Hey, cool video! I have the opposite Problem…. Where i live, it gets terribly cold. Less than 0°C. Mostly like -10°C. And you sadly cant charge lfp below 0. So the Victron Solar charge controller has a really nice feature. Streetlight. So i hooked an 18 watt heat-mat (with a little-cheap inverter) to the load output port of the controller and insulated my batteries. So, before the sun comes up, it will preheat my batteries for 2 hours (perfect) and after sunset for another 2 hours (only if its VERY cold). That‘s why victron is just the way to go! The tesla of solar companies! Very cool design, your battery bank. Lg
Good thinking, my outback flexmax 80 charge controllers have similar functions but I dont need the heating setup as we live in the tropics. It would be nice to install some air conditioning - gets quite hot in our utility/solar equipment room. We normally keep fans on full time to keep the temps. below 90°.
Aluminum is known for hot connections. When aluminum wiring was used in housing the plug terminals can get hot over time. Oxidation over time cannot be stopped so I would not recommend aluminum bus bars. go to copper or copper cladded.
When used within specs, there is nothing at all wrong with aluminum wiring. Most of the issues with aluminum wiring in houses come from either using aluminum wiring with components (switches/outlets/etc) not rated for AL, or from using unapproved methods to connect copper and aluminum wiring together. Aluminum expands and contracts more than copper when it gets hot, so when you connect aluminum and copper wiring together and pull a large load, the aluminum will move differently (more) than the copper. Over many such cycles, the connection can get to the point where it loosens up and can start arcing or making intermittent contact. As long as you follow code and use connectors/components rated for aluminum wiring, it is just as safe as copper. The cables that connect my 200 amp house service to my neighborhood transformer are aluminum. All of the high tension power cables on huge towers crossing the country, carrying electricity from the generating plants to our cities and towns, are aluminum (or aluminum wrapped around a steel core for extra strength).
@@ozonepat I believe you are correct about the house wiring issues with aluminum wiring. Also, it is true about your home service entrance being aluminum. But, you left out the part about the lugs being specifically for aluminum wiring and the required use of anti-oxide paste.
Resistance! There is a math formula.for the size conductors within the internals of the batteries. I have watch several series battery videos and the one thing . The center of a
@@ozonepat As you state, temperature changes and aluminum are a problem. This is due to the greater expansion of aluminum with respect to temperature, and the rapid formation of an insulating layer of aluminum oxide. This is especially problematic with connections that do not maintain constant tension. Like screw clamped battery terminals.
@@ozonepat I think there are significant problems with aluminium wiring. Aluminium oxide is not a great conductor and aluminium reacts with oxygen in the air very quickly after exposure. Within minutes.
I've been using my self-made flexible braided copper bus bars for two years now without any issues like what you're seeing. Small deviations/stresses on this type of terminal lead to bad contacts. A bit of thermal stress or slight movement - It doesn't take a much since they are only slightly torqued... You're also dealing with oxidation of the terminals. For that, I have a process: I take some steel wool and mineral oil and use a dowel he size of the terminal with a hole in it to remove the oxidation. Then, clean them with a rag with mineral oil. The oil prevents the oxide from reforming. Then I apply MG Chemicals 847 - one of the components of 847 is mineral oil as well (to prevent corrosion of the carbon in combination with the other materials of the terminal/busbar). As I said, no issues in two years.
I use MG Chem 847 too. I haven’t performed any A-B testing but I do it to be cautious. I have even considered using it between ring terminals and cell bus bars and also between lugs and the busbars in the Victron Lynx bus bars. Any thoughts on doing that for high current systems, especially 12v? Thanks
@@cuisinartOH1 You don't really need it in those cases. The reason to use 847 on terminals is twofold: it inhibits corrosion and it improves contact between the terminal and bus bar especially since you can't torque it down much. Lugs contribute negligibly to the current flow and there is no galvanic corrosion. Same with the ring terminal and bus bar: nickel plated copper, or copper on copper - so no galvanic corrosion between dissimilar metals, and you can torque them properly.
Cleaning aluminium under oil without exposure to oxygen is about the only way to stop the oxide forming. Most of the oxide layer will reform within a minute when exposed to air.
Hello Andy. To sand the buss bars, fix the sand paper on a very flat surface (not the wooden bench, I use the back side of a mirror), and move the bussbars, the one finger technique makes uneven surface, I suggest using 800 or higher sand paper. Cheers. Chritophe.
4nm ist definitiv nicht genug, hier von EVE :These cells have a 10.6mm M6 stud laser welded onto the terminal, which is capable of a torque rating of 8nM. We’ve tested a few at a torque of 10nM without a problem just to give you a bit of leeway and peace of mind. We have tested sample cells at a high C-rate discharge of 160amps and have seen a relatively minor temperature increase to around 40°C which is well within acceptable limits. We ran the high-C test for just under two hours. wiedermal super video.
ANDY PLEASE DEFINE A VERY FINE GRIT SANDPAPER IS THAT 100 200 300 PLEASE ELABORATE? Excellent example of a problem and the correct solution! Very much appreciated Andy!
Soft copper flat washers tend to "Smush" a little bit and help to make a better connection with a flat rigid bus/interconnecting bar. I've used this solution in a similar situation with Nissan leaf cells. There was no heat at all once they were applied. Cheap, easy to replace, and drop them in some Tarn-X and wash them with vinegar, all new again! Your solution seems to work well also. But, I found the copper washers to take care of the issue for longer without the need for cleaning as often. Great Video! LOVE your system! Its really looking sharp!
Most don’t realise that aluminium is actually an incredibly reactive metal. It reacts with oxygen almost immediately to form a thin, tightly bonded layer of aluminium oxide. That layer protects it from further corrosion so it “looks” unaffected. Iron or steel actual rusts much slower, but you can see the rust quite clearly because of the colour change.
Andy, by chance might you know what alloy those aluminum bus bars are? From the surface sheen and how they appeared to heat, I question if they might be 4000 or 6000 series aluminum, which is structural and because of silicon and other alloying have about half the conductivity of 1000 series pure aluminum. 2024 is alloyed with copper and a bit better for conductivity over 4000 or 6000. When we made aluminum to aluminum and copper to aluminum connections, in HV substations and MV switchgear, we polished the aluminum surfaces as aluminum builds a film of oxide in a matter of mins, and applied generous amounts of PENETROX A-13, and used duraluminum bevel washers rather than stainless or plated steel which will heat more and the Beveled duraluminum washers were to reduce loosening We had routine re-toque schedules for buss bar connections.I often observed that after high loads and heating seemed to induce corrosion and loosening, and I noticed that with Aluminum bus bars and terminal connections, that thermal cycling and expansion of the aluminum would often cause threaded connections to loosen. In 480VAC and 4160VAC switchgear that used Aluminum bussbars that i recall that for 200a the busbars were about 50mm wide and 10mm thick, and had a lot more surface area, with larger bolts and torqued to about 18-ft-lbs or 25 newton meters. As explained to me by the manufacturer of the industrial Aluminum buss bars I installed, that the surfaces need to be polished and NOT SANDED, and that it's not only the chemical corrosion inhibiting properties of 'No-Ox' paste is important but, that it be applied generously as to exclude oxygen impingement, and not of the type that dries out.
