You still are using a BMS. It's just separate with your configuration. Instead of having each battery pack having their own BMS, you have one for all the packs. I like it unless you need to charge more than however many the external BMS can supply. What is the maximum number of packs that can be charged at a time?
You have a 4s2p pack so each cell is 2 in parallel. So doing a balance charge like you are doing is better than nothing but it is still not going to overcome the problem if 1 cell fails. BMS is under the tip on the positive end of the battery and protects each cell being over charged in voltage and current and over discharged in voltage and current. You also need to use a special charger like you have as the batteries need to be charged in a particular way. First part of charging is constant current then it swaps to constant voltage to finish off until it achieves 4.2v.
Hey there Tommy Great video. Concerning the mains wire/cable, here in the UK we have imprinted onto the cable the following details; voltage range - cable size ( 0.5mm, 1.0mm, 1.5mm ) etc. etc. and an indicator conductor colour BN (brown) live, BL (blue) negative & YL/GN (yellow & green). Whenever I purchase anything that does not have a standard 3-pin UK plug BN (fused) BL & YL/GN (earth) I chop off the existing plug and rewire it with a standard UK 3-pin plug. Undertaking this lessens any main's cable-related problems that may occur in the future, and finally, UK plugs come with a fuse which two pin plugs do not. If in doubt get an experienced person to rewire the UK plug.
Let’s say it this way, it happen to all kinda of battery this way, not just Chinese battery. That is why we have and need a balanced battery charger for it, and by the way, thanks for explaining how to hoke up the wires, for most of us has been playing around with those electrical things, it is not hard to find out witch wire go where, but for some one who first time doing it, will be a hard time to find out how, or in a hard way to find out with a burned wires and exploded batteries. Great work, easy to understand .
( 6:30 ) ... exactly for the reason demonstrated at 6:33 those batteries MUST be charged individually to a perfect full charge before they get into those Parallel sets and they need to be rechecked now and then especially after heavy usage. Awesome video. Thank you for sharing
soldering in the middle of the bridge could melt the plastic covering the batteries in a spot that would be very likely to cause those two cells to touch where they are side by side. it would not be a direct short but could cause heating.
Nice wiring. You do realize however, that the hobby charger is functioning as a battery manager when it is charging? You just don't have a continuous one on the bank.
Tommy Callaway Great video , I would like to make a 12 cell pack wired in parallel to get around 22volts for rc planes as I am sick of puffy expensive lipos ,could you explain the wiring please ?
Nice video man. I only want to say that maybe you should not solder in the middle of the nickel strip as it is close to the edge of the battery (-terminal) you could if the heatshrink melted under the nickel short out your whole project!
If you want your camera to focus don't hold the target item in front of your eyes. Camera's are made to focus on eyes and many people don't realize it. Try it. It works.
How often do you "balance charge"? I have a similar charger (that design seems to be very common, rebranded a lot), with RC Lipo batteries I used to just monitor the packs and "balanced" them when the voltage differed between the cells by .2 volts. Balance charging is MUCH slower it seems. RC batteries are always 1p (cells are connected in Series to multiply voltage, rarely if ever, are cells connected in parallel). I think with Lipo it's too risky, also they have massive amp output so there is less reason to do this. If I understand this correctly the voltage you are reading is an average of that "Parallel group" which means that you could still have a "sick" cell in that group and it would read a normal voltage. I have broken apart old Makita packs and salvaged many good cells out failed packs, and seen exactly this case, there would be one "parallel group" that would read 2.9, but when I separated the cells there would be one cell at 3.5 and the other reading NO voltage at all..... These are 5s2p packs. Interestingly they seemed to fail because the BMS would draw off of one cell, when left on the shelf for long periods of time it seems to harm that one cell. Most of the packs that I have broken up have that one cell failed. Balancing only parallel groups would not show this as the good cell would try to overcompensate for the bad one and end up over charged....... The only solution for this would be to occasionally break up the packs. Professionally made packs seem to mitigate this risk by matching cells very closely in regards to capacity and internal resistance, but I suspect that it still causes issues as the packs wear. I am trying to create a pack that can be just un bolted and the cell taken apart and measured every month (this will be used on an ebike)
You're right. This is one of the most intelligent questions I've gotten on this video, thank you. That's something I didn't account for, and most professional packs I've bought don't account for it either - but a modular design for swapping and testing individual cells would be awesome. I would build something but I've gone toward filmmaking and camera-tech as my channel topic. Pinning this comment.
thank you for explaining how the wiring goes. true, many just assume others know hence the make nonsense of their effort because in the end, if you do not know how the wiring goes... it is just not worth the effort.
Thank you for this valuable info.. I do have a question though. You said you only needed 4 cell for the balance charger but your pack has 8 batteries. Is a single battery not defined as one cell? Hoping you still monitor this site since you have a new one.
Crocodile clamps on wires just "behind"/"below" the solder point, or place a normal Circuit Heat Sink on the left and right side of your nickel solder position to dissipate the heat from soldering if you're a new solderer and are unsure if you're about to overhead the battery because of prolonged soldering. Doesn't take much to dissipate the heat really, be careful out there! :)
People say Lithium batteries don't do well in cold temperatures. I wanted to ask if this also will make it harder for them to charge up in the similar cold weather since they already don't do as well in it? Thanks.
OK. So this can't really isolate each cell, it can only isolate each parallel set. So in this case, two cells at once since this is 4S and 2P for 8 cells. So the low 2.98 voltage is actually the voltage for a pair of cells. So this method can't address an individual cell, but can address an individual bank of cells. Have I got this right? Thanks.
+Jay Turberville yes, but it's the same type of isolation you get with a BMS. Parallel cells share the same voltage, the current is what increases, which is why this method works so well. Even if one cell in a pair dies it's safe, the max current would just decrease.
Tommy Callaway wouldn't the max current on the one remaining cell increase? Because you have all other dual cells putting XXamps in or pulling XXamps out but that one remaining cell will be the only one to match. The current should be the same through each cell in a series, the voltage per cell varies amperage per cell or set of cells should remain the same i thought. So if you use 5 cells then 2 them 5 the 2 should get hotter because more amps per cell are expected. I could totally be wrong though. I thought that's why cells tend to die as a whole group if left unchecked over time.
Awesome Video. I learned a lot. Small tip, next time lower the volume of the music or don't use music at all. Also the music chosen is not relaxing and do not help to focus on what you are saying and doing. Other than that, keep going. Great work!
