I am now 10 fold more paranoid about the battery bank I built 😂. Time to go back and redo some stuff. Thank you for explaining all this in a way us novices out here can understand. And thank you for not drowning it in cheesy background music. This is one LEGIT presentation.
I misspoke in the video when I said the copper busbars were equivalent to 1/0 copper wire. I meant to say 1 gauge. Not a huge difference but I wanted to note the correction.
You might better pin this comment that is stays on the top of all comments that people get aware of it without having to scroll through all comments. 1 tiny point that this is wrong cause you had calculated your busbar with the equation 20 mm x 2 mm = 40 mm² which then would equal a 7 mm diameter wire which equals 1 gauge, but if you drill a hole of 3 mm in that busbar everything changes from 20 mm to 17 mm x 2 mm = 34 mm² squareroot of ( 34 mm² / pi ) = 3,3 mm radius or 6,6 mm diameter which is a 2 gauge wire, not 1 gauge. Your hole of 3 mm (my assumption - could be 2 or 4 mm) diameter weakens the conductor property. The only counter argument is the terminal hole cause the contact surface is below and above and around the whole terminal. Which then would mean to be precise that the 20 x 2 calculation is completely off due to the bigger holes of 1 cm not just the 3mm hole unless the surface of half of the nut and its bottom counterpart is bigger than the squarespace of the bus bar cause the power will flow the shortest from the lower terminal surface up into the busbar and from the nut screw surface down into the busbar. Does the 3 mm hole lower the conductivity of a bus bar might be a question you could answer by measuring the resistances from a screw with 2 nut screws that fixes the busbar on each side. From such arteficial terminal screw to the other you can measure the resistance for a busbar without the 3mm hole and with the 3 mm hole to get behind the impact of such hole. And this might also change the answer to the question what awg size such 20 x 2 mm busbar equals depending on the 3 mm hole or not.
You misspoke as well when you said you can't sand the busbars down to make them flat. You put the sandpaper on a mirror and do figure 8's with the bar. I just saw it done yesterday and a heat camera was used before and after and the temperature dropped significantly. Just needs to be done on a flat surface.
This really is a bit of a master-class. Definitely puts emphasis on certain aspects of connections. I.e the importance of the heatshrink with the adhesive I figured was only important on marine applications. I'll be spending the money on heatshrink regardless of application next time.
Ray!...i believe the fact that u are very able to teach young generation of electricians. Beside of your knowledge u have also another virtue...to be patient. Good job!
Thank you for your perfection and your will to improve on something..l am a 54 years old master carpenter and l totally understand everything you are trying to do..
I think the step up to LiFePO4 from lead acid may cause folks to get "current drunk" and it needs to be restated that higher current and higher voltage, as you scale up all present increasing problems that require increasing diligence to offset the increasing risks. On risks. Here is a bit of bad judgement. When tightening my small 105Ah 4S pack's bus bars I lifted a ratchet spanner. Not the rachet and socket. I even said to myself out loud, "Don't do it. Get the right tool.", but I went ahead and on the 4th tightening I shorted a cell with the spanner. This not being the first time I have shorted a high current battery I knew the drill pull HARD! The plating on the post and the plating on the spanner will weld together, you have to put your weight into pulling it off.... do it EXTREMELY quickly too as in a matter of seconds that spanner will be cherry red and you will have a fire or cell explosion imminent, unless the battery internals are designed to fail as is often the case before the cell would be driven into runaway melt down. The connector tabs and the insulation between them can be design to fail, short and effectively destroy the battery without the explosion.... you hope.
Thanks for passing on such great advise and saftey tips. Also verify the wonderful connection advise with a temperature probe on all connections points under load for 20 or so minutes and verify it’s not to high above ambient.
Thank You! As a degreed electrical engineer, I learned about theory. However, your practical tutorial is far more valuable. Fortunately, I had a very good theoretical professor before you. He said, "Always keep learning. Theory is good, but practice is best."
