Charging multiple 18650's in Series BMS (MEHS) Episode 55
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- Опубліковано 15 лис 2016
- Charging multiple 18650's in Series (Battery Management System).
I review a cheap but effective battery management board that allows correct charging of 3 or 4 lithium ion batteries in series when combined with a 3S lithium charging board.
This is a great solution where you need 12v to 16v internal power for a project and intent or need to leave the batteries in the project.
To find board like this on Ebay just search for:
10A BMS Charger Protection Board for Pack of 3 18650 Li-ion lithium Battery Cell
Ebay product ID: 162046538604
My Website: www.mtechshow.com - Наука та технологія
Love your custom lightbox videos. If you build a 3S lithium-ion pack, the correct supply to charge it is a DC 12.6v wall-charger that comes with red/green led charge indicators. You can power 5v USB LED strips with a 5v downconverter. I use such a setup with USB motion sensors for emergency lighting. If you go with a 4S battery setup, you'll increase the light-time, but you'll have to get the correct BMS, wall charger and downconverter that can handle the higher voltage.
Wonderful tutorial to solve problem of 3s battery. All my arduino project powered with this module. Thanks.
thank you sir for you reply.. appreciate it very much.. keep up the great work..
Your videos are great and really informative. Thanks. I am new to li batteries. I was wondering can I use these bms for lipo batteries ? So in general is there a difference between li and lipo bms, apart from the obvious single cell voltage difference between the two.?
i WAS YOUR 1K THUMBS UP! : ?) Nice work, best of luck for 2020 to you...
So when hooked up to a powersupply with 12.6volts the cells will reach 4.2v each. Anything below the 12.6volts and the cells will end a lower voltage each? Now i know why my universal charger i got with the bicycle light is not charging to 4.2v but instead 4.1volt. Thanks for explaning. Another lesson learned and getting smarter every day. I do have a big balance charger and can make them myself but the voltage drop through the bms i did not know.
hi thanks for the video . uhmm am working on a diy bluetooth speaker which takes in a minimum of 8ﾄ8v but works beat with a minimum of 10.8v at 4A as i tested it a while back . my question is can i pair a bms board with a tp4056 for charging
Do I need to connect (weld, solder) batteries to the BMS board in sequence (from plus to minus or vice versa) how is it in the laptop battery so that the board does not go into protection?
Can I use a 2S BMS and charge the batteries with a 12V power supply? Please answer whenever you see this, thanks!
- Hi. If you are feeding the 12V directly to the 2S BMS then no you cant. You would be feeding a nominal battery voltage of 8.4v with a 12v supply. Thats too much. Lithium batteries are fussy. Use an adjustable step down voltage regulator to adjust the 12v to a max of 8.4v to go to the BMS. Alternatively use a TP5100 which will correctly charge 2 LIPOs in series. Cheers.
RCLifeOn I was thinking in the same. LOL But I think a good step up/down and a 10 turns potentiometer (to replace the board's one), a plastic box and a good power supply would work. Additionally, a mini voltmeter. That's not a bad idea and a really nice project to make.
I solved by using a 2S USB charger instead (8,4V). Video should be up tomorrow.
RCLifeOn Nice! I'm going to be there to see it, as always. :)
thank god BMS safe charge anything but waste so much current the same charge will have if you buy charger from store, but is cheaper to diy and also you can make 5 or 10 diy chargers for the price off 1 charger buy from store😁
It's ridiculous how many hoops we have to jump through to both charge and wire these batteries to our pcb builds. I still have yet to come across the 2s 18650 module with USB like the 4056 which only works for 1 single battery. Has anyone found anything?
It is a good tutorial. My project is working. thanks a lot.
Good to hear.
Thanks, that was helpful
Thanks a LOT for this video! Just subscribed! :)
- Great. Thanks.
Gracias me gusto el review
Sir, can I use three cells in parallel in 3 series. Altogether nine batteries?
Sir I have 3 3.6V 2600 mah battery and another 3 3.7V 3000 mah .Can I connect this two different amp ratings cells in series ?
Thanks, Very helpful.
anyone know a good way to charge a 24V cell? 7s 2p
great video, Good job
DoorToDoorGeek - Thank you.
Can we use 12v 5A adaptor for this, input supply
thanks a lot
And any difference between balance charging module and bms module
Thank you very much for all you are doing here.. I have been spending ages trying to decide how to handle 4s packs.. If I use a BMS for discharge only but have a connector for 2 x 4 individual TP406 boards to charge each 18650 in the 2 x 4s in parallel - Would it be Ok to leave 2 x 4s Packs in Parallel with a BMS on each pack of 4s.. and then charge each cell, 18650, individually ? I plan to use 4 compartment spring loaded cases so I can remove and charge seperatly or swap out an 18650 if need be.. Thank you..
Hi- It depends on how you wire things up but probably not. The TP4056 boards are great. Some variants actually have a BMS onboard, but when you connect more than one of them via a common ground you get undesirable results such as all the power being shunted through one IC, burned out IC's or other issues. Try it but take your time and do plenty of testing. You might come up with a workable solution with the inclusion of MOSFETS or blocking diodes etc. Cheers.
I have a battery with 5 li-ion cells in series. How can i charge this without using a balancing charger?
I just bought a lifepo4 golf cart battery and a 10amp lithium charger
from china Alibaba with a custom metal box to fit my existing frame for a
simple drop in installation. It's a 36 volt 100ah with 1 Bluetooth BMS
system. They told me not to series 3 12 volt batteries together as it's
not stable? My only concern is explosion. Any thoughts on 3 12 volts in
series with 3 BMS vrs1 36 volt and a single BMS?
