2:27 for Step by step top balancing instructions If you buy quality new cells, you can use BMS to top balance, then capacity test in a few cycles. That's the easiest way. Ian made a great point of using a blocking diode so you won't burn up the power supply. Smart idea. If you are quick charging, current sharing is an issue and you need to attach the positive and negative leads at opposite ends of the battery. In this video we are balancing and topping off at very low currents, so you can attach the leads anywhere. If it makes you feel better to attach at opposite ends, go for it. .1A on a 150A bus bar is not going to cause a current sharing problem. ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Does off-grid solar confuse you? Check out my DIY friendly website for solar system packages and product recommendations, and so much more! www.mobile-solarpower.com Join our DIY solar community! #1 largest solar forum on the internet for beginners and professionals alike: www.diysolarforum.com Check out my best-selling, beginner-friendly 12V off-grid solar book (affiliate link): amzn.to/2Aj4dX4 If DIY is not for you, but you love solar and need an offgrid system, check out Tesla Solar. Low prices and great warranty, and they can take your entire house offgrid with their new Powerwalls: ts.la/william57509 ~~~~~~~~~~~~~~~~~~~~~~~~~ My solar equipment recommendations (Constantly updated! Check here first): 12V/48V Lithium Batteries: www.mobile-solarpower.com/solar-batteries.html Solar System Component Directory: www.mobile-solarpower.com/solarcomponents.html Plug-N-Play Systems: www.mobile-solarpower.com/full-size-systems.html Complete 48V System Kits: www.mobile-solarpower.com/complete-48v-solar-kits.html DIY Friendly Air Conditioner/ Heat Pumps: www.mobile-solarpower.com/solar-friendly-air-conditioners.html Complete 48V System Blueprint: www.mobile-solarpower.com/48v-complete-system-blueprint.html ~~~~~~~~~~~~~~~~~~~~~~~~~~ My Favorite Online Stores for DIY Solar and Coupon Codes: -Current Connected: SOK, Victron and High Quality Components. Best prices and warranty around: currentconnected.com/?ref=wp -Signature Solar: Cheap Server Rack Batteries and Large Solar Panels: www.signaturesolar.com/?ref=h-cvbzfahsek -Ecoflow Delta Official Site: My favorite plug-n-play solar generator: us.ecoflow.com/?aff=7 -AmpereTime: Cheapest 12V batteries around: amperetime.com/products/ampere-time-12v-100ah-lithium-lifepo4-battery?ref=h-cvbzfahsek -Rich Solar: Mega site and cheaper prices than renogy! Check them out: richsolar.com/?ref=h-cvbzfahsek -Shop Solar Kits: Huge site with every solar kit you can imagine! Check it out: shopsolarkits.com/?ref=will-p -Battery Hookup: Cheap cell deals bit.ly/2mIxSqt 10% off code: diysolar -Watts 24/7: Best deals on all-in-one solar power systems, with customer support and distribution here in the USA: watts247.com/?wpam_id=3 ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contact Information: I am NOT available for personal solar system consult! If you wish to contact me, this is my direct email: williamprowsediysolar@gmail.com Join the forum at diysolarforum.com/ if you wish to hang out with myself and others and talk about solar FTC Disclosure Statement and Disclaimers: Every video includes some form of paid promotion or sponsorship. Some links on this youtube channel may be affiliate links. We may get paid if you buy something or take an action after clicking one of these. My videos are for educational purposes only. Information is subject to change/update at any time. Electricity is DANGEROUS and can kill. Be smart and use common sense :) DIY Solar Power with Will Prowse is a participant in the Amazon Services LLC Associates Program, An affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com
DIY Solar Power with Will Prowse Do you ever resale any of the cells you test? Wanting to build a battery for a small camper project. Just thought I’d ask. And thanks for all the info in your videos.
Hello is it okay to top balance cell 4 cell, parallel 2 cell at a time ? and another 2 after, because i only have 3 busbar but i need atleast 6 busbar to parallel all 4 cell at the same time. thanks
@@BlazeByte21 I would think you could balance 2 pairs and then balace the two balanced pairs. But Iif I read your question correctly, you'd eventually have to connect all 4 to balance them equally. You need 6 busbars to do that. If you have some copper pipe you can make great busbars with a hacksaw, a hammer, and a drill for the lug holes. Cut the pipe into the correct length, ,smash the pipe flat with the hammer, and drill the correct spaced and sized holes. You don't have to have commercial busbars.......
Hello, unfortunately I don't understand English very well but I really like how you explain things. I really like to watch your videos and learn a lot from you, for that I would like to thank you very much and I hope that you continue to shoot videos. Best regards from Vienna
Anyone building a DIY battery pack should follow these instructions. The last 48V battery I put together a couple of months ago was needed for a scheduled neighborhood transformer replacement power outage and unfortunately the Chinese prismatic cells did not get delivered until late the day before. Fortunately I had the cabinet, buss bars, wiring, BMS & cell balance board ready to go so I just installed the 16 cells right out of the box and charged at 56V until one the cells started to show signs of over voltage. While the system did work and get us through the entire power outage the next day, the cells were severely out of balance and it took a couple of weeks of "screwing around" by manually connecting ceramic resistors to over charged cells and trying to individually charge low cells with a 3.6V buck charger. Should have just taken the cells out of the cabinet, put them on a bench and done what Will said.
Last year I bought a set of 16 LiFePO4 280AH batteries to build a 48V system. After setting idle for a year they had an initial voltage of 3.16V per cell. I used a lead acid battery charger to bring 4 sets of 4 cells up to near 3.4V per cell which is where the lead acid chargers stopped charging. I top balanced 2 sets of 4 batteries wired in parallel at 3.65V with a 30V 10A power supply set at 3.65V and 10A. The power supply is struggling to charge the 3rd & 4th sets above 3.34V with the power supply set at 3.65V. Should I turn up the voltage a few notches and keep a watch on the batteries to insure they don't rise above 3.65V?
This video is great, but there's no instructions for what happens after the cells hit full capacity. Can I go to sleep and let them charge overnight? Is it safe if they hit full capacity (the power supply is at 0.1A) and stay connected to the power supply for 6-8 hrs? Thanks :) .
Hello Sir. Can I connect them in series for example 8*3.65=29,2 in order to give 29,2 volts and 5Amps with the charger and do it faster, or I will have other issues?
Please reply.. I have 8 cell of 3.2v 100amp, i will connect 2 in parallel then i will have only 4 cell of 3.2v 200amp then i connect all in series 12v 200amp.. the question is, before connect them all should i charge all of them indivisually and balance or i jusy only balance and connect my daly bms .. is my bms manage the capicity of all cells when i will charge the whole battery pack of 12v 200amp???
I Will - Just purchased 16 of those cells from Electric Car Parts for a new 48 volt system. Also purchased an AIMS 48 volt 6KW inverter. Would I be able to top balance using the charger in the AIMS inverter without buying the $50 power supply you used?
If you are using fortune cells I would hook everything up and do a capacity test. Should be fine. If you're not in a rush, you can let BMS top balance. Might take a few cycles
Is it possible to top balance 1 set ot 4 pieces then another set of 4 pieces... Once both sets are top balanced to be connected in series (8s for 24 v inverter)
When you say charge them in groups with a 12v charger, do you mean without a BMS and can an Intelli-power 9000 series RV charger (one of your recommendations) be used - and is there any thing to be careful of?