Preach it dude! I absolutely agree! I did a lot of work for people that if not done properly could have made them ill or worse. I had a gentleman that worked for me that was from Poland where he learned a saying that I really appreciated. The saying is, Aim for the stars and you'll at least hit the moon. I can think of plenty of circumstances when I was doing something for myself that good enough was okay as a temporary fix. But, good enough is never an option if it leaves the possibility for tragedy.
You are a pecfectionist, Ray. I really admire your "attention to details" in building your project, where others fail to consider. I learned a lot in this Vlog! I just subscribed to your channel and would like to learn more. Thank you very much!
Thank you Jojo. I think this part is really important. If you size the wires right, make good connections and protect it all with fuses, I think the risks are dramatically reduced.
holy crap - i didn't know BRASS bus bars were even a thing! thanks for the heads up/info. i'll definitely be checking mine when they get off the boat...
Having built sport boats in the past for a 15 year stint, I tend to agree with the use of a flexible connection between battery cells. Marine applications are a very high vibration environment subject to twisting loads that would certainly stress these terminals. Terminals that seem barely adequate for home use, let alone in boats where they will really take a beating, and high moisture exposure as well. It may very well be an ABYC (American Boat and Yachting Council) standard to use a flexible connection here. Have been away from industry for far too long to be certain. Maybe some others currently in the Marine industry can chime in with current standards. Thanks for all of your attention to detail, and the information you provide! I enjoy your videos very much.
I normally say to people i talk to. In Denmark its not allowed to do electrician work by yourself, but if you do. Do it better than the electricians! Im an former electrician and now wind turbine electrical design engineer of the biggest turbines. 15MW++ where we have thousands of amps in our busbars. I really enjoy watching your videos! Thanks for sharing!
resistance is always determined by the bottle neck not simply by measuring the 20 mm x 2 mm = 40 mm² area considering the amount of direct contact surface with the battery terminals can be smaller. If that contact surface area would be smaller than that terminal is the bottleneck. What is the real contact area of the terminal considering the nut is smaller than the 20 mm busbar? Assuming you have a 10 mm diameter terminal and a 13 mm ring surface on the terminal and a 13 mm outer diameter of the nut screw (with of cause 10 mm hole) you will have 2 same size contact surfaces each calculated with the radius as half of diameter = ( outer radius ) ² x pi - ( inner radius ) ² x pi = (outer radius ² - inner radius ² ) x pi = ( (13/2) ² - (10/2) ² ) x pi = (6,5 ² - 5 ² ) x pi = 17 x pi = 51 mm² This means you will have 51 mm² contact surface on the bottom terminal + such nut screw or 102 mm² and therefore the busbar squarespace of 2 x 20 mm = 40 mm² will be the bottle neck unless you get a 2,5 thicker busbar plate which would mean a 5 mm thick busbar. To be honest: 5 mm thick would not be enough Why ? The 3 mm hole lowers the squarespace from 2 x 20 mm to 2 x 17 mm which then means 34 mm² instead of 40 mm² which means a 3 times thicker busbar of then 6 mm x 20 mm (net 17 mm due to the hole) But that 5 mm thick 20 mm wide busdbar would equal what copper wire thickness ? 102 mm² is the total terminal surface and a cable of ( 102 / pi ) ^ (1 / 2) or bigger would push the bottleneck to the terminal. Remember that ^ 1/2 means square root, so squareroot (102 / pi) = 5,7 mm radius or 12 mm diameter copper cable That means a 12 mm diameter copper cable ( 4/0 AWG) would equal a 20 x 5 mm copper busbar if the joints are perfect. If you think twice you will realise that this comes close to a good 24 V jumper wire cable used for semi trucks or cars. But that all depends on terminal and nut screw diameters and has to be taken into account to get the best solution. Copper is expensive and therefore the chinese master lier dealer from the first battery batch order did work again on her reputation considering that the batch had arrived without busbars and needed a complain to be shipped. And those copper busbars come tinned cause tin looks better than the old oxided copper which makes it easy to fool us with tinned brassbars instead of tinned copperbars. China is called communist state but their dealers can be the most capitalist one you had seen sitting behind an iron curtain cause none chinese customer will no go to court.
My projects just took a turn for the better. Thank you for sharing your wisdom. So many of these build videos on RU-vid are lacking the basic analysis you have done. I am a new sub.