I know this is an old thread but hopefully you are still following. I wish to construct a charger for a 2S-3P 18650 pack charger using the subject battery manager board or suitable alternative with an adequate regulated DC/DC converter and seek your recommendation for appropriate components. As you observe, the battery manager board has little supporting information and I anticipate similar absence of information about regulators (from moderately priced Chinese sources).
My question is will the subject battery management board have sufficient margins to operate safely with a 2S-3P configuration as described in my requirement. I do not require operation while charging as you specified for your own application but don't want to charge cells externally/individually. I am interested in appropriate part types for goth the manager and regulated charger.
Thanks and thanks for your video posts.
Hi, if I connect the three batteries to 12.6 volts does the BMS also control charging current? or will the power supply need to be current controlled as well? Thanks! Also, i've read in the past that depending on the voltage of the battery different amounts of current should be applied at different times.
- Hi. The BMS wont CONTROL the current, only limit the current. You are correct, for proper charging of a lithium pack you need a Constant Current (CC) and then Constant Voltage (CV) approach. The BMS won't do this for you. You can control the charging method using a controllable power supply or an IC that will properly charge the pack for you such as a MAX745. You can use something like a bench power supply and simply monitor the current over time and then switch to a fixed voltage charge over time. EEVBLOG did a very good video of this method for a single cell but it applies to a pack connected together with a BMS. Just work with 12.6v instead of 4.2v. Cheers.
Good idea talking about BMS, not enough people use them
- Yep agree. Thanks.
hey nice video :) sry.. my english is not the best...so i didnt understand everything but i just bought a circuit board like this and i cant figure out how much voltage i have to put in the circuit board ? i bought a 2s 3s and 4s board, do i have to put the voltage in exactly like the output for the li-ions ???
- Hi. You need to put in the total charge voltage. If you have a 2S board that has 2 x 3.7V lithium batteries you need to apply at least 8.4V which is 2 x the charging rate of 4.2V per cell. For a 3S board with 3 lithium cells it would be 12.6V. For 4S its 16.8V. You should also check the voltage going to each cell as there could be a drop meaning you should increase the total voltage applied to the BMS. Also make sure you monitor the charge and don't go above 4 hours total. Remember its a BMS and not a proper regulated lithium battery charger. Cheers.
ok.. thank you very much.. i think i can manage it :D
keep up the good work :)
Great video, great solution.
I'm not getting a voltage reading between "P- andP+".
I do get correct voltage per battery and total batteries.
What could be wrong?
- Hi. Many BMS will cut off and remain that way unless a charge is applied to open the gates (so to speak). Connect a charger or power supply to the BMS and feed it at least 12v for 1-3 seconds and then try again. Cheers.
I'm planning to do a 6s bms, but I only have a 24v ac adapter, will boosting it to 25.2v yield the same results as a 25.2v ac adapter?
- Hi. Yes and No. Yes because you will get 25.2v if you boost the 24 to 25.2 but no because you will lose current or be limited to the current of the booster board. E.g. your original 24v ac adapter is capable of output 24v at say 3A. A booster board will boost the 24v up to whatever but often the amperage output by the booster board will be less than the 24v ac adapter, sometimes by a lot, say down to 1A or 1.5A. If you project doesn't care about the full 3A or more of current then all good. Just make sure the booster board is rated to give you more current than your project needs. Cheers.
Hi, I wanted to use these modules or simalar in a project for 12.6 volt output but have a fall proof way of
charging the 3s pack that jo blogs can manage without switchs etc, dont spose you know
of a way ?
regards Brett
- Hi. I will be doing a vid in a week or so about studio LED light panels that take power from a power brick and charge a 12.6V Li Ion battery bank and run the light, no switches. That might be right up your alley. In the meantime, once you have your 3 x 18650's connected to a BMS like the one in this vid, all you need to do is feed it 12 to 12.6V DC. You can do that from a 12V brick or you can use an adjustable step up regulator (like the ones I will be using in the next vid). You can find a lot on ebay for a couple of dollars (they use the XL6009 module) and will boost a 12v brick to 12.6v precisely. Set and forget. Hope that helps. Cheers.
Hello. Thanks for the great stuff. I need help with building a 18 volt power pack for my Bosch cordless drill. What type of bms board and where to get it. Thanks and regards.
4S 30A or 40A BMS Protection board, just search on ebay: 4S 30A BMS Protection board
At the p+ and p- where the outputs of the battery are, can i also solder a 12v input (using a limited current 12.6v supply) at those connectord as well? Or will I have to connect a ON/ON switch at the positive of the output of the BMS and the positive of the input?
- Hi. It depends on what else you have connected to the P+ and P-. Yes you can connect a 12.6V input to P+-, but you can have issues if your drain is also connected (whatever you are powering with the BMS pack). In other words it can be a bad idea to charge the cells and drain the cells at the same time as it causes stress and heat, and the BMS may not work correctly depending on components and BMS specifics. If you isolate the input and output, that should be ok. Cheers.
My Electronics & Hacking Show thanks for your reply. I will add a switch to isolate the power going into the bms draining straight into the output cables. I dont mind a few switches lol
i have a silly question. I want to make something like a stun gun. I need to have 4 X 18650 in series so i have about 14.6 volts. I want to make it convenient and charge it with a micro usb port. is it possible to charge a 14.6 V battery with a 5V usb charger? im thinking something like a 5VDC to 14.6VDC step up and then charge the batteries. I dont mind the time it will take to charge, thanks
You'll need a higher current
Thanks nice explanation
- Thank you.
what's a good board for charging 6 batteries for a 24v pack I'm looking to build, thanks.
