When talking about cell compression, that is a COMPLETELY wrong idea. When building a battery, leave them as they came. What the manufacturer of the cells mentions is that you should build a frame around the row of cells, the ends of which can withstand the compression force CAUSED BY THE CELLS. So don't squeeze the cells, but make a frame that can withstand unchanged the compression caused by the tendency of the cells to bulge so that they don't bulge. So here are two completely opposite ideas, one of which is completely wrong. Please stop spreading false information. Take responsibility for what you explain to people who blindly trust you. Do not squeeze cells. but build a compression-resistant frame for them.
@@MR-ub6sq You clearly do not know what you are talking about. Read the datasheet from the manufacturer. The datasheet FROM THE MANUFACTURER states 300kgf for the fixture. That is a measurement of applied force, aka "compression" or "squeezing". I suggest you take a minute to read the specifications before accusing someone of "spreading false information".
@@LithiumSolar 819 / 5 000 Thank you for your wonderful words of wisdom. I want to know the following facts. Could you please tell me these things: - How are you going to measure the fact that you use your frame structure to squeeze the cells into a smaller space than they originally need? So you need a sensor and a measuring device that measures the compression force, with which you can determine when you are stacking cells with the right force? - And how do you implement that compression in practice? That build you have - about 120 cm (about 48 inch) long frame requires you to use a rather special vise / glue gun. Even this is not enough: kivilinna.fi/storage/product_images/9/tuotesivu_Liimapuristin120x1000mm_102379_7010ac858486c06b38016bdc291e4b4c_1.jpg So please make me wise because I am so ignorant. Thanks!
I think the best / most important tip from this video was the cleaning of the terminals w/ fine sandpaper and the use of an anti-oxidant paste. I have 30 years experience as a marine electrician. I would estimate that 90% of the failures I've seen are related to corrosion at terminals and connections. I'm learning a tremendous amount about LiFePo4 from your channel. I live and travel aboard my 40'sailboat and will use this information as I convert from lead-acid batteries to lithium. Best regards from Key West!
Indeed, I replaced my starter when the real issue was first a badly soldiered battery terminal and then a poor ground that jammed before it was seated against the engine block. And terminals can look okay and still not conduct the amperage even when the voltmeter shows full voltage.
One thing you can do is put heat shrink tube on the buss bars leaving 1 inch bare on each end. Cuts down on the exposed metal so only the nuts and studs are exposed.
A note on the steel banding. I had a friend who lost an eye when steel banding snapped, sprung back, and destroyed his eye. It's under a fair bit of tension while compressing the LiFepo4 cells. If it breaks it will spring back and may/will do some damage. We used to use it for placing insulators or mounts on poles. You're much better off using "All-thread" (Threaded rod, bolt rod, etc.) as it simply tends to break in a linear fashion if overstressed . Additionally, you can always tighten or loosen the rods as required.
I found this. Is it suitable? Strapping Kit, Polypropylene, 3000 ft. L www.zoro.com/pac-strapping-products-strapping-kit-polypropylene-3000-ft-l-sp-w/i/G0648772/
@@jimmoore4548 i second this suggestion. any heavy object to fall on or around the batteries could allow the metal strap to rub through battery housing
All thread and a couple steel plates would work well and be easy to disassemble. That and you can dial in the exact pressure you want with a torque wrench.
Just a quick TIP: I like to use dielectric grease (very small amount) when putting studs or similar together. It helps to reduce stripping, cross threading etc, but since its dielectric it doesnt have any negative long term results.
A problem with 2s4p configuration is that you can’t discern individual cell imbalance, which, in my experience with many of these 280AH cells, can be important. I would prefer 4s2p configuration because there will be a dedicated BMS lead to each cell. In your 2s4p configuration, if a cell starts to get weak, you will have a more difficult time troubleshooting the problem. My four 48V batteries, built from these same cells are, 16s.
I like plywood ends and threaded rod. Cheap, very effective, and future adjustable if needed. I do like the look of the bands though, but the cost of it and the tools does detract from the DIY aspect of savings. Plactic non-conductive banding would be super cool.
I prefer a less permanent approach for maintenance reasons. It doesn't look as good, but I'm using a pair of ratchet straps to apply adjustable compression. When I got my cells they were already slightly swollen and I could not even connect the bus bars until I compressed them.
If you don't mind answering, what is the reason to avoid loctite. I am putting my battery in an RV with lots of road vibrations, I was thinking of using lock nuts plus loctite to be extra safe.
thanx mate. like your projects and videos and allways super contious about safety! 2 things I might add: Straps, as you mentioned you dont really know how much pressure you put on those cells. I would not like that. But there are systems out there where you have a 'lock' with screws with 2 advantages: you have more feel for pressure and you can undo them! 2nd: your cutting boards are PE, they get soft when warm real quick. As well, they will dent over time where you put the strap. Meaning the load on the face of the cell is not even. I suggest to put an aditional plane sturdy backing there. piece of thick timber in the size of your cell maybe.
Maybe I should just not use the cutting board at all and use a piece of wood instead? It looks like HDPE can begin to distort under pressure around 70C. I don't thinks it will be getting anywhere near that warm under normal operation? Wood would be considerably cheaper than the cutting board though too.
I like the way you did that. I have eight of those cells I will make a 24v battery but I do like your construction method, This will work great for my cargo trailer.
I'm curious. I also am building a 24V battery with these cells. How big of an inverter are you going to run with it, and what BMS have you found to power it. I haven't bought a BMS yet and need better options. Good Luck with your build too!
Looks nice all banded up. I would have liked to have seen you remove those screws from the board when the cells were compressed. Also interested to hear if the bands become a little slack when at a lower state of charge.
Nothing exciting happened when I removed the screws. The cells were tight but not under pressure. The wood just sat there in its original place once the screws were removed.
I like the metal strap with an isolation shield between the batteries and the strap. Qucc 200a bms is a perfect fit for this batteries and are on sale for 2 more days. But can't charge these batteries above 54v because bms shutdown for 3 min. My batteries 5, 6, 7 and 8 are expanded more than 1/4 gap and never top balanced or abused the cells. I had to replace the metal busbars with #4 cable. Screws were very hard to remove after expanded.
I hope you will be using the same bus bars to connect the 12V 'modules' together in series. Lots of amps going through those module bus bars. Because of that, I would have made a series bank using single cells and then paralleled those series banks together.
Me too. A 16S2P would allow the current in each string to be monitored and you would be able to see if both strings are carrying the same current. Judging by other people’s experiences, getting good contact with the bus bars is a challenge and having cells in parallel, getting consistent losses between parallel cells is going to be important.
Loctite I would assume is an insulator so insulating your electrical connections is not a good idea. Later when you have electrical problems you'll wonder where it comes from
@@eksine Yeah, I considered that. BAre in mind that the locktite only goes on the threads, and remember that the stainless studs cannot carry much if any current - they are relatively high resistance to begin with. The bulk of the current will flow through the interface of the terminal faces and the connector plates and that relies on consistent pressure to remain effective - hence the locktite. Thanks for bring that up by the way!
Great work as always, those cells look hefty. It's probably just me, but metal banding makes me nervous - I'd prefer something non conductive. I see someone else mentioned the plastic banding - I think that'd have to be the way for me on these. Keep up the vids, always great and informative content!