Ray, what a great video! I´m working professional as an expert for connectors in the automotive industy and I can sign every word from you! Especially the criming is in my point of view the most dangerous part of all. I have all the tools to do it by myself, but I didn´t want rely on it and ordered all the battery cables in the length that I needed with crmps from a hydaulic machine - all crimp parameters are controlled - there are alot! It was worth to me. Again THX for the good video an discussing that stuff!
Great video!! Lots of good info here - more people should be seeing this. I never understood the soldering of lugs. So many people tell me to "crimp then solder" and I'm sitting here thinking... well, if you crimp it properly, it's solid so where do you expect the solder to go?
Thank you for watching. I would love to see more people benefiting from what I am learning and what my 40 years of high end construction might add to all the great info that is currently available. Love your channel by the way. Keep up the good work.
Those guys are simply selling solder and soldering equipment cause the tin will melt and a bit will move into and look the soldering look tinned and shiny bright. you will not have a benefit except it looks good and what looks good makes you feel good unless you have the knowledge that it does not improve anything except the profit of the tin and soldering shops.
I've used Kopr Kote as it actually contains copper (not it's intended use however). Once that has been shrink wrapped, I'm betting it will last a long, long time. I'll really have to put that to the test beyond just using it on the battery terminals on the truck though (which are obviously fully exposed, in my salt air environment). Noalox might work as well due to the different types of metals involved. You continue to provide excellent and meticulous information for people and I'm thinking you should have far more subscribers (doing my best and liking all videos).
As a ham radio operator we have to look at great connections to get the lowest swr points for the coax and antenna connections, radios are expensive so great connections are a must. Power supply connections are also very much necessary. The info you put out is not only good but it is excellent info that can be used in high energy hobbies.
If perfection makes the difference between no harm and harm/death, a little more time, a little more money and the more attention to detail is a small price to pay. I have learned a lot via your explanation in just 2 of your videos. Great work.
I now understand the importance of good connections, so I'm off to get some new tools. THANK YOU!! for making my project safer than it would have been.
Thanks for the experienced knowledge we all need it. Don't feel bad about the bus bars there are a lot of people out there that love to cheat us out of our money.
I am just starting out on a solar project with very little experience in anything electrical. I have read and watched so many decent videos but needed this reality check of the dangers and the perfection that needs to go into everything.
Extremely helpful video, Ray. Thank you for covering the bus bars. I will be checking my bus bars because you put this video online. Will try to emulate your example.
Thats a bugger with the brass bus bars, I almost bought a bunch of CCA wire (Copper Clad Aluminum), the sellers boasted the copper part but man it was cheap. Now i know it exists i check carefully. Same with bus bars, they say they're copper but somewhere in the description it says brass.
I love this video! This is the kind of info that we don't normally see. Would love to see a video of the crimper in action! and the type of lugs you are using.
When I make battery cables for our farm trucks and tractors I use both crimp and solder to maximize the conductivity. First I crimp like normal and then I drill a hole on the ring side of the crimp and fill the end with solder. Leaves no space inside there for corrosion on the terminal side. I've cut open enough battery lugs to realize a crimp alone often can't be trusted....because eventually you see the green corrosion form on both sides of the crimp. For a battery like this inside away from the extreme weather conditions of a tractor or farm truck I wouldn't waste my time with solder....but I always solder connections on a battery that will be outdoors.
I really appreciate all the hard work and education you're giving me and I agree with you if we practice for Perfection we're as close to perfect as we can get when we fall short cuz no one's perfect
Thank you for all the information you give us. I knew that "big wires" are important, but I would never have come to the idea that corrosion is such a big risk. That should remind everyone to check their batteries and all their connections regulary.
Just be careful with split ring or star washers, in damp areas. I help write a paper on that years ago. The washers got white material on them causing high resistance.
Hi Ray , I love the passion you have for this and helping people like me with very little knowledge on building batteries . The reason they have thin wire on overhead distribution systems is because they run at high voltage, when volts go up amps come down and no need for big heavy cables in the air, that's why they have the step down transformer boxes . I'm in no doubt that you know this already 👍
That is a big part of it and the other part is that they are uninsulated so heat is not as big a factor and in the air, the heat disapates better by radiation and convection. Thanks for your kind words of encouragement.
