Top Balancing DIY Lifepo4 Cells and Using Multiple Power Supplies!!

This video shows step by step how I set up my battery for top balancing and goes on to show how I use the previous battery during its capacity test to provide the power for 5 power supplies while they top balance the next battery in this project. I am building 16 of these 14 KWh lifepo4 batteries. Come along for the ride.

[@marktheunitedstatescitezen185]

Thanks Ray ! You’re Wisdom in this area is decades beyond you !

[@USA-GreedyMenOfNoIntegrity]

“Redundancy”...You sounded like a fellow AV8R. Probably one reason why I enjoy your videos. It’s nice to see your sweetheart videographer involved. 80 Amps max for mine. It will sure get them done quickly.

[@appalachianamerican7171]

Appreciate you doing these in real time, for some reason. Showing your mistakes and accomplishments. Thanks Ray

[@TheGurthang99]

Another great video!

[@RayBuildsCoolStuff]

Glad you enjoyed it!

[@michaelivory7606]

Hey Ray...loving this hands on/explanation on the go format....I get so much more out of your videos compared to just others who point and explain....I don't think they are too long at all...there's always f/forward for those that do :)

[@RayBuildsCoolStuff]

you can set it to 1.25 speed and it makes my slow talking sound like when I was younger. hehehe

[@BrianCook-dc8pz]

Thanks Ray. I'm learning so much. I really appreciate your videos.

[@matthewknight5641]

You build the best batteries I've seen on youtube. I'm a truck driver and lately have been delivering huge batteries to the solar fields near Vegas. The batteries are so big that only 2 will fit on my 53 foot flatbed. I'm curious to know what they look like inside the huge metal box enclosure but I'm sure I'll never get to see that. I like the batteries you build and your builds are what I need so bad for my off grid camper that me qnd the wife live in while not on the road in this semi. Hopefully soon I'll have the money together to order cells from alibaba. I'd like a 30 kw battery for powering our minisplit and everything else in the camper. Thanks for all the videos you do. I'm learning alot from you

[@SoutheastOhioSolarHaven]

Great Stuff man. I love your battery build !

[@RayBuildsCoolStuff]

Thanks! 👍

[@flyinguy123]

To get the threaded rod in.....tape some dental floss to the end and then feed through the hole...pull the string...

[@user-mz8mq6xe9p]

Thanks Ray!

[@michaelcoghlan9124]

Very interesting thank you. Michael

[@francoisguyot9770]

Hi Ray, wonderful work you're displaying here. I just wondered why you didn't opt to make a giant 16S16P instead of 16 individual 16S1P batteries. That should meet your redundancy concern better. You would need a fairly large 500A BMS to meet your needs, and a spare one as a spare, but it's less expensive than 16 BMS of 320A. That's the strategy of Tesla to parallel a huge number of small cells into a single giant cell to get each cell to draw as little current as possible, thereby making their battery more robust. With each cell drawing such a small current, the cell should last "forever" maintaining their overall balance of charge.

[@RayBuildsCoolStuff]

Hi François The sales that I am using I am putting into 16 S1P but I am only joining them into a batteries in parallel because I am building two systems. I am using 200 amp BMS. If I need to remove a cell for service it is easy to take one battery off-line. The effective drain on anyone’s cell is the same whether they are in parallel or in multiple batteries that are in parallel after the BMS. There are no commonly available 500 amp BMS on the market. In any case, I would not want to go that route as I feel. It is very important to monitor each cell individually. If you have a cell that is defective but it’s voltage is hiding amongst lots of other cells it could easily go below a safe discharge voltage, but that would not show up because the BMS would be looking at the average voltage of the multiple cells on that cluster. It is always made more sense to me to individually monitor each sale in 16 S1P batteries which are then connected to a single large busbar. That allows you to take batteries off-line if there’s a problem while still having most of your capacity available.

[@francoisguyot9770]

@@RayBuildsCoolStuff Thanks for your fast reply. You're right as far as the 500A BMS: It does not exist. Daly claims having one with such a large continuous discharge current, but it's only for a 4S battery! I did not see that. I understand what you're doing and it makes actually sense too. I assume that the 2 systems have more than just two 16S1P batteries hooked in parallel? Each system has its own 200A BMS and 48V inverter?... because you said you have 16 of those boxes. Am I right? Mine is configured almost like that, except that they're not the same capacity. one is 100Ah and the other is 280Ah. Both have their own ANT BMS. I'm working on a third, which is also a 280 but with a 320A HiBMS (a black Daly?). I joined all the negative to the same bus. But their positive can be paralleled together or separated by switching some DC breakers.