I think its okay to not have a bms while doing a top balance like Will has done.. as long as you control the voltage and current with your power supply.. in Wills case he set it to 3.6V.. and a fix amount of current..
Li ion chargers usually do a constant current charging.. and when it reach a certain point it will transition to constant voltage charging... this is done in order to not damage the battery.. be sure to consult the specs of your battery to do this bec they have different values of voltages and current to use..
Hi Will, nice vid! Only one small advice: connect the batteries like you did but connect the power supply diagonal. In other words, put one of the wires on the right side of the pack. If done so the current goes thru as many busbars for each cell. Like you did, the current has to travel via ALL busbars for the right cel while the left cell gets it direct from the charger. I know, if you leave this setup stand for a while it will balance eventually but it can be done a little quicker the diagonal way.
@@finnskellig7422 Simple,just connect the + wire (from the power supply) at one end of the 16 cells, 16P, and the -- wire to the OTHER end; the way he did it makes no sense, it's a beginner mistake; The difference here, with a SMALL power supply, is negligible; BUT it CANNOT be tolerated on large (100 Amperes +) power supplies/chargers!
There are many conflicting theories about this subject including the long bus bars on battery rack units and I would agree in principle, however, if the resistance of the bus material is negligible, I would assume the current to be equally distributed across the array. Having said so, I would prefer to individually charge each battery up to its max capacity before installation but then again I'm no expert in this area (yet 😍). Thanks for your input 🙏
Came here to say this. Makes an even bigger difference if using smaller temporary wires instead of bus bars. The current can choose to go through a battery instead of toward the next battery, so by forcing the current to go all the way down the line to get back to the power supply, the delta V across each cell is much closer during the whole process, without relying as much on sitting for a while at the end.
WHY DO YOU SAY 48V WITH 16 CELLS IN SERIES, THE NOMINAL IS 54, I DON'T KNOW WHAT THE HELL IS HAPPENING WITH MY BANK IT HAS 15S 48V, IT IS BALANCED BUT IT NEVER SHOWS MORE THAN 5O VOLTS AT THE END OF THE CHARGE, IT IS SOMETHING VERY STRANGE, BUT MAYBE THEY SOLD ME RECYCLED OR SECOND HAND?
How does that bench power supply know when to stop charging? Or do you just need to monitor the voltage and stop it manually? It was my understanding overcharging LiFePO4 is very bad :)
You should always use a blocking diode to charge batteries with a lab power supply to prevent the current from flowing back into the power supply outputs. Those power supplies usually have a crowbar circuit across the outputs that can short and cause a short circuit across the outputs. This will blow your power supply instantly.
Ian, What would be looking for in the blocking diode you suggest - assuming one of the recent 24V surplus BYD packs ( like David Poz's) using a charger like Will was using? A link would be nice🙂 Thanks
Basically, your video is harmful. 3.7V significantly shortens the lifetime of LiFePO4 batteries. When starting charging and balancing, use the lowest possible voltage, extending the charging time of the cells. Check the voltage of each cell. Start with a low voltage, say 3V per cell and absolutely no more than 3.65V (much better 3.5V) remains in series on the more discharged cell. That is because there is no charger that gives exactly 3.7V multiplied by the number of batteries and there is no BMS that is so perfect that will not introduce voltage measurement errors on the cells. I use a BMS mounted directly on the cell terminals, without the long test leads. That kind of BMS, transmits only the measurement data to the BMS or balancing energy to/from cells. Long test leads, that are thin, couses measurement errors, sometimes 0.1..0.2V, as well as connectors and fuses, which should be installed there. Such errors disqualify that kind of BMS in professional applications where batteries cost tens of thousands of USD. If you charge the batteries with a laboratory power supply, such cheap crap Chinese as in the video, then at least measure what this power supply spits out with some reasonable meter. Otherwise, you can just destroy the batteries with a voltage surge, for example, just in the monent when connecting the battery to the Chinese. Charge in something like that cycles: - first step equal celles voltage with 2A current without balancing (1..2A depending on the equipment), at this stage, charging follows the steep part of the charge curve for LiFEPO4 chemistry. - then use 30A charging current, - next use 2A current for balancing phase and switch to next charging cycle, and so on (high charging current, of course, depends on the cell's capacity). In general, you need to navigate the charge curve for all batteries in the package while charging! What else comes to mind: - charge up to 80% of battery pack capacity, - recharge the batteries as often as possible, do not allow them to deep discharge, - do not leave batteries discharged for a long time. - never charge LiFEPo4 batteries that have been exposed to frost! - do not let the battery freeze, it blew up like inBoeing Dreamliner 787 batteries. Always check the temperature while charging. It cannot be too low or too high. charging below 10C and above 60C might destroys the cells. LiFePO4 cells are almost eternal as long as you reduce the charging current and charge multiple batteries in a digitally controlled manner. To shorten the charging time, shorten the rebalancing time of the battery pack by discarding the weakest (most used) and replacing it with a new one. For this you need a BMS that will analyze the capacity of each battery. To save energy while charging, use a BMS with an active balncer circuit. Charging a battery is always a compromise between charging time and service life. Battery manufacturers usually don't care because they want to sell as many cells as possible. If you follow what I described, you will easily achieve 3500 ... 4000 charge and discharge cycles.
One note that, while not too important once the current drops to a low level, to properly balance the voltage of the pack is to connect one charging lead to the right side and the other charging lead to the left side. This is to balance out the resistance in the length of the wires and buss bars. Otherwise the last cell in the string of parallel batteries may be at a slightly lower state of charge from receiving less current from a higher resistance. Connecting one on the left and another to the right balances this all out
That sounds pretty reasonable. Though we are talking about 1-2mm thick buss bars. Only pressure fit connections, but I can't imagine the resistance being significant - do you have any numbers of what kind of resistance this could be and the corresponding voltage drop/unbalancing?
I agree with you Jason. I used short pieces of small wire to top balance all my cells because I didn’t have enough bus bars and I measured 9mV drop in each cell as I got further away from the PS leads. It did finally all balance out once I switched the leads around like the you said but it probably took much longer than it should have.
@@gkeith4120 yes, this would be slightly better. I would connect the + on the first cell and the - on the last cell. This way the total buss bar length (+ & - together) is the same for each cell.
Hi Will thank you so much for the information that you provide and this video. A few places that I've read on top balancing mentioned letting the pack settle for an hour or so and then check the pack voltage. Keep charging and resting the pack until the pack settles in at 3.65. Is that necessary in your opinion? Or just let the charger get to 3.65 and then reassemble the pack? Thanks again.
How often should this be done with your system? Is it recommended to disassemble a 24v bank down to 12v run in parallel to ensure its balanced every couple of years?
Great advice. I would like to add something I learned. Lower quality cells can drift from one another by time (ex :when not in use) . If they are too far apart for your bms to cope with this, then I charge the individual cells (that have a lower state of charge) little by little with a 3.65v charger. They don't need to be super balanced at the end. Just enough so your bms can do the job again. Hopefully Mr Prowse agrees with this. It works for me with older sinopoly batteries from my boat, that sometimes sit idle for 6 months
Hi Henri. Do you put a load directly on a cell that is too high? And charge the low cells as you said. I have a boat and need to do this now. André in Sydney
Hi Will, ..as usual, great video. I would like to know your favorite test method for determining when a cell is heading for early failure. Is measuring the rise of internal cell resistance a good method for LiFePO4 chemistry. What and how is your method...