Thank you for making this video. You made a very good point on wire and battery connections and I found it very helpful considering that I am planning on building a 48v battery bank as my diy project I want it to be correct and as safe as can be. I been watching tons of RU-vid videos on this subject and find your to have made good and sound sense. I am now a new subscriber to your channel. Thank you again for taking the time to share your knowledge.
Good advices. I used solid copper bus bars, washers and nuts all over the battery. We are dealing with 300 amp. No need to say more. Even the connections between BMS and battery are made in solid copper bars. Same for connections from battery to inverters. No cables for 300 amp! It requires bending copper bars, but copper is soft...
Hey now sure if you have already done it. But I would be great if you can teach us how you make those 1/0 gauge cables with the hydraulic wire crimpers. A video on that would be great. My application is a little bid different. Its to build wiring upgrade for Amp and grounding cables wires. But you are right its important to ensure your crimps are of good quality.
Excellent content well delivered. I used pre manufactiured tinned braided 250A earth straps, onto aluminium studs and noalox, in a RV setting. Cells are under slight compression forces though, so shouldn't be going anywhere no matter how many years of jostling the van takes. Hoping the 'braiding' dissapates the heat better. Maximum i should be carrying is around 100A on a 24V setup.(like a good margin of error, means you sleep better at night). The torquing of the lugs onto the cell studs though was a nail biting moment each time. :-) (This was before all the 'welded' studs were available on the cells(which i'm not a fan of anyways).
The 280 Ah EVE cells I buy have 2 studs on each terminal, and on top of that I use oversized cable for bus "bars",so I don t have to waste time on all this back and forth, if something in spite of this, not likely, should create a bad connection,it will be easy to feel if getting warm on the highest charge/discharge rate you need,test with temp gage now and then,most likely the hot spots will be inside bms.
Thank you Ray good explanation of conductivity. Iam retired now but on my first jobs was in electronics for companies for Boeing and Lockheed there cables conductors were mil's specs, usually copper plated an alloy of nickel and platinum, teflon insulated. In avionics weight is critical so the look for best alloys to minimize resistance in a conductors in a lesser gauge wires I was amazed.
Excellent tutorial even for the more expert one of us because, as you said, good is never enough and only perfect can lead to no trouble (we hope) I really appreciate your work 🙏 and I will stay tuned 😊
Great info, Ray. I just discovered your channel & I’m really digging what your doing. Thank you for taking the time to film your work share your knowledge. God bless you, bro
Thanks Andrew. I'm sorry I don't spend the time to edit them and make them more entertaining and polished like the other channels but I spend all day every day working on this stuff and I decided it will just have to do. Sometimes I wish I could offer more than just the info I compile and implement but I guess you can't teach a fish to climb a tree. I'll just have to be satisfied with swimming. lol Thanks for joining our little group.
6:06 I have long ago preached solder as the better connection. However if one considers the fact that LEAD or TIN has lower conductivity that Copper, then press fit is much better.
to deburr the hole after drilling and tapping, get a small countersink with 6 or 8 flutes and just spin it in the hole by hand, with a small amount of pressure. great info, btw. Thanks for all your videos.
I tried several methods of deburring the holes but by the time you use a countersink on both sides enough to remove the burr, there aren't enough threads left.
I made my own busbars out of 4 x 20 mm copper bar - I cut them with large bolt cutters - I hold them down with bell washers and nyloc nuts - - for my ev conversion - no fire yet
They make nice flexible busbars…. REASON …allow FOR expansion/contraction of each to minimize terminal stress. Specifically I am going to compress battery bank to 12psi and use rods with compression springs to keep them constant pressure parameters.(8-17 psi) However looking at copper chart I would need about 6mm for my EVE304, 300amps. I’m going with 2/0 welding wire as my discharge draw on the 48v banks will not exceed 200 amps, allowing plenty of leeway.further I’m cutting 3/8” copper pipe and making my own terminals using the hydraulic crimp. When calculating busbars, each one rating to it’s combined total discharge amps for your system.