I feel much safer recharging using a smart balance charger vs going through a BMS especially for like 100+ Amps for my application, plus its just really expensive for 200A 22.2V BMS’s and I would need 4 of them
QUESTION SIR; I have these 7.4v 18650 4400mah packs and they only have 2 wires, red and black, but they say they are 2S, but my 2S Lipo Charger balance plug has 3 wires, one for - one for 1S and one for 2S. How do I get them to charge? Thanks.
Good Video. I have Imax B6 Charger. It is has 6 cells balance socket. How do I balance charge if 13 or 14 cell ex. 13S4P or 14S4P. Do I need a charger with 13 or 14 balance sockets?
Nice job. Good videography, clear language, and very logical discussion of important points providing background for beginners. Looking forward to more of these. - Jim
I have a question regarding the wiring, the batteries are connected in series? and the wires you have solder in is for making them a parallel? could you add the wiring schematic so i can understand better
Decent explanation of balance charging vs. employing a BMS to handle that, and much more. For me, the bottom line is: If you care about your battery, use a quality BMS. The only reason I can see for NOT using s BMS on a non-hobby application (solar storage, etc.) is foolhardy frugality. Much, much too risky for me.
The charger he is using acts as the BMS. There are MANY chargers similar to his that do the same. And I assume you are aware that even a "quality" BMS can fail, so what then? I've been making 12 and 18v packs like Tommy for almost 10 years, charging them the same way and have never had one blow up or fail in a crazy way. And they last 3-5 years using them daily in my drill, sawzall, circular saw, etc.
@@cjoakman7715 First of all, a comment to a 2 year old post? Really? Secondly, you're just plain wrong. The balance charger doesn't "act as the BMS." Again, this video demonstrates the use of a *balance* charger. As a professional battery designer/builder, I stand by my original comment. The balance charger in this video provides over-voltage protection. That's it! It doesn't provide any other protections that a *quality* BMS provides. For instance, on the charging side, low temperature and/or over-current. Unprotected battery packs are just that, *unprotected*, and discharging without protection is recklessly foolhardy. Over-current and under-voltage protections are every bit as important as over-voltage and over-current. Yes, BMS's do represent a point of failure. However, in my experience, they reliably provide all the stated protections. I've never had a BMS fail. I have, however, had BMS's save multiple packs from dangerous conditions on multiple occasions. Additionally, those equipped with Bluetooth provide real-time information on battery condition. This, in and of itself, is worth the cost. There's a difference between *misinformation* and *disinformation.* As you claim to be an experienced builder, I'll label your comment as dangerous disinformation as you're knowingly encouraging inadvisable behaviors. Here's hoping your luck never runs out.
If its difficult getting to the negative terminal then scrap off an area on the batteries and connect to case. The case is negative. The case is a tube.
How do you know how many amps and volts to charge the batteries at? I want to make a li ion battery pack, I thought you multiply the rated charging amps for each cell by the number of cells and keep the voltage the same as it would be for 1 cell.
@@drabberfrog 20 amps no way. plus i dont know of any lith ion cell that charges tp 4.2 volts at 5 amps. a battery pack may have s 5 amp speck but please advise me what cell it is u are talking about and i will help u out.
@@sbolton3039 since it's 5, 000mah wouldn't you charge it at 1C? So the charge current would be 5 amps right? I have some LiPO batteries so I'm just assuming lithium-ion batteries are the same in that regard. I'm wondering how to know what current to charge a pack at and how would the batteries being in parallel or series affect the charging current.
@@drabberfrog cells hooked in series u add the charge voltage but not so on the amps. In any event i believe that with lithium nickel cobalt cells the slower u charge them the better it is for the battery but u may not want to wait so long for them to charge. As you increase the charge voltage the cells will charge faster but i believe over amping charge cycles kills the cells quite quickly.
How do u determine when to stop discharging on whatever u use these on? Do u run a lipo alarm or do u hope the controller your using will stop them for u?
Yeah one thing that's not apparent is it's not the wire that really makes the difference. It's the fact that he has a hobby balance charger. If you were to plug that same wire up to just a regular 4.2V (or 12V) power source, it's not gonna balance charge the pack. Just FYI for anyone not sure the difference here is his charger. Otherwise good video though.
Ok so I’m just curious, my PS4 controller won’t charge so I have taken the battery pack out so I just wanted to know how to charge the pack itself can you help???
yer exactly right about mentioning that explicitly.Please do what this intelligent man is telling you.When You Make a Battery Videro,PLEASE BE EXPLICIT AND SHE EACH AND EVERY SINGLE STEP SO those with autism have a fighting chance to learn this new technoligy.Thank Yall
How about battery pack with both BMS battery protection and JXT-XH balance connector. BMS is so cheap and helps protect the battery. Thanks for the effort in sharing.
I checked and most of these hobby balance chargers only go up to 6s for li-ion (22.2v). I'm looking to build a 37v battery out of 18650 batteries to power an electric scooter. Can this kind of balance charger charge a battery with this high of voltage?
I’ve gotten a similar type hobby charger kinda like your! But I just made my first 18650 pack and I’m trying to do a discharge test with said charger to test the capacitor of my 4s5p pack with 20 18650 cells. And dang it’s taking a good bit of time. And I hope it don’t take that long trying to charge it with the hobby charger !!!
the battery box of metal and plastic dont required ventilation ?? when i saw their construction its looking like a closed box my query is that if it is a closed box then during the time of cell charging and discharging where heat is dissipating ??
Hey im trying to add some 18650 batteries to a jbl xtreme while keeping the battery it came with at the same time. Would it be ok if i add them to the same bms board ??????
If there are cells in series charging it without a bms is a pretty risky idea as it could cause the batteries to become unbalanced and get overcharged, if it's just one battery in series and the output is 4.2 volts or under and the current isn't too high for the type of battery you are charging it might be okay if you unplug it once it's done charging. There isn't a exact answer to your question but it definitely won't be good to do that and it's pretty easy and cheap to just get a cc cv boost/buck converter and a bms if needed so it would be kinda silly to improperly charge something that has about 1/4th the energy density of tnt...
Hey Tommy, I was hoping you could give me your input on this 18650 build I'm trying out, it goes something like this: Hopefully you can give your input: 3 packs of 24 18650 cells in parallel then wired in series to=12v@ 60ah(1- 100 amp 3s BMS added to pack) and another, 3 packs of 24 18650 cells in parallel. Then wired in series to =12v@ 60ah(1- 100 amp 3s BMS added to pack). Then Connected together in parallel, to make it a total of 120ah battery at 12volts? I really would appreciate some of your feedback. Do you think it's possible to achieve this? Not sure if I would have to in corporate diodes. Or would it be good enough on their own?