Nice! That is definitely a big battery!!! Also you don't need to tighten the studs at all, they could be loose before you put on the serrated flange nuts. The reason is that you want the nut to pull on the stud sandwiching the bussbar in between the battery terminal and the nut. If the studs are loose you will have to use the allen key to stop it from turning as the nut turns, but as far as the mechanical clamping force it makes no difference. It is similar to how tightening two bolts together on threaded rod works, the serrated flange nut is the top nut, and the battery terminal is the other!
You can hold the stud with an allen key if you use a crow's foot socket. The socket has an offset that will alter the torque but if you do not let the torque wrench ratchet, and keep the socket at 90º to the handle it will be the correct torque.
I’m looking at this same configuration for my charter bus, only in a 24v setup. Looks fancy. I like it. Can’t beat the price of these things especially when it’s the same battery (internals) that some the big battery builders are using. I’ll use the Daly bms
It's great that you focused so much on not overtightening the terminals. I have some similar 120ah cells and I stripped a terminal with very little effort. I had to rethread twice, making it larger each time, and I'm still not satisfied that it will hold. I need to find a new solution that won't damage the battery.
Stainless Helicoils? Or, some kind of epoxy on the threads as long as you don't get any epoxy between the lug or bar and the exposed metal of the terminal(flat part), maybe solder as well? those are a few ideas i thought of.. I wish all these batteries came with the eyebolt style terminals like Battleborn. No way to strip those.
@Randall Marshall I almost stripped one out of the original set of EVEs I tested before I purchased the Basen cells. That's what caused me to be super careful here. Aluminum bends with very little force!
I need to question the validity of folding the original strap UNDER the clamp at 5:18 but fold the second part of the strap OVER the clamp at 8:55. As others have stated, a nylon strap would provide more advantages than the metal one. When putting on the anti-oxidant compound, don't use your fingers. Sweat has a ph that could be as low as 4.5 and oils that will corrode metal. Use neoprene gloves to prevent that and possibly a solvent agent [as acetone or alike].
If you had at least some foam sheet in between...and you tested its deflection under the 12psi load.... you would be able achieve your target psi (~load) by measuring its deflection while tensioning the bands. I'm thinking of using "infinite" worm band clamp strapping.
The Band -it strap is a good idea and an easy way to compress them but what happens if after you tighten them you noticed that one cell was placed in the wrong polarity or if with time you need to service them and maybe swap a battery. Then at that point the band-it strap would be a waste of money. Maybe another idea would be to use some threaded rods (4 in total) on the sides to compress them.
yea I think threaded rods would be another great solution, you could use a torque wrench to get each bolt the equal and correct torque. If I remember right there was another UA-camr that used threaded rods.
oh nevermind, this is the video I was thinking of, he talks about expansion but not about compressing prismatic cells, as his are cylindrical and are already compressed to spec. ua-cam.com/video/kYx097cVR48/v-deo.html
@@LithiumSolar another thing that you could have done is replace the bands with threaded rod from the hardware store and use two nuts at the end that way you can provide your own torque spec and it's more accurate and you can remove it more easily. Just use longer aluminum bars and drill holes into them for the nuts and threaded rod
@@eksine Yep, like I said this is definitely not the cheapest route. I wanted to try banding them like I've seen commercial batteries done and see how it would work out compared to the threaded rod. The threaded rod is not only cheaper but much easier to assemble as the rod isn't super springy like the band is.
You did a perfect job! Thank you for not using loctite. you DONT need it and it shouldn't be used here. This is exactly what I did with my first packs, still going strong. We all NEED to use those extra cycles. The only thing I never did was torque mine down. I did it by feel from making so many batteries and crimp connections in my life. Never got hot terminals or fire or anything. I've also worked on aluminum motor blocks with threads equally as soft as these so I get it 100% why you'd use a torque wrench because most haven't ever stripped one :P
@@librulcunspirisy Its just not needed. Its not like your going to just slap cells into the trunk of a car and go slamming down bumps on the road. The terminals aren't a moving part nor are they under any stress. torque em and be done. The only thing you should apply is anti corrosive for aluminum to copper on the terminals. Build your pack once right, compress the cells and your good till they die and you recycle it in a decade or two
FYI... I had similar looking cells (144 of them). I welded an aluminum cage out of angle iron just to retain the cells in position. I put the whole thing in the car I was building. After first drive, the batteries swelled up so much that the welds were broken and angle iron looked mangled up. I got batteries replaced under warranty.
Ouch... Were they accidentally overcharged or undercharged? Would you mind sharing where you bought them? Was it where I got mine (Shenzhen Basen)? It must have taken a LOT of force to break that.
@@LithiumSolar I had not yet installed the charger so they were not overcharged, and I was careful not to over-discharge by only driving about 4 miles out of the 130-mile range of the pack. I had purchased them from "Electriccarparts.com". They had everything fail from their Chinese source of these batteries so they didn't argue with me, but they couldn't afford to make good on $11,000 worth of batteries right away. Since we were facing the winter months I said it was OK to make good in the spring. They did so with a different brand of prismatic battery. I don't know the name of the Chinese source for either battery. I will look for evidence I might have in my shop. The boxes likely had the name. That force involved in swelling is no joke.
If you want to cover the exposed metal on the parallel and series connections you can have some custom made 3D printed covers. You can easily design yours in Tinkercad
@@LithiumSolar Get a Prusa, definitely worth the money. 3DXTech in Michigan has Electric Safe Filament in different types, PLA, ABS, etc. Great company.
great video, man. Really learned a lot from your side comments here and there. Just speak your mind when making videos and you help a lot of beginners like me. I made the jump straight to a 16s batt and what you are doing is very very interesting.... may order another 16
@@kusnezoff8705 thanks for your reply. I think he's making the 12v blocks to make them easier to move around. I have 16 of them and they are very heavy. Really if he uses a 16s bms he should be fine, since each pair of parallel cells will always be balancing with each other even if their internal impedance is different. That's great you took elec. In school. I worked on avionics for a decade.
@@brothertyler I see a lot of guys putting 12 volts banks together and then hooking them up so that they don't balance correctly like using those stupid battle born expensive pieces of junk that will not last. as a 12 volt drop in they are ok but when you put them into a battery bank you are doing it ass backwards. I think I see what he is doing now. I was just really concerned that he was doing it wrong and leading others to do it wrong as well. I think I see what he is going. as long as he hooks them up the right way it will be good. I bought 202ah cells Lishen in China. I am living here for now will leave when we get the chance to go with this stupid virus/flu. anyway. I will be putting 5 of mine together and then hooking those 5 groups in series of 8 making a 24 volt system. I will be using Electodacus's products solid states mini inverter type things to bring the power from the PV panels to the battery bank and he also has a great BMS system that is also solid state and all of his stuff will last the life of me and my children LOL. I wish people would make their own battery banks instead of buying those 12 volt premade expensive things they are throwing the money away. One thing you should do it use cables to connect your cells and not the busbars if you are compressing. the busbars will eventually damage the terminals overtime with micro expansion movements. that is the latest thing that most people are steering away from now as it will damage the cells in time. his banding is interesting but I will use stainless plates and threaded bars with a motorcycle clutch spring on one end so if it wants to expand it can and when it goes back it isn't over compressed which is also back for the cells not enough compression too much compression. its a nighmare LOL. have a great day. I need to go to sleep. well I might as well stay up I guess. another night of insomnia. it sucks. 5:21am here
@@brothertyler make sure you order another 16 while you can. who knows when things will go nuts with politics these days. I may be able to get you a better deal if you want me to try as I am over here already. but if you don't its no worry. I got my 202ah cells with a 5 year warranty. how long was the warranty they offered you for your cells?