When I saw this vid I thought wow, Will is a mind reader 🙂. Please make that video! Have a EVT4000 scooter that I converted to 48 volt Elite Power Li’s w/ active balancing 10-years ago. Has worked great all these years. But recently have been experiencing voltage sag with higher demand accelerations. Suspect a bad cell or two. Coincidently, I let pack sit for a long period & active balancing drew pack down to 20% above absolute zero capacity. Amazingly, on full recharge, pack was revived with very little sag. It appears that “full” discharge helped things allot. Is that possible? Still plan on doing the manual cell balancing you outlined on this video. Will watch for your NEXT video about diagnosing bad cells!! Thanks for your highly informative channel 👍
Great video! Thanks. I didn't realize balancing with such a simple thing it sounded complicated until this video. I had one cell that was charging higher than the others and BMS over voltage protection was making the charge bang on and off repeatedly. I took my pack apart and strap them all in parallel and they top balanced themselves in a couple hours. Now the system charges quickly and without any banging on and off. The only thing I don't understand is why the BMS didn't do this automatically. Thank you sir!
Hi Will, Did you say that there is no need for battery balancing circuit ? are you sure about that ? what about the 32650 LFP cells do you also recommend no active balancer circuit for that ?
I was charging my 100AH LFP battery with a 20A charger that uses 9 stages. This battery has bluetooth and was watching the charging time left. Once the battery got to 99 percent charge the time left starting slowly increasing. Was this due to the dropping level of the Amp input? I was not for sure what was happen and stopped the charging. Why was time left for full charge increasing? I was using a HTRC 20A charger.
@@WillProwse SO FUNNY! I JUST convinced my wife to let me build a 12v 240AH battery bank with 16 cells! I've been thinking about these for DAYS, Will!! Hahaha
Will, I was checking the low voltage recommended cut off. Am I wrong- I see 8.8v as the 4 cell battery cut off? When checking the Lithium curve, it seems that using 11.5 (or slightly lower), or 10.8v would be cutting the BMS cut off kind of low, since 11.5v represents between 80-90% of the batteries total capacity, right? He asks, scratching his head?
@@DCGULL01 Oh I would not use the charts because it is dependent on temperature and whether its a charge or discharge curve etc. SOC curve is most accurate. I would use the recommended one I listed here: diysolarforum.com/threads/recommended-charge-profile-for-diy-lifepo4-batteries-sticky-post.5101/
@@WillProwse Thank you, Will! Last question- Promise! Because these will be going into an RV with solar, an AC converter, etc...I should BOTTOM BALANCE after testing post build? I was planning on capacity testing on the first full charge, then apply a slight charge and bottom balance at say 10.9V or 11v. Then, test each BMS: overcharge/discharge shut off, temp sensor shut off. install the caps, mount the BMS' on top, put inside of the Rubbermaid battery box (with black tank heating pad) and DONE!!! Thanks- still giggling over this video with my current obsession (electric joke there, Will!)
I never hear of anyone discharging multiple cells in parallel. Top balancing and charging up in parallel as you show here is fine. Is there a technical issue with discharging all cells in parallel for bottom balancing? This way balance is never a problem.
Damn kid! You are providing such a Wonderful service to the Solar Community at large and you Clearly enjoy what you are doing. We can’t thank you enough for sharing your knowledge with us!
@@WillProwse l did not do a capacity test. I'm new to this and found out how important it is to do that. Well here's the deal I have 6- 100AH batteries on a 12,000watt growatt inverter. The system has been up and running for 2 months now. In the last week I noticed that the batteries would not charge fully as they were. They now peak at 53.3 volts. I checked the screen and the voltage is off on some of the cell's. Now of course I tried to save money like most dummies and purchased the batteries from AliExpress. Also they hold up well until they hit about 49or 50 volts and then they seem to speed up discharge. But it varies on discharge. I don't work the system hard at all but I guess the capacity test will tell all. By the way the voltage different is like 3262mv and 3293 in difference. What do you think I should do.
Hi Will, I've just purchased a power supplier EBC-A40L and 96 EVE 314 Ah cells. I understand that I have to top balance the cells in parallel to 3.65 V but shall I have to mount the 16 cells in series on my DIY 48 V box at the high voltage level ? Many thanks for your help. Patrick
If your power supply has an option for sense leads you can add a second pair of leads from the power supply to the battery terminals. This lets the power supply sense the voltage at the battery and any voltage drop is eliminated. This makes the top-level charge quicker without the need to boost the voltage setting.
Whoa, I'm sorry. You lost me across the edit at (4:03). Why would the current drop to 0.1 amps again? Do you mean the current flowing INTO the battery pack from the charger? (indicating they are fully charged as a parallel unit and are not accepting any more current?)
Hey Will I've just had 15kw solar array with a 15kw Sol-Ark Inverter/charger controller and 48volt (16s) @740wh each LiFePo4 box. I am not aware that they did a parallel top-balance, and the meter is showing 100% power. Is this something mission critical? Or should I let the warranty play out?
So.. I charge a single LEV60 3.2v (3.5v max it says) and hours later its only at 3.3v. I am using the same power supply set at either 3.5v or 3.49v. Hours later its still only at 3.3v. When I take the power off, a couple hours later the battery is down to 3.28v or so. Is that normal? If so, how do I ensure all 16 are the right charge to assemble my 48v battery (Jehu 48v battery pack)?
Will, even though it has been a few years since you made this video I am hoping for an answer. I have 4 LiTime 12 volt 230 ah batteries. I will be connecting them to create a 2P1S battery bank. These are all new batteries. I had charged all of them individually up to their max charge state prior to connecting them first in parallel(and waiting 12 or so hours) and then into series. After the first discharge down to about 20%(estimate via voltage) the BMS turned the bank off. Now I am only able to charge them individually up to between 12.6 to 12.7. They are "Stuck" at this voltage. A cure I was given by LiTime support for when this happened when first charging on arrival was to add a small load to the battery and it would then show the actual voltage....which it did...it went from 12.7 almost immediately to 13.1 volts. This cure does not work now. Because I do not have any access to the internal cells I cannot do as you recommend without voiding the warranty. I have a support ticket currently with LiTime but have not an answer as of yet. Any suggestions?
I am confused ! Because float voltage recommended for this cell is 3.2 vdc . If you charge it till reach 3.65 vdc will be the max voltage or cut off voltage
I just bought four 280Ah grade A cells, connected them in parallel and set voltage to 3.65. it has been 3 weeks and the current is at 4.45 amp. What is happening?
I am trying this, with 16 new cells I bought, but it is taking forever to charge, using the power supply you recommended (weeks). The cells are 310 A-Hrs. All but one were 3.34-3.35V when I checked them initially, except for one that was 3.28V. Should I have tried to charge that low one up first? I have bought a BMS, and will be building a 24V battery block. Am I wasting my time trying to do this top balancing? Thanks.