[@carlosdelgado2922]

😊

[@francoisguyot9770]

The Hi-BMS (Daly?) has been working surprisingly well with the Daly bluetooth from Google play on my last 280Ah bank. It recharges it every morning without fault. I could not be happier because it has an active balancer that kicks in when the voltage is high. I actually paralleled it to my other two 48V batteries with Ant BMS, to the Hybrid solar charge controller, the PIP-MG5048 from MPP solar. It really works terrific as an offgrid system. I've been able to almost reduced my bill down to $0 for the past 2 months. I'm still connected to the grid which I cconsider a backup. My wife still likes to cook some stuffs using gas otherwise I'd cancel PG&E. Now, all I need to do is to slowly improving my installation by making it safer and more practical.

[@Michael-xc1ib]

hallo Ray. Ganz große Klasse selbstgebastelt.

[@user-di6oi7ih9s]

it is very nice

[@jeremyallard5449]

Hi Ray fabulous example again. Just a thought. Try making a hook with insulated 10 mm welding rods to assist with the threaded rod inserting on the compression panels.

[@RayBuildsCoolStuff]

Cool, thanks

[@RayBuildsCoolStuff]

I had a duh moment. I can just start the nuts before putting the last two cells in and then there is room to get my hand in to line up the rods. DOH!!!

[@jeremyallard5449]

@@RayBuildsCoolStuff Hi Ray I think your box designs are very clever. Had you ever thought about incorporating strain gauges to check on cell swelling?

[@RayBuildsCoolStuff]

@@jeremyallard5449 not even once my friend. I am a caveman.

[@weeks1871]

Hi Ray, I have a question but first great work on your battery designs. I’ve watched plenty of diy battery builds and no one takes the time and precision you do. Your build quality surpasses anything I’ve seen. I’m looking to build my own as well and your videos have been very informative compared anyone else. Small details are the most important, anyone can slap 16 cells together. Quality is very important for longevity in my opinion. Could you please talk a little about the shunt/display and the other lcd screen in the box. As well as the communication ports you’ve installed on the outside of the box. How are they wired and so forth. Thank you very much for all your detailed work. Please keep it up.

[@RayBuildsCoolStuff]

Hello, and thank you for all the kind words. I’m pretty sure that the way I set up the communication port is shown in one of my battery bill videos. I understand it might be difficult to go try to find it. I hope as soon start making videos again, as I have again been working on the systemand will have progress to show. When that happens, I will remember your request and try to honor it.

[@ceeweedsl]

Looking for a direct informational rundown on top balancing. So far, Ray is a rambling chat format about many things and who knows, maybe there's some top balancing happening for those who have time to let a video run. Will does it so quick and easy that it's hard to know what actually happened and was important. OK, let's go see if off-grid garage gets to the point and brings some information to the table too. Honestly, I miss the days when you could go to a webpage and scan for the part you needed.

[@RayBuildsCoolStuff]

Increase the playback speed.

[@ceeweedsl]

@@RayBuildsCoolStuff Hey Ray. Sorry to be all critical. I appreciate your energy overall and I get the impression that you are an old school Austinite. Like me. Long since gone. Just frustrated trying to get a few key bits of info. Not your job unless you want it. Cheers amigo.

[@AlexM-hc3tm]

Hello Ray. Your Videos are so much useful to build a batterypack for homes. Maybee you can tell whats the reason why the powersupply only charge with 0.28 amps? The whole cells have a load around 3,279 volts, when i plug the 5 amp powersupply on it with 3,65 volts it brings only the 0.28 amps... a massive bigger charger is on the way to me but i think the small one should be able to bring a lot more than the poor 0.28 amps. By the way, i put the amps to maximum on the powersupply. So that is not the reason 😀 Best regards, Alex

[@AlexM-hc3tm]