- Hi. If you are using unprotected cells you will need to start with a BMS. Take a look at this item on Ebay.com.au: 222172905654 Start from there and see what might suit. You will then need a dedicated charger to supply the proper charging voltage and current to the cells. Take a look at turnigy.com. Alternatively you could make your pack simpler to make by using less cells and just boost the 12v to 24v. 3 cells are easier to work with and easier to find boards - options for. Cheers.
What do i need for charging a 3S2P batteries? One BMS for each series and for charging both series? Thanks!
Hi. If you set up a 3S2P pack you just need 1 x 3S BMS with balancing and one MAX745 or equivalent charging IC / board. The board I used works well with 2S, 3S or 4S setups. That's it. Cheers.
May I ask a question?
Do I just connect a P+/P- parallel to the LOAD and my 12V DC Barrel Charger for charging?
Thank you for your clear explanation! Helpful!
You can but you should take a look at my latest video explaining the risks in doing that. There are a couple of conditions that you might need to manage as part of your implementation. Cheers.
please stop giving wrong answers here!
those boards need >12.6V input voltage to switch over to charging mode. they are not balance charging but every individual battery is protected when charging and discharging. the charging process itself is done conforming to specifications with CC and CV phase. they will do this with any simple CC/CV-unaware power supply, given that its voltage is a little bit over 12.6V.
so to answer the question: your 12V power supply won't work because the voltage is too low. nothing else is the problem.
about balance: if you deliver proper input power to the BMS but using batteries that don't match you ask for trouble. imaging charging stopping with a 3.6V - 4.2V - 4.1V chain: you have two incompletely charged batteries and ultimately lower than possible capacity (Wh). why? because the overprotection circuit will stop charging when "a cell" reaches 4.2V. if that is just one cell the other two are left undercharged.
again you have self asked for trouble! you would never just mix cells to form a power pack. you will use matched batteries with (mostly) identical specifications and charging profiles. commercially available power packs are normally made from cells produced the same day in the same factory on the same machine.
an balancing charger like the one you praise over this simple BMS board will charge all individual cells up to 4.2V but the problem of having unmatched batteries will reside. you will never reach full capacity when discharging. it is asking for trouble. really. don't do this!
by the way: paralleling unmatched cells is less risky than putting them in series. anyway you would never ever use unprotected cells in a parallel/series power pack. individual specifications can change over time thus better go for safety (lower capacity) than for balance charging (10% more capacity at 100% higher fire risk)!
@@bjornsteinmann3471 i know this is many years after but my question is, after connecting the batteries in series with the BMS like in the video can i use my RC charger in Lipo mode to charge them? Do i need to balance them ?
any recommendations on PCB that has max charge 4.1V and 3V discharge?
- Hi. I haven't come across anything that specific. Might just have to hunt around quite a bit. Cheers.
Have some 18 volt units I would like to fix. Any suggestions on a bms for this application ?
- Hi. No not really. Just make sure you are dealing with a 6S lithium pack and then hunt around for a 6S BMS - even try ebay. Cheers.
Should the battery be fully charged when adding a bms or the battery can be at different voltage but the bms will charge them back up to 4.2 volt
- Hi. the BMS manages cells individually so you can have cells at different voltages and the BMS will sort it out as long as the charging voltage is sufficient. Cheers.
Very nice video.subscribed.
One question i just built a 3s battery pack.i have turnigy accucell which i will use to charge.i wonder if i need a pcb board .since i use smart charger and i balance charge the pack it supposed i will not overcharge the batteries .the only reason it comes to my mind that i should put the board is to prevent batteries go below the minimum voltage when using .is this correct?can i use the pack as it is? Without pcb board keeping in mind that i have a digital voltmeter which keeps giving the voltage of the pack when i want to.
- Hi. Your correct, you need the BMS to stop the cells from being drained below their happy minimum. The BMS will stop the flow of power from the cells at about 2.9V per cell. That way the cells are never stressed much and will have a long and happy life. Without the BMS they could be pulled down to 2V each will will cause stress and shorten the life. If you use individually protected cells you won't need the BMS as each cell has its own mini BMS. Cheers.
Could we use this bms for a 3S5P- 3S6P battery ?
Thanks a lot! I had no idea that it was possible to charge all 3 cells in series for a less than a dollar.
what is the max input voltage to charge the 3s board?
can you explain why the bms needs to be combined with a 3s charging board? what is the difference between bms and charging board?
thanks for the video
floxflux - Hi. The max input voltage is 12.8v because the BMS IC will cut power off if the voltage per cell exceeds 4.25v. Take a look at my latest video which looks at why a BMS doesn't correctly charge batteries and some of the risks to keep in mind. Cheers.
Helpful video you talk like a teacher slow and clearly,you get to the point.After watching many videos about battery packs i have some questions.Pls take some time to answer,i would appreciate.
I want to build 12v battery pack about 9-12 ah
1) Some 18650 batterys have built on protection circuit.This means that if i want to build a battery pack with that cells i do not need protection board (pbc)?just balance cable or neither that?
2) How to choose the correct protection board when building battery packs.What to consider?Only for how many series is built (1s-2s-3s)?In my case when i choose board at 10ah means i can charge at most 10ah the battery pack right?I can give 12 v directly to board and it will charge at 10ah?In this way does it need balance cable or the board balances the voltage of cells?Is it safe?
4)last question is i have smart charger with max 6am charge is it better to use it to connect to board and have balance cable for 3s?
- Hi. Lots of questions there. I'll see if I can answer some.
1. Correct, protected cells have their own version of a BMS so no, you dont need a separate one.
2. There are lots of BMS boards, just need to look at the reviews and specifications. The main issue is how many cells in series (1s, 2s, 3s etc) and the current handling such as 6A through to 20A. The current rating is usually the max current that can be sent through the BMS in total. No you shouldn't just sent 12v through a 3S BMS as that is not charging, its just forcing the BMS to channel power to the cells. It will charge them up but its very rough. Take a look at my later videos on BMS for more info. The BMS will keeps things relatively safe but its not perfect.
