My Lifepo4 Battery Final Assembly Method. Best Result For Least Cost? Let's Find Out!!
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- Опубліковано 1 гру 2021
- After spending the last video testing different methods and deciding for myself what is important and what isn't, I've settled on the best compromise in my estimate of effort and cost vs highest performance. I've tried to find and correct the mistakes and keep an open mind. I hope it helps others to find an easy effective approach amongst the many choices and concerns we have in this DIY Lifepo4 journey towards personal energy independence.
On completion of the battery the range of resistance test results between the cells ranged from .18mohms to .23mohms. This is a big improvement and I think it is now an acceptable range. I will find a way to test the resistance of the balance wires to see if the extensions of the farthest away terminals makes a substantial difference.
EDIT TO ADD: In the follow up video posted on December 8, I show how to speed up this process and get a little better results at the same time. Getting to the best methods is usually a process and this is no different. Thanks
Ray,
Maybe I'm slow. Can you explain the loss differences? And why they're so significant between 0.44mOhm and 0.21mOhm? It's half the losses, but if you're only talking a few watts between the two: why the astronomical struggle over cents worth of power loss? Even multiplied 24 times, still seems _overly_ pedantic 🙂
It shouldn't matter with balance wires. They will only see 150mA. Hardly anything to affect the voltage. A loose terminal would be far more likely for a cell to look too high/low.
@@jamess1787 Two reasons I think it matters. One is it's an indication of the quality of the connection. Take the .23 improvement you point out(sometimes it is much greater) of that, .12 is from replacing a brass busbar with a copper busbar that has 3.5 times the ampacity. The aluminum oxide represents the bulk of the remainder. When the busbar doesn't make a flat connection with the terminals the difference is much greater and indicates a poor connection. Testing is how I find the issues. Secondly is the BMS I am using and others I'm sure, rely on a consistent external resistance to properly read and balance the cell voltages.
I will repeat over and over. I don't care about a few watts of loss from this small resistance. That isn't important. What is important is what it represents and how it affects the BMS. I have one best chance to get it right. The protocol I'm using now is fairly simple and quick to do. Compared to what some people are spending and doing on these connections, this is nothing. I am building 16 of these 14KWh batteries. It is important to get them right and to do it efficiently, with the least effort for the most gain. This is the balance I have arrived at and I've shown how and why I settled on this approach, not based on heresay or guessing but on the testing that I'm able to do. YMMV
One thing for certain from reading the forums is that no matter what the approach that is taken, there will be those that think it is foolish. I'll just work to stay out of the part of the forum reserved for those that started fires and such.
@@RayBuildsCoolStuff there are some in the forums with no common sense and read too much into things that are not accurate at all. I took analytical chemistry so accuracy was important and you record your results as you went. about 40 years ago but accuracy and measurement are important, then one has to get the best solution.
@@RayBuildsCoolStuff - liking the reason - thanks Ray!
Yep you got the lithium obsession bad lol. Thanks for sharing
Get me off this danged grid!!
@@ursodermatt8809 Happens to a lot of us
I guess you haven't watched the Off-Grid Garage and the hunt for lose connections. Or the Digital Mermaid making multiple versions of battery cables to minimize the length of cable. Good enough is easier to attain for some people. Fun to watch either way.
^this^
I find this project fascinating. Just found it lately, so now I'm starting to view all from the start. I'm going to continue to track and follow your work.
Thanks so much. It’s going to get better. I promise.
You're doing great, that's why I keep coming back ❤️
Great Video! Thanks for doing this so we don't have to! :) You are really good at refining your processes and builds!! Excellent Outcome!
Great video. You are doing a real service. I am learning a lot from you and very grateful. Thank you. Please keep up the good work.
you are the Michelangelo of lifepo4 assembling , my compliments, i like very much your creations
do i see a ponytail ?
love the althar of lifepo4 ;)
Great - my "late" critique on the video before washed away with the next video - gonna watch and enjoy old videos before commenting :).
Thx for the work in progress videos (some would "say try and error" or somewhat nicer "iterative process") - i really do enjoy them!