Hello Ray. Thank you for your great and helpful Videos. Can you tell me how exact do you clamp the cells together. I mean the torque you use on the screws? In the most descriptions there is a torque about 300kgf. But how to get this torque and how to meassure? I plan to build a batterypack with 16 cells like yours but i decided to use 6 threaded rods to clamp. 2 peaces on the outsides and 2 peaces in the middle to get an equal pressure on the whole surface from the cells. Do you have any tips for pressing? Best regards Alex

[@RayBuildsCoolStuff]

If you can spend a little time watching the videos where I assemble the battery packs, including the I love this stuff video I describe my ideas about restraining the battery cells. I don’t want to compress the cells, per se, I really just want to restrain their movement. This is the belief I’ve come to after watching all the different opinions and philosophies out there. So far so good. I use approximately 1 N meter on four rods. I don’t need the other two through bolts to provide the amount of pressure that I desire. I believe there is a lot of over thinking involved in this topic.

[@tootsscaf]

A big thanks from Belgium for making these nice videos! You explain it very well and now i start to see how to make my own battery. Do you leave all the power supplies running until they deliver about 0 amperes? kinds regards, Dirk

[@RayBuildsCoolStuff]

Set the cutoff at 1 amp

[@tomgray2938]

Hi Dirk, today bought 16 cells 280 AH CATL LFP cells, delivered to me in Belgium around the 1ste of dec. I'm following Ray and his work, aiming t to learn from his experience. A journey starts...

[@houseofancients]

nicely done ray.. i may not have put those nuts inbetween those busbars, that could have been a big ol spark ;)

[@RayBuildsCoolStuff]

Yeah I saw that in the video. In real life it didn't seem dangerous. Perhaps like when you are a passenger rather than the driver. The thing is they aren't thick enough to contact the bottom of the bus bar but in the video it looks like they are. Two stacked together might barely reach the lowest bus bars. I won't do it again on camera though.

[@davidaliperti]

so, i buy a certain number of these cells just to reach the wanted DC voltage (example 24 - 48 volts) an inverter and fine? no electronic to help to dialogue between batteries and inverters?

[@RayBuildsCoolStuff]

Please watch my videos for an understanding of the need for a battery management system BMS and the sizing and need for fuses and disconnects along with the best techniques for creating proper electrical connections.

[@tomgray2938]

Hi Ray, after building so much batteries, i was wondering what you think about the use of solid bus bars vs flexible bus bars. You use compression for your cells; what are your thoughts about movement and putting stress into the battery terminals?

[@RayBuildsCoolStuff]

I have videos explaining my position on these issues. I can give the cliff notes version but it will be incomplete. Here goes. I don’t really view it as compression. I use ~1 nm on each of 4 bolts divided by two cells wide. That is very little. Most manufacturers that use these cells actually weld solid bars onto the cells and provide the same type of restraint to their cells. This is in vehicles! Even the bars that are sometimes used that include a small bump in their shape can’t possibly provide much flexibility. The restraint is a gentle hug that will hopefully do two things. It should minimize the strain on the terminals with the rigid busbars and it should also prevent the long term growth from cell cycles. Here’s the deal. Many people use their intuition to foresee problems that don’t actually exist and then create solutions to those problems. It happens in every endeavor I have ever educated myself about. Rigid busbars are used on most of these projects and it isn’t causing actual problems or it would be widely reported and it isn’t. The things that actually do cause problems over and over a short list. 1 wire that is too small 2 bad joints or failing to prevent corrosion. 3 loose terminals 4 failing to provide adequate insulation and isolation. There are a few others but those are the main ones and I have made videos that cover all of it. Enjoy Ray

[@igorkvachun3572]

Yes sistema Akb LiFePo4 🔋 ⚡ 👍

[@Moonlight-zt5uf]

Hello again Ray. I’m still in the process of building a battery for my 48V off grid system. Currently I have 32 cells but am planning on getting another 16 by the end of this month when I can find them. I would prefer to build three separate batteries each with their own separate BMS. But trying to stay in budget here. I’m thinking of building a single battery by doing a parallel/series system and using a single BMS which is a Daly 300A unit. I’m sure it will work but I’m wondering how kosher this is. I can always later break it down into three separate systems with their own BMS which I suspect is the preferred route. My question is, do you see a problem I’m overlooking? Something about this doesn’t feel right to me but I can’t put my finger on it. As always, thanks for taking your time and energy to educate us. It really is much appreciated. Thanks again from sunny Arizona. 🐢🌵

[@RayBuildsCoolStuff]

The reason to use a BMS is to protect your cells from over or undercharging. If you put them in a parallel configuration and one of them has a problem, it can hide behind the other cells and the BMS won't know it is in an over voltage or under voltage condition. I wouldn't do it but others do.