How does for example my robot vacuum charge the lithium ion battery with only two cables coming out of the battery? Just with the easy way that damages the battery as described in the beginning of the video?
Is it possible to for instance I have a 2700mAh 11.1v 29.97Wh 21.6 continuous discharge rate battery with a max charge of 3.5 can I make something to put a charge on this battery safely???
what about a12V 200Ah LiFePO4 Battery, Deep Cycle Battery with Max 2560W Output Power, Perfect for Your RVs, Solar System, Off-grid can it it be ok on a charger like this the battery bms was removed this is for solar charging and off grid usage
So could you tell me the easiest way to charge a henzhen nalon battery co. LTD liion battery product mode LN-AWK-07 normal voltage 46.8v normal capacity 10.5Ah limited charging voltage 54.6v
Is there a charger with multiple single cell charging ports with clips so if you wanted to charge each cell individual you could. As each cell reaches the target voltage charging would stop.
Im just learning about this stuff and want to make a battery pack to run a led light bar on my dirt bike, and i was thinking of 4 batteries in series and 4 or 5 sets of the 4 olin parallel, how would i wire that up?
Great video, thanks. I learned a few good tips being a noob. The smile over your plasma sword though I have no idea what its good for was vicariously shared and brought a smile to my face as well.
Is it 1 postive and how much ever negatives I was thought it was all the positives and 1 negative or does it not matter or diesnit b cone down to the charger you use I have the imax b6.
Awesome I have been wondering about this as the banggood BMS only charges to 3.8 volts per cell . Thanks Tommy hey Banggood sells large black heat shrink tubing to make a clean looking setup . I don't know if I missed it somewhere but maybe a maximum voltage per cell when charging would be a good mention .
I am looking for a BMS for my custom Li-Po 48s4p battery pack. The pack consist of 32 packs total (6s1p each, 100C output max). Each pack have his own balance plugs, I have the connector for them. My idea is to get an ajustable direct DC power supply (0-250V/0-20A or maybe more), hook it up to the pack with BMS attached to charge it, Would it be safe and works ?
You should get a external balance charger like the one in the video and just a bms for overcharge and over discharge protection. BMS are not chargers they are protection circuits, charging with a dc voltage with that many cells in series seems kind of like asking for a disaster lol... maybe try using a boost converter to step up the voltage from a lower voltage more realistic pack.
I already have a PowerLab 8x2 but can only do 12 packs at once. I wish to do the whole pack as one. My second idea was to use the Y-Harness of the balance plugs to the balance board to do parallel charging but it seems I need to hook up the output wire as well otherwise the balance connector fried up...
Nice video. Since you have a 4S2P pack does the hobby charger treat each parallel group as one cell? Is this good balance charging practice or should you balance only 1P packes?
So I guess the next question would be if each battery in a parallel group will end up with a voltage equivalent to the voltage of the others in that group? Will the result of balance charging in this manor bring each parallel group to an equal voltage and neglect the fact that each battery has a different voltage as long as each parallel group has an equal voltage?
Mr Callaway. Is it possible to charge batteries dc ( lithium ion ) with the power generated by a turbine or solar panels. What would I interface the batteries with ie; generator, alternator etc?
@@silasyount1785 After looking through your music playlist. Your outburst makes perfect sense now. I'll speak with you after you've powdered your nose miss.
@hoofheartedicemelted296 Thats kinda strange, but Im flattered you're so infatuated with me. You ask the straight up stupid question. You asked how to interface a solar panel with a battery? like bro is called a charger. You're going to get all butt hurt over my smart-ass "OMG" and an exclamation point you're in for a rough ride. man up, stop crying, and go buy a 30amp Solar Charge Controller 12/24 V Solar panel regulator with adjustable LCD Display Dual USB Port Timer Setting on Amazonn for 12 dollars
Packing the battery cells that tight without additional insulation/distance between them, (especially between the groups in series) is dangerous. Fully charged, there's 4.2 volt difference between neighbouring groups and relying only on the battery cell wrapping is far from safe.
i have charged a 18560 battery and connected couple of leds as load for 24 hours. The leds stayed lit for the whole day and the voltage came down from 4.2V to 3.89V. Is there a way to tell if this battery is good or bad.
I dont really understand how you connect the batteries to each other to basicly make 1 battery im trying to make 1 with 8 18650 lithium ion batteries I charged all of them with my old vape mod lol but i want to make it output 5V 2amps separately to 2 female type A ubs ports they are going to power 2 raspberry pi LCD screens at the same time to produce the same image on both not like a pc has netflix on 1 screen and youtube on the other no same image on both screens im using an hdmi splitter and then using a Y 2 male to 1 female 3.5mm audio jack for both of them and basicly hooking up all of that in a what used to be a plastic VR for a phone but now going to be a real VR im still working on building a wireless HDMI transmitter and receiver and my friend is super good at programing so he worked on headtracking only took him like 3 hours to figure out cause he has done a lot of stuff like that for robots he made
Hi, I would like to make a 2S or 3S pack with protected li ion18650 cells, do i need to put a balance plug on it since the protected cells do not exceed charge above 4,2V or discharge below 2.75V?
Tommy Callaway thank you, I thought that when a cell reached its maximum the circuit of this cell cut the charge to it but the current normally followed to the other cells.
I apologize, but this freaks me out. How can batteries be balanced charged, without separating them first? How are those balance wires not creating short circuits? And the main positive & negative of the whole battery pack, is also connected to the charger, what are they doing? Does that also mean a battery pack can be balance charged, while it's being used? I'm sorry if these are stupid questions, I'm still learning electrical-engineering, and I don't have much money to blow on trial & error experiments.
if I have a, say 10s, how can I possibly charge it? your charger is up to 6s, this has been my major concern. is there another equally safe was of doing this?
