Solar Charging Lithium Ion 18650s - Part 2, Getting the balance right - 12v Solar Shed
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- Опубліковано 5 сер 2024
- After a week of charging 18650s from a lead acid solar charge controller things are working reasonably well but as we all expected - the cells are getting out of balance and this could lead to problems.
It turns out the balance board I bought isn't up to much either.
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7s Lithium Ion BMS: goo.gl/49na7t
Videos in this Series:
Part 1, The Concept - • Solar Charging Lithium...
Part 2, Getting the Balance Right - • Solar Charging Lithium...
Part 3, The Results - • Solar Charging Lithium...
Part 4, Expansion - • Solar Charging Lithium...
I do like your candid no downers hidden style, this is valuable insight, a great addition to the by the book stuff that can be found anywhere. Problems are very instructive, thanks for another good video, please continue :-)
Yes please continue upload video for us 🙏
Interesting Channel! Those battery capacity meters have a balancing circuit inside of them. To Enable Press and hold the 'TYPE' Button until you hear a double beep and the battery voltages will start cycling in sequence. The voltage from the highest battery is brought down to the lowest cell voltage by passing a small leak current. They will eventually be in balance but the leak current is very small to do a fast job. You will naturally feel a little bit of heat after an hour or so from the battery capacitor meter whilst it does its job.
+billywhizzy Funnily enough I describe red this just today. Thanks for the kind comments and thanks for pointing this out.
billywhizzy wow thanks for the info, I might risk recovered batteries... if get a capacity controller in Dhaka first 😂🤣😂😅😂🤣😂😅
This testers have 3 resistors of 82 ohm in paralel witch should give 153mA at 4.2V but actialy it gives aroud 60mA while balancing batteries. The tester it self drains 20mA . Interestedly after jou pres for long time Type button once it will balance always until you disconnect the battery pack. If you pres the type button again long time it will continue balancing. I'm thinking of hacking this balancer by adding one mor ressistor in paralel which will give it more mA
actually there are at least 2 versions of this capacity meters around one with the balancing capability one w/o it. I can press the TYPE-button as long as i want with no reaction. You can find both versions on ebay and there is a little difference in price. There is also a 8S-version with further options.
Hopping you find a solution for this interesting problem. Keep up the good work.
Hhhh ģ
Your videos prompted me to subscribe to other channels too! Great work mate
Good drawing board work, and enjoyed the video.
+Surging Circuits Thank you.
Adam may God bless you and your inquisitive mind this question lingered as i am building my 7s pack. Now i know
Glad to have helped. Thank you
I use a Capacity Controller for balance. And switch to balancing the Battery by pressing the 1st button and holding until it beeps twice. And it balances me pretty well. It only takes a long time.
Very nice! With your videos i dont neet to do it on my own 👀😂
We use singlelab 50a 8s BMS they have tiny LED on the board when the cell has hit its cell voltage limit and is in bleed mode they light up - its kind of reasuring to see them twinkle - they also have a thermal over temp sensor which shuts down the issolation mosfets if it goes above 65c - we cut into the sensor and put additional sensors in the cell pack and even one to the motor (its a single seat electric car) - These BMS bleed only at 65mA so when ballancing a pack we put it on a very low charge of 0.2 a if you pump 5a in its easy to trigger the overvolt cut out before the cells have chance to ballanced - we only ballance cells ever 50 charges or when there more than 0.01 Volt out as unnecersary ballance charging shortens the cell cycle life - normally we bulk charge at 5amp and use the pack in a 25-80% envolope - our oldest Headway pack is now 5 years old and still going strong - I find your video's very interesting and your modest honest manner easy to follow - its like sharring a journey
I re-visited this 4 year old video to check your comments about the 7s balance board, you said the 14 pin chip is a micro, on my version it is a Texas instruments chip CD 4011B a quad nand gate.
Its great to see the good the bad and the ugly tests so thank you Adam. Could you explain how you wired your caddy in order to balance the batteries in parallel please?
+Young Seal Sure. All the positives connected together and all the negatives connected together. Obviously not connected to each other!
Thanks for your comments. Hopefully more positive news in the next video!
I have spent a long time controlling the balance of my lifepo4 battery pack and I have been very disappointed with the balancers that I have tried.