I make my year balance everything when it's December. Then the sun is not showing so much and I can swap out cells and load them up. Usually I wait until the cells are at 80 to 90 soc. I have 16 cells with 105Ah as a 12V system. So if iam putting 4 cells out I have reduced capacity but I don't care. Then I load the cells single to 3.65V and take the next and so on. The last 4 cells I swap out with the remaining full loaded 12 cells. And then I can load the 4 cells up and integrate them into the battery after that. It's a little work but it pays off. Only after 1 and a half years now I get cell block 3 slightly off at 0.1V when iam at 100Ah left on the battery... I make top balancing because my battery is more time in an higher soc then at low. So due summertime I have always over 70% soc
If you can charge each cell, individually, wouldn't it take just the time of 1 cell to charge ?? Regardless of how many cells! as long as each cell has its own charger?? This is why I'm horny for super caps ultracaps. and a mix!! Feedback appreciated
Hi mate I'm a little puzzled I've just bought 4 280ah cells from China set them off top balancing 3.65v the amps were at 7.5 next morning they were at 5.7amps which is OK I think by tea time I came in and amps were 10.9 and not budged over next 12 hours so turned off as don't seem right do u have any suggestions please
my batteries has now been charging för 10 days and not reached 3,4V. I started on 3,29V and is now on 3,38V 10 days later. it started to charge at 5Amps and has dropped now to 0,8Amps as its closing in to 3.4V. But 10 days??!! can that really be as it should ? Thanks for great Video!!
Doy you have a tip on how to di it with a ready built 48V pack with welded busbars? I have a kind a crappy chinese battery with one massivly drifting cell, I still need to measure the cell resistances but I cant parallel them as they are welded together. (and I top balanced them a couple of times via the bms but no effect)
Anyone know if it is safe to set a target with Variable DC Power Supply and just leave it there over night or do you need to disconnect it relatively quickly? If I just set a target of 3.5v is there any issue with damage to the batteries if I leave that for 24 hours if I'm not available to check the batteries?
Ok, I've seen top balancing videos and understand how and why it's done but why it works is what escapes me. Let's say you have some cells hooked in series. All of the resting voltages are pretty close . When you charge them, one cell gets to 3.6ish or enough to cut off the BMS hi voltage limit, while rest of the cells are at 3.3ish. What's causing the one cell to charge so much faster than the rest? If it's a lower internal resistance, individually discharging that cell to match the rest (let's say the arrangent is spot welded in-place) should not change the internal reistance of that cell, yet discharging it often fixes the problem so what else is at work here?
Hi. I have new eve 280Ah cells. I have had them on a dc power supply to try and top balance. Been sat at 3.65v for 3 days. Not dropping below 2.6amps. If I disconnect the power. Bat at 3.35v ??
@willprowse Hey will i have 2 lifep04 10k batteries, one in new than the other and they are connected to a hybrid inverter. I have notice that one is charging and discharging faster than the other. Any suggestion here?
Sorry for many a stupid question 🙌 ive just started watching videos like this, about battery's. And i want to learn more, i have a ebike i like to gettt Long range on (my battery is almost finish now 60v 26 amps) can you use cells like this for that?
so I have 6 x 48V batteries with their own internal BMS and individually I can not get them past 54.6V even though I have my charge controller set to 58.4. I'm guessing that one of the internal batteries in each one is charged higher and cutting off the charge early? How do I get around this, the battery vendor is saying to cycle the batteries multiple times to get them to increase capacity...
hi mr Thanks for the good information you share .. I need a 12/24V charging circuit for lifepo4 batteries to do a project, please help me if you have a map of the charging circuit. tnx
Lifepo4 battery does'nt need float charge if use normal 12 volt lead acid charger on 4s lifepo4 12v pattery pack with daly bms is it ok? Or harmfull my cells?
I bought 8 LIFE PO4 12 v 200 ah with 200 BMS in it to subtitute some 12v 200 ah gel batteries I have in a solar system, Do I need to top those batteries ?
Do you think it’s ok to use stranded 12awg wire for bus bars when top balancing? I don’t have enough bus bars and figured since it was low volts and low amps it would be fine. Does anyone know?
Just FYI, if you are thick like me, if there are big sparks, you got it connected wrong. Tried 3 times in a row before I realized I had the cell connected wrong
Hi , super :) but you know that there is no energy storage, the use of the right materials in the process of oxidizing them and stimulating it, and during this process, the appropriate strength of hydrogen is extracted :) so the planet feeds us and breathes energy packets :) we already know about it, it's technology about plasm, interesting what?
If I have a 16 cell bank ran in series to make 48v But I want to add more cells to increase the storage capacity can I get an additional 8and run them in parallel to the 16 in series?? Would this work
Do you need to put the cells in compression before top balancing? Do you need to use busbars when connecting the cells or can you use 10ga or 12ga wire?
by connecting the power supply to the first cell, it will be a higher voltage than the cell on the far right due to the resistance off the busbars and the connections between them. Better would be positive from charger to the left positive terminal and negative from the charger to the right negative terminal
Thank you very important step ! Most LiFePO4 type cells I have dealt with are only charged to about 80% or so new when shipped. I like to pre test each cell first .bring up than parralo charge . takes more time but can do 4S banks get them over 90% . then let go for a day or 2 in parralo.
Hint. . .put the Positive on one end of the battery and the Negative at the opposite end of the battery. . . . Draw it out on paper. . . . Resistance of the interconnections is balanced this way. . . Better thismway when discharging to.
Thanx for this brother Will. I have a 4P4S 12v battery and one of my 4P sets were at 3.7 SOC while the other three were at 3.5 so I am following your vid... Shalom
Hello, thanks for explaining the procedure. I appreciate your enthusiasm. I have a small question: Is it safe to keep them charging overnight? Technically, if I keep the supply voltage to 3.6V, then it should be safe, as once all of them charged and balanced, the input current will be o eventually, right? Just wanted to confirm from you who must have been doing this often.
I never do actually. I have a lot of my habits form charging lipoly cells for years. I try to avoid charging unattended often. It shouldn't take more than a few hours if your cells are at high soc.
Parallel connections should be connected with the first cell positive and last cell negative to better equalize else like the way t You had it will full charge the first cell.
I am using two lead acid batteries in series and they are unbalanced. how can I balance lead acid battery ?. is it possible with same way after connecting in parallel and charge it?
2:27 for Step by step top balancing instructions
If you buy quality new cells, you can use BMS to top balance, then capacity test in a few cycles. That's the easiest way.
Ian made a great point of using a blocking diode so you won't burn up the power supply. Smart idea.
If you are quick charging, current sharing is an issue and you need to attach the positive and negative leads at opposite ends of the battery. In this video we are balancing and topping off at very low currents, so you can attach the leads anywhere. If it makes you feel better to attach at opposite ends, go for it. .1A on a 150A bus bar is not going to cause a current sharing problem.
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Can I do this top balancing at a higher amperage, say 3.6V @50A?
DIY Solar Power with Will Prowse Do you ever resale any of the cells you test?
Wanting to build a battery for a small camper project. Just thought I’d ask. And thanks for all the info in your videos.
