How does a BMS (Battery Management System) work? | Passive & Active cell balancing Explained

#BMS #BatteryManagementSystem #CellBalancing
In this video we will see:
0:00 INDEX
0:53 cutoff MOSFETs
2:23 fuel gauge monitor
4:00 Cell voltage monitor / Cell voltage balancing circuit
5:32 Passive cell balancing
7:21 Active cell balancing
8:45 temperature monitor system
9:41 Logbook & real-time clock (RTC)
and working of each block with an easy and understandable explanation.
Earlier Videos:
Battery management system 1 : • What is a Battery Mana...
Battery basics part 4 : • Electric Vehicle batte...
Battery basics part 3 : • What are the types of ...
Battery basics part 2 : • What is SOC, SOH, SOP,...
Battery basics part 1 : • Which Battery is used ...
EV motor controllers part 2: • Motor Controllers in E...
EV motor controllers part 1: • Motor Controllers in E...
Charging of EVs: • Working of Electric Ve...
EV basics: • How does an Electric V...
EV parameters: • What is inside the Ele...
EV Motors: • Motors used in electri...
References
1.uk.schurter.com/content/downl...
2.circuitdigest.com/article/cel...
3.www.renesas.com/in/en/doc/whi...
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Batteries - a href="www.freepik.com/free-photos-v..."Banner vector created by pch.vector - www.freepik.com/a
Spark - a href="www.freepik.com/free-photos-v..."Water vector created by macrovector - www.freepik.com/a
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Temperature range - a href="www.freepik.com/free-photos-v..."Arrow vector created by pch.vector - www.freepik.com/a
microcontroller - a href="www.freepik.com/free-photos-v..."Background vector created by freepik - www.freepik.com/a

[@rgollas]

The best presentation for dummies like me to get an overall picture of how a BMS works. Great animation and very lucid. It removed a lot of confusion in my mind. Thanks a million!

[@kumarbalaji3344]

Simply superb. I was long time fascinating about BMS. Now I finded correct source to learn basics.

[@FoolishEngineer]

Thank you so much for watching!! Please subscribe to our channel

[@rajasekaranthangaiyah5547]

I found - not I finded

[@MarioDallaRiva]

Excellent battery videos, dude! 🤙🏼 Graphics and information are first rate. Bravo 👏🏻 I've learned a lot from your content.

[@FoolishEngineer]

Thank you so much, Glad you liked it!!

[@dipakjoshi8640]

Very detailed explanation which will understandable by all level of audience. This video is nothing but a jackpot who are looking for fastrack revison before attending a electric vehicle related job interview. Thank you for adding this vital content.

[@FoolishEngineer]

I am so glad you liked it! Thank you so much!

[@minhhaonguyen1702]

Thank you for sharing your video. It was packed with exciting knowledge and contained everything I needed. Excellent job!

[@FoolishEngineer]

Glad it was helpful!

[@rushikeshmali1164]

Very informative and well explained, Thank you

[@FoolishEngineer]

Glad it was helpful!

[@muinmohammadmozammel281]

Fantastic explanation. Very much informative and well narrated. Thanks a lot.

[@FoolishEngineer]

Thank you so much, Glad you liked it!!

[@kanejia865]

Very useful tutorial for BMS! thank you!

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@paulmillard1130]

Just what I needed excellent thank you

[@FoolishEngineer]

Glad it helped!

[@frikkiesmit327]

Thank you sir that even though you are indian , you stay true to title and language. But that i mean the title is emglish and you speak english. Not like other videos with english titles but unknown languages that few people would understand.

[@FoolishEngineer]

Thank you so much! Please show support to my video with Super thanks and don't forget to subscribe to our channel

[@kulkarnipriyanka2823]

simply fantastic!

[@pyladian]

Thank you for this informative and well explained video.I have very little knowledge of electronics,so your use of simple language helped me deepen my understanding,well done!

[@FoolishEngineer]

You are welcome! So nice of you!

[@learninggivescreativity6997]

@@FoolishEngineer why RTC is used in BMS? I did not understand that?