Recently I found the "active balancers" and the worry of damaging the batteries ended.
I found out the hard way that the mosfets hate any static charge. i think you have to ground yourself when handling them too. i had a 48VDC spark fry a BLDC motor controller on me twice when it was out of its aluminum box. The spark was more than a foot away. I put my 3rd new controller in a faraday cage i made with an antistatic bag wrapped in foil tape and it stopped the problem with sparks.
A high voltage cut-off might be doable by reading the voltages using the analog pins on a microcontroller. It could use that information to switch off a relay on the solar input when any of the cells reach near 4.20 volts.
It would be a quick and dirty solution I guess. The issue is that the arduino would need a series of voltage dividers as the voltages got higher from the shared ground. Accuracy might be more difficult as the voltages get higher through the pack.
I'll give it some more thought though. Thanks
Weird, I have an older version of that "Capacity Controller" and mine does not have the feature that cycles through the cells and it doesn't update the reading once it's connected....
You could try to test charging the Li-ion batteries directy connecting the panel to balancer. If power of solar panel is too hight and Amps exceed charge capacity, put a few ohms power resistor in between and you will test if balancer is OK. If balancer works, you can then try to place in between charge controller and balancer a filter made of capacitors to eliminate the PWM component of controller output. See what happens, I think it is worthy to try.
Hi Adam
Can't we charge these 18650 batteries on dedicated A/C power charger off a separate solar power supply.
what about adding a buck regultor between the charge controller and the battery? some buck controller say that have costant current and costant voltge. and the voltage can be regulated
Is it possible that your bms is for LifePO4 batteries ? They have a voltage range of 2.5v-3.6v and a nominal voltage of 3.2v where as Li ion cells are 3.0v-4.2v range and 3.7v nominal voltage .
Or ...my other thought is ...
If the pos and neg were reversed you would not have one direction diode protecton and the power from the batteries could flow back to the pannels.
hi, here is a tip. If you connect at least 2 cells in parallel for each cell, it will be harder for the cells to go out of balance. putting more cells in parallel forces each cell to stay very close in balance ; as each cell try to balance each other automatically. I mean 7 cells, but in group of 2 or 3 or more in parallel in each cell.
+Pablo Nunez Yeah, thanks Pablo
Doesn’t your capacity controller have a balance function ?
I never use same colour wire for possitive and negative to avoid confution and safe my boards from burning.
can someone explain the difference between solar charge controller and bms? the charge controller just supplies voltage from the panels, while the bms actually handles putting that energy into the batteries? If I have a tiny 5v solar panel, do I still need a charge controller or can I just use a BMS or like a TP4506?
Why do we need to balance the voltage of individual cells? Is it because current will be drawn from highest voltage cells?
Can we charge through public electricity instead of solar power
Adam, A stupid question probably. But I have 3 (2.85 euro) powerbanks cases filled with old laptop batteries and they work great. 6 18650 per case. (except when you charge them and you turn of the power they charge back. I suddenly had 4.8 volts on my rv 12 volt system.) But I wonder about the balancing which I never did (no equipment to do so) but since they are in parralel should'n they ballance them self? Ie if one lags behind the rest will discharge a bit until all are equel. And the next charge they will all be in balance again?
Anyway I got myself a liitokala lii 500 because I saw you use a similar one (300?) in one of your vids. so I can test the capacity of my 18650's so I can at least group them together a bit that should help I think. Not building any power walls yet.
Sometime I wonder it is is not better to charge the entire pack with your own charge controller. Charge them in parallel at 3.7V and use a boost converter(s) to get it back at boost. The problem might be lvd - low voltage disconnect, thus you might have to use an inverter or device that has a lvd.
You could create your own battery balancer using a Arduino it would be a very simple and fun project.
I might look into that one day - might delay things a bit though! Thanks
i have done this project with a mppt charger i found that if the voltage balance ciruit only works from 4.19 to 4.22 pluse or minus torance on the balance chip for each cell if the voltage on the input is too high it gose too out of balance and the curent gose higher than the balance reistors can dissipate the voltage gose above 4.26 ish the overvoltage ciruit kicks in. you need to manualy parrel charge the cells and start again with a max voltage of 29v no higher if possible
+gk1mpo I think in hindsight I was using the balance board in a way it wasn't designed.
