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- เผยแพร่เมื่อ 23 ก.ค. 2017
- I have been asked about how I charge my Li-ion battery pack before. I made a video on that subject and put simply, I use a hobby balance charger. Using BMS or Battery Management System boards has come up in the comments. In this video I do some basic testing of a couple that I bought on Amazon. Now to be fair the red one is advertised as a protection board not a proper BMS and as a protection board it does an OK job. The second one, however, was advertised as a BMS though I would classify it as a protection board.
Here are links to the boards though I wouldn't recommend buying them.
30 Amp Protection Board
www.amazon.com/gp/product/B01...
20 Amp "BMS":
www.amazon.com/gp/product/B07...
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you're misunderstanding what these boards does. you don't get the same voltage at the end of charging, neither do you get the same at the discharge. it's normal. These boards prevents cells from being overcharged, overdischarged, and short current. Your test should have been to check that the charge stopped when at least ONE cell will reach the max value. It's the same for discharge, check that at least one cell reach the min value. This will protect your pack from having cell damaged. At the end it will save your pack from being destroyed. You should have had a voltage history of all cells to give a proper conclusion.
Hi I've noticed many blames the board, actually they should take a look at each cell of used laptops.
It took me some time to realize that MANY of these boards, even the ones INCLUDED in a battery are not BMS but merely PROTECTION boards as you have discovered here. It explains why some batteries cut charging or discharging off too early; no cell balancing is done, and some cells eventually go too high or too low while the rest of them are fine, but these protection boards simply look at the worst one of them and cut the whole pack off.
Thanks for the run down on those boards, i was thinking of purchasing a few but now im thinking twice. +1 on the Arduino balancing, i too was thinking of using arduino as a smart balance board.
Your analyse got some good points.
A lot people dont understand properly how to use and what are those boards, and then get disappointed from them, and give them bad feedbacks because they did not happen to be what they were expecting them to be.
Yeah I know they lack the balancing feature,but some other got it, and of course they cost more.
Anyway, from all the info gathered, those simple model board, I mean mainly here without BMS are best used with battery of same capacity, at that time you are kind of doing a pasive balancing, when they are discharged and recharged by you, and also the board itself managed the overdischarge and the overcharge protection part, of they lithium dudes, that kind of important I guess....
After a few months, if is recommended to balace the cells individually also! Best , is to fully charge batteries before connecting the BMS board....
And now about the charging!!! Those board are not charging board for God seck!!! A proper charger should be used to charge them!! Most people arround apply 12v to charge them, and that is wrong!! Check around about the topic.
Excellent video, I was just doing testing with the red board myself. You made me order new multimeter as mine was el cheapo Biltema and ordered PeakHold-clamp multimeter with bluetooth-function :) I'm trying to confirm my findings with your video, but I might have some wiring issue as I read around 5V from P+/P- but 11V from Bat+/Bat- (yep, pretty empty cells). Thanks for explaining things throughly.
They make boards with balance circuits for this purpose. They weren't designed to balance cells, so you still need to use a balance charger to charge them equally, or else you'll run into the issues you experienced. I've used two versions of these from eBay for a 3S and 4S lithium pack. They do what they're supposed to do to protect the cells, but I noticed that the short circuit protection is indeed lacking. There's no substitute for proper charging.
Nick Bruns
Hi I want to replace my 14.4V NICD for my drill with lithium batteries.
I thought about
- 4x 18650 high drain in series
- 4S BMS
- CCCV charger 16.8 V
Should I use protected or unprotected 18650?
Is it cheaper to use a 16.8V CCCV charger or a charger board with a generic ~20V charger? Thanks!
Im really in a need for proper bms.. i saw one guy replacing protection chips on a green board with different ones so it shunts at 4.2 instead of 4.27, im wondering in addition to this, could lower resistance resistor be used for shunting to get more powerful balancing?
I believe that the red BMS board was designed to handle up to 4S, but they only put parts in for the 3S.
You can probably add a few parts into the empty spots to make it into a 4S board.
Yeah you're right. I looked up the datasheet for the chip that it uses and it has an enable pin that allows for 4s.
Good video, but the protection board maybe is not bad. The cutoff voltage of the DW01 chips is about 4.25-4.35v depending of which version is, so maybe that is the reason why the source was not disconnected until at least one cell has reached 4.3v. This is not the best for just a protection circuit but is perfect for a balanced protection circuit, because the balancing chip starts to works at about 4.2v and if the protection circuit stops the charge, then the rest of the batteries will not charge until the one that has triggered the OC protection will release that protection. That will not happen because the release voltage of the DW01 is lower than the release voltaje of the balancing IC.
About the 30A of the second BMS, maybe it can, because with a 6mOhm mosfets every one will have to disipate only 1,7W.