4. Yes this will give the best charge and get the best out of the cells.
Cheers.
Very nice video!
I have bought a similar board for charging a custom-made battery pack. (3S)
Is there any data on how high th charging current is?
Have you measured it on yours?
- This was a 6 or 10 amp version meaning it can handle switching up to that current. Because it's not CC it draws an average of 4 amps. A bit over 1 amp per cell. The current will vary based on wiring and the cells you use but should not exceed 2 amps per cell. Cheers.
Thanks a lot for your reply. I bought a version which is "20 Amps" (what ever that means...) What I really do hope ist that it wont charge my three batteries with about 7 Amps each...
I guess some testing will be necessary.
Manuauto - No it won't.
Bless your soul for making this video. Answered so many questions.
- Thanks for the feedback. Remember to watch my other videos on BMS to get a full picture. Cheers.
very nicely demonstrated.i am going to make a 2S 18650 pack for my brushless camera gimbal.the total will be 8.4V max.the problem is how to charge these two cells that are wired in series and use the standard TP4056 4.2V micro-usb board????
- Use 2 TP4056 boards and a FET between the output lines that disconnects the output (and the shared ground plane) when the input is connected. Cheers.
dreamwisperer use tp5100 module it can charge 2s cells
Saadman Mohammad - Thanks for the tip. Cheers.
Do you have a suggestion for a 14S288P battery bank with the LGEAMF11865 cells
- Hi. My suggestion is to make sure you do your research and take precautions ensuring you have sufficient fuses and circuit protection to protect you, the project and the cells. 15,000 watts is serious power (and expense). Aside from that, just take your time, whatever the project is. Cheers.
Helpful, thanks
- You are welcome.
If I understood right, since the voltage gets distributed with a 4.2v max, then we should be able to use de BMS board do charge up to Xs cells, right? If I have a 5s board but only need to charge 3 cells, I could connect a 12V power source and use only 3 steps of the 5? XD would it be possible?
- Hi. You shouldn't rely on the BMS alone to charge your cells. It will protect them from over voltage etc but its not supplying the correct current over time. Take a look at my other BMS vdeos for more info. Ok, some BMS will allow you to connect a less number of cells (3 cells on a 5S BMS) but this depends on the BMS configuration and the IC's being used. Just test your BMS by connecting 3 cells and applying power. If the BMS is allowing current to flow to each cell (test with your meter voltage 3v or more) then it will work as you describe. If you dont get any voltage then your BMS wont work that way. If you think about it, a 4S BMS will be tolerant of voltage between 12v to 16.8v. If you wanted to supply power to just 2 cells you would apply 8.4v. The BMS is likely going to see this voltage as too low and block the current. Test and see. Cheers.
My Electronics & Hacking Show thank you very much! I'll do just that. Cheers
aaaha,now i understand;),tnx
My plan is to build a 3s3p battery pack.
I bought one of the bigger BMS but they have the same connections so I wanted to ask a question.
Can I charge it with any 12V 1A power supply? When do I now if it is fully charged?
- Hi. Remember that the BMS doesn't really charge it just allows power to flow to the cells which gives them some power but its not a full charge. You need to use a TP4056 or a MAX745 IC for real charging. Cheers.
Well presented vid.
-Thank you. I try :)
I want to know when its fully charge because no led indicator on BMS
- Hi. Yes you are correct. If you use a BMS only to charge cells you need to use a multimeter to measure the voltage. Once it reaches 4.2V the cells are fully charged. For better charging you should pair the BMS with a dedicated charging board like the MAX745. Cheers.
@@michaelsstuff4402 I know this is a 2 year old post but I have the same question as ishag zakaria to whom you reply is directed.. The MAX745 appears to handle one cell only. I have used the small MAX745 boards in several 1S applications. How can, or how will, it work on 3S to show 3S pack is fully charged? Your videos are very informational. Thank you very much.
@@90FF1 Hi. The MAX745 boards are set up to charge 1 to 4 cells. Many have dip switches so you can select the desired number of cells. When you select 3 cells then the MAX745 board will act as a 3S charger and provide charge up to 12.6V through to the BMS and then 4.2V to each cell depending on the operation of your BMS. The MAX745 uses the Constant Current CC and then Constant Voltage CV charging methodology which is how lithium cells are supposed to be charged. Cheers.
@@michaelsstuff4402 I was not aware of this board. I will subscribe and watch your previous offerings. Thank you very much.
Hello,
I want to power a bluetooth amplifier with 3 lithium cells and recharge these cells with micro usb (for covenience). I also want to provide 24V to the amplifier board. How I can do that ? This BMS module have only 1 input/ouput so ?
I can connect a step up boost converter with a micro usb socket and step up the voltage from 5V to 12.6V (to recharge the cells through the BMS) but can I connect another step up boost converter in parallel to the amplifier board to step up the cells voltage from 12.6V to 24V (to power the board through the BMS) ?
Thanks (sorry for my English)
- Hi. Many BMS just have one set of input output pads. You connect the charging module and the load to these pads. Yes you can boost the 5V to 12.6V but you aren't correctly charging the cells (no real charger module). Take a look at my later videos on BMS for more information. In this case you can do what you suggest, one module to boost 5v to 12.6v and another to boost 12.6v to 24v but you will loose a lot of current as the booster boards have limitations. How much current does the project draw. That will determine the way forward. Cheers.
Hi Sir, thank you for a good video. what is the right BMS for 4S 12V (1500mAh 3.2V) Battery pack ?