The wires that transport electricity betwen houses is alternative ... So... Is capable of more power. But if you use dc on them, you will loose a lot of power. Bigest the wire lenth, biggest the looses.😉 About those brass brackets... Are good for less power...for other projects...etc. you don't need to thow them.
Very thorough. You can solder after you crimp. Could be a good idea if you are protecting from corrosion. But you don't ever want to solder before crimping. So they put the buss bars in for free right? You got what you paid for. Aluminum buss bars might do better mating to the aluminum terminals. Good idea on tapping the bars for the small ring terminal.
Since these cells expand and contract with SOC, I decided it was worth paying for the laminated/flexible bus bars, rather than using the solid bars that shipped with the cells.
I understand. I chose to restrain the movement instead and use the solid busbars. I'm only using 7 inch lbs of force on the nuts at 50% charge. When fully charged, they don't measure even two inch lbs more. It is actually hard to tell a difference in the pressure so I don't think they are going to be an issue. None of the battery pack manufacturers that I have seen use flexible bus bars. Most use long bus bars that are spot welded and the cells are not restrained with any real system that measures the force. It is an ongoing discussion that isn't settled but solid bus bars do not appear to be causing problems beyond theoretical. Poor connections seem to be at the root of the issues that happen. That and some isolated instances of very poor judgement.
@@asderven the bus bars have oval holes in them but it is only for the variation in the cell sizes for the initial install. Once the terminal nuts are torqued to 5nm there won’t be any sliding on the terminal and if you leave them loose enough to slide in the oval holes it will be a problem electrically. So I’m still left with needing to restrain the movement of the cells.
Nice video,I've sold over 500 traction forklift lead acid batteries,we used to weld the lead( pb)connectors to lead terminals with oxy acetylene torch then whilst hot we would smear vaseline to protect the terminal before we put the insulator. ive seen my batteries twenty years later and they were as shiny as the day they went out never a single problem,then the batteries became bolt on..long story short it was a total disaster..but just to give my opinion on your Anderson battery connectors I always just flux soldered them,we were doing serveral per week and again no problems,I find the crimp can very easily deform the shape of the pin those pins are spring loaded for contacting each other and any deformity can change this spring pressure/ alignment and cause burning... anyway, that's just my input for what it's worth! Good luck, Paul from Ireland.
hmm something you didnt talk about which is important with DC over a few volts is galvanic corrosion, especially on the + terminal side, which is sped up by orders of magnitude by the joining of 2 different metals. Ive always wondered about sacrificial anodes, not for marine use but just regular air use. you can make a bunch of pretty much pure zinc disks by putting pennies into a disposable cup and adding 2% OTC hydrogen peroxide and white vinegar and stirring. dont drink the bahja blast that results, and they should be newer post 1988 or whatever pennies. in my enclosed battery/supercap thing im building in a somewhat airtight "ammo can" build, I was going to put some at the bottom for thermal mass and just to preferentially take the oxygen out of the air and lower the level. add some desiccant packs too to keep an eye on things. this isnt really a true use of a galvanic sacrificial anode but it is how i would make some for basically free. maybe ill look for some nooks and crannies in my car's frame to stuff some extra ones in. most modern anti rust coatings are pretty good now days... but the mild steel used for car mfg is the absolute lowest quality in terms of anti-rust ingredients like chromium and they are really making the paint/finish do all the work... an example is basically every car battery in N america. look at the wires connecting the + terminal vs the negative, the + terminal is always significantly more rusted....