Thanks for the great video. I have made a 3 battery pack with a BMS. It's working great but I have no idea about how to charge the pack. Please advise. Thanks
Essentially you plug up the first cell in series with the first two wires on the little wiring harness, then move to each cell thereafter. In this video he says you connect the positive for the first cell then the negative for that same first cell. Then with the third wire you move onto the second cell in series and put it on its negative side. Then fourth wire goes to the third cells negative and so on. However, all the balance leads I've used are actually the opposite of what he stated. Meaning the first two wires goes to the negative of the last cell in series and then positive respectively. Then the next wires follow the same guideline as above of jumping cells but they're connected to the positive ends of each. I think technically it's the same thing (just depending on how you flip or plug in the little connector at the end) but the balancers I've used specifically point out that negative goes into the first pin so I guess it depends on your device. To make it easy to think about though, the first wire usually goes to the negative for the entire battery PACK. The last wire will go to the positive for the entire pack. Then each wire starting with the second will need to connect to the series connection between cell 1 and 2. Next wire is connected to the series connection between cell 2 and 3. And so on. So basically each cell will have one wire on either end of it. That's why there's always one more wire than the total number of cells you have in series
Can I charge my lithium ion battery pack of 78 AH in glass box or you can say in air tight container, Please mention what will be the effect of this.Is it safe to do so ?
I use solar panels in a sine wave inverter admits frequency to charge batteries safely and get the longest life out of them using too small 12 volt 1.5 amp solar panels I can charge the batteries and roughly 8 hours to full capacity choosing my own voltage limiter going to the batteries works as an excellent long-term battery pack lightweight fast recharge with long time use before recharging
A bms is just for overcharge and discharge protection to prevent the battery pack being damaged. It does NOT charge the battery and any balancing feature on one would simply be to drain the highest cell to the lowest over all with a resistor. You need a charger with the logic functions and ability to control current and voltage dynamically to each cell, a laptop battery has a BMS pcb inside it and the laptop itself probably has the balancing circuitry on its internal circuitry using those many pins on laptop battery to read the battery state. You need a decent charger to charge multi-cell li-ion packs like these if you don't want to destroy the pack quickly or eventually have a nice smokey battery pack that melts whatever it is your using it for as it burns... a BMS is still a good idea even a cheap one, but you should charge it with a charger like the one in the video also.
Peter Mbiria make 2x 24v (6s) packs with to separate balance leads and link the power in series for operation, then charge separately. That's the Simple way. Alternatively you can get an 11s (33v min 46.2v max) or 12s (36v min 50.4v max) bms and a 46v~50.4v charger pack 12s plus bms is best if the voltage range is compatible with what your doing. Most devices that run on 48 will run on 50.4 It's worth noting that you will possibly get better power and longer run times without bms by a small margin initially. But also can potentially over discharge and damage the longevity\quality of the cells. Use a simple low voltage alarm meant for 18650s to help with that because it will beep when a cell reaches the low voltage you have specified and then you know after the alarm that it's operate at your own risk and risking the batteries.
Why is every other video tutorial showing one black wire and multiple red wires, in which the black wire goes to first negative parallel group and the red wires to each positive group.. Is it six one half dozen the other? Idk it would be cool if you could answer this because atleast one other person in the comments is confused.. I can or you can delete this but I think it's really really important to address
I've got a stealth bomber ebike with 72v battery and 5000 watt motor... It came with a single battery, but I've since built my own from six 36v 20ah lime scooter battery packs, which are made from 18650s... So I took 2 hooked in series to double 36v to 72v making 3 packs of 72v, then hooked all 3 in parallel... Only problem is each individual original lime pack has its own BMS, so for the entire battery its got 6 BMS's hooked in both series and parallel in a funky manner, but so far my 84v charger has been working when I connect it, and the BMS's seem to be functioning properly, but it still seems like a sketch set up... I wanna break it all down and do it right so its functioning thru a single BMS... Cuz as is, it's 6 times more prone to failure at a minimum, right? Because instead of having just one BMS that can fail, it's got 6... I think that math is correct...
In this video, the BMS is in the digitally controlled charger and works once you add the extra connections.
i was just thinking, isnt the BMS already in the powersupply
You still are using a BMS.
It's just separate with your configuration.
Instead of having each battery pack having their own BMS, you have one for all the packs.
I like it unless you need to charge more than however many the external BMS can supply.
What is the maximum number of packs that can be charged at a time?
You have a 4s2p pack so each cell is 2 in parallel. So doing a balance charge like you are doing is better than nothing but it is still not going to overcome the problem if 1 cell fails.
BMS is under the tip on the positive end of the battery and protects each cell being over charged in voltage and current and over discharged in voltage and current.
You also need to use a special charger like you have as the batteries need to be charged in a particular way. First part of charging is constant current then it swaps to constant voltage to finish off until it achieves 4.2v.
Hey there Tommy
Great video.
Concerning the mains wire/cable, here in the UK we have imprinted onto the cable the following details; voltage range - cable size ( 0.5mm, 1.0mm, 1.5mm ) etc. etc. and an indicator conductor colour BN (brown) live, BL (blue) negative & YL/GN (yellow & green).
Whenever I purchase anything that does not have a standard 3-pin UK plug BN (fused) BL & YL/GN (earth) I chop off the existing plug and rewire it with a standard UK 3-pin plug.
Undertaking this lessens any main's cable-related problems that may occur in the future, and finally, UK plugs come with a fuse which two pin plugs do not.
If in doubt get an experienced person to rewire the UK plug.
take a little extra care when putting battery packs together... don't just slap glue and tack weld them together
Let’s say it this way, it happen to all kinda of battery this way, not just Chinese battery. That is why we have and need a balanced battery charger for it, and by the way, thanks for explaining how to hoke up the wires, for most of us has been playing around with those electrical things, it is not hard to find out witch wire go where, but for some one who first time doing it, will be a hard time to find out how, or in a hard way to find out with a burned wires and exploded batteries. Great work, easy to understand .
( 6:30 ) ... exactly for the reason demonstrated at 6:33 those batteries MUST be charged individually to a perfect full charge before they get into those Parallel sets and they need to be rechecked now and then especially after heavy usage.
Awesome video. Thank you for sharing
Yup! If you match two badly unmatched voltage batteries, you could melt the nickel strips, or start a fire.
Good video, but isnt the charger basically a "external" BMS?
soldering in the middle of the bridge could melt the plastic covering the batteries in a spot that would be very likely to cause those two cells to touch where they are side by side. it would not be a direct short but could cause heating.
Nice wiring. You do realize however, that the hobby charger is functioning as a battery manager when it is charging? You just don't have a continuous one on the bank.
Well, in that regard, consider this how to only require a single BMS, rather than one for every battery you own.
Tommy Callaway Great video , I would like to make a 12 cell pack wired in parallel to get around 22volts for rc planes as I am sick of puffy expensive lipos ,could you explain the wiring please ?
+interman 77 2 parallel, 6 in series to get to ~22v
Tommy Callaway Thanks mate ,I have been studying how to make packs up and rig the balance connectors ,your videos are very helpful .