This boards is not bad if you use CC CV charger and additionally ballacne board. They cost is very chip now. You must buy BMS with ballance in the same PCB and test it :).
"Let just short these out and see what happen"
*Ali-a intro*
The balance charging boards are limited in their balance capability.
They 'balance' by shunting current around the cells with the higher voltage on them to the cells with the lower voltage on them.
BUT they cannot shunt large amounts of current.
They can't shunt amperes of current; they can only shunt milliamperes of current.
If the cells that's bad cannot reach the proper voltage with an extra 200 milliamperes of current then it will not balance with the others.
Hopefully; after a few full charge/discharge cycles your cells will balance.
If they do not balance after a few full charge/discharge cycles then you have a bad cell or one bad cell in your group of parallel cells.
.
If you are not sure of the condition of the cells, then charge at a much lower current; like 1/4 to 1/2 ampere for a few full discharge - recharge cycles, because then the balance board will have more control over the individual battery voltages.
.
Balance chargers that are large and external to the battery pack have much higher balance current shunt capability so they can charge at a 2C or a 3C rate and still do a good job of balancing because instead of being able to shunt only 200 milliamperes; they can shunt amperes of current if necessary.
Yes that is exactly how they work. The problem with these boards is they simply don't have the shunt resistors at all. All of those little resistors on that green board are 1 meg or higher and the red board just doesn't doesn't have much for resistors on it. I was checking for current returning on the different leads of the balance connector and there was nothing flowing through them when the voltage was higher than what it should have been. The only current that ever flowed was on the main positive and negative wires. As for external chargers the cheap hobby grade ones actually use the exact same method that these boards are supposed to and are only capable of handling like 200-500 ma of balance current. But those chargers are smart enough to limit the current going into the battery pack to whatever the charger it capable of balancing if one of the cells starts going over. It is also worth noting that the amount of current going into these packs was under 1/2 an amp at the end of the charging cycle and the balance was getting worse every time I put a charge cycle on the pack with these boards attached.
The ones that have no power resistors either turn on shunt fets full time; or pulse width modulate the fets to adjust their average current flow.
Most of these have a maximum shunt current of 60 Ma. or less to keep those tiny fets from overheating.
.
Whoever EDITED my post to add the following paragraph is providing BAD information, and making it look like it came from me!
I don't know how it was possible to do that, but I do not appreciate it!
You would gain NOTHING by shunting good cells during discharge because the batteries are series connected, and no matter how much current you shunted around the good cells, you would still be limited by the bad cell to the same extent you were before...
BAD INFORMATION BELOW THIS LINE...........................................................................................
.
Be aware that there are two types of balance boards out there.
The most common ones are called bottom balance boards and do little or nothing during the charge cycle but do all their 'balancing' during the discharge cycle; at which time they shunt more current from the GOOD cell(s) to make up for the smaller currents available from the bad cell(s).
The end result is that when balance finally occurs; all of the cells are 'balanced' to the weakest cell in the series....
You will NEVER get full capacity on discharge with a bottom balance board; but the batteries may last longer and only suffer a lower maximum capacity rating.
I use TL431s with an external pnp transistor as a high power shunt check the TL431 datasheet
even with balancing circuit .. if the balancing current ability is too low .. the overcharging will still happen ..
Witch is better in that 2 board
Is the low voltage cut-off for these protection boards based upon the lowest cell/parallel group voltage during discharge? So that if we had, for example, a 3S2P pack with one cell that wouldn't take a charge well resulting in relatively rapid depletion of its parallel group, the protection circuit would shut off the load when this weaker parallel group reaches the prescribed minimum criterion?
Chicago John Yes. It only applies to the series cells. If one cell is low, the protection circuit will cut the output regardless of the other batteries condition. You could have them way out of balance. These boards don't balance cells, so it will over charge some cells until the total cutoff voltage is reached. This is why you need a balance charger to get the most out of these boards and protect the batteries. The balance charger won't allow you to charge a pack that's below its high/low voltage thresholds.
Read a comment that if you short p+ and b+ for a sec or two it will activate the board. Also all power goes in and out of p+ and p- unless you keep it transferable from pack to pack
It is auto cut charging if voltage 12.6v?
And cut off discharge if low voltage? If yes!!! What voltage discharging cut off??
Help me plis answer?? Sory
Im bad anglis language...cannot understand when listen you.
mybe i can do if you write the answer.
Thanks
The BMS boards I've looked at seems to have balance functions and only cost from 1,5 to 3$ on average with shipping over at Aliexpress.
thats the same as shown in the video. and they do have balancing but only able to shunt 40-60mA, and not during the charging, but at the end
Need I make it the 3S 18650 without this bme protector.. bro? and.. is this bms so suggested for device works?