[@Moonlight-zt5uf]

@@RayBuildsCoolStuff Thanks Ray. I suspected as much. I’ll just have to wait until I can pony up enough for two extra BMS’s. Things could get pretty messy with all of the current involved. For now I’ll just do the simple 16 cell build. It will still be superior to the 8 240Ah Trojan lead acids I currently run. 🐢🌵

[@sforce05]

You start making a point at 23:00. Nice vlog but we could be lazy to edit video a 35min long into 12minutes. This is why prowse and off grid andy are preffered because of the effort they are making on editing video

[@RayBuildsCoolStuff]

I don’t even find enough time to make the videos I’d like to make. I resisted making a channel for years because of the time editing takes. I finally gave into the requests to create a channel by deciding to do my videos in one take on my phone without editing. I understand the limits. I’m very grateful for my friends here who are able to tolerate the quality of what I produce. I hope the content will carry the channel and will continue to recommend turning up the playback speed to those that find it tedious. Thanks for caring enough to comment. It means a lot.

[@sforce05]

@@RayBuildsCoolStuff i guess you are more knowledgeable than them. You are also amusing to watch. But sometimes i see you tighten some screws and setting voltage takes more minutes or focusing which some people do not have patience

[@RayBuildsCoolStuff]

Thank you Sly. One thing I noticed is that this video is from two months after I started the channel and almost a year ago. It's changed a little since then as I've tried to consider the concerns like yours about the videos running too long. I'll keep trying to find the right balance between laid back and boring. I'm glad we have different kinds of KZbinrs in this community. I hope I can continue to offer something of value.

[@todamnbad]

So a little off topic but what are the tanks behind you for?

[@RayBuildsCoolStuff]

Blending trimix for technical scuba diving.

[@marktheunitedstatescitezen185]

Good morning Ray , if I could please have like 1 minute of you’re wisdom? I know you covered this 11 hours to charge 13.2 V battery to 3.65v ! I have 20 PCS 280AH 3.2v batteries all in parallel 1 big loop at both ends the positive thought connected in the negative so I connected through battery charger cables ! But the batteries will not go over 3.3v after sitting 24 hour my 2 battery chargers 1 at each end set at the same voltage 3.6 v at the highest pushing into the batteries 28 Amp ! Why does not the battery bank increase Not over 3.3v after the surface charge is gone after about 12 + hours ?

[@RayBuildsCoolStuff]

I I’m sorry, I don’t understand how you have them set up to charge. Are you saying you were using two chargers with a total of 28 A? And you have set the charger to 3.6 V? I would set the charger to 3.65 V which will speed the process up a little bit I would also be patient if the chargers are indicating that they are charging at 28 A. These batteries take a lot of energy to charge. If they are at 50% state of charge, that means each cell would take five hours to fully charge. That would mean you would be looking at 100 hours to charge a parallel bank of 20 of them.

[@marcoarpago]

nice project, need to be more carefull. use glasses to protect your eyes, you connected all in parallel but if you made a mistake huge explosion would occur. Better safe than...

[@RayBuildsCoolStuff]

Thank you for your concern. I only use safety goggles when assembling the pack in series. An arc at 3.2 volts does not create a huge explosion. Perhaps I should reconsider because if my mind is distracted I may forget that I'm in series and act as if I'm in parallel. OK I'll make the change to my protocol.

[@BlakeConnor]

Pull the end cell out start the rod and slip the cell back in

[@SkypowerwithKarl]

Time and amps. You got enough amps to get somewhere. Big cells need it.

[@mattg8787]

to pull up the bars that your using battery cable for i would use something like fishing live in a loop so you can Gide it then cut it

[@RayBuildsCoolStuff]

I just did the next box and I just inserted the rods prior to installing the last two cells. Easy Peasy. Learning everyday

[@mm-wh4jx]

put the 1/16- 16/16 stickers on top of qr codes, they will all be on one line. (Upside down every other) Put red stickers on positive terminals.