Nice video man. I only want to say that maybe you should not solder in the middle of the nickel strip as it is close to the edge of the battery (-terminal) you could if the heatshrink melted under the nickel short out your whole project!
Thank you. That was the easiest and best description on how to wire up a balance lead. Thanks.
No problem!
If you want your camera to focus don't hold the target item in front of your eyes. Camera's are made to focus on eyes and many people don't realize it. Try it. It works.
You can get contact paper from Michael's. Cut to size and insulates very well
How often do you "balance charge"? I have a similar charger (that design seems to be very common, rebranded a lot), with RC Lipo batteries I used to just monitor the packs and "balanced" them when the voltage differed between the cells by .2 volts. Balance charging is MUCH slower it seems. RC batteries are always 1p (cells are connected in Series to multiply voltage, rarely if ever, are cells connected in parallel). I think with Lipo it's too risky, also they have massive amp output so there is less reason to do this.
If I understand this correctly the voltage you are reading is an average of that "Parallel group" which means that you could still have a "sick" cell in that group and it would read a normal voltage. I have broken apart old Makita packs and salvaged many good cells out failed packs, and seen exactly this case, there would be one "parallel group" that would read 2.9, but when I separated the cells there would be one cell at 3.5 and the other reading NO voltage at all..... These are 5s2p packs. Interestingly they seemed to fail because the BMS would draw off of one cell, when left on the shelf for long periods of time it seems to harm that one cell. Most of the packs that I have broken up have that one cell failed. Balancing only parallel groups would not show this as the good cell would try to overcompensate for the bad one and end up over charged.......
The only solution for this would be to occasionally break up the packs. Professionally made packs seem to mitigate this risk by matching cells very closely in regards to capacity and internal resistance, but I suspect that it still causes issues as the packs wear.
I am trying to create a pack that can be just un bolted and the cell taken apart and measured every month (this will be used on an ebike)
You're right. This is one of the most intelligent questions I've gotten on this video, thank you. That's something I didn't account for, and most professional packs I've bought don't account for it either - but a modular design for swapping and testing individual cells would be awesome. I would build something but I've gone toward filmmaking and camera-tech as my channel topic. Pinning this comment.
thank you for explaining how the wiring goes. true, many just assume others know hence the make nonsense of their effort because in the end, if you do not know how the wiring goes... it is just not worth the effort.
I decided build my ebike without BMS after watching your video. Thanks.
Thank you for this valuable info.. I do have a question though. You said you only needed 4 cell for the balance charger but your pack has 8 batteries. Is a single battery not defined as one cell? Hoping you still monitor this site since you have a new one.
Positive poles maters, His battery is 4s 2p, so you have to get only positive poles for 4s, and that are 4.
Batteries connected in parallel become 1 cell
You are using a bms. Its in the charger.
Do you have a 12v 5,ooo mah battery video? I know it’s a 3s2p but I just want to see if you had a video making one.
Crocodile clamps on wires just "behind"/"below" the solder point, or place a normal Circuit Heat Sink on the left and right side of your nickel solder position to dissipate the heat from soldering if you're a new solderer and are unsure if you're about to overhead the battery because of prolonged soldering. Doesn't take much to dissipate the heat really, be careful out there! :)
People say Lithium batteries don't do well in cold temperatures. I wanted to ask if this also will make it harder for them to charge up in the similar cold weather since they already don't do as well in it? Thanks.
They do work great for a quick solar pack with the right charge controller and as long as you don't use too big of panels
OK. So this can't really isolate each cell, it can only isolate each parallel set. So in this case, two cells at once since this is 4S and 2P for 8 cells. So the low 2.98 voltage is actually the voltage for a pair of cells. So this method can't address an individual cell, but can address an individual bank of cells. Have I got this right? Thanks.
+Jay Turberville yes, but it's the same type of isolation you get with a BMS. Parallel cells share the same voltage, the current is what increases, which is why this method works so well. Even if one cell in a pair dies it's safe, the max current would just decrease.
Is there any advantages of balance charging charging 1P or is this method ideal?
Tommy Callaway wouldn't the max current on the one remaining cell increase? Because you have all other dual cells putting XXamps in or pulling XXamps out but that one remaining cell will be the only one to match. The current should be the same through each cell in a series, the voltage per cell varies amperage per cell or set of cells should remain the same i thought. So if you use 5 cells then 2 them 5 the 2 should get hotter because more amps per cell are expected. I could totally be wrong though. I thought that's why cells tend to die as a whole group if left unchecked over time.
Jay Turberville when two cells are paralled, they act as a single cell. Only series cells can have different charges. But need to be balanced.
Jay Turberville and the cells in series need to be close as possible in capacity and internal resistance and voltage.
Awesome Video. I learned a lot. Small tip, next time lower the volume of the music or don't use music at all. Also the music chosen is not relaxing and do not help to focus on what you are saying and doing. Other than that, keep going. Great work!
Thanks! Yeah, I think my videos have gotten much better since this one. :)
The original plug is for 240 volts AC, or can you switch between 240 and US voltage?
I feel much safer recharging using a smart balance charger vs going through a BMS especially for like 100+ Amps for my application, plus its just really expensive for 200A 22.2V BMS’s and I would need 4 of them
QUESTION SIR;
I have these 7.4v 18650 4400mah packs and they only have 2 wires, red and black, but they say they are 2S, but my 2S Lipo Charger balance plug has 3 wires, one for - one for 1S and one for 2S. How do I get them to charge? Thanks.
Good Video. I have Imax B6 Charger. It is has 6 cells balance socket. How do I balance charge if 13 or 14 cell ex. 13S4P or 14S4P. Do I need a charger with 13 or 14 balance sockets?
Could you please turn off that melody im the background, it's distracting.
Nice job. Good videography, clear language, and very logical discussion of important points providing background for beginners. Looking forward to more of these. - Jim
Pretty sure the black wire is to first negative parallel group and the rest (red wires) are to subsequent positive cells in parallel.
I have a question regarding the wiring, the batteries are connected in series? and the wires you have solder in is for making them a parallel? could you add the wiring schematic so i can understand better
what brand are those blue 3.7v 6000mah batteries and where did you get them? regards
Decent explanation of balance charging vs. employing a BMS to handle that, and much more.
For me, the bottom line is: If you care about your battery, use a quality BMS.
The only reason I can see for NOT using s BMS on a non-hobby application (solar storage, etc.) is foolhardy frugality. Much, much too risky for me.