@@tevincampbell1735 Sure as long as you don't exceed the c rate of the battery
Hello is it okay to top balance cell 4 cell, parallel 2 cell at a time ? and another 2 after, because i only have 3 busbar but i need atleast 6 busbar to parallel all 4 cell at the same time. thanks
@@BlazeByte21 I would think you could balance 2 pairs and then balace the two balanced pairs. But Iif I read your question correctly, you'd eventually have to connect all 4 to balance them equally. You need 6 busbars to do that. If you have some copper pipe you can make great busbars with a hacksaw, a hammer, and a drill for the lug holes. Cut the pipe into the correct length, ,smash the pipe flat with the hammer, and drill the correct spaced and sized holes. You don't have to have commercial busbars.......
Hello, unfortunately I don't understand English very well but I really like how you explain things. I really like to watch your videos and learn a lot from you, for that I would like to thank you very much and I hope that you continue to shoot videos. Best regards from Vienna
Using the same power supply today as is in the video lol. It's great!
Anyone building a DIY battery pack should follow these instructions. The last 48V battery I put together a couple of months ago was needed for a scheduled neighborhood transformer replacement power outage and unfortunately the Chinese prismatic cells did not get delivered until late the day before. Fortunately I had the cabinet, buss bars, wiring, BMS & cell balance board ready to go so I just installed the 16 cells right out of the box and charged at 56V until one the cells started to show signs of over voltage. While the system did work and get us through the entire power outage the next day, the cells were severely out of balance and it took a couple of weeks of "screwing around" by manually connecting ceramic resistors to over charged cells and trying to individually charge low cells with a 3.6V buck charger. Should have just taken the cells out of the cabinet, put them on a bench and done what Will said.
Will, l think your a great teacher-Solar Guru🇦🇺
Last year I bought a set of 16 LiFePO4 280AH batteries to build a 48V system. After setting idle for a year they had an initial voltage of 3.16V per cell. I used a lead acid battery charger to bring 4 sets of 4 cells up to near 3.4V per cell which is where the lead acid chargers stopped charging. I top balanced 2 sets of 4 batteries wired in parallel at 3.65V with a 30V 10A power supply set at 3.65V and 10A. The power supply is struggling to charge the 3rd & 4th sets above 3.34V with the power supply set at 3.65V. Should I turn up the voltage a few notches and keep a watch on the batteries to insure they don't rise above 3.65V?
This video is great, but there's no instructions for what happens after the cells hit full capacity. Can I go to sleep and let them charge overnight? Is it safe if they hit full capacity (the power supply is at 0.1A) and stay connected to the power supply for 6-8 hrs? Thanks :) .
Hello. When do you will test the new Yinlong LTO battery? Thanks. Good work.
Awesome Video!
Hello Sir. Can I connect them in series for example 8*3.65=29,2 in order to give 29,2 volts and 5Amps with the charger and do it faster, or I will have other issues?
I Wish you could fly over to South Africa and help me install a system for my house
Please reply.. I have 8 cell of 3.2v 100amp, i will connect 2 in parallel then i will have only 4 cell of 3.2v 200amp then i connect all in series 12v 200amp.. the question is, before connect them all should i charge all of them indivisually and balance or i jusy only balance and connect my daly bms .. is my bms manage the capicity of all cells when i will charge the whole battery pack of 12v 200amp???
Please tell me how i can balance and 28 cells lithium ion 3.7 volt
I Will - Just purchased 16 of those cells from Electric Car Parts for a new 48 volt system. Also purchased an AIMS 48 volt 6KW inverter. Would I be able to top balance using the charger in the AIMS inverter without buying the $50 power supply you used?
If you are using fortune cells I would hook everything up and do a capacity test. Should be fine. If you're not in a rush, you can let BMS top balance. Might take a few cycles
Is it possible to top balance 1 set ot 4 pieces then another set of 4 pieces... Once both sets are top balanced to be connected in series (8s for 24 v inverter)
When you say charge them in groups with a 12v charger, do you mean without a BMS and can an Intelli-power 9000 series RV charger (one of your recommendations) be used - and is there any thing to be careful of?
I think its okay to not have a bms while doing a top balance like Will has done.. as long as you control the voltage and current with your power supply.. in Wills case he set it to 3.6V.. and a fix amount of current..
Li ion chargers usually do a constant current charging.. and when it reach a certain point it will transition to constant voltage charging... this is done in order to not damage the battery.. be sure to consult the specs of your battery to do this bec they have different values of voltages and current to use..
Hi Will, nice vid! Only one small advice: connect the batteries like you did but connect the power supply diagonal. In other words, put one of the wires on the right side of the pack. If done so the current goes thru as many busbars for each cell. Like you did, the current has to travel via ALL busbars for the right cel while the left cell gets it direct from the charger. I know, if you leave this setup stand for a while it will balance eventually but it can be done a little quicker the diagonal way.
Hi Rik, any chance you could elaborate a bit more on how to do this please? cheers
@@finnskellig7422 Simple,just connect the + wire (from the power supply) at one end of the 16 cells, 16P, and the -- wire to the OTHER end; the way he did it makes no sense, it's a beginner mistake;
The difference here, with a SMALL power supply, is negligible; BUT it CANNOT be tolerated on large (100 Amperes +) power supplies/chargers!
There are many conflicting theories about this subject including the long bus bars on battery rack units and I would agree in principle, however, if the resistance of the bus material is negligible, I would assume the current to be equally distributed across the array. Having said so, I would prefer to individually charge each battery up to its max capacity before installation but then again I'm no expert in this area (yet 😍). Thanks for your input 🙏
Came here to say this. Makes an even bigger difference if using smaller temporary wires instead of bus bars. The current can choose to go through a battery instead of toward the next battery, so by forcing the current to go all the way down the line to get back to the power supply, the delta V across each cell is much closer during the whole process, without relying as much on sitting for a while at the end.
Finally, a clear, concise, rational explanation. Tons of half-assed information on TH-cam.
I've been having this problem, one of my cells run away at high voltage. I'm gonna take my bank apart again, and top balance. Thanks Will...
Did you manage to solve the problem?
WHY DO YOU SAY 48V WITH 16 CELLS IN SERIES, THE NOMINAL IS 54, I DON'T KNOW WHAT THE HELL IS HAPPENING WITH MY BANK IT HAS 15S 48V, IT IS BALANCED BUT IT NEVER SHOWS MORE THAN 5O VOLTS AT THE END OF THE CHARGE, IT IS SOMETHING VERY STRANGE, BUT MAYBE THEY SOLD ME RECYCLED OR SECOND HAND?
How does that bench power supply know when to stop charging? Or do you just need to monitor the voltage and stop it manually? It was my understanding overcharging LiFePO4 is very bad :)
You should always use a blocking diode to charge batteries with a lab power supply to prevent the current from flowing back into the power supply outputs. Those power supplies usually have a crowbar circuit across the outputs that can short and cause a short circuit across the outputs. This will blow your power supply instantly.
Oh that's smart!!!! Will add that. Good point
Only needed on the + side?
Be sure and take the voltage drop across the blocking diode and subtract from your metered voltage.
Ian,
What would be looking for in the blocking diode you suggest - assuming one of the recent 24V surplus BYD packs ( like David Poz's) using a charger like Will was using? A link would be nice🙂
Thanks
What size/type it should be ?