As Jojo mentions, you are a perfectionist and so am I. Sometimes however I do ask myself if this is all worth the effort (and before you even ask: yes it is because I know when I did not pay attention to every detail 😉) But I doubt the copper/brass difference on the bus bars matters. At 100A (4.8 kW energy draw) a 0.04 mOhm resistor consumes (I² x R) 0.4 Watt and a 0.17 mOhm resistor 1.7 Watt. With 15 bus bars this sums up to a 19.5 Watt difference ((1.7-0.4)*15) in power loss. This is not the amount of power that will heat up your batteries and surely not enough to result in a fire hazard. In a boat I would definitely use flexible bus bars. I have a limited budget to spend so when looking at replacing bus bars with copper or replacing my Ikea (Tradfri Floalt) LED panels that take up 1.5 Watt even when switched off (and this is 24/7 !!!) I know where I will spend my money
If you watch a few more of my videos on this subject you will see that my reasoning isn't about energy loss. Undersizing your conductors is a bad idea for several reasons, but on the subject of brass bus bars, a 2x20mm brass bus bar is the equivalent of 7AWG copper wire. 7AWG copper wire with a 90c insulation is rated for around 65 Amps.
@@RayBuildsCoolStuff My battery packs for a power wall would be completely different from yours. I would be more concerned about the thermal isolation properties of the wooden box than I would be about brass bus bars instead of copper or even flexible ones. Not saying you are doing things wrong here - I would just do things differently. I have always used a mechanical crimping tool and thought this was the perfect tool for me. After seeing this video I am convinced I need to get a hydraulic one instead to make our new power wall. Even if I would get the same results with my current tool, I want the perfect tool for a perfect result 😁
Like the video. Very well presented. I got a simple question…. You know how most BMS’s have a couple of cables for their input and output… how to properly determined the correct size lug to use? Let’s say two 7AWG; which size lug to use?
There are charts that show the cross section of different wire sizes. For instance, if you look at the cross section of a 4 gauge wire and multiply it by three you get a combined cross section that is very close to 1/0 wire size so I use that size lug when joining three 4 gauge wires in one lug. Is that what you are asking?
1.3mOhm * 200 Amps = 0.26V drop. 0.26V drop * 200 Amps = 52 watts of heat! Copper has an air transfer coefficient of around 14W/(m^2K). The bus bar has a total surface area of around 0.005 sqr meters. Works out to roughtly a 60*C bus bar in 20*C air. Or I messed up teh maths somewhere.
Kudos to your camera operator, what's the name of the carbon conductive compound. Is it necessary for the temperature leads that you tapped off of the bus bars? Nice catch on the difference in resistance between copper and brass.
Nice catch with the brass instead of copper. You need to check everything from China, they don't care if their cost savings starts a fire. The seller might not even know themselves. The right tool for the job is indeed critical.
hello ray, thanks for this video, I learned some things. I would like to tell you that I don't agree with the resistance measurements that you make, I think that the resistance should be measured with an equal length, I would be curious to know the difference in resistance between a rigid and flexible bus bar of the same length, in copper of course. Thanks for what you are doing.
Thanks for a great video. I am a little concerned about how to connect batteries to bus bars using cables. Eg. I am using 2/0 welding cables with tin coated ring type crimp terminals to go between the batteries and bus bar and the same type of cables and terminals to go between the bus bars, fuses, and switches. I am using Victron 600A bus bars, Three Renogy 12V 200Ah LiFePo4 batteries connected in parallel. It seems like I should make the connections as short as possible and as simple as possible. Could you give suggestions on the conductive paste and anti-oxidant you use. When looking, I saw a MG Chemicals 847 carbon conductive assembly paste. Would that be okay? Should the paste go on every connection? What milliohm meter do you use and do we need one? Thanks again.
very detail explanation, i hope you don,t go overboard trying to squeeze the last drop of juice. I been using Lipo4 battery for my cars for 10 years now. Its very robust and can take lots of abuse unlike Pb battery. I think you should concentrate on all connection and joints during wiring as this are the weakest link in the whole system...and do you know the losses of the wiring from the solar panel to your battery? it is way more than what you gain from the saving in the busbar . Finally if you keep your charging below3.4 to 3.5v and discharge preferable above 2.8v the lipo4 batteries voltage differential between cells is not critical. This also means your battery will last a whole lot longer as you use about 70% of it max capacity . Regarding the brass ,copper or aluminium busbar, you must remember you are getting it free . Try paying 3 USD for 1 pc you will probably get a beautifully craft masterpiece that you can use as display in your living room. The Chinese seller make a pittance selling you the battery set so you cannot expect perfection.