I think a bottom balance would be sensible (I balanced these at 3.7 volts initially). My bank is charging to 28.4 and could go to 29.4 if I changed the profile. I found this a really interesting little experiment and it's still in use every day at the moment.
Thanks for your input.
Great videos! I want to build a similar project. This method of charching only includes the constant current phase of charching so you loose around 5-10% capacity, am i right? Also what would happen if you have a proper li ion charger and get to the constant voltage phase... you would loose the efficiency of the pannel? I am new in this stuff...thanks for the help
+Anton Penchev I'm reducing the voltage I am charging these cells to on purpose. I'm wanting to reduce the risk of over charging them past 4.2 volts because I'm not using a charge controller that has a lithium charging profile.
In a lead acid charge controller the charging profile is bulk, absorb, float. Bulk supplies as much current as possible until the voltage reaches the absorb level. At that point the charge controller maintains that voltage by letting the current fall away. Float maintains a lower voltage after a fixed time period of the adsorb stage. It's quite similar to lithium.
Solar panels are most efficient at their MPPT point. Only MPPT charge controllers keep a panel in this region. All other Solar charge controllers (or devices connected straight to a solar panel) will tend to hold the panel in a different place. PWM solar charge controllers are typically only 70-80 efficient or somewhere around there anyway.
can use parralle to charge it?
just a quick question the lg 18650 battery from ebay (Lithium Ion ICR18650 MF1 2150mAh ) 20x cells each cell is 2150 ah. The spec sheet says Max. Charge Current 1.0C(2,150mA). So when you have this pack 36v 10s 2p what is the maximum ah current can you charge it 2ah 42v current or 2ah current x 20 cells ~ 40 ah current at 42v. Now if you have 3x 10s 2p in parallel which is 36v 12.12 ah what is the maximum ah current you can charge thats 60 cells is it 60 cells at 2ah current which is 120 ah current for 60 cells or just 2 ah for 60 cells using cccv charger
Thank you very much
nice experiment, that saves me wasting money . I want to charge my 24v 18650 pack using solar, but need to have correct way to do it and avoid killing my batteries or introducing risk to the charge process. so far learned gel seems to be correct voltage to be used.
+Serviciosymas Well it's a matter of consulting the datasheet or manual for your controller and deciding where you want to charge to. 4v per cell seems to be working out quite well for me.
Adam Welch. yes the problem i see its solar charge controller directly connected to the battery pack may unbalance some cells
+Serviciosymas It can yes. If you balance your cells well, build large and even packs you'll find they keep pretty well balanced. My setup is quite small so a balance circuit is required.
how you solder BMS Wire???????
I made your battery capacity checker some time ago that works well but would like to purchase a watt meter but your wattmeter is no longer available from the Portapow such a shame and the Chinese one are so inaccurate they are not worth buying so any suggestions, please?
Sorry not really. There doesn’t seem to be much that takes the place of the portapow - I guess there wasn’t much demand for these types of things. Best suggestion would be a usb power doctor with some custom cables. Like a rdtech one capable of monitoring a wide voltage range might be the closest stand in.
I think I know what happened : your Capacity Controller device must be using the first 3 cells to power itself, and that's why they're lower in voltage than the 4 last ones ...
+Christophe HUBERT interesting theory. I'll look into that. Thanks.
Christophe HUBERT also possibly wire resistance
Christophe HUBERT just a quick question the lg 18650 battery from ebay (Lithium Ion ICR18650 MF1 2150mAh ) 20x cells each cell is 2150 ah. The spec sheet says Max. Charge Current 1.0C(2,150mA). So when you have this pack 36v 10s 2p what is the maximum ah current can you charge it 2ah 42v current or 2ah current x 20 cells ~ 40 ah current at 42v. Now if you have 3x 10s 2p in parallel which is 36v 12.12 ah what is the maximum ah current you can charge thats 60 cells is it 60 cells at 2ah current which is 120 ah current for 60 cells or just 2 ah for 60 cells using cccv charger
Thank you very much
After watching many of Adams videos I now understand this comment ☺️☺️☺️☺️
It would have been good if you had put in links to the items , of were you buy them prices etc thanks Shane uk ,,thumbs up and subbed
+shaneweightman There will be links in each video about the items featured in that video. So if you catch up on the rest of the series there will be links. Cheers and thanks for the sub.