[@chris2011ireland]

Is there issue with using several power supplies or do you need a specific type? I'm charging with a 10 amp power supply but have two more on way and hope to use all 3 but hoping haven't missed that you need a specific type?

[@RayBuildsCoolStuff]

If you have a power supply that manages the voltage and reduces the amperage as the voltage gets close to the set point you should be fine. I keep an eye on it as it gets close until I feel I can trust the units.

[@chris2011ireland]

@@RayBuildsCoolStuff thanks a mill Ray appreciate the advice. I ordered two POWERBES DC Power variable supplies. I can't attach the Amazon link on KZbin as gets deleted but that's their description on Amazon. Would these be suitable?

[@PatrickKQ4HBD]

11:00 In Georgia we'd call that "finger-tight".

[@RayBuildsCoolStuff]

It turns out that I can over tighten a little bit by using a deep socket and just tightening by hand. If I really got on it, I could way over tighten it. Hand snug is about right but I prefer tools lol.

[@kimmogensen5390]

hey Ray , good video i have a quick qestion so my main house on my farm burned down i okt last year , and with power being so expensive here my plan is simply to not get connected to the power company again , now the amount of power i use is very limited ,, it is at most 5kw a day in 240v at that power comsumption i pay about 4-5000bucks a year , i figure i could cover most of that with a 4 kw solar array a 1500w 24v istabreeze vindturbine , the qestion is what is the lovest abount of cells i can get by with , i have already purchased 8 280ah cells from jenny in order to make a 24v battery i have 24v mil surplus generators , and i am aware that i am gonna have days without wind and sunlight where i am gonna run these, i also have diesel gernrators for high loads i hoped i could get away with running on 16 cells my normal draw is about 200-250watt as most of my aplianses is propane

[@RayBuildsCoolStuff]

I suspect that you will want to get off the propane refrigerator in the long run as propane can be a volatile market in difficult times. You should build as much storage as possible and consider the possibility that a battery will fail and not be too close to the edge of your critical needs in case a battery must come off line. Where are you approximately located? Your utility cost sounds outrageous.

[@kimmogensen5390]

@@RayBuildsCoolStuff i am located on a small island in the baltic ,called bornholm , it is part of denmark ,power have always been exspensive here but now it is outragius , about 5000bucks a year is where i live now with my freind where we use refrigiration e,c,t about 10-12kw a day our bill is about 5900dkk a quarter yes i know that propane is a problem in the long term , but for heating water and refrigiator short term it is hard to beat,,i have build a woodgas generator so i can run my small generators on that and a older 12v solar and vind system on lead acid batteries , i need to buy more batteries yep,,,

[@RayBuildsCoolStuff]

@@kimmogensen5390 I find the hot water doesn’t use a lot of propane but back in the old days the refrigerator used a lot. Are they much better now?

[@kimmogensen5390]

@@RayBuildsCoolStuff it is just a small refrigirator in a caravan it is fairly economical but very slow to cool down ,, the tankless hot water systems are very good and econimical , but no one uses them here in denmark , most uses elitrical hot water tanks, i have just recived the 1500watt istabreeze windturbine today ,,it seems to be a fairly good peice of kit, unlike most of the cheaper turbines, do you have any exspirence with wind turbines?

[@RayBuildsCoolStuff]

@@kimmogensen5390 I don’t want the noise of a turbine

[@readyhouse]

what happens if you didn't put the dividers?

[@RayBuildsCoolStuff]

The blue plastic wrap is thin and the cell case is conductive. The dividers add a layer of insulation so we can sleep better at night.

[@ronstarner1103]

I am using and do you think it's ok to use plummer's strapping to equalize the cells? Don't have extra buss bars.

[@RayBuildsCoolStuff]

I don’t think you should do that. How many do you need?

[@ronstarner1103]

14

[@ronstarner1103]

Just thought it would be ok for the low amperage

[@ronstarner1103]

All cells tested at same voltage but paralleling them to equalize for 24 hours

[@RayBuildsCoolStuff]

What is the voltage?