@@diyEVguy There's a lot of complicating factors such as connecting numerous low-voltage, low internal resistance cells, connected in series and delivering high current. Any substantial resistance in any connection will disrupt the balance and performance of the system.
From the beginning of your great channel and when you were facing the problem of high temperature in the Busbar, I advised you to use the flexible Busbar, as there is a type of it that looks exactly like busbar, but it contains in the middle a flexible copper part.
Came across your video. Decided to grab my fluke temperature gun and check all of my bus bars. They're all ambient outdoor temperature. So I touched them, I touched the posts, I touched the wires everywhere. I have no heat at all. I built my own bus bars out of 3/8ths i.d. copper tubing. I cut my lengths. Punched holes in the ends with a Harbor Freight punch and die set. Rounded the corners with the bench grinder. Covered the center with heat shrink for looks and to cut down the amount of exposed contact area. I believe copper is the solution to the heating problem. Aluminum is high resistance. And has the oxidation problem. I rented an apartment 30 some years ago. We were laying in bed at night and I thought I was seeing a faint blue light occasionally. My ex wife couldn't see it and thought I was crazy. After thinking about it and seeing it again I removed the cover from the service panel and I found it. One of the breakers was arcing under the terminal. I tried tightening it but it continued to happen. Next day maintenance fixed it. That's where I learned about paste. They also had to replace the breaker because it cooked.
It could be an interesting idea to add real-time temperature monitoring for the busbars to automatically detect faults and loose connections (before there is smoke). If you already have Raspberry Pi in the cabinet, it should be pretty easy and cheap to add DS18B20 or similar 1-wire sensor for each busbar and other critical component. Just have to be careful to safely isolate the sensor leads from the busbars not to cause short circuits. Also adding a piece of tape on the busbars or other metal surface makes them less reflective (and more emissive) on IR and allows you to see the real temperature with thermal camera.
To maintain consistent constant pressure on conduction terminal connection points, consider using concave flat washers between the nut and flat washer at the stud busbar term point. They are available in different thicknesses for different torques (terminal nut forces).
Well there ya go. Nice work. Spose it is hard to see allum oxide as apposed to iron oxide (rust) I used copper busbars, buffed with scotchbrite and carbon contact paste. Wouldn’t have thought allum oxide on the busbars would have made that much difference. Clearly it does. Very informative vid thanks for sharing
I'm wondering if the aluminum busbars have slight oxidation on the contact surface. From what I recall aluminum oxidizes quickly from an initial shiny surface.
I wonder if also adding conductive grease onto the terminal to battery connection might improve. Do you know what the terminals are made of? are they brass? steel? Also if the bus bars are getting warm under a slight change of conditions, I would build in a safety factor and maybe double up the Al bars so even if there is uneven battery height, there is another way to reduce the heat. Or switch to Cu bus bars. Copper is more ductile than Al, so it would probably conform better to the different physical terminal levels. This was good information. I want to know if you had sanded and greased with NO-OX-ID the first time you put the bars on? So was it due to new oxidation, or was there oxidation initially?
Yes, I have cleaned the aluminium terminals and busbars with NO-OX-ID when I built the battery (see video here: ua-cam.com/video/9RMTaaZr4M4/v-deo.html)
@@OffGridGarageAustralia I watch your videos out of order. if you did apply it the first round, that is not good if it caused problems later. Someone else recommended a different product that they say is better. It's sold on Amazon as "MG Chemicals 847 Carbon Conductive Assembly Paste, 1 oz Jar" also an anti-oxidizer, conductive grease and thermal paste. If you need a topic for a video, I'd like to see a side by side to see which works better.
Yes, love my thermal camera because it makes it easy to find bad connections. I have not watched the entire thing, but I did have to lightly hit my terminals with a wire brush attachment to my dremel before adding antioxidant to the terminals. Yes, keeping the cells level in respect to each other makes a big difference when using busbars, especially the thicker aluminum. FYI, you also need to clean the busbars. Watching, I see you figured that out. The paste won't clean oxide, it just prevents it after you clean. The aluminum starts oxidizing right away.
As others have posted, oxide forms quite fast, i'd be removing this on a very flat surface, such as marble bench top or a piece of glass. it's the same process as flattening hand plane or the back of a chisel, i go up to 8000 grit on my chisels, its a mirror finish. but 800 grit then 1200grit will do the job, the battery cell terminals will need a quick clean as well, as i'd imagine that you have the same oxide issue with those. I'm enjoying the content Andy, keep it up
Up here in Norway, we use a lot of aluminum cables. When we connect them we scrub/sand the connecting point immediately after removing the insulation. We also use contact grease. My old rule (15 years ago) was scrub, grease, scrub with grease, wipe then grease. Like one commented below, alloy oxidation happen very quick and is insulting much. Btw, really like this channel and hope you soon can calibrate after overcoming this heat challenge.
I wouldn't use Aluminum bus bars. Aluminum oxide is an insulator, and forms naturally on unprotected aluminum in air in seconds.Stick with Nickel plated copper, or raw copper. CuO is electrically conductive, the opposite of Aluminum. I say this as an electrical engineer who has done a lot of work with large battery systems.
I have tried different options in the past (it's in the older videos) but the result were always sketchy and not really great. I now have no paste in between the terminals and bus bars and it's been great since. I tried No-OX-ID and MG Chemicals 847 both with mixed success. Got them both linked on my website here: off-grid-garage.com/battery-accessories/
@@OffGridGarageAustralia Thx Andy! Same here since 2 months now. Tested with 100A all stays cold except the mega fuse, which gets lukewarm. Was just wondering if something should be done for longer term oxidation-avoidance...
Hi Andy, as always... nice video 😏. Maybe a problem with oxide layer on the aluminium busbars or terminals? When I build my battery last year (same cells) I found a paste from Wago to "crack" oxide layer and protect against oxidation when using aluminum wires in house installations (was popular in eastern part of germany). It is called "Alu-Plus-Paste". Before mounting my busbars I cleaned them with a sanding pad and used this paste. And up to now it works! Even with high loads I have no hot busbars. And another comment regarding the unstable voltages in the JK BMS. This is caused by your load with the inverter. The load current on the input of the inverter ripples with double grid frequency. And the BMS has no filtering included. With a pure DC Load the values are stable.
Yes. No. But it does not "correct" a problem, it will only help to "prevent" a problem. Must ensure the connections are clean before assembly and tightened correctly. Aluminum is horrible because it quickly forms oxide which is non-conductive. That needs to be removed, preferably in a non-oxidizing state (buried in grease, for example) and then assembled with no exposure to oxygen. This is standard practice required by code in the electrical power industry.
Andy, just something IV done on my 12v system. I hand turned my studs into the terminals to bottom then 1 full turn back. Then hold the stud with an alien key then tongue the nuts down (bit like doing old school tappets on engine) I'm using aluminium bar at 25mm X 3mm. IV pulled 150amps with little heat.
Learn how the electrical power industry makes high power aluminum connections. You are on the right track. The oxide grease does not significantly remove oxidation, just helps prevent new from forming. Aluminum oxide is very hard, and is a very good insulator, and begins forming immediately on exposure to air. Basic process: clean the aluminum (like you do with sandpaper) and remove resulting dust and particles, coat with oxide preventative grease, scrub with brass brush also coated with grease, assemble connection. (Obviously on aluminum to aluminum connections both parts need this treatment.) The second cleaning is to break up the thin oxide layer that formed while and immediately after the first cleaning, and doing it while covered in grease prevents new oxide from forming. Doing two cleanings and a brass brush on the second is to minimize the amount of non-conductive particles in the grease which will be included in the connection.