The charger he is using acts as the BMS. There are MANY chargers similar to his that do the same. And I assume you are aware that even a "quality" BMS can fail, so what then? I've been making 12 and 18v packs like Tommy for almost 10 years, charging them the same way and have never had one blow up or fail in a crazy way. And they last 3-5 years using them daily in my drill, sawzall, circular saw, etc.
@@cjoakman7715 First of all, a comment to a 2 year old post? Really?
Secondly, you're just plain wrong. The balance charger doesn't "act as the BMS." Again, this video demonstrates the use of a *balance* charger.
As a professional battery designer/builder, I stand by my original comment. The balance charger in this video provides over-voltage protection. That's it! It doesn't provide any other protections that a *quality* BMS provides. For instance, on the charging side, low temperature and/or over-current.
Unprotected battery packs are just that, *unprotected*, and discharging without protection is recklessly foolhardy. Over-current and under-voltage protections are every bit as important as over-voltage and over-current.
Yes, BMS's do represent a point of failure. However, in my experience, they reliably provide all the stated protections. I've never had a BMS fail. I have, however, had BMS's save multiple packs from dangerous conditions on multiple occasions. Additionally, those equipped with Bluetooth provide real-time information on battery condition. This, in and of itself, is worth the cost.
There's a difference between *misinformation* and *disinformation.* As you claim to be an experienced builder, I'll label your comment as dangerous disinformation as you're knowingly encouraging inadvisable behaviors.
Here's hoping your luck never runs out.
If its difficult getting to the negative terminal then scrap off an area on the batteries and connect to case. The case is negative. The case is a tube.
Valid point!
How do you know how many amps and volts to charge the batteries at? I want to make a li ion battery pack, I thought you multiply the rated charging amps for each cell by the number of cells and keep the voltage the same as it would be for 1 cell.
it is stated in the speck sheet
@@sbolton3039 so if the battery cell specs say to charge it to 4.2V at 5A and I'm charging a 4 cell pack I just charge it to 4.2V at up to 20 amps?
@@drabberfrog 20 amps no way. plus i dont know of any lith ion cell that charges tp 4.2 volts at 5 amps. a battery pack may have s 5 amp speck but please advise me what cell it is u are talking about and i will help u out.
@@sbolton3039 since it's 5, 000mah wouldn't you charge it at 1C? So the charge current would be 5 amps right? I have some LiPO batteries so I'm just assuming lithium-ion batteries are the same in that regard. I'm wondering how to know what current to charge a pack at and how would the batteries being in parallel or series affect the charging current.
@@drabberfrog cells hooked in series u add the charge voltage but not so on the amps. In any event i believe that with lithium nickel cobalt cells the slower u charge them the better it is for the battery but u may not want to wait so long for them to charge. As you increase the charge voltage the cells will charge faster but i believe over amping charge cycles kills the cells quite quickly.
How do u determine when to stop discharging on whatever u use these on? Do u run a lipo alarm or do u hope the controller your using will stop them for u?
Yeah one thing that's not apparent is it's not the wire that really makes the difference. It's the fact that he has a hobby balance charger. If you were to plug that same wire up to just a regular 4.2V (or 12V) power source, it's not gonna balance charge the pack. Just FYI for anyone not sure the difference here is his charger. Otherwise good video though.
Ok so I’m just curious, my PS4 controller won’t charge so I have taken the battery pack out so I just wanted to know how to charge the pack itself can you help???
yer exactly right about mentioning that explicitly.Please do what this intelligent man is telling you.When You Make a Battery Videro,PLEASE BE EXPLICIT AND SHE EACH AND EVERY SINGLE STEP SO those with autism have a fighting chance to learn this new technoligy.Thank Yall
Pls what the name and model of the charger snd the link to buy it?
How about battery pack with both BMS battery protection and JXT-XH balance connector. BMS is so cheap and helps protect the battery. Thanks for the effort in sharing.
That's silly why use BMS at all hobby chargers put you in control period
Just check. Every couple times BMS fail they are for people that don't want responsibility have faith in yourself
I checked and most of these hobby balance chargers only go up to 6s for li-ion (22.2v). I'm looking to build a 37v battery out of 18650 batteries to power an electric scooter. Can this kind of balance charger charge a battery with this high of voltage?
Ok this can avoid the overcharge, but what about an overdischarge.. the cells do not have to go below 3 Volts right?
I’ve gotten a similar type hobby charger kinda like your! But I just made my first 18650 pack and I’m trying to do a discharge test with said charger to test the capacitor of my 4s5p pack with 20 18650 cells. And dang it’s taking a good bit of time. And I hope it don’t take that long trying to charge it with the hobby charger !!!
Will this charger do 1s what is the charge and discharge current? I need one that will discharge at a fairly high current, to test a few 100p packs.
So what happens to the 0v cells. Did they get balanced to 4.2v???
i have a 4S3P battery pack im trying to find a way to charge both 4S and 3P how can i do that, do i need a custom bms or can i use this product?
And what if i connect all the small red cables with the big red cable and the black small cables with the big cable please i want for an answer
the battery box of metal and plastic dont required ventilation ?? when i saw their construction its looking like a closed box my query is that if it is a closed box then during the time of cell charging and discharging where heat is dissipating ??
Hey im trying to add some 18650 batteries to a jbl xtreme while keeping the battery it came with at the same time. Would it be ok if i add them to the same bms board ??????
need we the pcb protection in this 18650 pack when discharging process..bro?
how many charge cycles would a battery pack have if you just charge it with a dc charger?
If there are cells in series charging it without a bms is a pretty risky idea as it could cause the batteries to become unbalanced and get overcharged, if it's just one battery in series and the output is 4.2 volts or under and the current isn't too high for the type of battery you are charging it might be okay if you unplug it once it's done charging. There isn't a exact answer to your question but it definitely won't be good to do that and it's pretty easy and cheap to just get a cc cv boost/buck converter and a bms if needed so it would be kinda silly to improperly charge something that has about 1/4th the energy density of tnt...
Hey Tommy, I was hoping you could give me your input on this 18650 build I'm trying out, it goes something like this:
Hopefully you can give your input:
3 packs of 24 18650 cells in parallel then wired in series to=12v@ 60ah(1- 100 amp 3s BMS added to pack) and another,
3 packs of 24 18650 cells in parallel. Then wired in series to =12v@ 60ah(1- 100 amp 3s BMS added to pack). Then
Connected together in parallel, to make it a total of 120ah battery at 12volts? I really would appreciate some of your feedback. Do you think it's possible to achieve this? Not sure if I would have to in corporate diodes. Or would it be good enough on their own?