[@offgridwanabe]

Nice stuff and no sparks lol

[@JM-yx1lm]

What is your reasoning for using separate bms for each battery module?

[@RayBuildsCoolStuff]

I gave a long response the last time you asked that question. Can you go find where you asked it before please?

[@JM-yx1lm]

@@RayBuildsCoolStuff oh man I apologize, I looked for that message over the next couple days and never could find it or did I see a notification for it. Let me go see again if I can find it.

[@RayBuildsCoolStuff]

@@JM-yx1lm No problem bud. I think youtube is pretty inconsistent about notifications and their comment thread order is also strange. I can't figure it out sometimes.

[@denbeech6647]

Hi Ray. I have tried to google your torque wrench but without success. Would you mind sharing the brand name and model please. Our markets over here are somewhat limited so I would like to use the info to shop for something similar. TIA

[@RayBuildsCoolStuff]

Here is one that is similar. www.amazon.com/MASHA-TOOLS-Bicycle-Maintenance-Mountain/dp/B0B6CJB9PD/ref=sr_1_75?crid=327IHVCR5UC77&keywords=1%2F4%22+torque+wrench+1nm&qid=1671912676&s=hi&sprefix=1%2F4+torque+wrench+1nm%2Ctools%2C142&sr=1-75

[@denbeech6647]

@@RayBuildsCoolStuff a sincere thank you for the response and once again thank you for the excellent videos, your solar build are inspirational.

[@bbrown_sc]

I've read you should put a big diode between the PS and battery or have the PS on when making the connection. Otherwise you can backfeed the PS and blow it up.

[@RayBuildsCoolStuff]

That makes a lot of sense with the cheap ones.

[@Ist_Geheim]

What does the shortcut "PS" mean?

[@schwuzi]

@@Ist_Geheim power supply. the things he sets the voltages at and connects to the battery to charge it.

[@Ist_Geheim]

@@schwuzi Thank you!

[@Ist_Geheim]

If I would buy only 4 cells of LiFePo4 to get one mobile 12V-diy-camping-batterie - how could I check the cells after they arrive and how could I do top-balancing on them without buying equipment that is more expensive then the cells themselves? Do you have any recommendation on "testing & loading-equipment" that works for small batteries and does not cost a lot amount of money?

[@RayBuildsCoolStuff]

Buy a small power supply that will do 5v60a. Use it to top balance the cells. That’s the minimum I would ever consider doing.

[@Ist_Geheim]

@@RayBuildsCoolStuff Thank you, I'll do my research on that.

[@Ist_Geheim]

@@RayBuildsCoolStuff I did some research and what I could find are "laboratory-power-supplies". Most of them have very little amps, even a unit with "0-30V / 0-10A" costs about 150.- The other stuff I mostly find are the power-supplies that are used in computers for example, definitively not what I need. How exactly are the power supplies you talk about called? Maybe you could put a link here (not as a product-recommondation, just for me to get an idea of the kind of product I really have to search for)? (As I said - I'm not building a huge batterie bank, just a small 12V-camping-batterie with 4 cells, and maaaaybe in the future a 24V-blackout emergency system with not more than 16 cells - but I'd like to start cheap).

[@schwuzi]

@@Ist_Geheim Have you found what you were looking for? The lab bench power supply is exactly what you need. Falls du deutsch sprichst, dann such nach Labornetzteilen. 5V 60A sind ziemlich selten, aber zur not tun es auch die mit nur 10A, dauert halt länger.

[@Ist_Geheim]

@@schwuzi Hallo, danke für die Antwort. Tatsächlich habe ich mich zwischenzeitlich dazu entschieden, eine fertige 12V 150Ah LiFePo4 Batterie zu kaufen und habe (neben dem Solar-Laderegler) ein passendes Batterie-Ladegerät mit 25A Leistung dazu gekauft.

[@rickbattle5706]

The battery bank you are building is wired in parallel with the brass bus bars. The bank you are going to top balance with is wired in series. Can you explain why the difference? Thanks. Really appreciate your work.

[@RayBuildsCoolStuff]

I’m confused by your statement. I must be misunderstanding you. Top balancing occurs with the cells in parallel and the cells are charged to 3.65. They are then left to rest after which they are put in series with a BMS to create the 56 volt battery. In this video I use the newly created and fully charged 56 volt(48v nominal) to provide the energy to charge up the top balance on the cells in parallel. I hope I’m not wording this in a confusing way.