Will Power, Inc. Top global producer of solar and lithium products.. Nice ring to it. What do you think?
Jack Frick sounds like an antipodean NASCAR driver to me ;)
Basically, your video is harmful.
3.7V significantly shortens the lifetime of LiFePO4 batteries. When starting charging and balancing, use the lowest possible voltage, extending the charging time of the cells. Check the voltage of each cell. Start with a low voltage, say 3V per cell and absolutely no more than 3.65V (much better 3.5V) remains in series on the more discharged cell.
That is because there is no charger that gives exactly 3.7V multiplied by the number of batteries and there is no BMS that is so perfect that will not introduce voltage measurement errors on the cells. I use a BMS mounted directly on the cell terminals, without the long test leads. That kind of BMS, transmits only the measurement data to the BMS or balancing energy to/from cells. Long test leads, that are thin, couses measurement errors, sometimes 0.1..0.2V, as well as connectors and fuses, which should be installed there. Such errors disqualify that kind of BMS in professional applications where batteries cost tens of thousands of USD.
If you charge the batteries with a laboratory power supply, such cheap crap Chinese as in the video, then at least measure what this power supply spits out with some reasonable meter. Otherwise, you can just destroy the batteries with a voltage surge, for example, just in the monent when connecting the battery to the Chinese.
Charge in something like that cycles:
- first step equal celles voltage with 2A current without balancing (1..2A depending on the equipment), at this stage, charging follows the steep part of the charge curve for LiFEPO4 chemistry.
- then use 30A charging current,
- next use 2A current for balancing phase and switch to next charging cycle, and so on (high charging current, of course, depends on the cell's capacity).
In general, you need to navigate the charge curve for all batteries in the package while charging!
What else comes to mind:
- charge up to 80% of battery pack capacity,
- recharge the batteries as often as possible, do not allow them to deep discharge,
- do not leave batteries discharged for a long time.
- never charge LiFEPo4 batteries that have been exposed to frost!
- do not let the battery freeze, it blew up like inBoeing Dreamliner 787 batteries.
Always check the temperature while charging. It cannot be too low or too high. charging below 10C and above 60C might destroys the cells. LiFePO4 cells are almost eternal as long as you reduce the charging current and charge multiple batteries in a digitally controlled manner.
To shorten the charging time, shorten the rebalancing time of the battery pack by discarding the weakest (most used) and replacing it with a new one. For this you need a BMS that will analyze the capacity of each battery. To save energy while charging, use a BMS with an active balncer circuit.
Charging a battery is always a compromise between charging time and service life. Battery manufacturers usually don't care because they want to sell as many cells as possible. If you follow what I described, you will easily achieve 3500 ... 4000 charge and discharge cycles.
One note that, while not too important once the current drops to a low level, to properly balance the voltage of the pack is to connect one charging lead to the right side and the other charging lead to the left side. This is to balance out the resistance in the length of the wires and buss bars. Otherwise the last cell in the string of parallel batteries may be at a slightly lower state of charge from receiving less current from a higher resistance. Connecting one on the left and another to the right balances this all out
That sounds pretty reasonable. Though we are talking about 1-2mm thick buss bars. Only pressure fit connections, but I can't imagine the resistance being significant - do you have any numbers of what kind of resistance this could be and the corresponding voltage drop/unbalancing?
I agree with you Jason. I used short pieces of small wire to top balance all my cells because I didn’t have enough bus bars and I measured 9mV drop in each cell as I got further away from the PS leads. It did finally all balance out once I switched the leads around like the you said but it probably took much longer than it should have.
Would it make more sense during parallel topping off to put connection both on center cell?
@@gkeith4120 yes, this would be slightly better. I would connect the + on the first cell and the - on the last cell. This way the total buss bar length (+ & - together) is the same for each cell.
You should not charge them to 3.6V coz you can overcharge them with that low current
Hi Will thank you so much for the information that you provide and this video. A few places that I've read on top balancing mentioned letting the pack settle for an hour or so and then check the pack voltage. Keep charging and resting the pack until the pack settles in at 3.65. Is that necessary in your opinion? Or just let the charger get to 3.65 and then reassemble the pack? Thanks again.
should the battery pack be compressed during the balancing period?
How often should this be done with your system? Is it recommended to disassemble a 24v bank down to 12v run in parallel to ensure its balanced every couple of years?
Great advice. I would like to add something I learned. Lower quality cells can drift from one another by time (ex :when not in use) . If they are too far apart for your bms to cope with this, then I charge the individual cells (that have a lower state of charge) little by little with a 3.65v charger. They don't need to be super balanced at the end. Just enough so your bms can do the job again. Hopefully Mr Prowse agrees with this. It works for me with older sinopoly batteries from my boat, that sometimes sit idle for 6 months
Hi Henri. Do you put a load directly on a cell that is too high? And charge the low cells as you said. I have a boat and need to do this now. André in Sydney
Nicely done, thank you for doing this video! Straight to the point, accurate, and very helpful for those looking to put together packs.
Hi Will, ..as usual, great video. I would like to know your favorite test method for determining when a cell is heading for early failure. Is measuring the rise of internal cell resistance a good method for LiFePO4 chemistry. What and how is your method...
Good question. Should make a video on this
When I saw this vid I thought wow, Will is a mind reader 🙂. Please make that video!
Have a EVT4000 scooter that I converted to 48 volt Elite Power Li’s w/ active balancing 10-years ago. Has worked great all these years. But recently have been experiencing voltage sag with higher demand accelerations. Suspect a bad cell or two. Coincidently, I let pack sit for a long period & active balancing drew pack down to 20% above absolute zero capacity. Amazingly, on full recharge, pack was revived with very little sag. It appears that “full” discharge helped things allot. Is that possible?
Still plan on doing the manual cell balancing you outlined on this video. Will watch for your NEXT video about diagnosing bad cells!! Thanks for your highly informative channel 👍
Thanks, looking forward to your video on this often overlooked test.
Great video! Thanks. I didn't realize balancing with such a simple thing it sounded complicated until this video. I had one cell that was charging higher than the others and BMS over voltage protection was making the charge bang on and off repeatedly. I took my pack apart and strap them all in parallel and they top balanced themselves in a couple hours. Now the system charges quickly and without any banging on and off. The only thing I don't understand is why the BMS didn't do this automatically. Thank you sir!
Fantastic video. A proper initial balance will ensure the longest life and best capacity. I can’t wait to see you build a system with those cells.
You just keep coming with these tutorials! Wow!
This should be the first video anyone watches before building a battery bank. Wish I'd seen it much sooner!
Him - "You can't screw this up" Me - "Hold my beer"
Thanks Will. Great tips. Thanks for your insight.
Hi Will,
Did you say that there is no need for battery balancing circuit ?
are you sure about that ?
what about the 32650 LFP cells do you also recommend no active balancer circuit for that ?
He said that you shoulnd't need to balance your batteries that often in service, and if you are then maybe you have a bad cell you should replace.
another question - - - can you use a good 12 volt car charger to bring up 4 sells in series before charging all the batteries in parallel
I was charging my 100AH LFP battery with a 20A charger that uses 9 stages. This battery has bluetooth and was watching the charging time left. Once the battery got to 99 percent charge the time left starting slowly increasing. Was this due to the dropping level of the Amp input? I was not for sure what was happen and stopped the charging. Why was time left for full charge increasing? I was using a HTRC 20A charger.