To measure the pressure you are wanting to achieve, you could build a mockup of the battery's, insert an ac refrigerant scale in the middle. Then tighten it to the spec you mentioned. Then, use some type of fairly accurate tension scale or tensiometer to measure the force exerted on the band at a certain amount of deflection, and then just duplicate that on each set of cells.
Looking good! I'm considering compression like this. I like this design alot thanks for the great ideas. So far just capton taped mine. Cheers and sunny day!
The cutting board is HDPE. One could easily make it a bit taller and add a kerf cut to it. I have been using HDPE, including 'Starboard' brand for a variety of projects, and I plan to use it in my own battery build. It is very easy to work with, except that it cannot be glued. Wood screws work very well, though, especially if you heat them up first:)
I did think about this, which would significantly cut down on the exposed metal, but it still leaves the bolt chunks exposed. I really want to get everything covered but may be impractical without a 3D printer or something to do custom work (don't have the equipment or the time).
Pretty neat solution there I just did the same thing with 8 25Ah cells for a 12v 50Ah So smaller but about the same I did not use any separator I figure if they are tight they should not be able to move and wear thru I do plan on using something on the bottom because the heat shrink doesn't go all the way around the bottom and it will set in a steel enclosure for a gate with a camera and stuff
I completely like the banding tool setup. You should go on Wills forum and offer the tool for a rental trade setup. I like to charge full price for the tool, and refund most when he tool comes back. You could even charge for the banding cut to length for the rental.
That's a neat idea, but don't trust people with my tools/equipment enough - even with a deposit. Only way I would consider it is if there was someone local who wanted to borrow, but haven't seen too many others in my area building battery banks unfortunately.
@@LithiumSolar I agree there. Usually, the tool is sold full replacement prices the renter, and a weekly fee is deducted from the refund price after returned. Just a thought.
Giant zip ties. I have a bunch of 3/8ths wide 60" long zip ties. I'm sure they sell them longer and wider. Using a ziptie gun you can dial in the tension, or just use pliers.
I am very interested in replicating your build to take advantage of super off peek hour in my state. Can you please make a video of the 4 12v 560ah battery's being hooked up to a bms. Also if you include everything being hooked up to the inverter and finally the breaker box that would be great. Thanks for all your help.
You probably have a hole lot more compression pressure on the batteries than you think , the sound of the band tells me that . I have a bandit tool like that and it can clamp things very tight , remember that is a bolt and crank that is pulling the band , plus a two to one ratio , because of the full circle , just like a pulley on a loaded with a rope . I have slit a 3" metal pipe and shrunk it smaller diameter with this tool . It can pull a band till it breaks , that a lot of pull.
I have 8 of the same cells. The included studs seemed like cheap stainless so I cut replacements from good quality machine screws and used JB Weld to secure them. Im using a similar compression method but with 180# zip ties, 5 rows of em. Theyre going into a couple of seahorse cases, theyll just barely fit. Made some flexible buss bars out of grounding straps and copper pipe couplers. Those are easy to make smash the couplers on the ends solder on with a torch heat shrink across the middle. Top balancing taking forever with 5amp power supply I had bought a 60a BK 1900B power supply off ebay 275 used great deal but was DOA seller refunded no problem. That was gonna be my charger too so gotta keep looking.
You get other clips for steel banding that use a grubscrew to hold. Can be easier to use, but I'd probably just use small ratchet straps myself. Have the benefit of being non conductive and likely cheaper.
That's a great idea! I did look at those initially but couldn't find anywhere to buy them at the right price. Perhaps I didn't spend enough time looking...
Lithium battery will not discharge fast They say that lithuim battery can hold a charge of 80% While agm,gel and flooded battery will only hold A 50% charge And i think it is true Cause my lithium battery will not discharge easily
Crazy idea for covering the connections for safety: Determine the proper diameter of PVC pipe that when cut in half will cover the connections and touch the battery. The stuff is cheap and readily available. Cut the pipe to the correct length and cut in half and secure to the battery banks with tape. This would allow for cables connecting each bank to exit out the end as well. For one additional level of safety add a cap to the end of the pipe that won't have wire coming from it. PVC is easily drilled for passing the BMC connections through it as well. Thoughts?
that strap is a nice touch. the tools to do it is costly. the strap would still work if you used turnbuckles like made for a screen door. self tightening. i enjoy this video and its really good for me i plan to do the same thing
@@LithiumSolar you did it right.the reason you scuffed the battery post was to removed oxidation. There is no oxidation on nickel , which is exactly why it's there. Some people have ocd and when they see it done to 1 they think the other has to be done too. You didn't scuff the battery post to paint it, just removed slight oxidation.
You are awesome. I am going to order these for my next campervan. at the moment i try to make a 12v out of old 18650 laptop cells. maybe you can do a video about how to do a 12v battery for camping out of 18650 because the informations on the internet about this are really rare but the price for such a diy is attractive. especially if you would choose 3s or 4s configuration and how you would achieve the best range for the 18650 to use within the 12v range.
There isn't much out there on LCO/NMC for 12V applications because the voltages don't work out very well. The voltage is typically too low on a 3s system and too high on a 4s system. The optimal solution if using 3.7V batteries is a 24V 7s system or to use another chemistry, such as 3.2V LiFePO4 where the voltage works out perfectly for 12V applications.
I definitely wouldn't band the battery packs together for fear of restricting the expansion. But lithium is half black magic so nobody actually has the answer. Another thing that you could have done is just go to the hardware store and buy some threaded rods and just drilled a hole to the aluminum and then put nuts on both ends that way you can easily remove the clamping Force plus it's probably cheaper too. Also for my final setup I'm not using bus bars because that provides a rigid point of failure. Wires provide more flex
I don't think the end pieces are stiff enough to not bend and end up putting most of the force on the outer edges of the cells. From time to time I would put a straight edge across those aluminum and plastic pieces to see if they are bending. Most all of the force from the bands is going to the edges. You could add some shims under the bands to better even out the pressure.
I ended up changing my design in the final build. I'm using 3/4" plywood, 1/8" angle aluminum, and threaded rods. The idea here was fun to try but had too many concerns with it the more I worked with it.
I didn't even think to check plastic options because of the assumption metal would be stronger. The strap I used is rated for ~1500lbs breaking capacity.
@@LithiumSolar This is what I found IDL Packaging - MiniCW34 3/4" x 250' Mini Woven Cord Strapping Roll, 2400 lbs - Break Strength, I find it hard to believe that the cord is better than the metal as far as breaking strength. But the cord is way less cost at $31.
@@LrbinMT Interesting. That is significantly cheaper and stronger. I wonder if woven strap like that would stretch over time and loose the compressed force though? Like over the course of 5+ years? It may be worth trying it out though.
@@LithiumSolar You are correct, steel is best for retention of tension at 95%, polyester 70%, polypropylene 25% according to strapping tools and parts . com
very nice build and extremely informational as always! I have a non battery related note though... I'd appreciate it if you'd make the audio in your videos mono and just in the center because I find stereo distracting and also all UA-cam video pros record speech in mono, which is probably for a good reason.