Please specify the maximum voltage to stop charging
And also the minimum effort to stop work
The BMS S3 controller
Lithium ion battery of 351 volts of 95 cells came with its BMS but I'm converting it from 351 volt to 48 volts for my inverter. Can the stock BMS still work with it if stepped down to 48 volts configuration?
So these BMSs are basically to protect under-volt? and not friendly to charge for balancing? What if have bms on pack like 5s and as well add 5s balance cable as well and charge with Imax.
in fact there are sellers say they are bms but it is not, they sell and in the advertisement with balance or without, you that mark the option at the time of purchase, but very good video to alert people.
Non balancing chargers can be ok because it takes 100 charges to disbalance equal groups of lions in my experience, after which you can use an accucell to rebalance. if you can use a 12.3v charger on it then you ensure higher final cycle number because 4.2 wares them out twice as fast as 4.1.
i don't see a problem with slightly high voltages. my phone charges upto 4.4 volts
Technically, battery chemistry degrades if it's at the wrong voltage, and 4.4v used to be a fire hazard for lithium ion. Lithium Ion reaches 100 percent charge at 4.2 volts. If you carge to 4.1v, it's officially been measured that your battery will last 800 charges until it has 80% of it's original capacity. if you charge to 4.2v, you will get only 400 charges... If you leave the battery fully charged at 4.2v for 3 months, some chemistries will lose 20% of their capacity compared to a new battery. You can use 4.4V to charge the battery, but there should be a switch to disconnect the battery close to the 4.2 range. Tesla for example, which manages 15000 dollars of batteries in every car, sais that you can discharge the batteries 3 times more cycles in the 80 percent voltage range than in the 100% voltage range. So, if you leave your phone on the wall at 4.2 overnight sometimes, after 6 months you will probably have only 50-70% of your battery left. the battery just mineralizes or something when you push it too high.
18:50 why weird? Simple VL(Low) VM (Middle) and VH (High).
19:09 VL not connected not sure why: well it is for the 4S version (in case you have 4 batteries in series this is the last, Lowest middle point). That's the meaning.
Yeah. I figured this out later after looking through the datasheet a little more closely. Someone else pointed this out before as well. If you ask me the diagram should state that it is not connected to anything.
The board is configarable for 3s or 4s by selecting 3s or 4s on pin 10 of the chip 8254aa
I have the green unit and I checked the balance of my cells through the charge and discharge processes. They were all within 20 mV. Also, it shut down discharging when any one cell reached 2.5V. Likewise it shut off charging when any one cell reached 4.25V. Therefore for me it worked as described. My cells were identical part numbers that are capable of 4.35 V charging and had previously tested between 3100 and 3500 mA*h capacity. So I am not sure how active the BMS is, perhaps I was just lucky to have good balance. I suspect the unit is a battery monitor system not a battery management system.
I have the red unit, well what looks to be an upgraded version but still using that same chip, its like they listened to all his complaints in this video, the pads are now nicely spaced and it cutts off as soon as one cell hits 4.2, but thats the problem, the other cells are stuck at 3.7. I guess if you had them even to start which i didnt, it wouldnt be so bad. So if you just discharge that 4.2 cell then the bms should start charging again? i wonder if you could turn this into a proper bms with a micro controller and some discharge resistors. Seeing as this doesnt haven any discharge resistors, i dont see how it could do any balancing, at leaste mine wasnt advertised as a balancer either. Once the MCU senses the bms stopped charging then it would find the cell thats 4.2 and open a mosfet to let it discharge woudl be the idea. I wonder why this wanst included, simply adding huge discharge reistors made it too much? hmmm
So it keeps pushing voltage even if the others are full. That means you really need a good balanced pack from the start. That means for discharging to. It leaves others high when it cuts off.
Yeah, but over time they will slowly drift out of balance. Even if the batteries are brand new.
Eman2000. Maybe extra balance leads connected seperately to your batteries for a balance charger for periodic balance charging. More wires :-( . Why even bother with these things.
in fact there are sellers say they are bms but it is not, they sell and in the advertisement with balance or without, you that mark the option at the time of purchase, but very good video to alert people.
Would it be okay to use the red 4s BMS PCB with a 4s lipo using the balance port to connect to the BMS is this okay? Any help is appreciated. Thanks for the video.
So if I would find a working 18650 charger BMS with charge equalization - could I connect it directly to a solar panel with the right voltage? Like a 4S battery on a small 100W 18Vmpp with 5 amps or something? (Looking at "4S 30A Li-ion Lithium Battery 18650 Charger BMS Pack PCB Protection Board 14.8V")
I figure since solar panels are constant current, the voltage drops from 18V to to the battery voltage of below 16.8V if the batteries take enough amps. Then when you get up to full charge the BMS would just stop.