While balance board are important to keep all the cells the same voltage, you could say they reduce total system efficiency as the board is wasting power to heat while balancing. At this pint im not sold on lithium lion batteries Lead acid seems way cheaper
You're correct of cause, they can be wasteful if they are having to work hard. But most will be wasting energy when there is surplus - when a cell is full the balance board will start turning the surplus into heat. Now don't get in wrong in an ideal world that energy would be redirected into a less well charged cell, but that is very tricky.
I don't intend ripping out my lead acid system - it works well for me and I hope to keep it well maintained for years to come.
in theory the lead batteries are much saver too. they wont blow up...
They were discharging into the capacitor solved it for you
Nice video, but where can one buy the 1850 battery holders from .
Thios is the type I use - although I have to wire the back of them for series... rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575189419&toolid=10001&campid=5337903455&customid=18650+Holders&icep_item=322245409589&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg
my bms isn't working right either had 2 batteries drained to 3.1 v
Hey Adam, Have been following your series.. I just wonder how are you avoiding equalize/Boost feature of controller..
Hello. I’ve set the charge controller to Gel mode. This means it doesn’t do an equalise charge at all. The boost setting for the Gel profile is 14.2v (or in 24v mode 28.4 volts). In a 7s configuration that gives 4.05v per cell. This mode tries to stay in boost mode for 120 minutes. If it reaches that voltage it will adjust the pwm cycle to keep the cells no higher than 28.4 volts. After the two hours, the charge controller disconnects the solar panels until the battery voltage drops to 13.8v where it will float. In my experience, the cells never float because lithium doesn’t sag as much as lead acid. So to my mind it works quite well for s7 lithium. Changing to sealed or flooded would charge the cells higher and as you say also do a monthly equalisation charge which could charge your cells to 4.17 or 4.22 volts - which might be a bit high or at least reduce their lifespan. But with a reasonable bms attached, that may be a limit some are happy with and would maximise your storage.
@@AdamWelchUK Thank you so much detailed response. Appreciate the work.
Would it help cell to stab in balance if you had larger wires between cells?The first cells seem to of gotten more power faster the the last cells.
The cable between cells is 2mm copper. It should really be plenty for the job, but I am wondering if there is a poor joint causing resistance between the cells. Thanks for your ideas.
could be a cold joint. would it help to put more charge wires to you pack? maybe to every cell. It seems to me you may not be spreading the voltage evenly to all cells. You on to a good charger. I am thinking of doing the same, learning from yours. I am also looking a step down step up power converter set a the top voltage of my pack.
Great channel I enjoy all the projects & info. My wife says "are you watching that Lifestyles of the Rich & Famous guy?" :D I have to ask, where can I find a Battery checker cable? I have the checker but it never came with one & I can't find em on Amazon. ~C~
Thanks for the kind comments. I used a 7s JST cable just like these... rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F302934214211 or this one www.amazon.co.uk/dp/B07L2TH1FW/ref=cm_sw_r_cp_api_i_fXwUCbZ0DHAFK
Hope that helps.
I have a EPEVER Tracer controller. I can choose user battery and use a 3s battery?
Yes if you can program the parameters you can make it suitable for 3s.
so in this case what is the capacity of discharge of your balancer board
+Jose Garcia I’m going to be investigating that soon actually. Don’t know that off the top of my head I’m afraid.
hi adam, seems like your the bloke to ask, i need to charge 2 x 18650 batteries in series, from a small solar 12v panel, which pcb/device/module should i get to charge and not destroy my batteries?.....thanks in advance.
Two cells in series always means you’re going to have to keep an eye on their balance but the module I felt worked best was the CN3722. They aren’t ideal, but the adjustable version will allow you to set the charge voltage (and I’d suggest dropping it down a bit from 8.4 volts). It isn’t true mppt but does do dc to dc conversion to get more out of your panel. They are generally set for 36 cell solar panels - so the mppt of the panel should be around 17-18 volts which is typical for a panel sold as twelve volts.