- Hi. Any BMS rated for the pack you want to use should be fine. Just select a 4S BMS rated at 6 to 10A (depends on the draw etc) and correctly spec'd to handle your cells, especially if you're using LiFE04 cells or something other than 3.7V cells. Cheers.
very good Video but I got a question. Can I charge and manage 6 Li Ion when I use 2 in paralel and 3 of those in series with the same Board you are using?
- Hi. Technically yes you can. The two cells in parallel will work as one cell but will only balance if they are exactly the same. Otherwise you should consider a balance function as well. Cheers.
These batteries have a max charge current of 2150ma according to the datasheet. I know that the 2200 capacity stays the same when connected in series, only voltage output doubles. I have a multichem battery charger that has a share port up to 6S. I'm creating a 2S pack for my drone TX. My qusetion is. Does charge input current double, half, or stay the same when charging for 2S?
- Hi. Well something has to change if you change one of the variables, so if you have a power supply that has a max output of 1A and you are feeding that through a 2S BMS into 2 cells the current will be 0.5A per cell. If the BMS detected that one of the inputs going to a cell was over the voltage limit and it momentarily cut the power flowing to that cell , then the other cell would get 1A for a moment. Hope that answers your question. Cheers.
I have a Harbor Freight under hood LED light bar. It came with one 2000 milliamp 18650. I'm in the process of replacing it and noticed a spot on the other end where another battery would fit. I wasn't afraid to replace the one, but I am not at all experienced with these. I have no idea if the board in it will take another battery or if I need a different one. A guy does a video, and said that underneath the blue sheath around the battery with the wires that there is a chip. I have yet to verify, but what would I be looking for if there is. I never thought doing this was so complicated. I also went to batteries plus and bought a battery, and that may be wrong too. It has the button on one end flat on the other. I'm not even sure it will take solder. My buddy said it may have a chip in it since its a tad longer. I can build show winning cars, and build high horsepower engines, but I feel like a 5 year old with this. Ridiculous!
hi,tnx,so i need 12.6v and minimum 6amh to recharge them?
- Hi. Yes to the 12.6v but no to the 6A. 12.6v at 1A is heaps. Cheers.
I’m new so don’t bully but can you use a bms to charge and discharge the batteries at the same time or can you only do one of them
Hi. Technically a BMS will only do one or the other at one time, but most BMS can switch between power supply and power input within milliseconds. The real issue is the circuit you use because charging and power supply at the same time means you have external power connected somewhere in your project and that power is unlikely going to the cells and its the cells that are powering your project. Keep researching BMS and you will find out what you need to know for your application.
Hi, I bought a similar PCB but unfortunately it does not work. I'm pretty sure i hooked it up in the correct way, only at P+ an P- i don't seem to get current/voltage. I read somewhere that you need to activate the board first by using a charger. so i used different power supplies, a 12V 3.3A, a 12V 1.5A and a 12V 0.5A. i connected the power supply to the P+ and P- but still the PCB does not work. could this be because the voltage is ≈12V?(I read somewhere that the PCb needs 12.6V to activate) When I measure the voltage of the different power supplies they are slightly below 12V, around 11.9V. Thanks!
- Hi. Its true that you can't always test the P+ and P- and read the voltage with a meter. Depending on the IC on your board it could be that current will only flow when a there is a demand or drain. Try connecting a motor or light bulb to the P+ P- and see if you get flow. The input charge only matters if its below or above the threshold set by the IC. In most 3 cell cases thats 10V low and 12.8V high (or very close to that). Try running something from the board output and go from there. You can always check each cell voltage at the board (before P+ P-) to make sure all is connected properly. Cheers.
Thanks for the quick reply! I will try this asap.
Do they do any balancing when charging or does it just cut off whenever one of the cells reach 4.2V?
Hi. Some boards do have balancing but not these small ones. Cheers.
I found out the board in this video does not have balancer circuit so if one cell reach the charge or goes over the limit then the whole pack will shutdown leaving the other batteries in not fully charge condition and when you use this battery pack, the not fully charge batteries will drop down to the low Voltage shutdown first which will then shutdown the whole pack. I ending up buying the BMS with Balancer board.
nice video!
Benjamin Buljevic - Thank you.
Is the equivilant available for 5s packs?
-Hi. Yes I've seen boards that connect up to 6S (ebay usually). Cheers.
QUESTION: If in a pinch, would these particular BMS boards function equally with other sized 3.7-4.2 Li-ion batteries? Say something like the smaller CR123a's? Great videos! Great info! Subbed :)
- Hi. Yes absolutely as long as we are still talking lithium at 3.6 / 3.7 V and not phosphate cells at 3.2V. The only other consideration to note is the AMP rating which is usually not a problem since the smaller cells like 14500 (aa size) or CR123A's have a lower current draw anyway. Cheers.
Thank you!
Ok I understand that: If a circuit can handle 10 A, it can handle 3 A. But what about the maximum discharge current protection? If your batteries should not be discharged at a current above 6 A, will a 10 A circuit handle correctly and prevent to pull too much current out of the batteries?
I am a bit confused with this because a 3400 mAh 18650 battery has a max discharge current of ~6A. Which mean that, for security, I would like the BMS to cut at 5 Amps. Why is it so hard to find a 3S or a 4S BMS that cuts at 3 or 5 Amps. Most of them are 20 Amps! - Those 4S 20 Amps circuits, are they actually for Series (4) of packs of 4 batteries in parallel, i.e: 16 batteries? right?