I know, it's extremely annoying to myself as well. I bought a new camera a few months ago and it has no way to disable stereo mode... nor does my editing software have a way to mix the two channels. I'll have to figure something out. Sorry, and thank you for the feedbacks :)
so its going to be a nearly 30 kw battery and is under 3 grand? (unless my math is off). It seems like the whole 18650 battery pack for solar power systems game isn't really worth it anymore, but I'm still learning. Either way exciting times for all of the options available now.
The batteries were somewhere around $3450 by the time taxes, fees, etc were factored in. Including cost of additional parts like the straps and BMS, I'd estimate it comes in just under $4000.
great video. Like the plastic between the + & - sides of the batteries. and the thicker plastic on the ends. As others have suggested I think the banding idea is not great and a treaded rod solution would have been simpler and easier to implement. But it does look neat :)
@@LithiumSolar Ah cool. Thanks for inspiring here. I am thinking of doing a very similar setup soon. These batteries seem to be the best option available for most people.
Why the metal band if there are fiber/plastic ones too, that have around the same or even more strenght? And fiber ones aren't conductive and can't cut the shrinkwrap shielding.
Great info for new builders. I'm waiting on these same Batteries to be delivered for a 24v Magnum Inverter. i couldn't find any info whether a BMS would handle putting these in series / parallel.
Hello! Great work! I could not find next video - bms install on this set. I want to repeat this project 12.8V 560Ah 4s2p. Can you please send a direct link?
I like what i see..im living in 40' bighorn trailer after a house fire. Im in eastern Ontario, Canada. There is a microwave/ convection oven, gas stove, gas/AC mid size fridge freezer, two tvs, AC fireplace, gas furnace/ AC with blower, water heater, air condition, 110 outlets..charge phone and laptop..and when i run genni, 1500 watt space heater. I am currently getting power from a 12k king canada(runs on propane and petrol) genni 1 worn out agm. I have considerable power needs, without giving you all the numbers. I want to build a bank that can be charged, using approx. Maybe 4 solar panels( 1600 watts approx).. And run my genni when needed
I think I would try using a pipe clamp.to.clamp the cells together and then use a cloth tape to tape the cells together. Makes it easier to break the bank apart when one cell goes bad.
Over thought that one. Should have used some all thread in conjunction with a piece of timber at the end of the timber frame you had the cells in. Like a paper press.
Setup the 12 volt battery with 8 cells as you described the connection. I setup the jkbms connecting all the positives to the battery. Changed the parameters to 8 cells. The bms recognize 4 cells. Look for your video on the subject, no luck yet. Can you tell me how to setup the jkbms on this 12volt battery? Thanks for your video.
sir i suggest next time.. is btter to make are base to put the battery ,it prevent the bottom of the sell from rubbbing@the cell case is thin also sir you can put are bolt n nat on the cutting board then the other side the same way its like are vice🤣 this way you can compress you sel evently.. the expose bolt you can cover its using are plastic pipe or host.. btw sir keep the nice job n god bless you
I was wondering how this pack has worked out over time. Have you had any issues with keeping the pack balanced? I'm building an identical pack now, and I wonder if it would be better to build 2 batteries and parallel them.
The batteries are still working great, though I've been through quite a few pack designs since this video. The latest is shown in this video ua-cam.com/video/xZ_uL2tPO0I/v-deo.html at the 5:55 marker.
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When talking about cell compression, that is a COMPLETELY wrong idea. When building a battery, leave them as they came. What the manufacturer of the cells mentions is that you should build a frame around the row of cells, the ends of which can withstand the compression force CAUSED BY THE CELLS. So don't squeeze the cells, but make a frame that can withstand unchanged the compression caused by the tendency of the cells to bulge so that they don't bulge. So here are two completely opposite ideas, one of which is completely wrong. Please stop spreading false information. Take responsibility for what you explain to people who blindly trust you. Do not squeeze cells. but build a compression-resistant frame for them.
@@MR-ub6sq You clearly do not know what you are talking about. Read the datasheet from the manufacturer. The datasheet FROM THE MANUFACTURER states 300kgf for the fixture. That is a measurement of applied force, aka "compression" or "squeezing". I suggest you take a minute to read the specifications before accusing someone of "spreading false information".
@@LithiumSolar
819 / 5 000
Thank you for your wonderful words of wisdom. I want to know the following facts. Could you please tell me these things:
- How are you going to measure the fact that you use your frame structure to squeeze the cells into a smaller space than they originally need?
So you need a sensor and a measuring device that measures the compression force, with which you can determine when you are stacking cells with the right force?
- And how do you implement that compression in practice?
That build you have - about 120 cm (about 48 inch) long frame requires you to use a rather special vise / glue gun. Even this is not enough: kivilinna.fi/storage/product_images/9/tuotesivu_Liimapuristin120x1000mm_102379_7010ac858486c06b38016bdc291e4b4c_1.jpg
So please make me wise because I am so ignorant. Thanks!
I think the best / most important tip from this video was the cleaning of the terminals w/ fine sandpaper and the use of an anti-oxidant paste. I have 30 years experience as a marine electrician. I would estimate that 90% of the failures I've seen are related to corrosion at terminals and connections.
I'm learning a tremendous amount about LiFePo4 from your channel. I live and travel aboard my 40'sailboat and will use this information as I convert from lead-acid batteries to lithium. Best regards from Key West!
Excellent perspective
Indeed, I replaced my starter when the real issue was first a badly soldiered battery terminal and then a poor ground that jammed before it was seated against the engine block. And terminals can look okay and still not conduct the amperage even when the voltmeter shows full voltage.
One thing you can do is put heat shrink tube on the buss bars leaving 1 inch bare on each end. Cuts down on the exposed metal so only the nuts and studs are exposed.
A note on the steel banding. I had a friend who lost an eye when steel banding snapped, sprung back, and destroyed his eye. It's under a fair bit of tension while compressing the LiFepo4 cells. If it breaks it will spring back and may/will do some damage. We used to use it for placing insulators or mounts on poles. You're much better off using "All-thread" (Threaded rod, bolt rod, etc.) as it simply tends to break in a linear fashion if overstressed . Additionally, you can always tighten or loosen the rods as required.
If you want look into plastic banding. Used to ship loads and is friction welded with a banding gun. Non conductive and super strong.
I found this. Is it suitable? Strapping Kit, Polypropylene, 3000 ft. L www.zoro.com/pac-strapping-products-strapping-kit-polypropylene-3000-ft-l-sp-w/i/G0648772/
@@jimmoore4548 i second this suggestion. any heavy object to fall on or around the batteries could allow the metal strap to rub through battery housing
All thread and a couple steel plates would work well and be easy to disassemble. That and you can dial in the exact pressure you want with a torque wrench.
Just a quick TIP:
I like to use dielectric grease (very small amount) when putting studs or similar together. It helps to reduce stripping, cross threading etc, but since its dielectric it doesnt have any negative long term results.
Looks super sharp! In the good way.
Yeah!