And: by your nice voice you might become the Bob Ross of LiFePo4 Batteries ;).
If you ever test this again, clean the aluminium terminals with steel wool and some mineral oil - no need to sand them, just a light abrasive like steel wool (I'm using the same kind of tool you made, the wood dowel with a hole in it). The issue with aluminium is that it corrodes in fractions of a second in contact with oxygen (I know you know that, and I know it's less than what you take away in this time frame), the mineral oil prevents this (wipe with mineral oil as well). MG 847 also contains mineral oil, to encapsulate the carbon and prevent corrosion. I know you have stated before that you don't see the point of flexible bus bars, but with thermal fluctuations and slight expansion/contraction you get micro movements which will cause slight movement of the bus bars which can lead to worsening contact over time. Ready made packs with welded contacts don't have this problem since it's more rigid than a 4Nm torqued bolt. And yes, I have tested these things and have been running two 16x280Ah cell battery packs over a year and a half now. I also agree with you that the consistency in resistance between bus bars is very important; MG 847 definitely helps there too.
Up North and Personal
Have your readings changes at all/much in that time, have you checked or have you re-cleaned the cells since then ? I'm gong with the flex bus bars per your suggestion. Thanks
@@Skeptic100100 My batteries have been sitting in use going into their third year, no issues. I've not taken them apart, nor changed anything in the mean time. They just work.
keep showing us us vour knowledge ,thank you.
MG Chem 6463 silver conductive grease works well, and for pitted terminals, i sand and use an MG Chem 842AR-P silver conductive pen on the contact points.
Do you even need silver grease? An electrical grease would stop corrosion and get squished out when assembled. There is probably going to be something going on with Aluminum, tin, and the zinc nut to cause corrosion too. Molybdenum grease might be a better option.
I copied this from a site that sells the product.
"This Silver Grease provides maximum electrical and thermal conductivity between sliding surfaces, while providing protection from moisture and corrosion.
Typical applications include lubrication of substation switches or circuit breakers, heat dissipation from transformers, or static grounding on seals or O-rings."
It would appear that it is not designed for this application. It might work fine. Perhaps just overqualified for the task.
49$ for 7 grams
This is the description for the MG847 that I am using.
"1 - It inhibits corrosion, is economical, has a wide operating temperature range, long service life, and does not contain silicone.
2 - Improves electrical connections between irregular surfaces
3 - Ensures electrical contact between loose or vibrating parts and small gaps
4 - Does not separate or bleed, even at high temperatures
5 - Contains special corrosion inhibiting compounds
6 - Contains 25 ML
The 847 Carbon Conductive Assembly Paste is an electrically conductive, non-bleeding grease for improving electrical connections between non-moving surfaces and parts.
Applications & Usages:
The conductive paste performance depends on mainly on surface preparation.
Improperly prepared contact surfaces can degrade the stability, conductivity, and lubrication characteristics.
While the thickness and coverage are also important, the application method itself can easily be adjusted according to performance and application needs."
It would appear that this is the product more suited to our application and the cost is half for an amount that will never run out in our use.
Can you please tell me where to buy MG847
Great videos. Good to see that you are looking at this with an open view to learn.
Just one remark about the plug-on thermal cameras compared to professional multi thousand Dollar versions.
These both give a good view of thermal problems in cabling and electronics. The cheap (200 USD) camera that I used was great for this but the expensive (5k USD) Fluke camera is easier to use, has a higher resolution and has some great options that make it a good tool for a professional. For me both are an option. I prefer the more expensive Fluke one but if used by a colleague, I can also use the cheap clip-on FLIR camera. What I don't like on the clip-on camera is however that it needs my phone and an app. As soon as the app is no longer supported on a newer phone, the FLIR camera is unusable anymore.
Both cameras need a person who is able to read the picture and to know what is normal and what is not.