Is that module really a battery management module or only a battery protection module? Most of the modules I see on ebay are only protection modules meaning they only protect against over current, over voltage and under voltage. They do nothing for charging. Can you tell us what the chip numbers are. Thanks
- Hi. I will try to get the ID of the main IC when I'm home next. Yes it's sold as a BMS but it is really a Protection board as it doesn't have a charging IC. My second video on this board points out the traps and risks of using this board as a complete solution. Cheers.
can i use 15v adapter to charge with bms
- Hi. 4S yes, 3S No. Its not ideal but it will work. You probably won't get a full charge into a 4S BMS but the cells should get to about 70% - and 15v is too much for a 3S BMS.
Can i charge 2 (lot)s of these,let say 1 (lot) had 3 ,18650 in serie and i parallel another (lot) to it,can it still charge it
- Hello. You can do that but this board does not have a balance function. That means any cells you have connected in parallel will be charged as if they were 1 cell. When using a combination of cells in series and parallel you may find that some cells are at a lower voltage than others. If you use a BMS that also has a balancing feature then you will get a better result. Also remeber that a BMS is not a battery charger. It will just let the external voltage flow to the cells. You will need to make sure you provide the correct voltage and current to the BMS. Check out my other videos on BMS before you start your project. Cheers.
What chip does your board have?
Could you please tell me the easiest way to charge 4 cell or 6 cells battery pack by using the BMS and auto cut off when it's fully charged.... Thanks and subscribed..
- Hi. The BMS is there to protect the cells and manage the pack but it doesn't really charge, it just allows certain voltages and currents to flow to the pack. This can provide some charge to the pack but its not an ideal charge. You need a 4S BMS for a 4 cell pack and a MAX745 charging board or IC that can charge a 4S pack. A 6S pack is harder. You still need a BMS and 6S BMS are readily available but I don't know of a charging IC or board for a 6S solution that you could put inside your project. You could easily connect an external charger (turnigy) to a 4S or 6S pack and charge it that way but that's not an internal solution (but it is easier). So the easiest way is connect the cells to a BMS and charge the cells using a dedicated external charger, say from Turnigy. Cheers.
Thanks alot for sharing that information... Thanks
Hi
Assuming I have the same circuit in the video , 3 18650 and the board , i have a 12v 3amp charger already, can i just go ahead and charge the pack like that , is there anything else i should notice in term of safety and usage ? thanks and cheer for nice video
- Hi. The answer depends on the charger you have. Simply, yes you are good to go but the charger should be sending 12.6v at around 1 amp for a good charge using Constant Current then Constant Voltage modes. If it does that you are good to go. It depends on what the charger is doing. For a couple of charges you could simply supply the BMS with 12v at 1A for 2 or so hours and you will charge up your pack as the BMS takes care of the onder and over current and voltage risks. The reason you cant keep doing that is its not the way lithium cells like to be charged. Cheers.
This circuit might be good for charging But when discharging it won't turn off the current when discharging ! Because the input is connected directly to the battery and the load.
Hello how many cells parallel for bms 3s?
- As many as you like as long as you can provide enough charging current and take into account the limitations of the BMS you are using. E.g. for a 10P pack you would need to provide around 10A of current and your BMS would need to be rated at more than that to work without issues.
If I designed a battery pack with 21,18650 cells, would I have to buy 7 BMS boards in order to charge them all at once?
Excellent informative video, thank you.
Don't think of the BMS as a dedicated battery charger but rather a way to tie cells together to make a battery (a collection of cells). What is the voltage of the desired battery? Why 21 cells? Is it a 3S7P setup giving you a 12.6V battery with 7 cells in parallel or is it an 88.2V battery (21 cells all in series)?. If you use a 3S BMS and use all 21 cells you will have a 12.6v battery but capable of 20-40 amps or more. You can then charge the battery pack using a dedicated charger for lithium cells in a 3S configuration.
Sir, what will happen if I use my 5v mobile charging adapter for charging this 12.6v battery. Please guide
Hi. Don’t do that. A 3s lithium battery pack needs a very specific voltage, 12.6v. A 5v phone charger simply won’t work and you might damage the charger. Cheers.
can i use the board for charging 3series of 4 bateries in parallel
- Hi. Yes. The cells in parallel will balance out. Just need to keep an eye on the total number of cells as the input power might be insufficient to charge all the cells. You wan to get about 500ma to each cell.
hi.
I have 3 li-ion batteries. I need to charge the batteries in series. How do I do the charging cycle? I have to charge with solar panel. 12 v 400mah with solar panel.(one baterry 18650 3.7 6800mah )
- Hi. Take a look at my latest video. That might be what you are looking for. Basically you need a charging board in your circuit. It will take the input from the solar panel(s), usually 15-19v and drop it to 12.6v and feed the cells through the BMS. A similar approach was covered in my latest video including the board I mentioned above. Cheers. ua-cam.com/video/kuEgZELszLk/v-deo.html
Can i connect a 12v 1.5w solar panel to it and charge the battery? And then other questions is , i measured the voltage coming out of the solar panel , and it's 14v when the sun is bright! is it a problem for the bms to take 14v?
Hi. You could connect a solar panel but you are correct the voltage will sometimes be too low or too high. The BMS will cut off the too low and too high voltages which means your cells would be ok for a while but the BMS is going to do this abruptly and either the BMS or the cells won't like that impact over time. A sepic voltage regulator between the solar panel and the BMS would be a good idea. Cheers.
My Electronics & Hacking Show Thank you so much ! Just one last question, if i connect a step up boost converter and the voltage gets to 14 , would that be a problem for the bms? is there any tolerance or it have to be exact 12 volts to charge the 18650.