[@rickbattle5706]

@@RayBuildsCoolStuff Ray, your explanation is perfect. I did not understand the use of the parallel connections and the series connection. I saw a difference and didn't know why. You explained it perfectly. Many thanks. :-)

[@schwuzi]

@@rickbattle5706 The battery in series is not directly connected to the battery in parallel. The battery in series is connected to an inverter where all the power supplies are plugged in that charge the battery in parallel.

[@josepeixoto3384]

Building them 14 packs for yourself,or you sell them ? tks

[@RayBuildsCoolStuff]

8 for me and 8 for a friend

[@5885ronny]

Hallo 🤗👍

[@aminormaximum2446]

I changed the speed to 1.5X.... much better...

[@jackonthefarm5540]

I must be misunderstanding something... How can you have multiple power supplies connected to the same set of battery cells connected in parallel and have different amperages flowing from the different supplies when all the supplies are set at 3.65 VDC? The delta V between the supplies and the battery cells should determine the amps that flow. I would think all the amps should be the same from each supply. Where is the flaw in my thinking?

[@RayBuildsCoolStuff]

The ampacity of the power supplies will determine the amps supplied by each unit. Keep in mind that different power supplies will handle their constant voltage mode differently but still each unit will supply different amps based on their capacity and control protocols.

[@hydroalternation]

@ 6:34 a playing card would hold rod in place

[@RayBuildsCoolStuff]

Ah and then I can pull it out from the front. Great idea!

[@jmaus2k]

You could double the charging speed just by running the top and bottom in series so your power supplies run at 7V@xA vs 3.5V@xA. Then swap cables to be in parallel when you are close to full. But really, doesn't your BMS handle the top balancing anyway? How close do you really need to be. Just charge the first charge near the top at 1A or something low enough for the BMS to shunt extra balance current before a single cell has a high voltage shutdown.

[@RayBuildsCoolStuff]

My BMS balances at a max of 150ma and only at the top of the charging cycle. On 280AH cells that will take a long long time. How do you do it? What BMS are you using?

[@jmaus2k]

@@RayBuildsCoolStuff I have a similar balancing current BMS and my cells were already really close in charge so 5A initial and 1A over the 3.5V/cell range was good. It will taper current as it gets closer to the max voltage. I really wish these BMS designers would have a higher balance current. 5A at least so a typical charger won't have trouble balancing. And with off grid solar there is no hope in balancing if you just get maybe 1hr of sun charging after full every few days.

[@RayBuildsCoolStuff]

@@jmaus2k you can charge individual cells while in the pack with a PSU but knowing how far to go is a challenge because they drift down after you remove the charger. So much easier to just top balance.

[@9111logic]

Hi Ray, I started the Top Balance but I was worried about living it on during the night in case something went wrong and since I only have two chargers like yours, one 40A and one 5A, it's taking forever. I was wondering if it's a bad idea to interrupt the charge every night and if it would also count as multiple cycles so I don't know if I should risk to live it on charge unsupervised while I'm at sleep. I would appreciate your comment on this. Thanks again 🙏 for your tips that brought me up to this stage safely (so far) 😀 BTW, here's the voltage and resistance readings just before I started - kzbin.info/www/bejne/gn-5pZV3maaki80

[@RayBuildsCoolStuff]

Hello Mario. If you want to play it a little safe, you can leave the 40 amp running overnight and just disconnect the five amp. I have never had a problem with the 40 amp and I haven’t heard of anyone having a problem with them. I’m certain you will be fine.also, it is not a problem to start and stop the charging process. Cycle is only when you charge and then discharge. It is still the same charge cycle even if it is interrupted.

[@9111logic]

@@RayBuildsCoolStuff thanks Ray, I feel better now after what you said 🙏 thanks again 🥰

[@marktheunitedstatescitezen185]

I got my cutting boards from Walmart and inexpensive

[@otukucocker365]

The spacers need to at least be plastic. That paper is probably ruining it.

[@RayBuildsCoolStuff]

It is flexible nylon cutting board.

[@insippo]

Why top balance is needed ? Only if you used cheap bms. Top balancing is wasted money.