When you think about Aluminium and rust then the Aluminium oxcide is what's there, I think it makes sense to have the connection points sanded on both busbar and terminal. The tinned busbars don't have this issue and I think also the tinned connectors of Digital Mermaid. This might leave a bit of room to just strap all cells together, also not to have them move a bit. However with the temp differences in AU it might give other stress, so maybe flexible busbars are the way to go afterall, just to prevent issues with moving cells. You see, there are a lot of options, whatever you choose is the right one when chosen 😁👍 you checked all the options and this was best! Keep up the good work!
aluminum oxide is tough stuff. to get a good connection you need to be torqueing enough to bite through the oxide. tinned copper is probably the way to go.
Andy, I Tig weld Aluminium most days and yes, you are correct about it being an oxidation issue. The oxide layer on Aluminium has a higher melting temperature than the alloy base material and needs to be removed. This is done by welding in AC where the AC+ side of the waveform removes the oxide layer and the AC- side does the actual welding. Consider also the busbars have been laser cut and that introduces a problem as the cut edges are oxidised by the surrounding atmosphere as they cool. From a welders viewpoint as good work practises we will linish laser cut edges before welding and on some Aluminium plates that are particularly oxidised sand the area that needs to be welded prior to welding.
Andy, I think again that you can measure joins with ohmeter so no need to make these 100a discharge test and thermal camera, or only to check the final test. But with ohmeter you could go step by step.
Andy, you have the worst luck with those terminals lol... I have just crushed copper pipe i flatterned into bus bars and have zero issues with hot terminals like you. I would have thought the torque of the nut would have flattened the aluminum busbar for solid connection but that doesnt appear to be the case due to them being so thick. My busbars are just plumbing copper pipe i bought from hardware store that i flattened in bench vise and punched holes in the ends for connections.
I made buss bars like digital mermaid did for a 12v solar setup.no problems with them heating up at all.i used them due to keeping cells in their foam shipping package.might try them to see how they would work.
How are you getting the battery stats into the Victron Venus (Raspberry Pi)? Would you mind sharing the wiring details or even better talking about that in a future video?
When welding ally you have to sand the surface before welding as oxide surface layer can form in less than 10 mins if atmospheric conditions are right. So it makes sense that you would have to sand both alloy faces before assembly and the no oxide paste should stop the contact surface oxidizing once assembled.
Probably need to try some washers on the ones that’s reaching above the flat terminal surfaces . That’s probably why it’s heating because of them barely seating on the flat surfaces vertically . May the solar be with you .
the same problem with alum has burnt down many a house in the usa. the alum oxidizes that is why the paste. those bars look anodized (that is a oxide layer) that you have to remove to get to the metal under. hence the serrated nuts to bite thru the oxide layer and keep the nuts from coming loose (look at how they do the ground wires on a car for that reason). good catch / save. same problem when trying to weld . has to be clean to metal.
Hi Andy. Yes you have had your fair share with buss bar problems. That aluminum buss should work perfectly IF the terminals are the same hight AND parallel AND flat AND no oxides on contact surfaces. The first to criteria can not be reliably maintained because of battery regularities. The aluminum buss bars are too stiff to conform. The oxides, tho correctable, are a contributing factor as well. The flexible (2/0cable which I have used ) buss bar are the way to go, but they can be even improved upon( see my video). You should have no problems pulling 100+ amps. I find that the 2/0 cable itself becomes the limiting factor when they make nice hand warmers at 180 amps.
I would suggest a copper washer or in your case, aluminum washers on the lower terminals. I had similar issues on some different cells. 100 amps on a 16s is no small load! Stoked to see batteries on the shelves though Andy!
Is it possible that the busbars are very slightly warped or non-flat from the manufacturing process? It wouldn't take much deviation to produce a reduced contact area between the bar and the battery terminal and ramp up the heat generation. It would be interesting to run the problematic busbars across a nice new sharpening stone, and see whether any areas stay unabraided, indicating a slight warp.
I don't like using aluminum and rigid. I think you would be better off going with the flexible ones. I would imagine that they are copper. I've been using carbon conductive grease on all of my connections also. Similar to the grease that you used, but carbon. It's a little messy and hard to get off your hands. It increases conductivity and its anti-oxidation. Very informative video!
You can expect to have ongoing issues like this with the aluminum bus-bars. I suggest that you abandon the them and get some good copper bus-bars. If you don't want to pay the price for copper use the mermaid's copper-wire/copper-terminal jumpers. It seems to be that the aluminum expands and contracts so much with temperature cycling that you loose the gas-tight connection. Once air can get between the two surfaces, the connection will go "high" resistance. Also, the no-ox paste here in the US is black and sticky. It works okay but gets black onto everything around you - tools, wires, hands, clothes, etc. The stuff you are using just looks like grease.
Andy, you would be better off not using flat washers. The serration on the nuts are to dig into the aluminum, penetrating any oxide and creating enough pressure to make a gas-tight connection. As an experiment, you might try taking the temp of a connection w/o the washer.
I have ordered the No-OX-ID from the US, so I wouldn't expect this is different from what you get. The flat washers are just to protect the busbars from these flange nuts. The pressure should be the same with or without washers.
Hola: mi mas sincera enhorabuena por estas páginas tan interesantes y de las cuales he aprendido mucho; GRACIAS y Enhorabuena. Ahora si me permite un comentario relativo a este problema de los contactos. Permítame que le sugiera si la pasta anti oxido para aluminio es conductora o realmente si Usted mete la puntas de su polímetro en el tarro de la pasta anti óxido, este le indica falta de continuidad o por el contrario le indica como buen conductor. Si el polímetro le marca que esta pasta es aislante, ya sabe, es mala, no la use. Quizás lijando y después usar pasta de aluminio conductora y antitérmica, la misma que se usa para los procesadores del ordenador, quizás funcione. Perdone intromisión. Un saludo desde España.
I had some of those bus bars and they came rather rough. I cleaned up the edges and sanded them to get better contact. I ended up making my own thicker bars later on.
Still do not unerdrstand why those exremely sturdy bus bars are still your favourites. OK, OPTIC property ist very pleasing. From ELECTRICALprospective they have lower resistance than flimsy ones. But from a MECHANICAL prospective they generate a lot of stress to the poles of the cells because they do not adapt their shape at all. They do not cope with any mechanical tolerance or thermal strain . Additionally: those oval holes redeuce the CONTACT AREA considerably. So you aggregate lots of disadvantages just for one single advantage to have less resistance in the aluminium itself. On other hand copper lugs are pliable (even at 4Nm) and have round holes. Thus they enable maximum contact surface and lowest resistance. Mermaid got it right! I built my battery like Mermaid. Additionally I replaced the studs made from stainless steel by parts made from brass. All parts (studs, lugs, nuts) were cleaned with cleaning fleece (see plumbing) and coverd with paste before assembling. So the electrical current can go along two path: (1) direct from pole to lug and (2) second path via the brass stud/nut/lug. My suggestion is to setup a test where you measure the resistance along different means of pole contacts. Will be very illuminating to everybody.