- Hi. To get the best charge and keep everything happy and unstressed you want to get as close to 12.6V as you can. That way each of the 3 cells will be getting as close to 4.2v as possible. Remember (hopefully you have watched my later video's) that a BMS is not a charger. It can only control the voltage and current going to the cells. It won't correctly apply a CC CV charge to keep the cells happy and make them last as long as possible. The BMS will just allow current to flow which will charge the cells but they won't last as long as if they were charged correctly. If you just want to use a BMS then any voltage over 12.6v will result in the BMS cutting in very abruptly and it will flap rather quickly and violently until the voltage drops below 12.6V. Cheers.
My Electronics & Hacking Show I am charging with the bms board, but i have a volt meter on the battery and when it gets about 12, 12.3 i disconnect it and for now the battery is perfectly working. i use it in a boombox with amp tda7492p and on max volume for 1h the battery drains from 12.3 to 12. is it good?
- Yes it will work but incorrect charging will result in a shorter battery life. The voltage drop you mention is normal when draining the battery. Cheers.
I am doing a project with this battery safety board , but when I tested with the multimeter then total battery voltage was of the three batteries is 8.36v but when I was going to check the output voltage of this board through multimeter it is not showing any output voltage? could u please tell me what is the reason
?
You need to activate the board by connecting a 12v supply to the main positive and negative of the board for a second or two. This turns off the cutoff circuit of the board and allows the board to release the flow of power from the cells. Cheers.
@@michaelsstuff4402So according to you, when the battery voltage drop below 9 volt during that time this board not release any power from the board? In fact I am not able to see or check the output volt from the board !
Can I charge and manage a 3s2p Li-ion battery pack that I salvaged from a laptop battery with this BMS ?
If not please suggest a way to do so.
Hi. As long as its a 3S pack then yes you can. Make sure the BMS you chose is rated at the right amperage for your use. E.g. don't use a 5A BMS if you have a 10A project. Cheers.
@@michaelsstuff4402 thank you so much for the reply, i was stuck on a bms because the seller wasn't replying but now i can just buy it.
@@michaelsstuff4402 One more question i don't have a proper 12v 2A psu (as recommended by the manufacturer), i am planning to power the bms by a mobile charger rated at 5v and 4A and boosting it to 12.6v using the XL6009. Would that be a good idea ?
(Ps : i have a 19.5v 3.3A laptop charger too)
@@felinetech9215 - Hi. Yes it will work but keep an eye on heat as your asking a lot from the boost IC. If you had a step down converter you would be better off using the laptop power supply as it will do it easier. 40 watts for the 5V unit vs 60 watts for the laptop charger. Either way just watch your output current and the heat. Cheers.
From the diagram, input and output are on the same connection. When input power drops out the batteries will attempt to back feed through the the input transformer as well as the load…..
Is it possible to use this to charge only 2 18650?
- This is a 3S BMS so for 2 cells just get a 2S BMS. You could also use a TP5100 which is better for 2 cells and actually charges the cells properly. Cheers.
could you do the same with 21700 batteries and how would you get to 5v 2a for say a pi 4b
Hi. yes you can do the same with any Lithium Ion batteries (3.7v nominal). To get 5V just use a quality 5V step down regulator. Just make sure its rated at at least 2A, 3 or more is better. Cheers.
@@michaelsstuff4402 trying to get power to my pi4 handheld with 2x 21700
Hello, I have 6x 18650 batteries in series powering a 24V 2.1A motor. I would like to have a circuit that can safely charge all of these whilst also able to power the motor. Can I just wire 2 of these board up in series? Or do you know of a board that can do all of them? Charging/charged indicator pins (for LED) would be very convenient too. Thanks!
- It depends on the external power source. You can get 6S BMS but the external power would need to be specific and getting an inline charger would be difficult. Maybe run a 3S2P pack and use a readily available 3S board. You could also use a 12 to 24 v boost regulator to give yourself a clean and consistent 24v output. Charging could be done using the MAX745 set to 3S. Power supply could be 12 to 20v (check board details). That would give you just enough power to run the motor and keep the battery topped up. Still better to not have an inline solution even though inline is easier. Cheers.
Thanks a lot for your response, I will look into this.
This board don't charge, only limited and protect. You need a limited current power supply to charge.
- Hi. Correct. Those details have been discussed in the messages and the subsequent videos on the topic. Cheers.
i use this bms coz it fits on a power tool, but i have to mixed cells. on the 0v to 4.2 line i use a parallel of 2 high drain batteries coz the bms usually charge those parallel at only 4.0v and during cut off at 3.2v. the other parallel 8.4 line cuts of at 3.6v full charges the parallel at around 4.15. the last parallel charges fine to max 4.2v and cuts off at 3.6v
now for the off topic... i have other bms with balancer that some fully drains the batteries 3.3v. its alarming coz if i test each individual 18650 some of them cuts of at 3.6v using xtar vc4 and charging them to 4.2v thats how i usually get my total mAh of each battery. i dont usually drain my cells below 3.6v thats why i dont trust most bms i get unless i tested them each and had a safe low voltage of 3.6v cutoff for every series
Hello,,,,,
How to increas current in any bms.
Thanks.
Hi. The BMS typically isn't limiting the current. It will cut in when preset limits are reached but even a small BMS has 10A current handling and many are 25,A 40A or more. The BMS might not be your problem. Cheers.
Thanks, very good video. I need help please. I need 19.2 battery pack and I don't knoe hoe to do it. Do I need 5 cells? How I connect it?
- Hi. Yes 5 cells will give you a pack that ranges between 15v and 21v. Connect 5 cells to a 5S BMS (just google one). If you need exactly 19.2v all the time then that is too complicated to explain here. Cheers.
My Electronics & Hacking Show thankyou very much
If I have 3 li-ion Battery this charger will be god(3.7v,3000 mah one Battery)?