A problem with 2s4p configuration is that you can’t discern individual cell imbalance, which, in my experience with many of these 280AH cells, can be important. I would prefer 4s2p configuration because there will be a dedicated BMS lead to each cell. In your 2s4p configuration, if a cell starts to get weak, you will have a more difficult time troubleshooting the problem. My four 48V batteries, built from these same cells are, 16s.
i think threaded rod to compress is much easier, safer and can be adjusted and undone with no problem
I agree, threaded rod would have been easier.
I like plywood ends and threaded rod. Cheap, very effective, and future adjustable if needed. I do like the look of the bands though, but the cost of it and the tools does detract from the DIY aspect of savings. Plactic non-conductive banding would be super cool.
Thanks for this. I have to parallel sets up to 36, 108vdc, 560ah with an OrionBMS2. Safety is key.
I prefer a less permanent approach for maintenance reasons. It doesn't look as good, but I'm using a pair of ratchet straps to apply adjustable compression. When I got my cells they were already slightly swollen and I could not even connect the bus bars until I compressed them.
@john doe this is really not the place for that question. You should join a solar discord or something like that.
Definitely the right approach not using loctite. Your approach to the cells looks good!
If you don't mind answering, what is the reason to avoid loctite. I am putting my battery in an RV with lots of road vibrations, I was thinking of using lock nuts plus loctite to be extra safe.
Very cool setup, I follow your channel closely for a few months now. Great work here!
thanx mate. like your projects and videos and allways super contious about safety!
2 things I might add: Straps, as you mentioned you dont really know how much pressure you put on those cells. I would not like that. But there are systems out there where you have a 'lock' with screws with 2 advantages: you have more feel for pressure and you can undo them!
2nd: your cutting boards are PE, they get soft when warm real quick. As well, they will dent over time where you put the strap. Meaning the load on the face of the cell is not even. I suggest to put an aditional plane sturdy backing there. piece of thick timber in the size of your cell maybe.
Maybe I should just not use the cutting board at all and use a piece of wood instead? It looks like HDPE can begin to distort under pressure around 70C. I don't thinks it will be getting anywhere near that warm under normal operation? Wood would be considerably cheaper than the cutting board though too.
I like the way you did that. I have eight of those cells I will make a 24v battery but I do like your construction method, This will work great for my cargo trailer.
I'm curious. I also am building a 24V battery with these cells. How big of an inverter are you going to run with it, and what BMS have you found to power it. I haven't bought a BMS yet and need better options. Good Luck with your build too!
Looks nice all banded up. I would have liked to have seen you remove those screws from the board when the cells were compressed. Also interested to hear if the bands become a little slack when at a lower state of charge.
BooM !
@@onthelake9554 💥💥💥💥💥🤣🤘
Busbars are a silly idea introduces a hard stress point. Wires are way better. I'm also not good with clamping the shit out of your batteries.
@@eksine Good point. Bus bars should be arched to allow for expansion and contraction.
Nothing exciting happened when I removed the screws. The cells were tight but not under pressure. The wood just sat there in its original place once the screws were removed.
I like the metal strap with an isolation shield between the batteries and the strap.
Qucc 200a bms is a perfect fit for this batteries and are on sale for 2 more days.
But can't charge these batteries above 54v because bms shutdown for 3 min.
My batteries 5, 6, 7 and 8 are expanded more than 1/4 gap and never top balanced or abused the cells.
I had to replace the metal busbars with #4 cable. Screws were very hard to remove after expanded.
very clear video, where can I find the video about placing the BMS?
I hope you will be using the same bus bars to connect the 12V 'modules' together in series. Lots of amps going through those module bus bars. Because of that, I would have made a series bank using single cells and then paralleled those series banks together.
Me too. A 16S2P would allow the current in each string to be monitored and you would be able to see if both strings are carrying the same current. Judging by other people’s experiences, getting good contact with the bus bars is a challenge and having cells in parallel, getting consistent losses between parallel cells is going to be important.
Nice electrical and mechanical setup. I'll be using locktite because my application is in a offroad camper...plenty of bolt loosening vibration!
Loctite I would assume is an insulator so insulating your electrical connections is not a good idea. Later when you have electrical problems you'll wonder where it comes from
@@eksine Yeah, I considered that. BAre in mind that the locktite only goes on the threads, and remember that the stainless studs cannot carry much if any current - they are relatively high resistance to begin with. The bulk of the current will flow through the interface of the terminal faces and the connector plates and that relies on consistent pressure to remain effective - hence the locktite. Thanks for bring that up by the way!
@@MiniLuv-1984 I haven't understood why people keep pointing out the insulative properties of loctite, for the exact reason you pointed out...
@@LithiumSolar Its all good - we all learn from each other and you.
Great work as always, those cells look hefty. It's probably just me, but metal banding makes me nervous - I'd prefer something non conductive. I see someone else mentioned the plastic banding - I think that'd have to be the way for me on these. Keep up the vids, always great and informative content!
040521/0042h PST 🇺🇸 I was under the impression that metal strips are for securing shipments and lumbar, wow amazing now, batteries too? Good job🤣
Heat shrink the bands
Nice! That is definitely a big battery!!! Also you don't need to tighten the studs at all, they could be loose before you put on the serrated flange nuts. The reason is that you want the nut to pull on the stud sandwiching the bussbar in between the battery terminal and the nut. If the studs are loose you will have to use the allen key to stop it from turning as the nut turns, but as far as the mechanical clamping force it makes no difference. It is similar to how tightening two bolts together on threaded rod works, the serrated flange nut is the top nut, and the battery terminal is the other!
You can hold the stud with an allen key if you use a crow's foot socket. The socket has an offset that will alter the torque but if you do not let the torque wrench ratchet, and keep the socket at 90º to the handle it will be the correct torque.
Thanks for showing your banding process. I am happy to have used threaded rods instead.
Yep I ended up not going with the banding and used 3/8" threaded rod instead :)
I’m looking at this same configuration for my charter bus, only in a 24v setup. Looks fancy. I like it. Can’t beat the price of these things especially when it’s the same battery (internals) that some the big battery builders are using. I’ll use the Daly bms
It's great that you focused so much on not overtightening the terminals. I have some similar 120ah cells and I stripped a terminal with very little effort. I had to rethread twice, making it larger each time, and I'm still not satisfied that it will hold. I need to find a new solution that won't damage the battery.
Stainless Helicoils? Or, some kind of epoxy on the threads as long as you don't get any epoxy between the lug or bar and the exposed metal of the terminal(flat part), maybe solder as well? those are a few ideas i thought of.. I wish all these batteries came with the eyebolt style terminals like Battleborn. No way to strip those.
The torque specification is less than 8Nm. The 35 inch pounds you have used is 47Nm. It seems you have over torqued them.
@@stuartsmith945 The 35 inch-pounds I used converts to 3.95Nm. I think something is wrong with your conversion somewhere?
@Randall Marshall I almost stripped one out of the original set of EVEs I tested before I purchased the Basen cells. That's what caused me to be super careful here. Aluminum bends with very little force!
@@LithiumSolar I used google to convert. Very strange.
Thanks for all the videos and wealth of information. They helped us pull the trigger on our 36 cell purchase.
I need to question the validity of folding the original strap UNDER the clamp at 5:18 but fold the second part of the strap OVER the clamp at 8:55.
As others have stated, a nylon strap would provide more advantages than the metal one.
When putting on the anti-oxidant compound, don't use your fingers. Sweat has a ph that could be as low as 4.5 and oils that will corrode metal. Use neoprene gloves to prevent that and possibly a solvent agent [as acetone or alike].