Hi Andy. Very good joob, you're doing. Regarding the bus bars. Why not gold plate them? Than the oxidation is not a problem any more. In Australia they are gold plating all possible stuff. Parts of plants and even old miner's shoes. :)
I think the super thick aluminum and then with the washers on top prevents any flexing to absorb the tiny height differences. Maybe try the thinner bus bars without washer to help them flex and make a flat mating surface. Are there "flexible" copper washers, something like solder wick and put them underneath the bus bars.
Another great vid Andy. I think I like the copper cable or busbar idea, or at least cca, but if you want to get those aluminium bars flat and shiny, I would suggest the glass mirror and fine grit 1000-2000 grit paper idea, and to sand the whole bar perhaps utilising a sanding block to keep each side flat, then maybe a light buff polish and immediately apply the paste with a polishing cloth one at a time. Also, I dont know how flat or stable ur battery cabinet base is, it does look good, but would a thin excercise matt type density foam base under the batteries, may (or may not!) help them sit or settle into the base allowing a certain give in the terminal area for getting a more even contact. Love ya setup & vids.
Andy, if your going to take the time to clean & polish the bus bars, I would also remove the battery studs and sand the top of the battery terminals as well
it makes sense to do that, as they will have the same issue, i just used 25mm dowel and drilled a 6.5mm hole with the drill press into the dowel and glued 800 and 1200 grit wet and dry on each end. i hare the welded stud version, but it will work the same without drilling the thread hole for andys cell studs
Hello I'm not sure, but it seems to me the problem is that there is a small amount of material left after cutting the mounting holes. Therefore, when you moved the contact, it adjusted itself. If you have a tracing ink, try to determine what the actual contact surfaces are. And then take one contact and cut it with a knife (after the circuit) and check if something improves. Sorry for the rough translation but I'm getting to work. Regards and good luck 💪
Maybe the issue is not just variation in the terminal height but the plane of the terminals are not level and with the stiff bus bars, only part of the bus bar is making contact with the terminal.
Nice work Andy, good to see it was exactly as we expected after our conversation. I guess it goes to show that "Sunny hot Queensland" can be harsh on bare aluminium. I'll be using these learnings in my own processes from now on too. Never stop learning! It's always surprising how many people comment before they've even watched the video. For the people who suggest to use Copper, you should go back through some of Andy's previous videos, he tried that, and the Aluminium ones have consistently performed better. However they were assembled almost immediately after receiving the bars from me. This delay wasn't expected so we can see the results. Copper is more conductive, however it's also a dissimilar metal, so that can cause issues in itself sometimes. Aluminium to Aluminium seems to be very effective, and the extra size of the aluminium bars counteracts the extra resistance. Andy also won't need to worry about vibration or expansion/contraction, because it's a stationary system and there's already a small gap between the cells to allow for this size change (explained in a previous video).
For my banks I bought flexible busbars, 300 A, from Weberpower. I think this is better than the aluminuim busbars. Maybe there is an galvanic interference between busbar and terminal, due the excessive moist weather....
Hi Andy, thank you for your videos, I'm learning a lot. Have you tried flexible copper busbars? They are made with 30 layers of copper and compressed on the ends. This is perfect for good contact on the battery terminals. Please, can you do a test and check hot spots with the thermal camera? On aliexpress, these are the busbars with yellow plastic protection, made by Weber Power Tech Big kiss from France
When you sandpapered the busbar, there was a ridge showing around the outside and the bolt hole, see 20:23. Is this the same on both sides ? The ridge will reduce the contact area. If not ridged on both sides then sand the flat side and put that against the terminal.
Interesting discovery in this video. I'd be going with the flexible type instead. You'll be spending many hours fussing with those rigid bus bars I think. Your shelves might be perfectly flat, but the battery terminals could be slightly off perpendicular and/or they could be at slightly different heights... either will give you headaches.
Hi i had a large lead acid battery banks 48v 1200 ah i used aluminium busbaars and also had som heet up alot i replace all my busbaars wit flexible busbaars and thet solved the problem i thought it was because of different resistance in the aluminum busbaars but don't now if that was the case
The answer might be in the slots in the bus bars in that they don't make full contact with the batteries/posts/nuts on top. Lesser contact means higher current in less space or a slight reduction in capacity. The homemade connections with lugs allow fur full contact. Also consider that aluminum doesn't flow current as well as copper does.
Already before watching this Video I decided to make my own busbars same as Digital Mermaid, to provide breathing of the batteries, which are compressed in my case, with 4mm rubber sheets in between and tensed together with four round 4mm steel rods which are bended into a slight zig zag crooked line, so they act as a spring. At the ends I threaded them. The M4 nuts at the ends of the rods must be tighten with 0,565Nm (not oiled) to reach the 300Kg compression (with 4 rods). Just for comparison M4 standardized strength classes reach from 3,3Nm till 5,6Nm tighting force, which results in 438Kg up to 754Kg contact pressure with ONE tiny M4 bolt! I guess many others overdue the compression, when i see all this thick threaded rods others have. Nothing against your friend, but aluminum has at least 35% less conductivity compaired to copper. The contact surface will never cover 100% of the electrode, so theres a bottleneck for sure. Not to mention additional problems with movement, alignment and corrosion will occour. The solvation of all this Problems: Flexible busbars as them Digital Mermaid made - cheap and good!
I was watching another video about those batteries and he said you don't want the bolt all the way down touching. needs a gap. You might want to check into that and the quality of the bus bars. I see others also making pure copper bus bars to avoid issues like what you are seeing.
If you use aluminium busbars, you definitely should not use washers (at least not alone. The prevent the nut from scratching through the oxide layer. Better/best solution: You should use spreaded washers (don't know if it is the right name) e.g. DIN 6796 together with a washer and a spring ring e.g. DIN7980. This is what you learn in germany, when you are an electrician trainee. The spreaded washer will cut through oxides, the spring ring will keep the force mostly equal and the contact gas tight when temperatures change (at least the ones of copper) and the washer uncouples the spring from the spread washer. So, the screw stack is: Busbar -> spreaded washer ->standard washer -> spring ring -> nut. Aluminium oxide is one of the hardest and most isolating materials and only some atom thick layers of aluminium oxide will lower your conductivity reasonably. There is one quite new material on the market (CUPONAL), that has an aluminium core and a thin copper layer on the outside, combining best of both worlds. In my opinion, it could be improved by a tin layer to protect the copper from oxidizing, but the copper oxide is quite weak and easily can be scrached away by the screw. Sand paper will only be a short term solution. Temperature differences will change forces, oxidation will find it's way in and the resitance will increase again.
Could it be that alcohol does not remove Aluminum Oxide. Directions for using No-A-Lox compound on aluminum at the public utility I worked at before retirement required applying the anti-oxide, brushing thru the compound with a stainless steel brush to remove AL Oxide, and leaving the No-A-Lox compound in place to stop oxidation of Al (apparently it happens real fast if the raw Al is exposed to the atmosphere for any length of time). Make the bolted termination, wipe off excess NO-A-Lox compound and test. It might fix your problem. Also depending on how thick Al buss were fabricated, by sheer and Whitney punch for holes, the bus conducting surface may not be flat one one end and may not be parallel end to end.