Or as we say: "A fool with a tool is still a fool" and it does not matter if that tool costs 200 or 20,000 USD 😉
What I think of is something similar that I have done a few times but do not know if it makes any difference as I do not have meters that can measure it. Have used copper paste both to prevent corrosion and give a little better conductivity (partly prevent corrosion in cables) but then it is to have it on the whole thread and if the thread is also down in the cells, I would at least try with the paste on all surfaces that can lead Current.
So have you tried different pastors and tried on the threads so the current can also go through the nut?
it should be easy to test and see if it makes any difference in which direction
grate info i away,s wonted to try lifpo4 but dont know how to find the right bms the videos help to know more about them
I subscribed. Keep making good videos.
@6:35 the dowel works well if you use felt dots for cabinet doors on the end you can attach the sandpaper or use buffing compound for grit and a second dowel for applying the anti oxide grease next pretend your starting a fire with stick or hand lapping a valve
Cant wait till you start trying to get comms working between your inverter and the Selpos BMS.
Hoping you cover RJ45 pinouts.
You and me both!
great tips in your vids Ray I will order one of these. I am not building large packs like yours but I do want to pull 2000w out of a 280 eve pack I am putting together, having the lowest resistance across the bus bars will be crutial i will take lots of care like you have done and thourougly test i would not have even though of doing this. thanks again :)
@Ray Following along, really good stuff. Wondering Though, do those Seplos BMS' have a Precharge Circuit ? Or have you come up with another method for Precharging the Inverter Capacitors ?
They do! It's one of the things I like. It is the large rectangular white resistor visible on the PCB on the left hand side, near the top.
👍
Hello Ray! I do enjoy your videos even though they are long. I really like your battery boxes and would like to see more about how you came up with the design. What BMS you use. Maybe I missed it. I haven't watched all of your videos yet. I do like how you push the busbars to one end to maximize the contact area. Could you possibly do a test to see what difference a not slotted busbar would make to the resistance. Also, do you have any thoughts on addressing/maximizing the contact on the top of the busbar?
Keep us the good work!
I have a video that is specifically about your question and I followed it up with two others where I optimized the process of creating low resistance connections.
Ray, some buss bar are not flat! Run an indicator across the width! One side can also be much better than the other. I’ve lapped a few to get them nice: .0002” is what I believe is the minimum. Sometimes it’s necessary and even if the “tinned” surface is somewhat compromised. As long as you join very soon after to avoid oxidized surfaces. I clean the tops of the terminals with Scotch bright ultra fine with a finger twist buff and a carefully directed blast of air. No cleaner, not even alcohol. Everything starts the oxidation process.
Conductivity, Resistivity of Metals
Material Resistivity p(Ω•m) at 20°C Conductivity σ(S/m) at 20°C
Copper 1.68x10-8 5.98x107
Annealed Copper 1.72x10-8 5.80x107
Gold 2.44x10-8 4.52x107
Aluminum 2.82x10-8 3.5x107
copper has the best electrical conductivity and lower resistance, better than gold or aluminum. tinned copper is the choice to prevent the galvanic reaction between unlike metal coming in contact with each other as I understand it. this is the reason for the connection on your water heater to prevent corrosion/failure between copper and iron for example. Ray is definitely on the right road to a good long-term connection. this is what we are all after... fewer problems and long-term durability!!!!
search for conductivity or resistivity of metals. it will help to understand the connection issues a little better... great job Ray!
Thank you so very much!
When the BMS shows a cell that is way different to the others, I clean and tighten that!