Does this work?
Or do I NEED a PWM (or mppt) charger?
I'll check out your arduino BMS too, looks exactly like what I'm looking for!
Yes you can connect a solar panel strait into a BMS. Might not be the most ideal way of doing it but it should work just fine.
Which bms you use in this video
for 2 years i have been usin that 3S 20A dw01 board with a 12V 1 A adapter, backup was not complete , i knew the cells weren't getting fully charged, now i got to know about those 4 wire balance chargers, so i connected the wiring to the 3 cells the voltage showed 12.6 volt after all leds turned green, i disconnected the charger & now no 12V o/p , no components smoked or burnt, or do i have to apply more the 12V to activate the board.
have you found any economic balancing boards since you made this video?
How many cells are you trying to balance?
@@Dennis-mq6or , i am looking for something similar please, any help would be great, 3S and 4S ; Atleast something that cuts off at 4.2 ~ 4.25V ; I bought a few of these, all sometimes go beyond 4.3v per cell and cells get warm, And Almost all of them failed short test, my Output leads were about 16 ~ 18AWG.
@@MkhanEmkay ,
The DWO1 devices are there to protect the batteries from overcharge , overdischarge, and overcurrent during charging or discharging...
There is usually a completely different device used to 'balance' the cells and ONLY works during the charging process by diverting charging current around the cells with the higher voltages to the cells with the lower voltages....The diversion is usually through resistors, although I have seen fets used for that too. The safest scenario is fets in series with resistors to reduce the power dissipation in the fets.
If you have a weak battery that is higher than normal internal resistance, that battery with reach the maximum charge voltage first, and also reach the maximum discharge voltage first.
So your entire system is only as good as your worst battery or group of paralleled batteries.
The overcharge and overdischarge current limiting works by measuring the voltage across the active FET device(s). One group used for charging and the other group used for discharging
Long before you start using your BMS board on a 3S or larger pack, you should balance all the cells first by putting every one of them in parallel and fully charging, (around 4.2V), and fully discharging, (around 2.5 volts), them a numb,er of times. This is often called ''TOP BALANCING'.....
(the voltages I gave were for standard LiIon batteries. If you are using different types of batteries such as LiFePO4 or Lithium Titanate, the voltages will be different).
I hope that helped a little.....
@@MkhanEmkay ,
I found a video that might explain what I was trying to say in greater detail.
At about the 5 minute mark he shows a typical BMS with Balancing schematic, explains what the parts are, what they do, and where they are on the circuit board.
th-cam.com/video/OG-UUXEOZ8E/w-d-xo.html
Hi i have a question about the first board that you tested 20A Green one i have the same one but mine does actually ballance the cells as i had a old battery protection board from old laptop and my cells kept getting out of ballance cuz they were diffrent cappacity altho once i added the other board the cells slowly ballanced iam not sure how it does that but my batteries now charge up to 12.6V all batteries at 4.2V any idea how it does that? Same charger same battery pack
Will this board cut charge if you have an unbalanced pack connected it to it?
I have 3s battery pack that doesn't want to charge I don't know if the problem is from the BMS or no
Hi
Bms HX-3S-FL10A. is the protection or only for charging?
Great video..… but I am looking for a "Lithium Cell Charger Module (BMS) with Battery Protection board" that would output a 18V (5S) system..... any thoughts????
Any laptop battery pack. They have everything that you need.
My battery has 76v but I only have 12 volts coming out of my daly bms with no load. Is that okay or is it shot?
Hi i have a question about bms....If i put a bms on my battery pack ,do i still need to put a balance cable on it as well to connect to my balance charger ? ,if yes do i need to put it on the bms or do i just put it on the battery like the normal way?
If you get a good BMS that actually works there isn't a need to charge it with a balance charger.
I feel that all chargers should have CC/CV to Properly charge the lithium packs I do use a balance charger From time to time But normally on the smaller BMS boards , what I look for is over voltage and Short circuit protection and out of balance protection.
I've just done some tests on this board. If I have 3 cells, 4.1v, 3.33v, 4.18v and start charging, as soon as one of the cells (the last one) hits ~4.26ish it cuts off charging for ALL of them. While I understand this is not a balance BMS, I thought the behaviour was that it only cut off the charging on the individual cells that are already at max and continues with the ones that are not (the 3.33v one)? Is this the experience you're having?
What you are asking for is too much to ask for such a simple circuit board. That would require dc dc converter board as well. It’s just too much for this board
It cuts off charging of the cell that went to 4.26. It will use its resistors to burn excess power in that specific cell and charge all a bit more. Once the most charged cell just 4.26 again it will burn excess power of that cell and charge the whole pack again. If you are thinking that very slow and inefficient, you are correct! You should balance as good as possible all the cells before assembling the battery pack. I know you were purposely trying to test it with imbalanced cells
Is it possible to charge one cell with this 3S board?