If you had at least some foam sheet in between...and you tested its deflection under the 12psi load.... you would be able achieve your target psi (~load) by measuring its deflection while tensioning the bands. I'm thinking of using "infinite" worm band clamp strapping.
Looks good. It’s going to be a nice big and safe battery!
The Band -it strap is a good idea and an easy way to compress them but what happens if after you tighten them you noticed that one cell was placed in the wrong polarity or if with time you need to service them and maybe swap a battery. Then at that point the band-it strap would be a waste of money. Maybe another idea would be to use some threaded rods (4 in total) on the sides to compress them.
yea I think threaded rods would be another great solution, you could use a torque wrench to get each bolt the equal and correct torque. If I remember right there was another UA-camr that used threaded rods.
oh nevermind, this is the video I was thinking of, he talks about expansion but not about compressing prismatic cells, as his are cylindrical and are already compressed to spec. ua-cam.com/video/kYx097cVR48/v-deo.html
You should be able to determine(with relative accuracy) the tension of the band by recording the frequency the band makes when you pluck it.
Interesting idea. I'm sure there are phone apps I could use for that! I'll have a look and see what I can find.
@@LithiumSolar another thing that you could have done is replace the bands with threaded rod from the hardware store and use two nuts at the end that way you can provide your own torque spec and it's more accurate and you can remove it more easily. Just use longer aluminum bars and drill holes into them for the nuts and threaded rod
@@eksine This is the most economical way to solve the batteries compression problem. I'll do it this way instead.
@@eksine Yep, like I said this is definitely not the cheapest route. I wanted to try banding them like I've seen commercial batteries done and see how it would work out compared to the threaded rod. The threaded rod is not only cheaper but much easier to assemble as the rod isn't super springy like the band is.
@@eksine
my sentiments exactly
You did a perfect job! Thank you for not using loctite. you DONT need it and it shouldn't be used here. This is exactly what I did with my first packs, still going strong. We all NEED to use those extra cycles. The only thing I never did was torque mine down. I did it by feel from making so many batteries and crimp connections in my life. Never got hot terminals or fire or anything. I've also worked on aluminum motor blocks with threads equally as soft as these so I get it 100% why you'd use a torque wrench because most haven't ever stripped one :P
What's the reason for not using loctite? Thanks
@@librulcunspirisy Its just not needed. Its not like your going to just slap cells into the trunk of a car and go slamming down bumps on the road. The terminals aren't a moving part nor are they under any stress. torque em and be done. The only thing you should apply is anti corrosive for aluminum to copper on the terminals. Build your pack once right, compress the cells and your good till they die and you recycle it in a decade or two
FYI... I had similar looking cells (144 of them). I welded an aluminum cage out of angle iron just to retain the cells in position. I put the whole thing in the car I was building. After first drive, the batteries swelled up so much that the welds were broken and angle iron looked mangled up. I got batteries replaced under warranty.
Ouch... Were they accidentally overcharged or undercharged? Would you mind sharing where you bought them? Was it where I got mine (Shenzhen Basen)? It must have taken a LOT of force to break that.
@@LithiumSolar I had not yet installed the charger so they were not overcharged, and I was careful not to over-discharge by only driving about 4 miles out of the 130-mile range of the pack. I had purchased them from "Electriccarparts.com". They had everything fail from their Chinese source of these batteries so they didn't argue with me, but they couldn't afford to make good on $11,000 worth of batteries right away. Since we were facing the winter months I said it was OK to make good in the spring. They did so with a different brand of prismatic battery. I don't know the name of the Chinese source for either battery. I will look for evidence I might have in my shop. The boxes likely had the name. That force involved in swelling is no joke.
If you want to cover the exposed metal on the parallel and series connections you can have some custom made 3D printed covers. You can easily design yours in Tinkercad
I thinks it may be time for me to invest in a 3D printer...!
@@LithiumSolar Get a Prusa, definitely worth the money. 3DXTech in Michigan has Electric Safe Filament in different types, PLA, ABS, etc. Great company.
Why not just use U-shaped plastic conduit? Just find the right size that tightly slides over the busbars.
great video, man. Really learned a lot from your side comments here and there. Just speak your mind when making videos and you help a lot of beginners like me. I made the jump straight to a 16s batt and what you are doing is very very interesting.... may order another 16
@@kusnezoff8705 thanks for your reply. I think he's making the 12v blocks to make them easier to move around. I have 16 of them and they are very heavy. Really if he uses a 16s bms he should be fine, since each pair of parallel cells will always be balancing with each other even if their internal impedance is different. That's great you took elec. In school. I worked on avionics for a decade.
@@brothertyler I see a lot of guys putting 12 volts banks together and then hooking them up so that they don't balance correctly like using those stupid battle born expensive pieces of junk that will not last. as a 12 volt drop in they are ok but when you put them into a battery bank you are doing it ass backwards. I think I see what he is doing now. I was just really concerned that he was doing it wrong and leading others to do it wrong as well. I think I see what he is going. as long as he hooks them up the right way it will be good. I bought 202ah cells Lishen in China. I am living here for now will leave when we get the chance to go with this stupid virus/flu. anyway. I will be putting 5 of mine together and then hooking those 5 groups in series of 8 making a 24 volt system. I will be using Electodacus's products solid states mini inverter type things to bring the power from the PV panels to the battery bank and he also has a great BMS system that is also solid state and all of his stuff will last the life of me and my children LOL. I wish people would make their own battery banks instead of buying those 12 volt premade expensive things they are throwing the money away. One thing you should do it use cables to connect your cells and not the busbars if you are compressing. the busbars will eventually damage the terminals overtime with micro expansion movements. that is the latest thing that most people are steering away from now as it will damage the cells in time. his banding is interesting but I will use stainless plates and threaded bars with a motorcycle clutch spring on one end so if it wants to expand it can and when it goes back it isn't over compressed which is also back for the cells not enough compression too much compression. its a nighmare LOL. have a great day. I need to go to sleep. well I might as well stay up I guess. another night of insomnia. it sucks. 5:21am here
@@brothertyler make sure you order another 16 while you can. who knows when things will go nuts with politics these days. I may be able to get you a better deal if you want me to try as I am over here already. but if you don't its no worry. I got my 202ah cells with a 5 year warranty. how long was the warranty they offered you for your cells?
I’m curious to see what you are going to do for BMS! Love the detail in the videos! Subscribed
My question exactly. I ordered a 250A Daly 4S.
@@williamirizarry1113 8 batterers set up in pairs of 2 (parallel) are working as 4S then connected in a series setup only require a 4S BMS
8 batterers set up in pairs of 2 (parallel) are working as 4S then connected in a series setup only require a 4S BMS
To measure the pressure you are wanting to achieve, you could build a mockup of the battery's, insert an ac refrigerant scale in the middle. Then tighten it to the spec you mentioned. Then, use some type of fairly accurate tension scale or tensiometer to measure the force exerted on the band at a certain amount of deflection, and then just duplicate that on each set of cells.
Looking good! I'm considering compression like this. I like this design alot thanks for the great ideas. So far just capton taped mine. Cheers and sunny day!
don't do it... this is no good... see my post in main thread
very cool build, really like the metal straps
The other cool thing about using plywood ends is you can cut a kerf in it and slide a plexiglass cover over the entire top. Works great.