[@saeedahmed4651]

Man amazing video..... I don't have words to explain it. You are the best teacher.

[@FoolishEngineer]

Thank you so much! Please show support to my video with Super thanks and don't forget to subscribe to our channel

[@FoolishEngineer]

Thank you so much! Please show support to my video with Super thanks and don't forget to subscribe to our channel

[@palanik1960]

Excellant well made presentation. Keep it up.

[@FoolishEngineer]

Thank you so much, Glad you liked it!!

[@Nissrine-dg6ww]

Amazing I really enjoyed this course

[@FoolishEngineer]

Glad you enjoyed it

[@vinayventura5785]

very nice , short and use full.

[@FoolishEngineer]

Thank you so much, Glad you liked it!!

[@ShubhamSharma-oq4ru]

Very nice information 👍👍.thank you.

[@FoolishEngineer]

Most welcome

[@prakashsuryawanshi6211]

Very nice and lnformative video Thank you so much

[@FoolishEngineer]

Thank you so much, Glad you liked it!!

[@Megala1867]

Superb BMS explanation sir

[@FoolishEngineer]

Thank you so much! Please show support to my video with Super thanks and don't forget to subscribe to our channel

[@madhusudhananravishankar5786]

I Love your videos. Its simple, neat and effective. The graphics are very consistent and could see the thought process behind it. Can you give us some information where or how do you make the animations in the video?

[@FoolishEngineer]

Glad you like them!

[@madhusudhananravishankar5786]

@@FoolishEngineer Thanks. Can you share information on the Animation tool.?

[@sukritapanigrahi1740]

Great videos, can you also make a video on how a motor controller changes the direction of a 3phase motor in depth ? Thanks!

[@FoolishEngineer]

Yeah sure, I'll add it in my list.

[@notnecessaryok8066]

Sir we are waiting for this. ..

[@emissary1952]

Amazing video, thanks sir!

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@sahbeniwajdi129]

Thank you very much ♥️

[@FoolishEngineer]

You're welcome 😊

[@wanderider321]

Very good, tyvm.

[@FoolishEngineer]

Glad you enjoyed it

[@youssefelberriri3607]

such a great video !!

[@FoolishEngineer]

Thank you so much! Please show support to my video with Super thanks and don't forget to subscribe to our channel

[@savitriswathi3880]

excellent explaination thank you bro

[@FoolishEngineer]

Thank you so much, glad you liked it!!

[@Rajkumar-mi3uv]

Very good explanation :)

[@FoolishEngineer]

Thank you so much, Glad you liked it!!

[@deepakm.k2193]

Thank you so much for your effort. Please do the video of CLLC resonant convertor

[@peace5655]

Thanks bro ! I enjoy your channel .

[@FoolishEngineer]

Thank you so much, Glad you liked it!!

[@baldevsolanki4747]

Great man!!!

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@suntzu6122]

Love ur channel

[@evserviceabilityandmainten3945]

Great explaination

[@FoolishEngineer]

Thank You!

[@8754484388]

excellent! thanks a ton

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@anuradhaghotekar6618]

Nicely presented

[@FoolishEngineer]

Thanks a lot

[@bobmundeke5480]

Many thanks

[@xiaomiphone9349]

Nice, tnx

[@Filipius99]

very well explained

[@FoolishEngineer]

Thank you so much, Glad you liked it!!

[@myetis1990]

nice content thanks

[@FoolishEngineer]

Glad you enjoyed it

[@user-nz9tf9re7y]

thankyou for the video

[@FoolishEngineer]

My pleasure

[@arvindpande4325]

very good animation and explanation pls make video on Battery Modeling and BMS modelling in MATLAB

[@FoolishEngineer]

Thank you so much, glad you liked it!! I'll add in my video list

[@geesolar1282]

Very nice video

[@FoolishEngineer]

Thank you so much, Glad you liked it!!

[@notnecessaryok8066]

Very informative ..please make videos on autosar ..CAN, LIN,

[@FoolishEngineer]

Sure, it is in my List... Coming soon!!!