I don't see how you could even think the boards did managed charging.
The pictures of the boards show no parts on them that could do such a task.
Using a current-limited supply is really all you need and that is more or less a generic item already.
You can in fact use a high-current LED driver for fast charging as the protection board will cut off at the right voltage and the supply is a constant current type driver.
Not ideal but works.
so what bms would you recomend for a 3s 1p system? thanks
I don't have a recommendation. I haven't found a good BMS. Right now I still think using the hobby RC battery chargers is the best bet for smaller systems.
Use laptop battery packs. The have the BMS built in. For 3S just find old Netbook pack, they were 3S1P
I was thinking about this. use a DC to DC converter . about a 300-600watt. with cc and CV. and use a BMS to charge the pack. but I have seen BMS boards allowing up to 4.35 volts I had one it went to 4.4v . I don't want that to happen in the pack. I dont think it would be that much of a issue. if I use a DC to DC with constant voltage and current. wit the volts in at 4.2-4.3 . keeping cells at at least 4 volts per cell. but I'd like to see what you come up with. I need to charge my 12 volt lithium battery. from my 24v lead battery bank. is there a better way to do that? thanks.
That seems like a good way to do it (just make sure to use a diode to prevent the batteries form potentially passing current into the buck converter which will damage some of them). I think I have a couple of plans coming together for balancing...
What is the right BMS for 4s 10p battery pack ......cells are 18650 3200mah .....what is the current rating of bms ??
Hmmm, I think I would want a larger gauge wires on the load negative and the load positive wire from the batteries to the BMS board.
usually yes, but here load was monitored and low enough to be fine with these wires
A battery pack can only provide the capacity of the smallest (weakest) cell, so the 'balancing' that keeps charging the bigger cells to full does nothing but increase charge time and generates heat and reduces their lifetime. Once the weakest cell is fully charged, there is no good reason to keep charging the rest. And same for discharge, once one cell is fully discharged, there is nothing left.
These boards do this job. The next level is to shuttle charge from the stronger cells to the weak ones to get more capacity, which is a way more complicated design and only worth it if the cells are poorly matched.
Recently y build a 3S battery pack (3 cells) with a 12v - 10 A BMS board. In the pack get 12,5 v but in the output of the BMS board only get 9,8. Is this caused by a partially discharged cells or something is whong on this board?
-------------------
Solved. Was my fault, output terminals needs to be connected for the two sides of the board.
Any cheap circuit available which can balance charge 3S Lithium ions ?
13:21 why we need to turn on by the transformer, how can it turn on automatically?
Dear expert! The 3s 20a BMS module arrived yesterday. I used 3 industrial LG cells and assembled the circuit. The cells are charged to 4.15v. Only 5.15v voltage appears on the output! What could be the problem? Can you help me with this? Sincerely, István
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
It doesn't really matter. The point of the BMS is to be able to charge and balance the cells.
Eman2000 Thanks!
...thanks for your tutorial, I'm building a PS2 portable but recycling a lcd screen from a netbook that use 12 volts, well I used 2 the red BMS but connecting 3 batteries for each BMS in serial and connecting each to the other in paralel generating that 12 volts for the lcd and the playstation 2 board (It wants 8.5 volts), my question is, what can I use for check the level charge?, I charged it for 4 hours and I can use my portable for 1.5 hours, Is there a small display in the market that I can use to check the level charge?, thanks for the answer!
the dw01s over voltage is 4.3 volts so its normal for the battery cutoff to be that high
need some clarification on BMS can be suitable or not. if I use (3.7*4)4S,30w BMS can be used for (3.7v*2)2s,30w BMS
I want to make a battery pack of 3ps 18650 with 1500mAh each one.
How i will choose the ideal protection board?
(Because there are different boards for a 3s pack with different A)
For a pack like that, you will want a lower amperage rating. Something along the lines of 5A. Either that or a higher amperage board with a conventional fuse.
Eman2000 ok ty
Voltage high ? Not bms?
Dose this board increase "C" rating in output ..?
No, the C rating is entirely dependent on the batteries.
which one to buy ?Red board or green board ?whichever performs better bms job
Don't buy either of them.
The Bms can automatically off when the battery is fully charge sir!??
Pls can I charge 60p 3s 18650 batteries using the so called 100A 3s to 5s white colored bms using a 15v 10Acharger?
My 45amp mppt solar controller charge my batteries when I set it to 12.6v extremely slowly 1.5a (all settings were correctly done on the controller. And I have 1500w solar panel.
But when I set the charge controller to 15v, it charges with up to 12A.
My inverter charges batteries with 15v when connected to ac mains. I am scared to connect my battery pack to it.