Good morning A tip for lifepo4 24v After reaching the maximum charge in my case 27.52v. What is the voltage to set to resume charging the battery pack? Thanks
This is just my preference I prefer to more Polish than sander grind when making electrical connections I'm afraid that the voids I create by sanding are creating an air pocket Hence a place for Croatian and debris in the future I worked in automotive industry before I went to manufacturing and seem like about every other hood you lifted the battery terminals were crowded in a greener white many times it was because of battery failure having to replace cables or burned up starters no they were even engine fires from melting the cable while trying to get the vehicle started as I told you in a different comment that I had a couple of high performance vehicles and high compression can result in hard starting Especially in High heat, I'm not sure what you think of it but I remember in one of your other videos you were concerned about the slot I seen another do-it-yourself for making his own copper straps by taking copper pipe I think he used to thicker I believe it's album but maybe it's Ami don't remember and tapped it flat with a big hammer on a steel block and then drove the holes where he wanted them so he could get away from having the slots be curious what's your thought on that is I also seen 1 of those little videos where they were doing the 32nd fixes on things they took a piece of copper tubing smashed a flat on the end drove the hole and it made their own copper terminal ends and of course they filled it with saucer well it was clamp shut in device and stuck the wire directly in it while it was still hot I didn't see them put heat shrink on it like you do but I definitely agree with putting the heat shrink on because keeping the air and water out prevents corrosion which leads to longevity
What happened to putting the flat washers on I thought it was going to give you more contact unless resistance maybe I'm missing something
If you watch the video to the end (it was long and I'm sorry for that) you will see that I used my testing to show that my great idea wasn't that effective. It improved the conductivity a very small amount. My takeaway was that the small contact area isn't that big of an issue. Probably because it is still adequate and in a very tiny length of the circuit. The testing showed other issues to be more important. I addressed those in my final protocol. It isn't my goal to do everything possible to achieve perfection. My goal is to get as close as I can while minimizing the time and effort. I don't think prepping and using the washers is worth the effort. I have the resistance down to a low and consistent level of ~.2 of a 1/1000 of an ohm. I'm comfortable with that. I also proved to myself once again that not all my good ideas are as good as I expect them to be and testing our ideas tells us what we need to know. If we don't test, then we are perhaps letting arrogance decide our course.
I use a Copper Anti-Seize. It works great and is cheap.
Big fan of the gorilla gloves ;)
Ray, I think you are worrying too much about resistance. I’m in the camp of voltage loss. Put a constant load or charge on the bank and read the voltage on the terminals just under the bus bars to find the outlier. I believe this is where “the rubber meets the road”. The resistance may give you a heads up before you throw a load on it though. BTW you’re not the only one not to have a fully torqued terminal so I’ve joined your club. Just glad neither one of us had damage lol! I enjoy your videos. We all lean from each other. I’ve got a few more myself to upload soon too.
When I'm away from the computer and considering what you (Ray) are doing, I'm having similar thoughts. It appears that like-performing cells are most important, then second to that is to have BMS accuracy. Then comes input and output, which could be high amperage. Are minute resistance differences in the connections and bars going to affect life or performance of the box when placed in actual service? If this had to do with something like data bandwidth, then I would understand the focus on resistance, but for transfer of energy that should still be low enough to prevent the bars from heating?
whats the brand/type of resistance device/meter, to measure cables and the cells?
YR1035+
I was so anticipating seeing you check the resistance of the extended balance wires. I don't have an ohm-meter accurate enough, so I did some googling: 18 awg = 0.75 mm2 = 0.026 milli-ohm/meter (for copper). So if you extended some of the wires by 0.5m, you may have added 0.013 milli-ohm of resistance. Which is negligible. Makes me wonder why people say BMS-manuals stress about equal length balance wires...
my extensions are less than 9" and are 18 gauge. The balance leads that come with this BMS are only 24 gauge so equal length matters more. I'm going to test it but the mohm tester can't test the wire at the connector end. I have to build a way to get the tester attached to that end. I won't forget. I want to know too.
@@RayBuildsCoolStuff silly me, I was factor 1000 off, it seems 26 mOhm per meter, so that nudges it in the relevant range again with 9", for an theoretical 5.7 mOhm. Interested to see how that matches up with reality.
9" measures 5.8 mOhm with my tester. The 24 gauge wire must be a lot more.
Ray if you want to improve in the entire surface area of the battery terminal to the buss bar I know you have to make your own buss bars, drill exactly the holes for the studs of the battery. That will reduce the measurement to
.10 mohms or lesser. I suggest you to try it....💯👌👍
So I could buy copper bars and do this but I would prefer tinned copper to prevent corrosion. I could buy aluminum and make my own but I would prefer tinned copper. My testing showed that the surface area isn’t a problem worth chasing. I am happy to use the supplied bus bars with some minimal prep and have what I consider to be a totally adequate level of performance. I think I’ve found a good balance.