@@AdamWelchUK hi adam, thanks for your reply, i will take a look at those then, thanks very much,
Hi Adam, thanx for your vids. about that BMS: i think these things are rubbish, they will only limit and discharge the cells which have more capacity right? Better have a system that kan balance when charging i think. I had such a BMS on my bike with recycled cells. (7x7). It only stank realy bad and made the battery less powerfull. I do the balancing manually now when charging. All good after a year. Hope my thoughts are welcome. Happy charging!
+Jurik Ristjouw Everyone's thoughts are very welcome. Thanks for your suggestion and comments.
thanx, you came to the same conclusion! I reacted after one minute lol :) actually i do have a suggestion... is this the solution? electrodacus.com/ maybe even cheaper options are possible but I think the key is, that it will permanently stay on balancing when power is available and when powered on. Preferably completely configurable with top voltage, voltage to charge etc...
+Jurik Ristjouw Yeah a few people have suggested the electrodacus charge controllers. They do look amazing and I'd love to play with one at some point. This experiment (and more often than not this whole channel) is more about doing it on the cheap and with perhaps slightly unconventional solutions.
ok, i understand. If i come up with anothet idea, I will let you know. happy charging!
I will have a look! thanx
Press The "Type" Button until it shows Liion ore Lipo and then press and hold the "TYPE" Button until it Beeps
Then the Capacity Controler is doing the Balancing even if the "per cell voltage" is under 4.2
BMS´es only Balance when the Cells are up to 4.2 Volts (stress for the cells ) ;-)
Great explainer Adam, but sad that the balancer doesn't seem to be working.
Did you manage to show this video to its maker and get any feedback?
I'm still looking to do a similar thing for my 12S pack!
+Andy Lee Robinson I've not contacted the seller. I've had it a couple of months actually and hadn't been able to test it. Perhaps I just got a bad one?
It's always possible - maybe a scope will show if there's any activity on the processor?
I guess the bases of the balancing transistors should correlate with their relative states of charge - a low cell should be asking for more current, and a high one should be supplying.
If one of the TL01s is faulty, then it might affect the whole ladder? I dunno.
There are lots of circuit diagrams available, so it's likely you might find one that is a close match to this implementation and be able to deduce a cause.
This one doesn't appear to be programmable, no USB or FTDI port to set balancing parameters?
Yes it needs more investigation. I'll probe about and see what I can find.
I don't think this board is a clever as high cells supplying low ones though - just a simple shove a resister across a high cell type solution.
Thanks Andy for your input - useful as ever.
if you only hookup the capacity controller with no solar charge, will it balance the cells?
+Eric Mar Yes but without some charge going in occasionally it will empty them eventually!
As always, a good initial bottom balancing should take care of it;
You don't need any balancing device this way
What you're calling the controller chip on the BMS is really only a 4011 quad nand gate presumably for logically combining the cell states in order to turn on or off the charging or discharging currents through the power mosfets. There's no intelligence on the board. As I read the data on this board, the locus of balancing is 4.18V, so the charging voltage must be 29.4V for the board to work properly. As I understand top balancing, while the strong cell is being discharged (here at 80mA) the charging current is switched off (and is therefore off for all cells), and when the balancing release voltage is reached, the charging current is switched back on again. This means that the charging process is very stop-start and takes a long long time. Another thing I don't like about these boards is that the overcharge cutoff voltage is 4.30V (i.e. above the safe limit) and the undercharge cutoff voltage is 2.40V (possibly damagingly low). I would only use these things as safety backup (e.g. short-circuit protection) and not as primary controllers. Don't trust them.
+Andy Kay Thank Andy some great advice and a super explanation. Really appreciate your input.
Did you tested what kind of those 19650 are best with high capacity, which brand is best to buy?
All non chinese ( many on this site eu.nkon.nl/ )
It all depends on what you want
Pritty much avoid ebay, alibaba and banggood if you want genuine 18650s with the adverticed capacity.