Please help
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)
Thank you for vid..
Thanks for watching
Someone else trying to put his videos across as scientific evidence when he has dud batteries and a completely unregulated power supply. Try a regulated power supply and clamp the current at the Max C charge rating for these cells.
You should be powering it up at 12.6V and the current should probably be clamped (kept constant) between 2 and 3A for those cells (depending on what they are).
And why would you do a charging demo on batteries that were basically fully charged. I can see your point but the balancing will happen at the cells top out and the other cells come up to meet 4.2V They can't overcharge if you clamp the feed current. If they do overcharge it's because they are dead anyway. For example. If 2 strings in the pack are at 4V they won't be pulling much more than 0.2A as they are nearly charged but if one cell in the string is at 3V it will be taking the full current 3A for example, but you say there are 3 in parallel so those 3 will all be pulled down to 3V by the bad cell and then they will all be trying to take the 3A available. Now, it is possible that the bad cell will be soaking most of this and stopping the last 2 cells from reaching 4.2V but it is also possible that the bad cell would reach 4.2V quickly if it was on it's own this leaves the other 2 lagging behind pulling most of the 3A available when they should only be pulling 2A.
If all cells are in good shape then they will share the current you are giving them correctly.
There are two ways. Either use a power supply that is rated at your max C charging rate as it runs flat out. Or use a power supply that provides a constant current of your choice at any voltage totaling to how many multiples of 4.2V you have in series or 4.2V for a 1S charge.
Brother Please reply...
I want to use MI power bank as a UPS for router...
Is it safe..?? 24/7 plugged into power..
It should be fine. If it is not designed for that use, it may not last but it is probably ok.
Witch is better sir?
22:23 - 12.68V is high why? 12.68 is OK
look: 12.68/3=4.226V per cell; the charging voltage per cell is ussually 4.2V Max +- 1%
it mean you can have the cutoff limit from 4.158V to 4.242 V (to be precise)
You have 4.226 which is OK.
Of course only in case of a perfectly balanced cells, which is usually not the case. Therefore this kind of measurement (to measure voltage on colplete pack) says nothing.
22:40 - center cells were at 4.3 while the pack was charging...
Why not use 1 4.2 volt zener diode with a .1 ohm resistor in series, with both of these in parallel with each battery
That's not actually a bad idea for a simple balance circuit. Nothing but a beefy zener and a resistor. I may have to experiment with this.
hello bhai mai 3s 40A ka bms liya hu pr usko jb battery se connett kr rha hu to bms heat ho rha kya problem ho skti h maine bms dusra v lga kr try kiya pr wo v heat ho ja rhi h connection final hote hi
please reply fast.......
If the red board doesn't balance charge then what are the four MOSFETs for?
They just turn off the output if a cell goes over/under voltage.
Edit: you’re right. These boards are shit.
If that was the case, surely only one MOSFET would be needed. It’s a 4S board, with 4 MOSFETs; surely they balance charge by momentarily shorting each battery that finds itself over 4.2V?
No, it doesn't do that.
Eman2000 yep, you are correct. The 4 MOSFETs are connected as one in parallel.
Can someone please make a good BMS board PLEASE???
🤣 it put in 12v 3s 12 ah battery and charged with ups some of the cells get very hot 🥵🥵 that scared me and now I threw the bms which I was using 3s 40Amp into trash and purchased a balance charger which is extremely good 👍
I put 10ohm(5w)+2.7(2w)ohm in series with the cell charged with variable psu. The series resistor used to limit current and somehow decrease current as the voltage increases. Poor man(or lazy) solution to trikle charge.
What's the input voltage range? Can you go more then 12.6 volts?
No, these things don't handle anything above 12.6V very well.
Eman2000 do you have a recommendation, I want to replace a lead-acid battery where the charging voltage is 13-14.5V. I figured it would be too low for a 4S configuration, so Im thinking to get a 3S with a BMS that’s equipped with a voltage regulator of some sort.
@@PatrickHavilah 4s should give you 16.8v if fully charged. And 14.1v or a bit lower when discharged.
Azim Alif the problem is the charging voltage of my car is only around 13-13.5V, so the capacity (voltage range) between 13.5V and 16.8V would be unused, and the only usable voltage range is 12-13V. Meanwhile, with 3S configuration, I would be able to use the capacity range of 10V to 12.6V (I believe the car would still crank with only 10V coming from the battery)
@@PatrickHavilah 3s should work then. Problem is, alternator pulls a lot of current. Bms with high current output gets pretty expensive.
HX-3S-FL25A i got this one....seems ok
I've tried 3 different eBay 4s BMS's and none of them output. nowhere did i see on the sellers sight anything about activating them. do u think this holds true for almost all bms boards in that they need to to be activated?