How does for example my robot vacuum charge the lithium ion battery with only two cables coming out of the battery? Just with the easy way that damages the battery as described in the beginning of the video?
The battery seems to have its own bms
Is it possible to for instance I have a 2700mAh 11.1v 29.97Wh 21.6 continuous discharge rate battery with a max charge of 3.5 can I make something to put a charge on this battery safely???
What is a BMS ? Not familiar with the term. Thanks !!!
Battery management system.
what about a12V 200Ah LiFePO4 Battery, Deep Cycle Battery with Max 2560W Output Power, Perfect for Your RVs, Solar System, Off-grid can it it be ok on a charger like this the battery bms was removed this is for solar charging and off grid usage
So could you tell me the easiest way to charge a henzhen nalon battery co. LTD liion battery product mode LN-AWK-07 normal voltage 46.8v normal capacity 10.5Ah limited charging voltage 54.6v
The charger itself has balance charging function right?
Is there a charger with multiple single cell charging ports with clips so if you wanted to charge each cell individual you could. As each cell reaches the target voltage charging would stop.
Im just learning about this stuff and want to make a battery pack to run a led light bar on my dirt bike, and i was thinking of 4 batteries in series and 4 or 5 sets of the 4 olin parallel, how would i wire that up?
If I don't have a management changing system do I still can change batteries with regular charger? What about parallel and series changing?
You can but it's pretty easy to get batteries out of balance. When you do "Quick charge" on regular lipo chargers, they don't utilize the BMS
What if you have a battery pack that has more than the 6 wires how can you balance charge those?
The charging unit is a BMS. That's because a BMS is a battery management system.
Great video, thanks. I learned a few good tips being a noob. The smile over your plasma sword though I have no idea what its good for was vicariously shared and brought a smile to my face as well.
Thanks! It's actually great for charging my giant capacitor.. going to be making a video on that bad boy pretty soon.
Is it 1 postive and how much ever negatives I was thought it was all the positives and 1 negative or does it not matter or diesnit b cone down to the charger you use I have the imax b6.
Awesome I have been wondering about this as the banggood BMS only charges to 3.8 volts per cell . Thanks Tommy hey Banggood sells large black heat shrink tubing to make a clean looking setup . I don't know if I missed it somewhere but maybe a maximum voltage per cell when charging would be a good mention .
I am looking for a BMS for my custom Li-Po 48s4p battery pack. The pack consist of 32 packs total (6s1p each, 100C output max). Each pack have his own balance plugs, I have the connector for them. My idea is to get an ajustable direct DC power supply (0-250V/0-20A or maybe more), hook it up to the pack with BMS attached to charge it, Would it be safe and works ?
You should get a external balance charger like the one in the video and just a bms for overcharge and over discharge protection. BMS are not chargers they are protection circuits, charging with a dc voltage with that many cells in series seems kind of like asking for a disaster lol... maybe try using a boost converter to step up the voltage from a lower voltage more realistic pack.
I already have a PowerLab 8x2 but can only do 12 packs at once. I wish to do the whole pack as one. My second idea was to use the Y-Harness of the balance plugs to the balance board to do parallel charging but it seems I need to hook up the output wire as well otherwise the balance connector fried up...
Damn that charger you mentioned on video when I check it the shipping is cost more than item itself to my country
Nice video. Since you have a 4S2P pack does the hobby charger treat each parallel group as one cell? Is this good balance charging practice or should you balance only 1P packes?
It does, and it's normal practice to do so.
So I guess the next question would be if each battery in a parallel group will end up with a voltage equivalent to the voltage of the others in that group? Will the result of balance charging in this manor bring each parallel group to an equal voltage and neglect the fact that each battery has a different voltage as long as each parallel group has an equal voltage?
Mr Callaway. Is it possible to charge batteries dc ( lithium ion ) with the power generated by a turbine or solar panels. What would I interface the batteries with ie; generator, alternator etc?
a freaking solar charge controller! omg!
@@silasyount1785 After looking through your music playlist. Your outburst makes perfect sense now. I'll speak with you after you've powdered your nose miss.
@hoofheartedicemelted296 Thats kinda strange, but Im flattered you're so infatuated with me. You ask the straight up stupid question. You asked how to interface a solar panel with a battery? like bro is called a charger. You're going to get all butt hurt over my smart-ass "OMG" and an exclamation point you're in for a rough ride. man up, stop crying, and go buy a 30amp Solar Charge Controller 12/24 V Solar panel regulator with adjustable LCD Display Dual USB Port Timer Setting on Amazonn for 12 dollars
Packing the battery cells that tight without additional insulation/distance between them, (especially between the groups in series) is dangerous. Fully charged, there's 4.2 volt difference between neighbouring groups and relying only on the battery cell wrapping is far from safe.
If one cany get balsnce chsrger what next? Keeping silent id discouraging
i have charged a 18560 battery and connected couple of leds as load for 24 hours. The leds stayed lit for the whole day and the voltage came down from 4.2V to 3.89V. Is there a way to tell if this battery is good or bad.
what do you think I can use to charge an 18650 4S 50ah battery pack with solar? Thanks
I dont really understand how you connect the batteries to each other to basicly make 1 battery im trying to make 1 with 8 18650 lithium ion batteries I charged all of them with my old vape mod lol but i want to make it output 5V 2amps separately to 2 female type A ubs ports they are going to power 2 raspberry pi LCD screens at the same time to produce the same image on both not like a pc has netflix on 1 screen and youtube on the other no same image on both screens im using an hdmi splitter and then using a Y 2 male to 1 female 3.5mm audio jack for both of them and basicly hooking up all of that in a what used to be a plastic VR for a phone but now going to be a real VR im still working on building a wireless HDMI transmitter and receiver and my friend is super good at programing so he worked on headtracking only took him like 3 hours to figure out cause he has done a lot of stuff like that for robots he made
In the absence of a BMS, how do you make sure not to over discharge the pack??
you dont! happy gambling.
Hi, I would like to make a 2S or 3S pack with protected li ion18650 cells, do i need to put a balance plug on it since the protected cells do not exceed charge above 4,2V or discharge below 2.75V?
Yes, you'll get a bigger charge on your batteries if you balance charge - otherwise the whole pack will stop charging once the first cell hits 4.2v.
Tommy Callaway thank you, I thought that when a cell reached its maximum the circuit of this cell cut the charge to it but the current normally followed to the other cells.