[@startcherif]

VERY NICE VIDEO

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@priyankparikh434]

nice video

[@rushikeshmali1164]

Can u make a video series explaining Control strategies used (like Scalar and vector control)for induction motor controller ?

[@FoolishEngineer]

Sure, I'll add it in my list.

[@jacksonteneng7287]

Thanks for the video! please can you explain to me how to set the charging current for the BMS?

[@FoolishEngineer]

Yes! Soon.

[@ABC2007YT]

Excellent animation. What tool did you use to create it?

[@FoolishEngineer]

After Effects. Thank you so much for watching!!

[@nickheidl2260]

Hi, great presentation. However, this diagram does not relate to Electric scooters or similar because the battery has an internal BMS and it connects directly to the controller and the charging port, but not the motor. The controller of an e-scooter is connected directly to the motor.

[@anilrajpurra123]

Nice explanation. Can you please make a video on BMS operation when multiple modules are present like HV battery pack

[@FoolishEngineer]

Can you tell me what do you want to know?

[@GearGuy]

Hi Great Video. One BIG (but fairly novice) question: Does a standard BMS handle the CC/CV aspect of charging? Reason I ask is because so many vudeos show people building (sealed) series+parallel battery packs with only two wires emanating from the pack, which means that there is only the possibility of applying a single power to charge. For example, if a sealed 3S1P li-ion battery pack with a BMS is created with just two wires (the +/- combination Load/Charge leads) accessible then does that mean that an ordinary off-the-shelf 12volt DC power supply (either switching or transformer based) can be used to charge the pack? By that I mean, is the BMS taking care of doing the proper CC/CV charging of each of the internal cells? I see this question very often, but no one ever directly answers it, so I was hoping you could shed some light on this topic. If a standard 12volt DC charger cannot be used, then what charger could be used since only two wires are accessible ….and of course, a lithium balance charger would technically need 4 wires to effectively balance charge a 3S1P pack…but again most sealed battery packs that have a built-in BMS only have the two power leads accessible. Any info you could provide would be greatly appreciated.

[@FoolishEngineer]

there is no straight forward answer! most bms don't handle cc/cv charging part.

[@danieldoss1953]

What should be the input voltage and how much excess voltage it can accommodate

[@pritambissonauth2181]

Excellent video, if you could dedicate a video to active balancing, would be highly appreciated too.

[@FoolishEngineer]

Will work on it!

[@pritambissonauth2181]

@@FoolishEngineer Many thanks

[@georgegalanis2245]

Great video! I have a question, in an EV with a battery pack that is currently say at the end of its warranty period (i.e. 7 years/150,000 km) if there is the need to replace one of ten modules due to a faulty cell within that module, what are the issues with putting in a brand new module into the used pack? Many thanks and keep up the good work!

[@priyankparikh434]

capacity is the issue. the new cell is having higher capacity then the old one, hence it will cause cell balancing issue. compare the voltage capacity graph of 2 cells to know how it will behaves

[@12vLife]

Would it not make sense for BMS to serve as a DC charge controller? Are there batteries out there so smart that they can safely make use of voltage and current in a range? For example, my ebike 48v battery wants 48v-60v@2-4amp to charge. It has a BMS. Id love to connect a 250watt 24v solar panel with with no solar charger, just a boost step up converter set to 55v@3a, but what happens when the battery is full or when voltage and current of source fluctuates?

[@technicaltransistor2658]

nice

[@FoolishEngineer]

Thanks

[@clemonscg]

Can you explain about the second diagram about the separate charging and load and how it works

[@shuvendupattari8079]

🔥🔥🔥

[@Abdulkader-kz1xd]

Good Luck

[@FoolishEngineer]

Thank you so much! Please show support to my video with Super thanks and don't forget to subscribe to our channel

[@rgollas]

Can you please provide some info on how to charge Li-Ion batteries in CC/CV mode? And how BMS can help here, if at all?