I've been following your channel for sometime.. I am encouraged by your experience of connecting 2 banks in parallel do not matter even if discharge states are not same. I plan (dream) to connect 2 indentical 48v 100ah packs with individual BMS (Active & Passive) in series (96v, 100Ahr) then charge it at 96v and run an EV. However, inan emergency I will reconnect them in parallel making a 48v, 200Ah power pack to supply my home solar inverter. My doubt is, if there will be issues and might damage anything when alternating between 96v & 48v? Your advise would give me a direction on how to proceed. Watching here from the Philippines.
Raw aluminium will oxidise instantly and form most of its oxide layer in about a minute, then its full layer of oxide stabilises around 10 minutes. Not sure how to get around this besides the crushable stainless ridged washers, or a spring washer, to break through the oxide. I'm lucky to have copper terminals and bus bars.
Allium bus bars? Annodised? I've solar bus bars on my feed in. If I put the multimeter on them sometime I get a reading others not. However I have bare allium. That's no problem. Check the bus bar is actually flat. Scratch the surface. Sand them down more than you have. The bars come coated to stop the oxidation. Use copper compression washers under the bus bars.(not the gapped type but solid)
Hatte auch das Problem mit Wärme Entwicklung und driftende Spannungen. Ich habe mir von WAGO die Alu Kontaktpaste besorgt, alle Verbindungen davor noch geschliffen, dünne Schicht Paste drauf, seitdem ist Ruhe. Auch die einzelnen Zellenspannungen sind seitdem stabil.
Hello Andy. I’ve read the cells specification from Quishou. I can read. This. The pole is a double aluminum pole structure. The internal screw with size M6 is used in the poles. The anti-torsion of pole is 8Nm. The torsion should be less than 8Nm when used. The effective thread hole depth is 6mm. I suppose you far from the normal fork required? Thanks to yours vidéo I’ve ordered 32 cells yesterday! Big job is coming. 🤪
Did you order cells with or without welded studs? A week ago, I was asking to QSO for a quote and for now they have cells only with welded studs and i don't like it
@@zarbonida you’re correct. I did not like also but I prefer to order them. They was cheaper and much better quality return i saw on internet compared to the others company. I’m worry about the total surface for connection. It’s smaller but million of persons use them. Seems it’s not a big issu! Perhaps Andy have an idea on this point ?
I am a bit surprised you did not need to sand or wire brush the terminals!!! Just as an aside, you demonstrated one of the big dangers of Aluminum wiring vs Copper wiring. Copper oxide is conductive but aluminum oxide is an insulator. Consequently, it is much easier to get a bad connection with aluminum.
You can see the reason why most electrical connections in computers are gold plated, no oxidation ... mmmm ....Gold Plated Busbars. Next workshop for the garage is electro plating Busbars in the off-grid garage
I am on battery 4 of 10 using tin plated copper bus bars from Dongguan Lightning and Shenzen Luyuan. 90 Amps flowing per battery from two Sol-Arks. All running cool. Cleaned aluminum terminals with scotch brite/acetone, applied carbon conductive paste (MG 847) and torqued 6mm nuts guttentight (>35.4 in-lbs!). We told you before about aluminum's crappy conductance properties.
I predict you will have endless issues with those aluminum links. I'd ditch them yesterday!! Use the great flexible ones Mermaid sent you. Besides the thermal cycling your batteries will experience from the ambient and operating losses will cyclically try to move the batteries back and forth thru the terminals due to thermal expansion. Are those stainless washers on the terminals, I don't recall if you've mentioned that? Stainless and aluminium will always corrode.
Get some of this: Jointing Compound Grey Aluminium Crimps Aluminium joints (bolted and crimped) should have jointing compound applied to joint where it is not pre-loaded in the barrels of lugs or links, Grease acts as a corrosion inhibitor, Used after scratch brushing 30% suspended zinc particles and 10% fumed silica fill voids - Zinc and silica assists with current bridges in joint
Havs the bus bar material or other aluminium components been anodised / naturally anodised over a period of time (oxidised surface to the aluminium). Can be used to create colours on Spat devices. all the best.
Just came to this video, after testing 250A load on copper busbars with 2S4P setup (12V > ~3000W of power on inverter). The temperature on some terminals was around 70-80C.... Turns out I had to tighten them to ~5Nm, afterwards they were room temperature. So I can confirm, that copper busbars (I got elastic ones from Ali, rated for 300A) are the way to go.
Add some ventilation. Aluminium oxidezes really really easily. Basically if it's not shiny it's oxidized. But even with copper I think there will be some heat.
Hey, cool video! I have the opposite Problem…. Where i live, it gets terribly cold. Less than 0°C. Mostly like -10°C. And you sadly cant charge lfp below 0. So the Victron Solar charge controller has a really nice feature. Streetlight. So i hooked an 18 watt heat-mat (with a little-cheap inverter) to the load output port of the controller and insulated my batteries. So, before the sun comes up, it will preheat my batteries for 2 hours (perfect) and after sunset for another 2 hours (only if its VERY cold). That‘s why victron is just the way to go! The tesla of solar companies! Very cool design, your battery bank. Lg
Good thinking, my outback flexmax 80 charge controllers have similar functions but I dont need the heating setup as we live in the tropics.
It would be nice to install some air conditioning - gets quite hot in our utility/solar equipment room.
We normally keep fans on full time to keep the temps. below 90°.
Seplos BMS has a heater option you can request when ordering and they come with a heater so it is all managed on the bms level.
Aluminum is known for hot connections. When aluminum wiring was used in housing the plug terminals can get hot over time. Oxidation over time cannot be stopped so I would not recommend aluminum bus bars. go to copper or copper cladded.
When used within specs, there is nothing at all wrong with aluminum wiring. Most of the issues with aluminum wiring in houses come from either using aluminum wiring with components (switches/outlets/etc) not rated for AL, or from using unapproved methods to connect copper and aluminum wiring together. Aluminum expands and contracts more than copper when it gets hot, so when you connect aluminum and copper wiring together and pull a large load, the aluminum will move differently (more) than the copper. Over many such cycles, the connection can get to the point where it loosens up and can start arcing or making intermittent contact. As long as you follow code and use connectors/components rated for aluminum wiring, it is just as safe as copper.
The cables that connect my 200 amp house service to my neighborhood transformer are aluminum. All of the high tension power cables on huge towers crossing the country, carrying electricity from the generating plants to our cities and towns, are aluminum (or aluminum wrapped around a steel core for extra strength).
@@ozonepat I believe you are correct about the house wiring issues with aluminum wiring. Also, it is true about your home service entrance being aluminum. But, you left out the part about the lugs being specifically for aluminum wiring and the required use of anti-oxide paste.
Resistance! There is a math formula.for the size conductors within the internals of the batteries. I have watch several series battery videos and the one thing . The center of a
@@ozonepat As you state, temperature changes and aluminum are a problem. This is due to the greater expansion of aluminum with respect to temperature, and the rapid formation of an insulating layer of aluminum oxide. This is especially problematic with connections that do not maintain constant tension. Like screw clamped battery terminals.
@@ozonepat I think there are significant problems with aluminium wiring. Aluminium oxide is not a great conductor and aluminium reacts with oxygen in the air very quickly after exposure. Within minutes.