Would there be an issue with expansion and contraction of the cells if the buss bars didn't allow room? You don't want to put stress on the studs.
@@jimlaning3560 I don't think so Jim.
In almost every video, I state that I am restraining the movement of the cells to prevent strain on the studs. I firmly believe that this eliminates the need to concern ourselves with flexible bus bars. The manufacturers of prebuilt packs aren't using flexible bus bars with the exception of Volvo? Most are using laser welded connections with stamped plate bus bars. They simply restrain the movement of the cells. I know of none of them that apply compression as is required by EVE to attain their 6,000 cycle life yet some of the pack builders claim a 6,000 cycle life with simple restraint. shrug
That's just my opinion though. I haven't read of stories or any real evidence of internal shorts or other issues when using the bus bars supplied with the cells. The problems I have seen stem from other factors. I'm not sure where the whole flexible bus bar thing came from but I'm going to guess that some people felt it necessary when they learned that the unrestrained cells expand and contract based on their state of charge. Again, Just, My, Opinion. I don't get too riled up about it because I don't think it will ever cause me a problem, and I'm a dyed in the wool worry wart. lol
If anyone is reading this and has an old dead cell with a welded stud, please try this experiment. Use one of the knurled nuts with the little teeth that come with the bus bars and tighten the bus bar to 6nm. Now try to get it to slide in that oval slot without a hammer. The oval isn't to allow movement in use. It is to compensate for variance in the cells and terminal placement. Again Just My Opinion lol
@@RayBuildsCoolStuff Well I believe your opinion is dead on! There should be no movement while in use. Thank you for the great reply!
Appreciate you listening to comments and sanding the bars....even if you already tested it. That carbon paste is less conductive than aluminum or copper. You might do better with just an electrical grease(like bulb grease). You are just trying to stop corrosion not improve on conductivity. You could gold plate everything...but I mean, money is kind of a thing you don't want to waste.
Gold is less conductive than copper and slightly more conductive than aluminum. Gold is only desirable in circuitry because it doesn't corrode over time. I don't like what happens to raw copper over time so I use tinned copper and use MG847 on aluminum.
@@RayBuildsCoolStuff Right. The gold would stop the aluminum from oxidizing(assuming you can easily plate it to aluminum). The layer would be so thin, conductivity is really not a factor. And it is soft so it should fill any imperfections. Silver would be a better conductor, but it would oxidize. If these terminals were brass this would be such a non issue. I really liked the AGM batteries that did this.
Hi Ray, what thickness of plywood do you build your battery boxes with?
3/4” and I have my first videos about how to construct them.
@@RayBuildsCoolStuff do you mean you have made a video or are going too? I have my cells arriving from jenny wu, anytime soon.
@@deanrowles3665 Go back to the beginning of the channel. You will find the first maybe eight videos walk you through the process. If you haven’t watched those I think you may find them very helpful. You may also find that the videos have gotten a little better over time. If you decide to build them, I can share the dimensions but I think they are described in the video. I don’t have plans for them as a design and build from rough sketches. I recently reviewed the old videos and they are still quite accurate. Let me know if you follow this path. I am still very happy with the design decisions and that is hard to pull off because I am a picky bugger.😂😂
hi thanks for the vids could you let me know what the make of your meter is and you got it from 👍
YR1035+ available several places. I got mine from aliexpress because I had time. I plan way ahead. I’m sure you can get one faster for a bit more money than I paid.
@@RayBuildsCoolStuff thank you for replying to me
Hello, years ago I built a steel frame for a house on white bluffs at lake Whitney that eventually had to be torn down and the cliff it was on fell in the lake. You resemble the gentleman I worked for. Was that you by chance?
Nope not me.
What is the resistance difference when just changing the busbars, without cleaning the post?
.12 mohms. In order of importance seems to be.