The cutting board is HDPE. One could easily make it a bit taller and add a kerf cut to it. I have been using HDPE, including 'Starboard' brand for a variety of projects, and I plan to use it in my own battery build. It is very easy to work with, except that it cannot be glued. Wood screws work very well, though, especially if you heat them up first:)
@@toddrunfeldt6636 Excellent idea. HDPE is really great stuff and probably a lot cheaper than plexiglass which has gotten really expensive..
Wow, that's a fantastic idea thank you 😎
Just an FYI on the strap you bend the strap back over the clip before bending the ears over that way it binds itself and cant slip
Thanks for the video. Nice looking build.
You could slide a piece of shrink tube onto the busbars before installing them. This way only the ends are bare.
I did think about this, which would significantly cut down on the exposed metal, but it still leaves the bolt chunks exposed. I really want to get everything covered but may be impractical without a 3D printer or something to do custom work (don't have the equipment or the time).
I like the band idea, i purchased a different band brand, but going the same route!
Pretty neat solution there I just did the same thing with 8 25Ah cells for a 12v 50Ah So smaller but about the same I did not use any separator I figure if they are tight they should not be able to move and wear thru I do plan on using something on the bottom because the heat shrink doesn't go all the way around the bottom and it will set in a steel enclosure for a gate with a camera and stuff
I completely like the banding tool setup.
You should go on Wills forum and offer the tool for a rental trade setup.
I like to charge full price for the tool, and refund most when he tool comes back. You could even charge for the banding cut to length for the rental.
That's a neat idea, but don't trust people with my tools/equipment enough - even with a deposit. Only way I would consider it is if there was someone local who wanted to borrow, but haven't seen too many others in my area building battery banks unfortunately.
@@LithiumSolar I agree there. Usually, the tool is sold full replacement prices the renter, and a weekly fee is deducted from the refund price after returned. Just a thought.
Thank you for another interesting video / details :)
Love the banding. I looked into the plastic banding but the tools were kinda expensive.
Giant zip ties. I have a bunch of 3/8ths wide 60" long zip ties. I'm sure they sell them longer and wider. Using a ziptie gun you can dial in the tension, or just use pliers.
I am very interested in replicating your build to take advantage of super off peek hour in my state. Can you please make a video of the 4 12v 560ah battery's being hooked up to a bms. Also if you include everything being hooked up to the inverter and finally the breaker box that would be great. Thanks for all your help.
You probably have a hole lot more compression pressure on the batteries than you think , the sound of the band tells me that .
I have a bandit tool like that and it can clamp things very tight , remember that is a bolt and crank that is pulling the band , plus a two to one ratio , because of the full circle , just like a pulley on a loaded with a rope .
I have slit a 3" metal pipe and shrunk it smaller diameter with this tool .
It can pull a band till it breaks , that a lot of pull.
It was helpful.
Thank you very much.
in the UK we use pexalin its electrically used in fusebaords or sub panels
I have 8 of the same cells. The included studs seemed like cheap stainless so I cut replacements from good quality machine screws and used JB Weld to secure them. Im using a similar compression method but with 180# zip ties, 5 rows of em. Theyre going into a couple of seahorse cases, theyll just barely fit. Made some flexible buss bars out of grounding straps and copper pipe couplers. Those are easy to make smash the couplers on the ends solder on with a torch heat shrink across the middle. Top balancing taking forever with 5amp power supply I had bought a 60a BK 1900B power supply off ebay 275 used great deal but was DOA seller refunded no problem. That was gonna be my charger too so gotta keep looking.
Scotch brite works well to clean terminals and no risk of scratching to cause a bad connection
You get other clips for steel banding that use a grubscrew to hold. Can be easier to use, but I'd probably just use small ratchet straps myself. Have the benefit of being non conductive and likely cheaper.
extra long hose clamp might be a better option, more adjustable, i used a 20ft roll for my install
That's a great idea! I did look at those initially but couldn't find anywhere to buy them at the right price. Perhaps I didn't spend enough time looking...
the bandit tool used worldwide for street signs, but they do make plastic ones. You can find the plastic ones at most shipping supply locations.
Excellent job and I do feel that the batteries have to be compressed for sure
Wow it war the nicest diy battery pack i have ever seen
I can't wait to get my hands on some lithium batteries for my portable solar generator builds. Great video!
Lithium battery will not discharge fast
They say that lithuim battery can hold a charge of 80%
While agm,gel and flooded battery will only hold
A 50% charge
And i think it is true
Cause my lithium battery will not discharge easily
Please, show the final wiring and the BMS for you setup.
I will certainly be videoing this when I complete it. I'm still waiting for the BMS to be released :)
Crazy idea for covering the connections for safety: Determine the proper diameter of PVC pipe that when cut in half will cover the connections and touch the battery. The stuff is cheap and readily available. Cut the pipe to the correct length and cut in half and secure to the battery banks with tape. This would allow for cables connecting each bank to exit out the end as well. For one additional level of safety add a cap to the end of the pipe that won't have wire coming from it. PVC is easily drilled for passing the BMC connections through it as well. Thoughts?
yes.
Great setup. One question wouldn't rubber in between work better? Just thinking out loud..
I would say not a good idea because it will put more stress in the busbars.
Rubber may work. I really wanted something that doesn't flex though, like plastic or plexiglass.
@@LithiumSolar that's why you are an expert, I didn't think of flexing... 🤔🤔
that strap is a nice touch. the tools to do it is costly. the strap would still work if you used turnbuckles like made for a screen door. self tightening. i enjoy this video and its really good for me i plan to do the same thing
Wonder if furniture clamps and wood frame might be as effective to compress the batteries.
...this band hype is garbage... there are so many better ways.
Very inspirational, outstanding video.
Very informative video 👍
A lot of great ideas.
Nice low down, well explained,
I've never seen or tightened a battery with nominated torque ,
560 ah. YES PLEASE, DAVI B
Well done, scuffed the terminals then applied ox guard, the way its supposed to be done. Didnt see you scuff the buss bars but youre probably fine.
I did not scuff the busbars. I didn't have the same concern as I did with the aluminum posts, but perhaps I should do the same with the 800grit?
@@LithiumSolar you did it right.the reason you scuffed the battery post was to removed oxidation. There is no oxidation on nickel , which is exactly why it's there. Some people have ocd and when they see it done to 1 they think the other has to be done too. You didn't scuff the battery post to paint it, just removed slight oxidation.
I thought the buss bars were aluminum. Nickel I wouldn't scuff.
@@jakeandrules7724 Nope, they're nickel-coated copper :)
Any updates on that BMS solution? I'm anxiously waiting... lol
I really hope it's the Batrium Watchmon CORE+CellMate-K9 he'll be testing/using
When tightening fasteners, is best to start in the center and tighten them in a spiral pattern.
You are awesome. I am going to order these for my next campervan. at the moment i try to make a 12v out of old 18650 laptop cells. maybe you can do a video about how to do a 12v battery for camping out of 18650 because the informations on the internet about this are really rare but the price for such a diy is attractive. especially if you would choose 3s or 4s configuration and how you would achieve the best range for the 18650 to use within the 12v range.