I've been using my self-made flexible braided copper bus bars for two years now without any issues like what you're seeing. Small deviations/stresses on this type of terminal lead to bad contacts. A bit of thermal stress or slight movement - It doesn't take a much since they are only slightly torqued... You're also dealing with oxidation of the terminals. For that, I have a process: I take some steel wool and mineral oil and use a dowel he size of the terminal with a hole in it to remove the oxidation. Then, clean them with a rag with mineral oil. The oil prevents the oxide from reforming. Then I apply MG Chemicals 847 - one of the components of 847 is mineral oil as well (to prevent corrosion of the carbon in combination with the other materials of the terminal/busbar). As I said, no issues in two years.
I use MG Chem 847 too. I haven’t performed any A-B testing but I do it to be cautious. I have even considered using it between ring terminals and cell bus bars and also between lugs and the busbars in the Victron Lynx bus bars. Any thoughts on doing that for high current systems, especially 12v? Thanks
@@cuisinartOH1 You don't really need it in those cases. The reason to use 847 on terminals is twofold: it inhibits corrosion and it improves contact between the terminal and bus bar especially since you can't torque it down much. Lugs contribute negligibly to the current flow and there is no galvanic corrosion. Same with the ring terminal and bus bar: nickel plated copper, or copper on copper - so no galvanic corrosion between dissimilar metals, and you can torque them properly.
Cleaning aluminium under oil without exposure to oxygen is about the only way to stop the oxide forming.
Most of the oxide layer will reform within a minute when exposed to air.
I buy soft copper tubing and smash it flat.
Do you have any infos online about making the braided busbars by yourself?
I'm so happy to see them being used! ^_^
Hello Andy.
To sand the buss bars, fix the sand paper on a very flat surface (not the wooden bench, I use the back side of a mirror), and move the bussbars, the one finger technique makes uneven surface, I suggest using 800 or higher sand paper.
Cheers.
Chritophe.
4nm ist definitiv nicht genug, hier von EVE :These cells have a 10.6mm M6 stud laser welded onto the terminal, which is capable of a torque rating of 8nM. We’ve tested a few at a torque of 10nM without a problem just to give you a bit of leeway and peace of mind. We have tested sample cells at a high C-rate discharge of 160amps and have seen a relatively minor temperature increase to around 40°C which is well within acceptable limits. We ran the high-C test for just under two hours. wiedermal super video.
ANDY PLEASE DEFINE A VERY FINE GRIT SANDPAPER IS THAT 100 200 300 PLEASE ELABORATE?
Excellent example of a problem and the correct solution! Very much appreciated Andy!
Man. As an american, I love your accent with your personality. Very refreshing when paired up with the topic material.
What accent?
Soft copper flat washers tend to "Smush" a little bit and help to make a better connection with a flat rigid bus/interconnecting bar. I've used this solution in a similar situation with Nissan leaf cells. There was no heat at all once they were applied. Cheap, easy to replace, and drop them in some Tarn-X and wash them with vinegar, all new again!
Your solution seems to work well also. But, I found the copper washers to take care of the issue for longer without the need for cleaning as often.
Great Video! LOVE your system! Its really looking sharp!
Most don’t realise that aluminium is actually an incredibly reactive metal. It reacts with oxygen almost immediately to form a thin, tightly bonded layer of aluminium oxide. That layer protects it from further corrosion so it “looks” unaffected. Iron or steel actual rusts much slower, but you can see the rust quite clearly because of the colour change.
Andy, by chance might you know what alloy those aluminum bus bars are? From the surface sheen and how they appeared to heat, I question if they might be 4000 or 6000 series aluminum, which is structural and because of silicon and other alloying have about half the conductivity of 1000 series pure aluminum. 2024 is alloyed with copper and a bit better for conductivity over 4000 or 6000.
When we made aluminum to aluminum and copper to aluminum connections, in HV substations and MV switchgear, we polished the aluminum surfaces as aluminum builds a film of oxide in a matter of mins, and applied generous amounts of PENETROX A-13, and used duraluminum bevel washers rather than stainless or plated steel which will heat more and the Beveled duraluminum washers were to reduce loosening We had routine re-toque schedules for buss bar connections.I often observed that after high loads and heating seemed to induce corrosion and loosening, and I noticed that with Aluminum bus bars and terminal connections, that thermal cycling and expansion of the aluminum would often cause threaded connections to loosen.
In 480VAC and 4160VAC switchgear that used Aluminum bussbars that i recall that for 200a the busbars were about 50mm wide and 10mm thick, and had a lot more surface area, with larger bolts and torqued to about 18-ft-lbs or 25 newton meters. As explained to me by the manufacturer of the industrial Aluminum buss bars I installed, that the surfaces need to be polished and NOT SANDED, and that it's not only the chemical corrosion inhibiting properties of 'No-Ox' paste is important but, that it be applied generously as to exclude oxygen impingement, and not of the type that dries out.
oomph...and I thought "slapping a bunch of cells together" was straightforward...
@@diyEVguy There's a lot of complicating factors such as connecting numerous low-voltage, low internal resistance cells, connected in series and delivering high current. Any substantial resistance in any connection will disrupt the balance and performance of the system.
From the beginning of your great channel and when you were facing the problem of high temperature in the Busbar, I advised you to use the flexible Busbar, as there is a type of it that looks exactly like busbar, but it contains in the middle a flexible copper part.
Came across your video. Decided to grab my fluke temperature gun and check all of my bus bars. They're all ambient outdoor temperature. So I touched them, I touched the posts, I touched the wires everywhere. I have no heat at all.
I built my own bus bars out of 3/8ths i.d. copper tubing. I cut my lengths. Punched holes in the ends with a Harbor Freight punch and die set. Rounded the corners with the bench grinder. Covered the center with heat shrink for looks and to cut down the amount of exposed contact area.
I believe copper is the solution to the heating problem. Aluminum is high resistance. And has the oxidation problem. I rented an apartment 30 some years ago. We were laying in bed at night and I thought I was seeing a faint blue light occasionally. My ex wife couldn't see it and thought I was crazy. After thinking about it and seeing it again I removed the cover from the service panel and I found it. One of the breakers was arcing under the terminal. I tried tightening it but it continued to happen. Next day maintenance fixed it. That's where I learned about paste. They also had to replace the breaker because it cooked.
It could be an interesting idea to add real-time temperature monitoring for the busbars to automatically detect faults and loose connections (before there is smoke). If you already have Raspberry Pi in the cabinet, it should be pretty easy and cheap to add DS18B20 or similar 1-wire sensor for each busbar and other critical component. Just have to be careful to safely isolate the sensor leads from the busbars not to cause short circuits.
Also adding a piece of tape on the busbars or other metal surface makes them less reflective (and more emissive) on IR and allows you to see the real temperature with thermal camera.
Thanks for the info. I should not have this problem any more. It will be in the next video...
To maintain consistent constant pressure on conduction terminal connection points, consider using concave flat washers between the nut and flat washer at the stud busbar term point. They are available in different thicknesses for different torques (terminal nut forces).
I'll look into this and see if I can find some for 4Nm. Thanks.