Adam Welch+ I had two questions. Firstly great video. The first question I have is I understand that 7 batteries in series will make a 24 volt battery but your batteries appear to be all in parallel unless you are wiring them from the back positive to negative from the back of the battery holder. The next question I had was what if you used from the solar charger to a smart charger like a hobby charger or a regular charger like a "efest LUC v6" or a "xtar dragon 18650 vp4" would that work? Obviously then to use the cells in a 24 volt configuration to draw power from them they would then need to be put into a battery holder with a 24 volt configuration. But just for charging purposes. I would guess it would work because the smart charger would convert the power accordingly I would assume. But then there would be the hassle of then putting the batteries in another holder. One other third question I just now have also. I noticed in your first video you had all the batteries linked together with magnets. I have seen other videos that people have charged single 18650 batteries with a hobby charger using magnets to hold the connectors. Do you think it would be possible to charge a large configuration of batteries with use of magnets to hold the charging wires in place? It might not be the most secure way even though neodymium magnets are very strong and would mostlikly hold them securly even through a earthquake. But Im wondering if the magnets would create a energy transfer and unbalance things. But just wondering if you could answer a few of these questions and if you make a follow up video addressing any of these things please let me know. And if you could post a answer to some of them I would appreciate. It thank you. Also one other follow up question. I see many experienced people on youtube making large battery packs and they are using reclaimed laptop batteries. Obviously they have sorted out some of the batteries but they are always mix matched brands and capacities etc they try from what I understand to match batteries with capacities of 2Mah or higher as their standard for making their large battery packs and from what their videos claim unless there is some trickery which is always a possibility but from the videos I have seen they seem reputable. But they are able to power large power walls and even vehicles with these large mix matched 18650 cell power banks that they have made. But understanding that each 18650 cell is rated differently within brands and understanding that there is internal resistance and charging speeds that vary between different battery types and brands as well that Ive been told and have heard often times never connect batteries of different brands or even ages together in paralell or series.. What are your opinion and thoughts on this? Thank you.
Hi Derek.
Yes you are right, the wiring behind the seven cells is diagonal - so it truly is a 7s pack.
You can power a battery charger like the ones you suggest from a battery pack as long as the battery voltage is suitable for the input of the charger - I power my Liitokala and Opus chargers from my 12v lead acid bank, but they can't be powered from my 24v lithium pack.
Neodymium magnets are great for a temporary connection, but probably a bit risky to use permanently - plus they probably have a high-ish resistance - I should check that.
There are lots of people out there using recycled cells to store power, run their homes and save money. I've mentioned in a couple of my videos that I think testing your cells and sorting them into well balanced packs is really important. I also recommend the use of repackr.com to help with that process. More videos from me on this subject coming soon!
Adam Welch HI Adam thanks for the info. I wanted to share also a tip with you that you might already know I found it on this UA-camrs channel and I'll leave a link to the video explaining it. But if you come across dead cells that read zero volts you can bring them back using this technique. I'm actually going through my zero cells bin that I've harvested from laptops right now and trying it myself and it seems to be working. I just need to fully charged them and discharge and cycle them and store them to see if it will bring them back fully. But you basically " jump start them" with another good fully charged cell. So far I'm finding it's working. Just a tip you might already know. But might save some zero voltage cells you might other wise throw out. Here is the link to the video and thanks for you videos. They are the best I've seen for information easy to understand and you demonstrate everything well. Thanks.
m.ua-cam.com/video/tbEfhPbqTDE/v-deo.html
what for you are using those batteries, those 25v ?
He just wants to test charging them with a solar panel system to see if it works safely.
24v 7s is a better match than 12v and 3s or 4s. That is why 24v.
HBPowerwall found issues with his BMS the key figure from the ebay listing is.
Balancing Current: 80mA
which potentially means if you charge at a higher current than that, they you can over charge cells.
That you cannot tell if the BMS is working or not, is a key design flaw with these series of cheap chinese BMS. See if you can find something with CANbus, serial, or the like.
Yeah I did consider that figure, but hoped that with a spare volt across the pack at absorb level (which delivers very little current) it would be within spec. I'm going to attach my scope and see if I can see it doing anything before I declare it completely dead. Thanks for the input. I subscribe to HBPowerwall myself too. :-)
Hi Adam, thanks for all of your video (very instructif).
in this case (with 7 18650s), what is the output voltage on the solar controller ? 12v / 24v or setable in the controller menu ?