1) proper torque on nut
2) copper bus bars NOT brass or wire
@@RayBuildsCoolStuff This is great info. I did see you were adding a coating, but didn't catch the brand.
How much touque are you tightening the nuts?
final assembly is 6nm. before that I use only 4nm for top balancing and moving things around like chargers, prior to the final assembly. Supplier says 8nm max.
Yes Akb LiFePo4 battery 🔋 👍 ⚡
Should always use copper bus bars I made my own out of 1/4 “ x 1” copper stock and drilled holes . I’m using Nissan Leaf batteries packs , 74 of them on one bank
Question. Aren't you more likely to get galvanic corrosion between the metal terminal als on the cells and the copper bus bar?
Would it not be more prudent to use similar metal to reduce longterm corrosion?
I also used 1/4”x1” copper bars, but I tinned them, since tin is more cohesive with aluminum than copper.
@@jameschristie4596 the small amount of galvanic corrosion would not affect battery connection for years . It’s not a jet plane . You would be long dead and gone before you would see any real damage to the connection!
I just hammered down a copper pipe for the longer buss bars and drilled some holes in it. Worked better than the chineaseum bars I was sent with batteries. I did sand to get clean copper before attaching. If you are worried about corrosion, just add some Vaseline or battery terminal/bulb grease.
what is the black carbon paste? you surely said in one of the videos. sometimes UA-camrs put links to the products. that could be a helpful addition to your videos. I just received the last box for my next 32 cell build of EVE LF280K cells direct from China. about 86 days total shipping time. keep up the great documentation. I gave you a positive reference on my DIYsolar post! 😎
Thanks for the props. Did you test the cells. The seller claiming they are 290AH is a falsehood. They are 280AH. The good news is that if they are LF280K cells then they can't ve very old because they were released last year. Mine are testing at around 284-285 mostly. There are a few outliers but they are all fairly close so far.
The assembly paste is MG847. UA-camrs put links to get an affiliate payment. I may do that eventually but I'm busy 18-19 hours a day already and I have a list of things to get to. I only find time to reply to comments when I stop for a break or a cup of coffee. Assembling those links is another small project to fit in and right now I need to design a building for my friend's solar shed/garden shed. It's on the list but requires a commitment of time I don't have right now. Sorry.
Thanks so much for your subscription and taking the time to comment.
@@RayBuildsCoolStuff sorry about the fat finger typo ---- they are EVE LF280K with welded-on terminals vs the tapped terminals in my Lishen cells. no testing yet. I was mounting panels and other things yesterday and only unboxed the final 4 last night, I really need to put on the dollar store cheaters more often, and check my typing more.
@@pilgrimvalle I see. Often sellers inflate the claimed rating to the highest value that is tested when the cells are brand new. That’s where we get 310ah cells which don’t exist and 280ah catl cells which don’t exist, etc. I thought that might have been what happened but a misplaced finger crossed my mind.
If you would sell that battery what would you charge for it??
My labor rate on the open market is very high so it would not be a price that would seem reasonable to most people.
Great video so were all the previous ones. A small suggestion, try a different microphone, the audio can use some improvement.
I use my iPhone to make the videos. My wife looked into an add-on microphone but I let it fall by the wayside. I will look again.
@@RayBuildsCoolStuff Looking forward to see the result !!
I'm not sure how meaningful those circa 0.2 mOhm readings are. Do you have any means of calibrating the YR1035+? I have one too and the user manual explicitly cautions against trying to measure values below 0.3 mOhm because the expected measurement error around 0.2 mOhm is said to be plus or minus 0.05 mOhm, which is 25% of the measured value in either direction. In the words of the manual, "the uncertainty will make the reference of little significance". If the question is "is it below 0.3 mOhm" then yeah sure, I'd agree we can say that with some confidence, but I don't think chasing differences measured in microohms is meaningful here.
If I was concerned with the absolute value that would matter but I’m more concerned with relative values and consistency. As long as the tester is charged up it performs very well, returning repeatable results. There is an important distinction between accuracy and precision. And yes, eliminating unnecessary resistance is important and beneficial.