Well there ya go. Nice work. Spose it is hard to see allum oxide as apposed to iron oxide (rust) I used copper busbars, buffed with scotchbrite and carbon contact paste. Wouldn’t have thought allum oxide on the busbars would have made that much difference. Clearly it does. Very informative vid thanks for sharing
Thanks for your feedback
I'm wondering if the aluminum busbars have slight oxidation on the contact surface. From what I recall aluminum oxidizes quickly from an initial shiny surface.
I wonder if also adding conductive grease onto the terminal to battery connection might improve. Do you know what the terminals are made of? are they brass? steel? Also if the bus bars are getting warm under a slight change of conditions, I would build in a safety factor and maybe double up the Al bars so even if there is uneven battery height, there is another way to reduce the heat. Or switch to Cu bus bars. Copper is more ductile than Al, so it would probably conform better to the different physical terminal levels. This was good information. I want to know if you had sanded and greased with NO-OX-ID the first time you put the bars on? So was it due to new oxidation, or was there oxidation initially?
Yes, I have cleaned the aluminium terminals and busbars with NO-OX-ID when I built the battery (see video here: ua-cam.com/video/9RMTaaZr4M4/v-deo.html)
@@OffGridGarageAustralia I watch your videos out of order. if you did apply it the first round, that is not good if it caused problems later. Someone else recommended a different product that they say is better. It's sold on Amazon as "MG Chemicals 847 Carbon Conductive Assembly Paste, 1 oz Jar" also an anti-oxidizer, conductive grease and thermal paste. If you need a topic for a video, I'd like to see a side by side to see which works better.
Yes, love my thermal camera because it makes it easy to find bad connections. I have not watched the entire thing, but I did have to lightly hit my terminals with a wire brush attachment to my dremel before adding antioxidant to the terminals. Yes, keeping the cells level in respect to each other makes a big difference when using busbars, especially the thicker aluminum. FYI, you also need to clean the busbars. Watching, I see you figured that out. The paste won't clean oxide, it just prevents it after you clean. The aluminum starts oxidizing right away.
As others have posted, oxide forms quite fast, i'd be removing this on a very flat surface, such as marble bench top or a piece of glass.
it's the same process as flattening hand plane or the back of a chisel, i go up to 8000 grit on my chisels, its a mirror finish.
but 800 grit then 1200grit will do the job, the battery cell terminals will need a quick clean as well, as i'd imagine that you have the same oxide issue with those.
I'm enjoying the content Andy, keep it up
Up here in Norway, we use a lot of aluminum cables. When we connect them we scrub/sand the connecting point immediately after removing the insulation. We also use contact grease. My old rule (15 years ago) was scrub, grease, scrub with grease, wipe then grease. Like one commented below, alloy oxidation happen very quick and is insulting much. Btw, really like this channel and hope you soon can calibrate after overcoming this heat challenge.
I wouldn't use Aluminum bus bars. Aluminum oxide is an insulator, and forms naturally on unprotected aluminum in air in seconds.Stick with Nickel plated copper, or raw copper. CuO is electrically conductive, the opposite of Aluminum. I say this as an electrical engineer who has done a lot of work with large battery systems.
Good info here. I think I have now fixed it -> next video 😉
Hey Andy! Are you using any anti-occidation/corrosion paste between cells and busbars? If so, which one would you recommend?
I have tried different options in the past (it's in the older videos) but the result were always sketchy and not really great. I now have no paste in between the terminals and bus bars and it's been great since.
I tried No-OX-ID and MG Chemicals 847 both with mixed success.
Got them both linked on my website here: off-grid-garage.com/battery-accessories/
@@OffGridGarageAustralia Thx Andy! Same here since 2 months now. Tested with 100A all stays cold except the mega fuse, which gets lukewarm. Was just wondering if something should be done for longer term oxidation-avoidance...
Hi Andy, as always... nice video 😏. Maybe a problem with oxide layer on the aluminium busbars or terminals? When I build my battery last year (same cells) I found a paste from Wago to "crack" oxide layer and protect against oxidation when using aluminum wires in house installations (was popular in eastern part of germany). It is called "Alu-Plus-Paste". Before mounting my busbars I cleaned them with a sanding pad and used this paste. And up to now it works! Even with high loads I have no hot busbars.
And another comment regarding the unstable voltages in the JK BMS. This is caused by your load with the inverter. The load current on the input of the inverter ripples with double grid frequency. And the BMS has no filtering included. With a pure DC Load the values are stable.
I'd like to know more about the anti-oxidation paste. Is it made for electrical connections? Does the presence of the paste effect conductivity?
Yes. No. But it does not "correct" a problem, it will only help to "prevent" a problem. Must ensure the connections are clean before assembly and tightened correctly. Aluminum is horrible because it quickly forms oxide which is non-conductive. That needs to be removed, preferably in a non-oxidizing state (buried in grease, for example) and then assembled with no exposure to oxygen. This is standard practice required by code in the electrical power industry.
Andy, just something IV done on my 12v system.
I hand turned my studs into the terminals to bottom then 1 full turn back.
Then hold the stud with an alien key then tongue the nuts down (bit like doing old school tappets on engine) I'm using aluminium bar at 25mm X 3mm.
IV pulled 150amps with little heat.
Learn how the electrical power industry makes high power aluminum connections. You are on the right track. The oxide grease does not significantly remove oxidation, just helps prevent new from forming. Aluminum oxide is very hard, and is a very good insulator, and begins forming immediately on exposure to air.
Basic process: clean the aluminum (like you do with sandpaper) and remove resulting dust and particles, coat with oxide preventative grease, scrub with brass brush also coated with grease, assemble connection. (Obviously on aluminum to aluminum connections both parts need this treatment.)
The second cleaning is to break up the thin oxide layer that formed while and immediately after the first cleaning, and doing it while covered in grease prevents new oxide from forming. Doing two cleanings and a brass brush on the second is to minimize the amount of non-conductive particles in the grease which will be included in the connection.
That's exactly what I have done now and it seemed to have worked.
When you think about Aluminium and rust then the Aluminium oxcide is what's there, I think it makes sense to have the connection points sanded on both busbar and terminal. The tinned busbars don't have this issue and I think also the tinned connectors of Digital Mermaid. This might leave a bit of room to just strap all cells together, also not to have them move a bit. However with the temp differences in AU it might give other stress, so maybe flexible busbars are the way to go afterall, just to prevent issues with moving cells. You see, there are a lot of options, whatever you choose is the right one when chosen 😁👍 you checked all the options and this was best! Keep up the good work!
aluminum oxide is tough stuff. to get a good connection you need to be torqueing enough to bite through the oxide. tinned copper is probably the way to go.
Andy, I Tig weld Aluminium most days and yes, you are correct about it being an oxidation issue. The oxide layer on Aluminium has a higher melting temperature than the alloy base material and needs to be removed. This is done by welding in AC where the AC+ side of the waveform removes the oxide layer and the AC- side does the actual welding. Consider also the busbars have been laser cut and that introduces a problem as the cut edges are oxidised by the surrounding atmosphere as they cool.
From a welders viewpoint as good work practises we will linish laser cut edges before welding and on some Aluminium plates that are particularly oxidised sand the area that needs to be welded prior to welding.
Andy, I think again that you can measure joins with ohmeter so no need to make these 100a discharge test and thermal camera, or only to check the final test. But with ohmeter you could go step by step.