I would imagine that most of these boards need to be activated. From what I have seen it seems as though it is usually a selling point if they don't need to be activated.
toobglued The eBay and Amazon boards pretty much come from the same factories in China, so the components/IC's and engineering are going to be the same for each model or version. In my experience, the 3 and 4S boards need the 12V input to activate.
12:53 If you have to do activation like that it makes it completely useless for dedicated projects.
True
@@xgamerbih I've tested 3 common BMSs since I made that comment and all have been garbage. I've just today tested a much more expensive "Active" 3s-7s balancer and it only got cells within 300mV of each other, instead of the 30mV it was advertised as. Very poor.
John Michael Stock I’m sad to hear so. I just bought a 3S 25A cheapo one, and thought that all the issues with balancing will be solved with using it... I guess not.
Added a capacitor to output
Please help. I see 0.15 V between P+ and P- . Why?
first time you connect the battery to BMS, the BMS is not active yet (for protection). To activate it, you need to connect the P+ and P- to the 9v - 12.6v power source.
@@tokojeleksurabaya9716 Hello again.
It stops for forcing when the drill is working. and bms goes into protection mode. then how can I start the drill again?
@@kermdncer9981 disconnect from the load for about 5 seconds. Then the BMS will active again.
Is it stop charging when the battery was full charge?
They overcharge the battery by quite a bit.
Have you tried the Noco genius G7200?
No, but I just looked it up. You still have to have a BMS on your batteries in order to use it (says so right on Noco's website). Also I have only heard bad things about Noco electronics so I probably wouldn't buy one.
U can turn the 90min safty off
DROK Numerical Control Regulator DC 8-60V to 10-120V 15A Boost Converter, Constant Step Up Module Adjustable Output 48V 24V 12V DC Power Supply with LED Display
this is made for charging no diode needed and also this depending on which way you want to go i went with the step up due to my 4S
DROK DC-DC Buck Conveter Digital Control Voltage Regulator 10-75V to 0-60V 12A 720W Step Down Transformer with Volt Amp Capacity Time Meter Power Supply Module with Constant Voltage/Current
older post but some one may read it some time or another
where does one get a good bms , the amazon ones seem like junk , how is it suppose to be applied to a battery pack , another video says it still doesnt even charge the batteries properly !
Where can i find a schematic? / pdf ?
The Amazon links should have the wiring diagrams as part of the product images.
Eman2000 hook up was easy to find. The schematic was much harder .... and part lables did not match but what i did find helped me to make modifications
KC7NOA yeah they aren't open source boards so actual schematics aren't really available for these.
Hello,
I made a 18650 lithium-ion battery pack. It holds 30 cells: 3 rows in series, 10 cells in parallel. This brings it to 12v, 22amps.
I purchased a 3s 25amp bms board from eBay model# cf-3sjh25a-c
The balance problem is not an issue, because I can easily charge each individual cell every so often in order to bring them back in line with each other.
It seems to work fine.
My question is, can I leave it plugged into my 12v lead acid batteries which I use for my cabin. The lead acid batteries are charged from a 30a MPPT solar charger.
I'm trying to slowly transition from lead acid to lithium-ion on the cheap.
Thanks for any help.
I probably wouldn't recommend leavening them hooked in parallel just because of the voltage difference even if the board does technically disconnect them. I've heard of people setting up a small secondary system of lithium and using that to run some things and keeping their big lead acid packs to the heavy work.
Eman2000 thanks for the advice, I have come to the same conclusion. I have also noticed that the BLM unit wants to over charge my lithium batteries. Will definitely need a separate adjustable voltage charger. And keep them separate from the lead acid. Thanks again.
Linda M you're welcome, glad I could help.
Iam about to make the same set up for my cabin
It’s hard to work out what to do with so much conflicting information that is on line so I will try it and put it outside in a blast proof shed just to be safe lol
Matthew Walker you should join this Facebook group: DIY Powerwalls, if you have not already. Great place to ask questions. Learn as you go. Here is a small pack I made just for now: facebook.com/groups/diypowerwalls/permalink/590059184673980/
You connection was incorrect. Read manual.
P+, P- are for charge and discharge.
No it was correct, that's exactly how it was hooked up. These things don't really have manuals either. I showed the wiring diagram that I went off of in the video.
to balance cells why not put them all in parallel and leave them for a while? worked for me
Because even a small difference in voltage can cause a massive current when a higher voltage cell is draining into a lower voltage cell (remember, you're short circuiting multiple cells by placing them in parallel). When larger battery packs are made commercially, the cells are precisely balanced before the parallel groups are made so that this doesn't happen. The BMS alleviates this problem by slowly draining each series group through a small resistor if they're too high a voltage compared to the other cells.
