Bravo bravo, great presentation!!

[@backdemoletor4654]

Finally another great video to watch

[@valteroscarjentsch]

Faz tempo que estava procurando um circuito como esse. Muito bom. Interessantes explicações. Congratulações!

[@sebastianelcaio8040]

Amigo, que buen proyecto!!!! muchas gracias!!!! saludos desde Argentina GENIO

[@ronostrenski8359]

Thanks. Built a 5S version and works well.

[@rolandoreytorfonseca3112]

Excelente proyecto! Muchas gracias desde Cuba

[@jstro-hobbytech]

What an awesome circuit and I actually have all the components except the battery box but I could just print one

[@captivator13]

Awesome content, Thanks bro :) Sam 🎵✌🏻

[@artursmihelsons415]

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!

[@BorisSiber]

Thank you. May the force be with you :)

[@fiandaja2594]

Thank you for the circuit explanation

[@IgorSantarek]

This is great explanation!

[@Clark-Mills]

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.

[@mahargha_debnath]

bro have you tested your circuit please tell me it'll be a great help

[@suzznshkya1098]

So the reference pin of tl431 must be between R1 and R2 resistor?

[@InduwaraPerera_YT]

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.

[@alexvanstaden6734]

I also found that out after struggling setting the TL431. Good observation

[@waltercortescarvajal7254]

Hi, would you be so kind as to share the corrected plan, with the values of each component, thanks

[@power-max]

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.

[@vtorsi610]

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.

[@Brian_Of_Melbourne]

Look at Adam Welch's channel kzbin.infovideos and search for 'diyBMS'.

[@olaleyejoshua949]

Good 1. Thanks for sharing the knowledge.

[@vobinhthu5299]

This project is very good!

[@rinokentie8653]

Very interesting again!

[@JamesFraley]

Great tutorial. Thank you

[@ScienceLab760]

Hi good video I always enjoy your content and learn about electronics, thanks for share

[@inventorkr1]

Great video my friend👉❤️

[@prashantrai5102]

THANKS THANKS THANKS A LOT FOR THE WONDERFUL EXPLAINATION

[@greatrespect1549]

Your intro is great.

[@AndriiBilous]

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.

[@mahmoudtayel229]

The best one ❤️😃

[@vojta2519]

Super video! Thanks

[@sinjhguddu4974]

Very educative!

[@Rick_Sarkar767]

You are Legend Legend 🥰🥰💝💝

[@hoofheartedicemelted296]

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.

[@edwinr4378]

Thankyou so much❤️❤️❤️❤️ Awesome 😘

[@Dark_Phoinix]

now need one with thermo control! gj!

[@Steve-wx1gk]

Thank you so much mate :)

[@richardandrade6079]

Un sub mas te felecito lo estaba buscando gracias Dios te bendiga

[@venom_ftw9316]

Thank you so much for this. What about for Parallel cells?

[@startcherif]

Very nice video

[@dharmakissoon]

hey great vid mad props. can this that lead battery charger?

[@Johnpugwash]

ThanQ excellent explanation 👍

[@user-ih3kk8lh1v]

Nice video! What benefit is there to using this circuit over just putting the diodes in parallel with the battery?

[@aprilsegura2597]

Thank you very much

[@pdanayal]

Excellent bro .what a valuable circuit. Like it .

[@JeEeEs87]

Best explanation

[@pradumanghosh2422]

Amazing !!!!

[@josedasilva4904]

Excellent BMS explanation, congrats!. I only have NPN transistors, how will the circuit be? Thanks a lot.

[@sandeepjare9403]

Very helpful...

[@leehewitt9559]

Spot on

[@Bianchi77]

Nice video, thanks, like it :)

[@tejusbm7309]

Keep inspiring more..bro

[@jainsanjay470]

nice presentation

[@nuklengnobility]

I love it.

[@nomanhossain1838]

Really nice 🥰 ❤️❤️❤️

[@shivamvaid601]

It's good. Not highly efficient but works in a jiffy.

[@technicalideas1234]

Useful video👌👌👍🙏

[@judahosuigwe]

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.

[@blmb4274]

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!!!!

[@JohnDoe-xv1se]

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?

[@purvr4626]

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?

[@Mega-24]

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!

[@shinobufookoobu4260]

Wow thanks.

[@mehdikhan]

Nice for understanding the concept of charging but there are very low-cost chips to the same thing with much more effencency.

[@akhilsubhash7644]

right

[@orwellophile]

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

[@harikamalakarreddydarapu7410]

awesome

[@user-bz3mi1vf7p]

Высококачественные видео, у этого гениального парня! и почему то , так мало лайков? Ау люди проснитесь, ваш лайк - это уважение автору видео , за его труд.

[@lexander9686]

👍 thanks brother

[@user-pl5oj1hr8n]

Very understandable. Bit what aboit parallel battery configuration?

[@OwerChildhood]

It's really good. If i want charge 5 cell. What i change in this circuit

[@High-techstuff]

Hi quality video ,have an idea for a 40 v battery pack

[@africantech5]

Thanks soooo much

[@nalinux]

Pay attention, there are several quite similar 431. The TL 431 pinout is Ref Anode Cathode, while the LM431 is Cathode Anode Ref or Cathode Ref Anode It's a mess ...

[@bartholomewkottey7230]

Good teacher! Please I need the full picture and diagram for two or more cells. The explanation is perfect! Thanks God bless you

[@superflystar8621]

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.

[@Seu_Lunga]

Maybe you could improve by using an opamp to compare total output voltage to input and cut the charge

[@VrumsAdventures]

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 :)

[@vtorsi610]

Great Idea ! Or use a Buck Converter with adjustable voltage and current regulation built-in

[@SocialPerspective101]

Can you elaborate on this?

[@VrumsAdventures]

@@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.

[@SocialPerspective101]

@@VrumsAdventures current limiter will be > 2 orders magnitude... I did not get this part

[@VrumsAdventures]

@@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 :)

[@freshersofbose456]

commercial bms also has over discharge protection and balance discharge features.

[@aymanmostafa7230]

Thank you. I have benefited from your explanation, but I have a question: why 4 diodes and not one?‏‪

[@jstro-hobbytech]

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?

[@sohamgaud7120]

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 🙏 ]

[@kasper3355]

спасибо. статья на сайте вообще супер👍💥

[@shafeeqahamed3669]

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 ??

[@clarencementor4862]

Can you explain how to make the the JLBC circuit board with the template and solder paste?

[@Guttfried]

Can you also use it to charge a battery pack (5p connection)? So not each one individually but all together.

[@lurkingcorsa10]

so charming 😃

[@aryalesmana2501]

what you're doing is really cool, but can you modify the factory-made BMS to add a full charge led

[@Avnish-sk4ll]

That's amazing

[@Avnish-sk4ll]

I am Your Regular viewer. And I Always wait for next sunday around 9pm By Indian time zone Love you elctronoobs

[@unglaubichuberlieber8048]

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 !!!

[@ramesesmoses1741]

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.

[@jllmrr_1236]

Can you also make an active balancer circuit?

[@jaymedavis7567]

The link to the site has some capacitors in the circuit. What are those for?

[@andersonmontes4033]

Nice ....

[@mitza22]

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.

[@user-kf7yc2fo2k]

Good Day is there any problem with the circuit? Can i ask since we are having trouble adjusting the potentiometer. Is there any corrected schematic and instruction on how to adjust the potentiomer? Do i need to adjust the potmeter without connecting the lm317?