Can you make video with bms motorcyle battery
Thank you so much just got enough for a pack and wasn’t sure how to do this
Awesome video
I love that studio setup by the way. Sound is very very pure.
I apologize, but this freaks me out. How can batteries be balanced charged, without separating them first? How are those balance wires not creating short circuits? And the main positive & negative of the whole battery pack, is also connected to the charger, what are they doing? Does that also mean a battery pack can be balance charged, while it's being used? I'm sorry if these are stupid questions, I'm still learning electrical-engineering, and I don't have much money to blow on trial & error experiments.
And thank you for showing me how to set up balance charging, on a custom battery pack.
if I have a, say 10s, how can I possibly charge it? your charger is up to 6s, this has been my major concern. is there another equally safe was of doing this?
+Chibuzo you can make two 5s batteries, charge them separately, and connect them in series to use.
Thanks for the great video. I have made a 3 battery pack with a BMS. It's working great but I have no idea about how to charge the pack. Please advise. Thanks
Rushed through the hookup sequence for the black wires....and lost me: "next negative and the next and the next....done in five seconds hey what?
Essentially you plug up the first cell in series with the first two wires on the little wiring harness, then move to each cell thereafter. In this video he says you connect the positive for the first cell then the negative for that same first cell. Then with the third wire you move onto the second cell in series and put it on its negative side. Then fourth wire goes to the third cells negative and so on.
However, all the balance leads I've used are actually the opposite of what he stated. Meaning the first two wires goes to the negative of the last cell in series and then positive respectively. Then the next wires follow the same guideline as above of jumping cells but they're connected to the positive ends of each. I think technically it's the same thing (just depending on how you flip or plug in the little connector at the end) but the balancers I've used specifically point out that negative goes into the first pin so I guess it depends on your device.
To make it easy to think about though, the first wire usually goes to the negative for the entire battery PACK. The last wire will go to the positive for the entire pack. Then each wire starting with the second will need to connect to the series connection between cell 1 and 2. Next wire is connected to the series connection between cell 2 and 3. And so on. So basically each cell will have one wire on either end of it. That's why there's always one more wire than the total number of cells you have in series
I have a noco gb40 booster that the micro USB port has broke . How can I charge my booster pack without using the USB port on it
I need a 3s3p battery with more than 35c rating will it work sir
Can I charge my lithium ion battery pack of 78 AH in glass box or you can say in air tight container, Please mention what will be the effect of this.Is it safe to do so ?
You'll want to keep an eye on the heat. I'm not sure :(
You have pairs of batteries connected parallel....?
hello tommy...what about a diy electric vehicle battery pack with more than 100 cells? is it possible to charge it without a bms?
You could.. but you'll probably have to divide the pack up into a bunch of smaller packs and charge them individually.
and the number of cells in each bunch depends on my hobby charger?
yes
thanks sir
So! The charging boxes are similar to BMS. Lol! Also, removing the battery from the unit costs more money and time.
I use solar panels in a sine wave inverter admits frequency to charge batteries safely and get the longest life out of them using too small 12 volt 1.5 amp solar panels I can charge the batteries and roughly 8 hours to full capacity choosing my own voltage limiter going to the batteries works as an excellent long-term battery pack lightweight fast recharge with long time use before recharging
But bms is for li po for li ion doesnt need that the laptop doesnt have balancing right
A bms is just for overcharge and discharge protection to prevent the battery pack being damaged. It does NOT charge the battery and any balancing feature on one would simply be to drain the highest cell to the lowest over all with a resistor. You need a charger with the logic functions and ability to control current and voltage dynamically to each cell, a laptop battery has a BMS pcb inside it and the laptop itself probably has the balancing circuitry on its internal circuitry using those many pins on laptop battery to read the battery state. You need a decent charger to charge multi-cell li-ion packs like these if you don't want to destroy the pack quickly or eventually have a nice smokey battery pack that melts whatever it is your using it for as it burns... a BMS is still a good idea even a cheap one, but you should charge it with a charger like the one in the video also.
Thanks for this, it is very helpful. I would like to make a 48v 30A Li-ion battery, how would I charge it???
Peter Mbiria make 2x 24v (6s) packs with to separate balance leads and link the power in series for operation, then charge separately. That's the Simple way.
Alternatively you can get an 11s (33v min 46.2v max) or 12s (36v min 50.4v max) bms and a 46v~50.4v charger pack
12s plus bms is best if the voltage range is compatible with what your doing. Most devices that run on 48 will run on 50.4
It's worth noting that you will possibly get better power and longer run times without bms by a small margin initially. But also can potentially over discharge and damage the longevity\quality of the cells. Use a simple low voltage alarm meant for 18650s to help with that because it will beep when a cell reaches the low voltage you have specified and then you know after the alarm that it's operate at your own risk and risking the batteries.
Hi . I reside in New York. I have some 18650 cells. I need someone to help me make an ebike battery. Where do you reside?
I'm confused, didn't that charger show 2 batteries with 0 Volts?
Because its only a 4s battery so the last two balance leads aren’t connected, so the last two show 0v.
Positive negative...Negative Negative Negative ??? HUH? that was confusing and unexplained...Got it...Thanks
This video is old. Now, I am reviewing solar generators and other newer battery tech. ua-cam.com/users/tommycallaway
Why is every other video tutorial showing one black wire and multiple red wires, in which the black wire goes to first negative parallel group and the red wires to each positive group.. Is it six one half dozen the other? Idk it would be cool if you could answer this because atleast one other person in the comments is confused.. I can or you can delete this but I think it's really really important to address
@@bmzaron713 find your answers yet?
Great video. I have a noob question. I have a 4s (18650) pack also so for charging do I select 4S, C= 2000mah, 2.0A? Just want to make sure thanks.
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I've got a stealth bomber ebike with 72v battery and 5000 watt motor... It came with a single battery, but I've since built my own from six 36v 20ah lime scooter battery packs, which are made from 18650s... So I took 2 hooked in series to double 36v to 72v making 3 packs of 72v, then hooked all 3 in parallel... Only problem is each individual original lime pack has its own BMS, so for the entire battery its got 6 BMS's hooked in both series and parallel in a funky manner, but so far my 84v charger has been working when I connect it, and the BMS's seem to be functioning properly, but it still seems like a sketch set up... I wanna break it all down and do it right so its functioning thru a single BMS... Cuz as is, it's 6 times more prone to failure at a minimum, right? Because instead of having just one BMS that can fail, it's got 6... I think that math is correct...