Will? Are you speaking, cuz- I can't hear you! Those Fortune 12v Cells are screaming at me!
Fortune cells are hands down, my favorite. I love them.
@@WillProwse SO FUNNY! I JUST convinced my wife to let me build a 12v 240AH battery bank with 16 cells! I've been thinking about these for DAYS, Will!! Hahaha
Will, I was checking the low voltage recommended cut off. Am I wrong- I see 8.8v as the 4 cell battery cut off? When checking the Lithium curve, it seems that using 11.5 (or slightly lower), or 10.8v would be cutting the BMS cut off kind of low, since 11.5v represents between 80-90% of the batteries total capacity, right? He asks, scratching his head?
@@DCGULL01 Oh I would not use the charts because it is dependent on temperature and whether its a charge or discharge curve etc. SOC curve is most accurate. I would use the recommended one I listed here: diysolarforum.com/threads/recommended-charge-profile-for-diy-lifepo4-batteries-sticky-post.5101/
@@WillProwse Thank you, Will! Last question- Promise! Because these will be going into an RV with solar, an AC converter, etc...I should BOTTOM BALANCE after testing post build? I was planning on capacity testing on the first full charge, then apply a slight charge and bottom balance at say 10.9V or 11v. Then, test each BMS: overcharge/discharge shut off, temp sensor shut off. install the caps, mount the BMS' on top, put inside of the Rubbermaid battery box (with black tank heating pad) and DONE!!! Thanks- still giggling over this video with my current obsession (electric joke there, Will!)
I never hear of anyone discharging multiple cells in parallel. Top balancing and charging up in parallel as you show here is fine. Is there a technical issue with discharging all cells in parallel for bottom balancing? This way balance is never a problem.
Damn kid!
You are providing such a Wonderful service to the Solar Community at large and you Clearly enjoy what you are doing.
We can’t thank you enough for sharing your knowledge with us!
Thank you for the video. At what Nm should those prismatic cells be tightened?
Can i use a buck charger to balance the cells.? How many amps will i put to charge 12 pcs lifepo4 3.2v 30ah.?
What do you do if you buy a pre-assembled battery from a manufacturer and the cells are not balanced in a 48v server rack battery.
Cycle it. It will balance over time. Is it pulling full capacity?
@@WillProwse l did not do a capacity test. I'm new to this and found out how important it is to do that. Well here's the deal I have 6- 100AH batteries on a 12,000watt growatt inverter. The system has been up and running for 2 months now. In the last week I noticed that the batteries would not charge fully as they were. They now peak at 53.3 volts. I checked the screen and the voltage is off on some of the cell's. Now of course I tried to save money like most dummies and purchased the batteries from AliExpress. Also they hold up well until they hit about 49or 50 volts and then they seem to speed up discharge. But it varies on discharge. I don't work the system hard at all but I guess the capacity test will tell all. By the way the voltage different is like 3262mv and 3293 in difference. What do you think I should do.
Hi Will,
I've just purchased a power supplier EBC-A40L and 96 EVE 314 Ah cells. I understand that I have to top balance the cells in parallel to 3.65 V but shall I have to mount the 16 cells in series on my DIY 48 V box at the high voltage level ?
Many thanks for your help.
Patrick
I'm a bit confused. I can just attach a PSU directly to the battery via the BMS and I don't need a charger/charge controller?
If your power supply has an option for sense leads you can add a second pair of leads from the power supply to the battery terminals. This lets the power supply sense the voltage at the battery and any voltage drop is eliminated. This makes the top-level charge quicker without the need to boost the voltage setting.
Does 3.65 volts mean 100% charge and 3.4 volts will charge the cell to 80%?
Or are 3.65, 3.5, or 3.4 volts the charging speed of the cell?
Whoa, I'm sorry. You lost me across the edit at (4:03). Why would the current drop to 0.1 amps again? Do you mean the current flowing INTO the battery pack from the charger? (indicating they are fully charged as a parallel unit and are not accepting any more current?)
Thanks for sharing Will. May I know why we have used 16 LFP cells to make 48V pack instead 15?
Hey Will I've just had 15kw solar array with a 15kw Sol-Ark Inverter/charger controller and 48volt (16s) @740wh each LiFePo4 box. I am not aware that they did a parallel top-balance, and the meter is showing 100% power. Is this something mission critical? Or should I let the warranty play out?
So.. I charge a single LEV60 3.2v (3.5v max it says) and hours later its only at 3.3v. I am using the same power supply set at either 3.5v or 3.49v. Hours later its still only at 3.3v. When I take the power off, a couple hours later the battery is down to 3.28v or so. Is that normal? If so, how do I ensure all 16 are the right charge to assemble my 48v battery (Jehu 48v battery pack)?
Will, even though it has been a few years since you made this video I am hoping for an answer. I have 4 LiTime 12 volt 230 ah batteries. I will be connecting them to create a 2P1S battery bank. These are all new batteries.
I had charged all of them individually up to their max charge state prior to connecting them first in parallel(and waiting 12 or so hours) and then into series.
After the first discharge down to about 20%(estimate via voltage) the BMS turned the bank off. Now I am only able to charge them individually up to between 12.6 to 12.7. They are "Stuck" at this voltage. A cure I was given by LiTime support for when this happened when first charging on arrival was to add a small load to the battery and it would then show the actual voltage....which it did...it went from 12.7 almost immediately to 13.1 volts. This cure does not work now.
Because I do not have any access to the internal cells I cannot do as you recommend without voiding the warranty. I have a support ticket currently with LiTime but have not an answer as of yet.
Any suggestions?
I am confused ! Because float voltage recommended for this cell is 3.2 vdc . If you charge it till reach 3.65 vdc will be the max voltage or cut off voltage
I just bought four 280Ah grade A cells, connected them in parallel and set voltage to 3.65. it has been 3 weeks and the current is at 4.45 amp. What is happening?
Thanks for a concise video Will, thanks for not wasting our time with 11 minute BS if there is no need for it
I am trying this, with 16 new cells I bought, but it is taking forever to charge, using the power supply you recommended (weeks). The cells are 310 A-Hrs. All but one were 3.34-3.35V when I checked them initially, except for one that was 3.28V. Should I have tried to charge that low one up first? I have bought a BMS, and will be building a 24V battery block. Am I wasting my time trying to do this top balancing? Thanks.
I make my year balance everything when it's December. Then the sun is not showing so much and I can swap out cells and load them up. Usually I wait until the cells are at 80 to 90 soc.
I have 16 cells with 105Ah as a 12V system.
So if iam putting 4 cells out I have reduced capacity but I don't care. Then I load the cells single to 3.65V and take the next and so on.
The last 4 cells I swap out with the remaining full loaded 12 cells. And then I can load the 4 cells up and integrate them into the battery after that.
It's a little work but it pays off. Only after 1 and a half years now I get cell block 3 slightly off at 0.1V when iam at 100Ah left on the battery...
I make top balancing because my battery is more time in an higher soc then at low. So due summertime I have always over 70% soc
If you can charge each cell, individually, wouldn't it take just the time of 1 cell to charge ?? Regardless of how many cells! as long as each cell has its own charger??