- Hi. If I understand you correctly, yes you can use this BMS to make a single 3.7V battery out of 3 x 3.7V cells. Cheers.
Can anyone recommend a good boost converter to step up a single 18650 cell to 12v?
I'm designing my own emergency lighting ballast for a fluorescent fixture.
I ordered some, but their drop-off voltage is too low. They start playing up at around 3.5v and below.
Since the working voltage of an 18650 is from 4.1v down to around 3v, I want to make the most of that available power in the cell.
Basically a boost converter that will convert an input as low as 3v exactly to 12v.
The output only draws about 500ma.
I know the input current will be higher (12/3 = 4, so 4x the current + 20% for inefficiency of the boost converter.) But half an hour of operation will be more than enough. And could always parralell cells if longer life was needed.
Look around for a good quality cn6009 step up. Very cheap on ebay those.
I have 6s 12a batter pack which bms I have to use
- Hi. Any should work fine. Just search for a 6S BMS that is rated for more than 12a. Cheers.
My Electronics & Hacking Show thanks a lot
Nice video which explains basic charging. What volt-amp ration required for 3S60P setup for 3.7 volt Lithium Battery? and what kind of charger required if I connect 4 above modules in series? I am trying to figure out proper battery charger can you help me plz? I know that putting more current I can reduce charging time but how much current is safe?
- Hi. Was that supposed to be 3S6P or was it really 3S60P?
My Electronics & Hacking Show My bad,yes it is 3S60P
it is higher amp pack 3 in series 60 in parallel
Krish - oh ok. I would start by heading over to the battery university website and reading enough so your confident about your approach. That many cells will give serious current and you will need to think about active balancing and power handling. Without seeing everything in detail I would be hesitant to give partial answers. That's a BIG project!
appricate that,will wait for that
how to connect 10x18650 to use them for ups backup? 12v
- It depends on how you intend to charge them and how many amps you need from your UPS but you can always connect 10 packs of (3 cells and a BMS) together in parallel to get a large 12v battery pack.
+My Electronics & Hacking Show in put 2a out put 5a for laptop and cell phone
Hi,
Tried it. I have 11.8v at P1/P2 but my bluetooth module won't power on.
Tried a separate 12v battery and bluetooth module powers up fine.
Any thoughts?
- Sounds like your reading a voltage but don't have any current coming out of the BMS. Try the charge trick to get the BMS to activate. Connect a charger or 12v power supply to the + - of the BMS for a second or two. That should activate the BMS and all should be good. Cheers.
Tried that. I can see voltage at P+ and P- but nothing goes out to the terminals to power the bluetooth. Eliminated the BMS and now it's working but no protection. Thanks
- You can test the BMS IC itself by bypassing the p+ p- pads. Connect you multimeter to the main negative that all (or the last) cell is connected to and probe each pad until you get a 11.8V reading. Connect your bluetooth module to those two pads and if it works then the BMS IC is damaged or not activated correctly. Cheers.
a pity, no led for the indicator charge
One link for a charger!
And whats the difference between the protection boards which are 10A and other are 25A etc.... For 3s battery pack
- Hi. The only real difference is the rating of the components and IC's used. Many claim 10A or 25A which is the rating of all the power handling FETs added together. You should be able to push or draw 10A in and out of a 10A BMS. Most 18650 cells (not IMR) max out at 5A each and you would never charge at 10A anyway. If you has 3S2P then you could pull more current (up to 25A) from a 3S BMS. Cheers.
I have 3ps 18650 of 1500mAh capacity
I will have any problem with the charge and the discharge of the batteries? If i use one board with 10A or it will be better one with 6A?
- The 10A or 6A depends on how fast your project will drain the cells. If your project is less than 4A draw you should be fine with the 6A. Otherwise go with the 10A. Cheers.
My Electronics & Hacking Show Oh ok thank you for your help
i have this exact chip and was planning on supplying power from a deep cycle lead acid battery. I tested the BMS 3 cell with a 15v 5a power supply and the BMS was heating up drastically. I then tried a 12v pack and it cooled down instantly.
would i be able to use 12-14 volts to charge a 12.6v pack? or will it overheat like 15v?
I have already built the encasement for the device and adding anything extra would look really stupid. I Tested the charge at 15v and charged the batteries to 11.1v without explosion. also the device will be connected to the 14 volt lead acid charger which is powered by a generator. It will be outdoors all summer but i sealed the case really well.
Am i gonna have to make an inline voltage regulator in the charge cable? or could i get away using the 13.6 volt lead acid?
Hi. The BMS is only a protection circuit so it doesn't really handle power regulation. It just stops more than 4.25v going to each cell. To keep everything happy you need to feed the BMS 12.6v. If you use a higher voltage you are forcing the BMS to continually kick in the fets to stop supply of the excess voltage you are sending it. It won't last and will get very hot. You will need to find a way to supply 12.6v max to your pack. Remember the BMS is not a voltage regulator. Cheers.
Just use an adjustable step down voltage reg and set the max voltage to 12.6v. They are cheap and easy to get on eBay. Cheers.
but they do not supply constant current do they? also could i get away with using only a 3a step down? would the step down fry itself?
- there are a few LM2577 based boards that have Cc Cv on them. Also there are some that handle 4a ok, with little heat sink. All are cheap enough and should work ok. Shop around if you must have 4a or more current going to the pack. Cheers.
well thanks for your help but i guess ill have to tear apart the casing. hand made balsa wood case with clear coat varnish. ARGHHH! took me 4 hours to make it. but ive learned now that i need a balance board and i can't just make that inline with the charge cable. Also i might replace the batteries with protected ones for added redundancy since this project is for my dad who know nothing about lithium.