@@RayBuildsCoolStuff I don't think we're in disagreement then. It wasn't clear to me exactly how you were using the measurements, but as I said I agree that this method is certainly good enough to tell a difference between (say) 0.4 and 0.2 mOhm.
What torque are you tightening to?
4nm for temporary connections and 6nm for permanent connections.
@@RayBuildsCoolStuff Wow. I have been seriously under-torquing...no wonder I have had weird internal resistance numbers!!! I've pushed to 35 inch pounds, and I'm finally seeing the proper values. The YT1035 is a game changer.
Never go higher than 8 nm
@@RayBuildsCoolStuff I was torquing to 20-inch pounds or 2.25nm. No wonder I was having problems!!
What no brass nuts? That could lower it another mOhm. And while we are at it, Belleville washers will help if you see the terminals starting to get loose after cycling. They keep a consistent pressure around the outside of the terminal unlike a split lock washer.
Careful putting things near the terminals....would be easy to cross two posts and smoke some stuff. Layout cardboard on top of the terminals you are not working on. You are welcome to ignore that too....we like videos of smoke and flames. LOL.
Before I measure resistance in this range I always hold the tips together to check just how zero a short is.... But I guess you do as well it just did not made it in the video. Its for other viewers and not meant as a critic.
Yes I do that out of protocol but honestly can’t see a difference when I don’t but if I have trouble getting a consistent reading, I do it again. Have a great day!
Nice video Ray. I fully agree with your approach. To be honest i see less obvious reason even to change those busbars. After all If it is 0.5mOhm per one so it is about 8 mOhms total.
- If it was low voltage system..sure..like 12V ..every things count but for 48V system with voltage of about 50Volts i don't see much benefits.
- I think it would be much better to show results why it is important with numbers. or better use some high load with 1-2C so lets say 10kw or about and then show what is voltage drops from normal cheap busbars and then with new copper ones..and then make calculations. I think this would show how much it matter
- I'm also thinking about low resistance tester ..that is for sure good idea. even i don't plan make bussiness as you do :)
- I will just add that any improvements is good but as you said ..how much you will invest matter..after all you can spend much more on connections and cables and busbars and who knows what than on battery itself..and that would be a mistake , again nice video to watch
- One late comment i want to add I'm usually make my own busbars but they are pure copper and that could be problem if they are in contact with Aluminium(as there will start electrical corrosion if they are put together)..so i would need special washer used to connect copper and AL blocks together..i didn't have time to check that out yet
The entire amperage flows through each busbar. This size busbar in copper is the minimum appropriate size for these amperages. Brass will only carry 27% of the current at the same resistance. They are wrong for the application. Important to note is that the BMS takes its readings from the busbars and for it to function optimally it needs to have very similar and low resistance values for all the busbars as per the manufacturer. They even measure the delta between the 8+ and 9- terminals to calibrate for the resistance of the busbars. This isn't about resistance losses and transmission efficiency. Of course I don't want to spend a huge amount of time or money to achieve this result which is why I kept testing and modifying my process until I came to this method which is a compromise I am very comfortable with. Does that make sense?
@@RayBuildsCoolStuff It has sense Ray. No doubt of that. I understand lovering losses is important but i still don't understand how important to be exact. As that was never mentioned not by you and not be manufacturers (when they usually don't bother with that..it is china after all..) .but i don't mean it bad way i just don't understand the huge importance of it. IF we were talking about overheating yes then that would have sense..or huge voltage drop..yes big sense.. but i still don't see it. maybe i'm just too slow to understand
Alright - throwing out a question to the Ray Builds Cool Stuff YT family. Anyone have a source for solids copper bus bars? Thanks to the group!
You can get them from Jenny wu
@@RayBuildsCoolStuff - thanks Mr. “Cool Stuff” - much appreciated; can I mention your name Ray?
I just got a shipment from Jenny Wu to New Zealand 64x EVE 280Ah cells, still testing them all, ok so far and they came with copper busbars. Got the JK-B2A24S15P BMS which has built in 2A active balancing.