This is why I'm horny for super caps ultracaps. and a mix!!
Feedback appreciated
Hi mate I'm a little puzzled I've just bought 4 280ah cells from China set them off top balancing 3.65v the amps were at 7.5 next morning they were at 5.7amps which is OK I think by tea time I came in and amps were 10.9 and not budged over next 12 hours so turned off as don't seem right do u have any suggestions please
Hi has anybody seen a review of the Suoer PS 3k 24v PWM hybrid inverter sold in Asia. I want an English language critic , much love 💕
my batteries has now been charging för 10 days and not reached 3,4V. I started on 3,29V and is now on 3,38V 10 days later. it started to charge at 5Amps and has dropped now to 0,8Amps as its closing in to 3.4V. But 10 days??!! can that really be as it should ? Thanks for great Video!!
Doy you have a tip on how to di it with a ready built 48V pack with welded busbars? I have a kind a crappy chinese battery with one massivly drifting cell, I still need to measure the cell resistances but I cant parallel them as they are welded together. (and I top balanced them a couple of times via the bms but no effect)
Anyone know if it is safe to set a target with Variable DC Power Supply and just leave it there over night or do you need to disconnect it relatively quickly? If I just set a target of 3.5v is there any issue with damage to the batteries if I leave that for 24 hours if I'm not available to check the batteries?
Ok, I've seen top balancing videos and understand how and why it's done but why it works is what escapes me. Let's say you have some cells hooked in series. All of the resting voltages are pretty close . When you charge them, one cell gets to 3.6ish or enough to cut off the BMS hi voltage limit, while rest of the cells are at 3.3ish. What's causing the one cell to charge so much faster than the rest? If it's a lower internal resistance, individually discharging that cell to match the rest (let's say the arrangent is spot welded in-place) should not change the internal reistance of that cell, yet discharging it often fixes the problem so what else is at work here?
Hi. I have new eve 280Ah cells. I have had them on a dc power supply to try and top balance. Been sat at 3.65v for 3 days. Not dropping below 2.6amps. If I disconnect the power. Bat at 3.35v ??
Hi Will.. can I use this same method if I have 16 12v lifepo4 that I intend to wire 4s4p?
@willprowse Hey will i have 2 lifep04 10k batteries, one in new than the other and they are connected to a hybrid inverter. I have notice that one is charging and discharging faster than the other. Any suggestion here?
I bought 4 CHINS 12V 200AH (200A BMS). Do I have to balance them with an equalizer before to begin using them in my solar system?
Sorry for many a stupid question 🙌 ive just started watching videos like this, about battery's. And i want to learn more, i have a ebike i like to gettt Long range on (my battery is almost finish now 60v 26 amps) can you use cells like this for that?
Where can I find quality used LiPo4 batteries for an EV project? 180ah and higher? I am open to Alibaba. Thanks and really enjoy the content.
so I have 6 x 48V batteries with their own internal BMS and individually I can not get them past 54.6V even though I have my charge controller set to 58.4. I'm guessing that one of the internal batteries in each one is charged higher and cutting off the charge early? How do I get around this, the battery vendor is saying to cycle the batteries multiple times to get them to increase capacity...
hi mr
Thanks for the good information you share ..
I need a 12/24V charging circuit for lifepo4 batteries to do a project, please help me if you have a map of the charging circuit.
tnx
The 1st battery may not be the same as the last,there are 10 or more bus bar to pass through creating resistance and voltage drop....
Lifepo4 battery does'nt need float charge if use normal 12 volt lead acid charger on 4s lifepo4 12v pattery pack with daly bms is it ok? Or harmfull my cells?
I bought 8 LIFE PO4 12 v 200 ah with 200 BMS in it to subtitute some 12v 200 ah gel batteries I have in a solar system, Do I need to top those batteries ?
Do you think it’s ok to use stranded 12awg wire for bus bars when top balancing? I don’t have enough bus bars and figured since it was low volts and low amps it would be fine. Does anyone know?
Just FYI, if you are thick like me, if there are big sparks, you got it connected wrong.
Tried 3 times in a row before I realized I had the cell connected wrong
Lots of people say charge them up to 3.6. I have never managed to charge my 105ah ones past the point of 3.4v before my BMS cuts them off.
Hi , super :) but you know that there is no energy storage, the use of the right materials in the process of oxidizing them and stimulating it, and during this process, the appropriate strength of hydrogen is extracted :) so the planet feeds us and breathes energy packets :) we already know about it, it's technology about plasm, interesting what?
If I have a 16 cell bank ran in series to make 48v
But I want to add more cells to increase the storage capacity can I get an additional 8and run them in parallel to the 16 in series?? Would this work
Hey Will, I have a 200ah I have for emergencies. Should I keep this attached to a trickle charger for long term storage?
hi i want to make a battery for my ebike 72v 30ah... I have a 3.2v 30ah 24pvs. what active balancer and bms to use and what charger can i use? thanks
Do you need to put the cells in compression before top balancing? Do you need to use busbars when connecting the cells or can you use 10ga or 12ga wire?
Great video! But what kind of charger should I use to balance to 3.6v?
by connecting the power supply to the first cell, it will be a higher voltage than the cell on the far right due to the resistance off the busbars and the connections between them. Better would be positive from charger to the left positive terminal and negative from the charger to the right negative terminal
What about compression? I thought they must be compressed during charging, or can I compress them afterwords in series?
Thank you very important step ! Most LiFePO4 type cells I have dealt with are only charged to about 80% or so new when shipped. I like to pre test each cell first .bring up than parralo charge . takes more time but can do 4S banks get them over 90% . then let go for a day or 2 in parralo.
Hint. . .put the Positive on one end of the battery and the Negative at the opposite end of the battery. . . . Draw it out on paper. . . . Resistance of the interconnections is balanced this way. . . Better thismway when discharging to.
Did you not read my pinned comment. Current sharing is not an issue when pushing .1-4 amps across 150A bus bars. Attach it wherever you please.
Thanx for this brother Will. I have a 4P4S 12v battery and one of my 4P sets were at 3.7 SOC while the other three were at 3.5 so I am following your vid...
Shalom
Hello, thanks for explaining the procedure. I appreciate your enthusiasm. I have a small question:
Is it safe to keep them charging overnight? Technically, if I keep the supply voltage to 3.6V, then it should be safe, as once all of them charged and balanced, the input current will be o eventually, right? Just wanted to confirm from you who must have been doing this often.
I never do actually. I have a lot of my habits form charging lipoly cells for years. I try to avoid charging unattended often.
It shouldn't take more than a few hours if your cells are at high soc.
@@WillProwse Got it! Thanks :)
Can someone explain to me why 16s equals 48V, if the cells are more than 3V nominal?
You mentioned using a 12v battery (car) charger. Do you still recommend?
I will be using Daly BMS with active Balancer, do I still need to top balance the Cells?
Parallel connections should be connected with the first cell positive and last cell negative to better equalize else like the way t
You had it will full charge the first cell.
I am using two lead acid batteries in series and they are unbalanced. how can I balance lead acid battery ?. is it possible with same way after connecting in parallel and charge it?
How many Ampre (A) need to charger (12v 12Ah) lifepo4 battery?