There isn't much out there on LCO/NMC for 12V applications because the voltages don't work out very well. The voltage is typically too low on a 3s system and too high on a 4s system. The optimal solution if using 3.7V batteries is a 24V 7s system or to use another chemistry, such as 3.2V LiFePO4 where the voltage works out perfectly for 12V applications.
Is it possible to balance each cell individually in this configuration? Or is it not that important?
I definitely wouldn't band the battery packs together for fear of restricting the expansion. But lithium is half black magic so nobody actually has the answer. Another thing that you could have done is just go to the hardware store and buy some threaded rods and just drilled a hole to the aluminum and then put nuts on both ends that way you can easily remove the clamping Force plus it's probably cheaper too. Also for my final setup I'm not using bus bars because that provides a rigid point of failure. Wires provide more flex
Also using threaded rods and nuts gives you the chance of providing your own torque spec
@@eksine
you can release or add tension afterwards.
@@ursodermatt8809 he said you cannot use the tool again because he trimmed the ends off. Also you cannot easily remove it and reuse it as much as rods
@@eksine
i was agreeing with you with the threaded rods
@@ursodermatt8809 oh sorry my bad I thought you were talking about the bands he was using
I don't think the end pieces are stiff enough to not bend and end up putting most of the force on the outer edges of the cells. From time to time I would put a straight edge across those aluminum and plastic pieces to see if they are bending. Most all of the force from the bands is going to the edges. You could add some shims under the bands to better even out the pressure.
I ended up changing my design in the final build. I'm using 3/4" plywood, 1/8" angle aluminum, and threaded rods. The idea here was fun to try but had too many concerns with it the more I worked with it.
any reason you went with metal banding vs plastic strapping?
I didn't even think to check plastic options because of the assumption metal would be stronger. The strap I used is rated for ~1500lbs breaking capacity.
@@LithiumSolar This is what I found IDL Packaging - MiniCW34 3/4" x 250' Mini Woven Cord Strapping Roll, 2400 lbs - Break Strength, I find it hard to believe that the cord is better than the metal as far as breaking strength. But the cord is way less cost at $31.
@@LrbinMT Interesting. That is significantly cheaper and stronger. I wonder if woven strap like that would stretch over time and loose the compressed force though? Like over the course of 5+ years? It may be worth trying it out though.
@@LrbinMT My vote is for tie down strap. It will be suffice.
@@LithiumSolar You are correct, steel is best for retention of tension at 95%, polyester 70%, polypropylene 25% according to strapping tools and parts . com
Inserting those plastic separators between the batteries makes for a good capacitor.
Was looking for anaditional cell isolation, found it here, thanks
very nice build and extremely informational as always!
I have a non battery related note though... I'd appreciate it if you'd make the audio in your videos mono and just in the center because I find stereo distracting and also all UA-cam video pros record speech in mono, which is probably for a good reason.
I know, it's extremely annoying to myself as well. I bought a new camera a few months ago and it has no way to disable stereo mode... nor does my editing software have a way to mix the two channels. I'll have to figure something out. Sorry, and thank you for the feedbacks :)
Maybe I can post-process it with ffmpeg before uploading. I'll test some things out for the next one.
Funny I dont' notice any issue when listening.
so its going to be a nearly 30 kw battery and is under 3 grand? (unless my math is off). It seems like the whole 18650 battery pack for solar power systems game isn't really worth it anymore, but I'm still learning. Either way exciting times for all of the options available now.
You are right. Gone down the same path: used 18650, then Lifepo4 280 Ah.
The batteries were somewhere around $3450 by the time taxes, fees, etc were factored in. Including cost of additional parts like the straps and BMS, I'd estimate it comes in just under $4000.
Yep and 2 years from now this will be old news and we will be on to something else ,maybe.
great video. Like the plastic between the + & - sides of the batteries. and the thicker plastic on the ends. As others have suggested I think the banding idea is not great and a treaded rod solution would have been simpler and easier to implement. But it does look neat :)
Yeah I ended up going with threaded rod after experimenting with a few different ideas like this.
@@LithiumSolar Ah cool. Thanks for inspiring here. I am thinking of doing a very similar setup soon. These batteries seem to be the best option available for most people.
These are the cells I would use when I build my off gilded set up unless something else is better for cheaper.
I'm using a 4S 2p setup also been working great for me
Why the metal band if there are fiber/plastic ones too, that have around the same or even more strenght? And fiber ones aren't conductive and can't cut the shrinkwrap shielding.
I was thinking the plastic straps would stretch over time, keeping in mind that I want this to last 10 years. Maybe the won't, not sure?
Great info for new builders. I'm waiting on these same Batteries to be delivered for a 24v Magnum Inverter. i couldn't find any info
whether a BMS would handle putting these in series / parallel.
I have a 3P 4S prismatic plastic encased 200 ah cells 12 cells in my van currently bought all for 480.00 total and a 200 amp daly BMS
Hello! Great work! I could not find next video - bms install on this set. I want to repeat this project 12.8V 560Ah 4s2p. Can you please send a direct link?
I like what i see..im living in 40' bighorn trailer after a house fire. Im in eastern Ontario, Canada. There is a microwave/ convection oven, gas stove, gas/AC mid size fridge freezer, two tvs, AC fireplace, gas furnace/ AC with blower, water heater, air condition, 110 outlets..charge phone and laptop..and when i run genni, 1500 watt space heater. I am currently getting power from a 12k king canada(runs on propane and petrol) genni 1 worn out agm. I have considerable power needs, without giving you all the numbers. I want to build a bank that can be charged, using approx. Maybe 4 solar panels( 1600 watts approx).. And run my genni when needed
Oops wasnt finished..im sure you will hear from me, ill keep watching, hope you dont mind a question or two
I think I would try using a pipe clamp.to.clamp the cells together and then use a cloth tape to tape the cells together. Makes it easier to break the bank apart when one cell goes bad.
Over thought that one. Should have used some all thread in conjunction with a piece of timber at the end of the timber frame you had the cells in. Like a paper press.
Setup the 12 volt battery with 8 cells as you described the connection. I setup the jkbms connecting all the positives to the battery. Changed the parameters to 8 cells. The bms recognize 4 cells. Look for your video on the subject, no luck yet. Can you tell me how to setup the jkbms on this 12volt battery? Thanks for your video.
What's your opinion of installing a small (hollow) spacer in between the cells for heat dissipation ?
Couldn’t hurt
sir i suggest next time.. is btter to make are base to put the battery ,it prevent the bottom of the sell from rubbbing@the cell case is thin
also sir you can put are bolt n nat on the cutting board then the other side the same way its like are vice🤣 this way you can compress you sel evently.. the expose bolt you can cover its using are plastic pipe or host.. btw sir keep the nice job n god bless you
I was wondering how this pack has worked out over time. Have you had any issues with keeping the pack balanced?
I'm building an identical pack now, and I wonder if it would be better to build 2 batteries and parallel them.
The batteries are still working great, though I've been through quite a few pack designs since this video. The latest is shown in this video ua-cam.com/video/xZ_uL2tPO0I/v-deo.html at the 5:55 marker.
I'd love to see how you cover the terminals from exposure. Great video!
In the navy they were "terminal board covers" and they were made of fiberglass, screwed into the end posts, and were a "u" shape.
Do you already have the video of the BMS with this 12v parallel set up? I am glad to see it...thanks
Thanks you for detailed and to go slowly.