[@saeedkr8439]

Thank you very much for the great explanation. Could you please also explain how to make the real BMS circuit board with active balancing too? Do you have the circuit diagram please?

[@FoolishEngineer]

Nobody uses active cell balancing. I'll try to explain actual circuit soon.

[@astrofamily6081]

thanks

[@FoolishEngineer]

Thank you so much for watching!! Please don't forget to subscribe to our channel

[@omkarbhatt2729]

Can you make a video on how to select bypass resistor and MOSFET ?

[@FoolishEngineer]

Sure, I'll.. soon

[@orenbustani]

Hi, thanks for the video, it is very nice explanation. I have a question regard the cell balancing. When it happens in EV. does it happen during charging time? if yes when exactly? DC or AC charging?

[@FoolishEngineer]

it happens while charging or even when the car is not moving. Depends on how it has been prgrammed

[@dharmakissoon]

thank you for english, do anybody know how to diy a bms for lead acid battery? thanks

[@bouazzirejab9560]

Hello, thank you very much for your explanation. I have a question if you can answer me, I will be grateful. What should I check if my Li-ion battery soc is not over 80%?

[@FoolishEngineer]

Please refer this video kzbin.info/www/bejne/aGGzlYilhMt4aZY

[@alexanderbalakhontsev5563]

Yes, English is broken, but the animation is good. Demonstration of current flow paths always helps. I like it!

[@FoolishEngineer]

Thank you so much, Glad you liked it!!

[@5er312]

Hi, just to confirm the cell balancing is performed on the same circuit/cables/pinsouts as the, cell monitoring?

[@yashwanthl1768]

Really nice thanks for sharing your knowledge I have questions with respect to cell balancing and charging of cells please help me 1.when this cell balancing will occur is it when charging the battery or when any cell goes more then rated voltage. 2.can you please explain how changing in battery will happence 3. please explain how this scenario works Suppose a battery contain 4 cell in it 0v is minimum 5v is maximum 3.5 is the normal operating voltage If one cell goes to 1.5v and am using passive cell balancing method and remaining cell are at 3.5 voltage Please explain when charging will happence and when cell balancing will occur

[@FoolishEngineer]

1. cell balancing occurs continuously, irrespective of charging and discharging 2. Please check this video kzbin.info/www/bejne/j6XMf313idFosJI 3. I am sorry, I did not get your question

[@yashwanthl1768]

@@FoolishEngineer thanks for the reply

[@sanjayshinde1787]

My 2yr old 48v 25amp battery... Scooty stops after 2km... I checked 1st rack pack voltage low 3.4v and other packs 4.1v...so i replaced pack of 10 cells. With New 3.7v 2500mah each...old pack does not have information cell mah... Now after changing....scooty stops if speed goes above 15 Kmh... But after reconnecting if speed less than 15 kmph...drives continue... My question is bms. Faulty......or pack has to be of same mah like old one...?

[@boojiecentoobie4272]

What happens in over voltage and over current situations? If two high a charge voltage is applied does the battery merely cut off the charge supply but continue to provide power? My PV controller typically goes as high as 15.2 volts on a cloudy day

[@FoolishEngineer]

in over voltage & over current scenarios. BMS detects those values & disconnects the series pass switch which connects battery to the load.

[@danieldoss1953]

Since input and the output from the BMS is same, so how the BMS will have control on under voltage discharge.

[@babhishek5284]

Sir, please make other informative videos about electric vehicles as soon as possible🙏🙏

[@FoolishEngineer]

Sure I will, Please don't call me sir.

[@babhishek5284]

@@FoolishEngineer ok bro.... I will be waiting for your osm video....

[@eriksvensson2762]

Could you somehow access the information in the BMS (log book)? Really great video! :)

[@FoolishEngineer]

Thank you so much for watching!!

[@christopherowens2635]

I’m rookie at BMS. Quick question...Are bms only to safely charge and balance the batteries during charging time? As far as using or discharging the batteries, does the bms play a role? Ultimately, can I use my batteries on a ebike without bms and charge the batteries later on a Nitecore portable charger?