@@ethansuter9095 Good point. I would never hook near flat cells with charged ones for the very reason you mentioned. For what I'm doing I admit I don't know what kind of current we're talking about when the voltage difference is barely a volt. The whole purpose is to get the cells to meet the stringent voltage match requirement of the typical balance board. In any case it did work so I guess I got lucky
@@ethansuter9095 1.700 ohm resistors prevent over current
I've been struggling with the green 3S 20A board for a while....and now I realize that I have to apply a load and then apply charging current while the load is connected......Jesus, Joseph and Mary who thought that was a good idea???? Do I have to do this every time I restart the load? I wanted to use this on a drill battery but then I'd have to add a charging port and hit it with a charge every time I wanted to use the drill.
I really hope I'm wrong and its just a one time thing
해석이 안되네요;; ㅠㅠ 둘중 어떤게 밸런스 균형을 지원하는건지 아시는분 댓글 부탁드립니다..
cant see what your doing btw camera angle is not very good
3 cells hobby charger ezpz. Try 10 to 14 ebike. Pain. 3 cells nothing
Very interesting information. I hope what I've learned here is correct though.
People judge our intelegence by the words we use.
The name of the technology is LITHIUM not LI*N*THIUM.
The non word ACCROS*T*, instead of ACCROSS, is commonly used by the poorly educated of Ontario Canada. You sir do, not appear to be uneducated but speak like you are.
Yes, I may be picky but using correct wording and pronunciations of words shows others that thought is being used before speaking.
I share these constructive criticisms for your benefit and success.
Good luck.
Don, if you are going to speak down to someone about "intelegence", please learn how to spell "intelligence" and "across" first. Get off your condescending high horse and just appreciate the message he is trying to tell you.
@@djp9747 It is a bit distracting though. I almost commented about the use of "across-t", but then I saw that someone already did it.
How do you get a good bms for a diy battery pack? Isn't there any manufacturer making good bms's for more money?
I'm just starting to learn about building 18650 packs but I'm really surprised how most people just seem to trust the claims about the garbage unbranded chinese products they buy on alixpress or whatever.
@Eman2000 , i am looking for something similar please, any help would be great, 3S and 4S ; Atleast something that cuts off at 4.2 ~ 4.25V ; I bought a few of these, all sometimes go beyond 4.3v per cell and cells get warm, And Almost all of them failed short test, my Output leads were about 16 ~ 18AWG. i.imgur.com/zqQOJLu.jpg
A proper way to is to use a cc/ CV power supply. The bms is just a switch
Any of this thing balance anymore my friend....... makers believe that when a cell differs from the others.... that's the end of life of the all battery pack......... you can get a Makita or Milwaukee or Dewalt or any other mayor brand..... and you'll see that not only are they NOT balancing them anymore........ but they are actually recharging them in series!!....... to push the cell that is different... to differentiate even more.... and make the entire package fail.... to make the user believe that the battery no longer works....
Your tester looks annoying. You need a second one to use for voltages.
All I can say, you have very good English-speaking skills with a good voice, but very limited battery-related electronics skills. You misunderstood this board. You are testing the 3S1P board with 3S2P(not really) . Furthermore, you need two boards and should not attach the battery like that. You may use DPS5005 or any other lab power supply to make the testing very easy so that you can monitor current and voltage.
Suss city
So, if you get a power cut on your charger, and you use this board to supply somehting in the event of a power cut.. it wont turn on, as it needs a turn on pulse from the charger.. which wont happen if there's a power cut.. yeah yeh ok.ok.. so you nede another batteryu power supply to turn on your battery power supply.. i wonder what hapopens if your other battery power supply wont turn on.. maybe youd be fcked..!
I I solved this problem by soldering in a capacitor to the output
Man, you comlicate the simple test. And what is the conclusion? Buy a profi charger.
The cables are very weak, this test is faulty.
Doesn't matter with the small amount of current I was pushing through these boards.
My very humble request, please acquire sufficient knowledge before making ignorant comments which misguides hobbyist more. Both the pcbs include BMS meaning Battery Management System. Also understand the limits of balance. Don't short the battery pack output so mercilessly, just once or twice, preferably through a current meter. The upper limit is different upto 4.4v & lower limit is also a matter of preference & may be even less than 2.5v. what a lousy voltage source you have for such a sophisticated experiment. Learn before you make such videos. Please don't take it in wrong sense.
omg try not to touch high voltage you will hurt yourself base electronics this board charge up to 5v 2A battery. you have 12v 18000mah (18A)how much current mah need to charge theam. learn the basics of electronics😲
You need to do some learning yourself 😜
so you think you need 18 amp to charge the battery? you can charge at any current
up to 1C.
most plug in lithium charger blocks also have current limiting in them.