Regards
Thanks. The charge controller automatically chooses 12 or 24 volt and the pack is being charged with the 24 volt Gel battery charging profile. This charge controller is not adjustable (except for choosing gel, sealed or flooded lead acid), I wanted to use one which I had not adjusted. I talk more about the why's and the how's in the first part of this series - ua-cam.com/video/YoH7V56RtkM/v-deo.html
thanks
so balancing a cell is look if the cell is higher voltage then discharge this cell right. What happen when the balancer is doing it's work the charge controller stop charging waiting for the balancer to finish its job. So this is one cell what about if your have more than one cell connected parallel.
A balancer will work on a group of cells in parallel as well as a single cell. The only additional thing to consider is if the balancer is able to discharge that larger group of cells at a reasonable rate. In my next video in the series you'll see I increase the capacity of the bank by placing more cells in parallel.
There is no link between the balancing circuit in this case and the solar charge controller. As a result some power is wasted - but in reality it is very little. Balancing cells whether solar charge or not does unfortunately waste charge - until someone works out how to take charge from the highest voltage cell and move it to the lowest we're stuck with just burning off some of the power from the highest cell.
use a hobby grade charger with a screen to charge them a imax b6 is good charger
+Walter Jackson Sadly my pack is 7s so the imax b6 isn’t going to do it easily! Thanks for the idea though.
Maybe the board balances the cells whyle they are charging thats why you need to charge them using the board. This prevents the waste oft energy
Odd that the top 3 in both scenarios become overcharged. Maybe the battery holder has a short/problem? Shot in the dark :P
I'm confident there is no short, but I am wondering if there is a higher resistance on that link. I'll check this, thank you.
I concur. My first thought when I noticed the holder split line. I suspect a connection between the two holders introduces some resistance to the lower 4 cells. Those trays are definitely not perfect conductors....
That doesn't bode well as i have the same balance charger sitting in a box ready to use at some point :-(
+Colin Hickey (Lets make stuff!) I might have damaged it but I can't really see how. To be honest it isn't likely to kick in until the cells are high, but the top of my pack was high. :-(
Mine doesn't seem to work either. Good luck.
Given that TP4056 chargers are very cheap, as are buck converters (which are pretty efficient), why not simply use the solar rig to charge the lead-acid battery that it's designed for, and then use a buck converter to drop the 12V down to a little under 5V to power a bunch of TP4056 modules, one per 18650? No calculating, no messing about balancing: the technology is tried and tested already.
Why do the batteries appear to be parallel?
Yes I guess they do, but they’re not. The wires behind are diagonal. I was concerned if I alternated the cells top to bottom, bottom to top I’d make a mistake at some point and put one in in reverse. I promise they’re in series.
Dear friend, you have soldered the bms wrong and maybe even fried the bms already. Before wiring it you should have checked the wiring diagram. Also check the A for charging port. Also do not keep the capacity meter all the time as it only draws power from the first battery out of 7. The bms are working good if you read instruction first. I have the same config with no issues none so ever.
Do proper wiring from the first time and try not to fry the bms, also connect the batteries when the are top balanced (all 4.2) or bottom balanced. this will keep them in perfect sync as the bms balancing capabilities are only like 1,5 wats maximum. Also some charge controllers (very cheap ones like yours) they let you define custom voltages for low voltage and end high also. check in the settings for battery if you have "user" or custom. This will work great if properly done. As on work around you can use CC CV step up/down converters to safely charge you battery from basically any solar charge controllers - the way that you have done for the output, but you need cc/cv boost buck as when the batteries will reach 4v*7=28 they will go to constant voltage and also you will be able to set the maximum charging current also the extend your battery life.
Cheers bro.
Thanks Petre. I think I said in the video I may well have fried the board. I know others are having success with it. I've got a update to this setup coming soon. I explained in my first video that I wanted to use a charge controller which wouldn't allow me to change the voltages and look at how I could make it work with Li-Ion. I have other controllers I could use that allow more adaptation, but that would make it too easy :-) Thanks for your advice.
you can still use this one as i told you :P; also me i do not like easy things :P
Sorry, but the title is misleading, and the entire video is the story of a failure. If someone is searching for a good way to balance a pack, this video should not be poping up.
Thanks for the feedback. If you watch the full series of videos you may see some better solutions.
Can we use those tp4056 in series at 15v, and the 18650 also in series so no ground would be shorted?
+malicious1111 Sadly not. The boards are not isolated so they would share a common ground and short.