[@FoolishEngineer]

This is not a smart approach if you don't use BMS eventually you will choose your battery pretty soon, However you can use Batteries without BMS for small projects, but not for EVs

[@donaldwright2426]

I like your video and explanation, however, can the BMS handle regenerative braking ? For sure, a boost converter is needed to boost the voltage higher than actual voltage to recharge the battery pack! So can the CFET be used as a basic boost converter ? Or should one of the IGBT or Power MOSFET of the inverter be used according to the rotor position or a combination of both, CFET on BMS and IGBTs of the inverter? Thanks!

[@FoolishEngineer]

We don't need to worry about that, Motor Controller acts a Boost converter while regenerative braking to charge the batteries.

[@donaldwright2426]

@@FoolishEngineer So if the the charger is not plug (or not connected), the µC will not sense any voltage and by default, it will turn ON the DFET to allow the motor to run. However, I do not understand how the current provided by the motor while in generative mode will be alllowed to store the energy to the batterie since the CFET is open and the diode of the CFET will not allow current to return to the battery. The only explanation is if the motor is in regenerative braking mode, as you explained, the µC will sens voltage. This will turn OFF the DFET mosfet and turn ON the CFET mosfet to allow the energy to be store! Is my explantation correct ? Thanks.

[@maheshvarpe3631]

Can you please make a video on Modeling and simulation of battery pack's using Matlab and Simulink. What parameters need to be considered while designing BMS for an EVs? Waiting for your positive response. Thanks

[@FoolishEngineer]

I'll try for the same

[@maheshvarpe3631]

Have you make that video?

[@MrTonyo1981]

Can we put only bms and battery in motorcycle its automatic cut the chareging if fullcaharge or need other device.

[@FoolishEngineer]

BMS & battery is sufficient

[@panditamol12]

I have issues with my circuit ..would u help me I hv designed half bridge topology based smps .. i already implemented dead time in two gate input Bt when I check the input of primary of transformer then dead time does not present And if I reduced the duty cycle of gate .still transformer primary still gives 50% squre out with no dead time ..will u help me ..thank u very much

[@therainman8703]

Subscribed .Why does MOSFETs fail if a wrong charger is connected pls help understand in simple words

[@AdityaSharma-vi8ky]

Can you make a video on inductive active balancing

[@FoolishEngineer]

Sure, I will add it in my list, Thank you

[@gkrishnaprasadee-0197]

I want some calculations like charging time and discharge rate of a battery in a electrical vehicle please help me...!

[@bartabz2199]

Voltage matters with a BMS but does the milliamps of the batteries matter when re-celling a Li-on battery pack?

[@FoolishEngineer]

Yes, it definitely does. The battery needs to be same if you are replacing the cells.

[@zhanghongyang8171]

May I ask why real time clock can help reduce the energy cost?

[@royalsingh]

Good informative video. @2:12 you mentioned that if Voltage @ input pin is not present - BMS senses load is connected and Mosfets are closed. But this does not hold good - as why would there be voltage even if load is disconnected? Could you elaborate more on the BMS logic for Load detection.

[@FoolishEngineer]

When the BMS is in operation there will be only 2 possibilities 1. The Charger is connected 2. Load is connected But due to some fault, there might be an occurrence of a condition where the load is disconnected. If you take the eg of EVs, BMS & Motor controller talk with each other over CAN bus if some fault occurs at the load side, the Motor controller conveys the message to BMS & BMS can switch the FETs Off.

[@royalsingh]

@@FoolishEngineer yes, but i'm interested in knowing logic of how BMS detects when load is connected and it should close the FETs to provide power to it?

[@sauravmehra4503]

@@royalsingh did u find the answer to this? I think BMS injects small amount of current to the load pin (this will be like a separate senory pin) which will be connected to the motor itself, so if the voltage at this pin doesn't rise that means a load is present at it's drawing that injected current.

[@royalsingh]

​@@sauravmehra4503 ​ No, I didn't pursue this design but went onto make a passive one with resistive loads to burn out excess charge. Arduino could do all your calculations much easier if you are not an electronics engineer but need help with control systems.

[@johnaweiss]

With passive balancing, isn't the pack connected in series? Won't the cells discharge directly to the load, without passing through the balance R's?

[@FoolishEngineer]

No

[@krishnagupta9667]

My 17s battery pack is not charging above 69v I have series 13s and 4s bms There is a bit of unbalance in the cells about ± 0.05 volts Also the bms cuts the power at only at 61 volts about 3.56 per cell Please 🙏 tell me the reason so I can repair it (About two times the positive and negative terminal also get short fow a few second with bms installed)

[@jeffsit_davidli.333]

When the battery pack is not on a load (not connecting to any appliance or device) or even charging, will the BMS be still working automatically to balance the cells ?

[@FoolishEngineer]

Yes!

[@HubliCityeGroup]

How do you select Which BMS capacity in Amps like 30A, 60 or 100 A to choose for eg 48V 250, 500 & 800 Watt Motor

[@FoolishEngineer]

There are plenty of Selection guidelines available on internet, you can find it easily

[@HubliCityeGroup]

@@FoolishEngineer Thanks for your reply, any link would help .

[@FFNFlyingsnake]

What is the size of the Bypass resistors if u decide to make a passive balancing ?

[@FoolishEngineer]

it depends on the balancing current & the maximum cell voltage. so Rbypass = Vcell / Ibalance

[@navya2675]

I have a doubt in building the circuit with single lithium ion battery if vcc is 5v and connected to battery so this circuit is not feel safe it may catch fire at any time in order to save battery from this what should I add in between battery and I m taking 8 pin ic so I m bit confused whether I can go with transistor or any other solution for this?

[@FoolishEngineer]

You can use input protections such as Fuse, reverse polarity protection etc

[@blackred5155]

Now I'm know how to BMS work

[@FoolishEngineer]

Glad, It was helpful!

[@blackred5155]

@@FoolishEngineer thanks 😊

[@blackred5155]

@@FoolishEngineer thanks 😊

[@Mikeb8134]

I'm very new to ebikes. If you have 10 seconds I have a quick question sir; if someone was running 2 hub motors and their combined max current from the controllers was 60 amps, and you used a battery with 50amp BMS (52v 20ah), what would happen? If you ran WOT you may trip the BMS of the battery and it come back on after a few seconds? Or something worse? Thank you!

[@stanislavdamyanov6041]

Why does my battery stop working at half charge, 1500w 48v 13s 50A BMS

[@tayohvincent9947]

What if my battery turns off at even 90% when I have not used phone for six months but when on charge it funsion well.

[@FoolishEngineer]

So sorry to hear that , Your Battery might be damaged my friend

[@johnaweiss]

You said passive balancing only doesn't help with discharging, only charging. Do you mean active balancing helps with discharging?

[@manojkarajol6122]

i had read that when a cell from a battery pack reaches its nominal voltage say 4.2V the charging of that cell stops while other cells keep charging till they reach 4.2V. what is the actual case?i'm really confused.

[@FoolishEngineer]

This depends on the different types of BMS, We have demonstrated widely used BMS here...

[@manojkarajol6122]

@@FoolishEngineer thank you very much

[@nakulchauhan6713]

do BMS involves Embedded System programming? I am asking this because i am thinking to join BMS company, so i want to know is it worth ti join BMS company if i want to get hands-on on Embedded System programming.

[@FoolishEngineer]

Yes, BMS needs very strong firmware to work, you will get a very good exposure if you work on BMS

[@koyarbakir775]

Di I need a bms for parallel batteries?

[@FoolishEngineer]

Ideally we don't need balancing for the batteries which are connected in parallel

[@bhavnashukla9315]

Please make more videos in Hindi

[@asraahmad2288]

can i make it in simulinlk, matlab ? please answer as soon as possible as i have deadline of this project

[@FoolishEngineer]

Yes, you can