That's better then the 3-inches of snow delivered today in Michigan. 🌨
Andy, you have the worst luck with those terminals lol... I have just crushed copper pipe i flatterned into bus bars and have zero issues with hot terminals like you. I would have thought the torque of the nut would have flattened the aluminum busbar for solid connection but that doesnt appear to be the case due to them being so thick. My busbars are just plumbing copper pipe i bought from hardware store that i flattened in bench vise and punched holes in the ends for connections.
I made buss bars like digital mermaid did for a 12v solar setup.no problems with them heating up at all.i used them due to keeping cells in their foam shipping package.might try them to see how they would work.
How are you getting the battery stats into the Victron Venus (Raspberry Pi)? Would you mind sharing the wiring details or even better talking about that in a future video?
Hi Jon, this is explained in all details here: ua-cam.com/video/50V50lISnC8/v-deo.html
When welding ally you have to sand the surface before welding as oxide surface layer can form in less than 10 mins if atmospheric conditions are right. So it makes sense that you would have to sand both alloy faces before assembly and the no oxide paste should stop the contact surface oxidizing once assembled.
Probably need to try some washers on the ones that’s reaching above the flat terminal surfaces . That’s probably why it’s heating because of them barely seating on the flat surfaces vertically . May the solar be with you .
the same problem with alum has burnt down many a house in the usa. the alum oxidizes that is why the paste. those bars look anodized (that is a oxide layer) that you have to remove to get to the metal under. hence the serrated nuts to bite thru the oxide layer and keep the nuts from coming loose (look at how they do the ground wires on a car for that reason). good catch / save. same problem when trying to weld . has to be clean to metal.
Those are extremely nice battery cables Digital Mermaid made.
Yeah, she did a very nice job with these cables. I really like them.
Hi Andy. Yes you have had your fair share with buss bar problems. That aluminum buss should work perfectly IF the terminals are the same hight AND parallel AND flat AND no oxides on contact surfaces. The first to criteria can not be reliably maintained because of battery regularities. The aluminum buss bars are too stiff to conform. The oxides, tho correctable, are a contributing factor as well. The flexible (2/0cable which I have used ) buss bar are the way to go, but they can be even improved upon( see my video). You should have no problems pulling 100+ amps. I find that the 2/0 cable itself becomes the limiting factor when they make nice hand warmers at 180 amps.
I would suggest a copper washer or in your case, aluminum washers on the lower terminals. I had similar issues on some different cells. 100 amps on a 16s is no small load! Stoked to see batteries on the shelves though Andy!
You mean a washer in between the terminal and bus bar?
thats risky dude, hit it with a little sand paper in every contact might help in heating problems
Is it possible that the busbars are very slightly warped or non-flat from the manufacturing process? It wouldn't take much deviation to produce a reduced contact area between the bar and the battery terminal and ramp up the heat generation. It would be interesting to run the problematic busbars across a nice new sharpening stone, and see whether any areas stay unabraided, indicating a slight warp.
I don't like using aluminum and rigid. I think you would be better off going with the flexible ones. I would imagine that they are copper. I've been using carbon conductive grease on all of my connections also. Similar to the grease that you used, but carbon. It's a little messy and hard to get off your hands. It increases conductivity and its anti-oxidation. Very informative video!
Thanks for sharing. I'll see how I go.
You can expect to have ongoing issues like this with the aluminum bus-bars. I suggest that you abandon the them and get some good copper bus-bars. If you don't want to pay the price for copper use the mermaid's copper-wire/copper-terminal jumpers. It seems to be that the aluminum expands and contracts so much with temperature cycling that you loose the gas-tight connection. Once air can get between the two surfaces, the connection will go "high" resistance. Also, the no-ox paste here in the US is black and sticky. It works okay but gets black onto everything around you - tools, wires, hands, clothes, etc. The stuff you are using just looks like grease.
Andy, you would be better off not using flat washers. The serration on the nuts are to dig into the aluminum, penetrating any oxide and creating enough pressure to make a gas-tight connection.
As an experiment, you might try taking the temp of a connection w/o the washer.
I have ordered the No-OX-ID from the US, so I wouldn't expect this is different from what you get.
The flat washers are just to protect the busbars from these flange nuts. The pressure should be the same with or without washers.
@@OffGridGarageAustralia It is that the nuts need to dig into the soft alum. The flat washers prevent that.
This may be explaining my issue too. Thank you community!
Hola: mi mas sincera enhorabuena por estas páginas tan interesantes y de las cuales he aprendido mucho; GRACIAS y Enhorabuena. Ahora si me permite un comentario relativo a este problema de los contactos. Permítame que le sugiera si la pasta anti oxido para aluminio es conductora o realmente si Usted mete la puntas de su polímetro en el tarro de la pasta anti óxido, este le indica falta de continuidad o por el contrario le indica como buen conductor. Si el polímetro le marca que esta pasta es aislante, ya sabe, es mala, no la use. Quizás lijando y después usar pasta de aluminio conductora y antitérmica, la misma que se usa para los procesadores del ordenador, quizás funcione. Perdone intromisión. Un saludo desde España.
It may also be do to the thickness of the Aluminum bar , it does not flex to the surface of the post , just a thought.
I had some of those bus bars and they came rather rough. I cleaned up the edges and sanded them to get better contact. I ended up making my own thicker bars later on.
You’ve got an amazing property Andy. Keep the videos coming my friend they’ve been helpful
Still do not unerdrstand why those exremely sturdy bus bars are still your favourites.
OK, OPTIC property ist very pleasing.
From ELECTRICALprospective they have lower resistance than flimsy ones.
But from a MECHANICAL prospective they generate a lot of stress to the poles of the cells because they do not adapt their shape at all. They do not cope with any mechanical tolerance or thermal strain .
Additionally: those oval holes redeuce the CONTACT AREA considerably.
So you aggregate lots of disadvantages just for one single advantage to have less resistance in the aluminium itself.
On other hand copper lugs are pliable (even at 4Nm) and have round holes. Thus they enable maximum contact surface and lowest resistance. Mermaid got it right!
I built my battery like Mermaid. Additionally I replaced the studs made from stainless steel by parts made from brass.
All parts (studs, lugs, nuts) were cleaned with cleaning fleece (see plumbing) and coverd with paste before assembling. So the electrical current can go along two path: (1) direct from pole to lug and (2) second path via the brass stud/nut/lug.
My suggestion is to setup a test where you measure the resistance along different means of pole contacts. Will be very illuminating to everybody.
Hi...use copper bus bars,and aluminium throw to trash.
do you have stainless screws and nuts?
they are very high resistive. maybe you can improve the connections a little with copper or brass screws.
Hi Andy. Very good joob, you're doing. Regarding the bus bars. Why not gold plate them? Than the oxidation is not a problem any more. In Australia they are gold plating all possible stuff. Parts of plants and even old miner's shoes. :)
I think the super thick aluminum and then with the washers on top prevents any flexing to absorb the tiny height differences. Maybe try the thinner bus bars without washer to help them flex and make a flat mating surface. Are there "flexible" copper washers, something like solder wick and put them underneath the bus bars.
Another great vid Andy. I think I like the copper cable or busbar idea, or at least cca, but if you want to get those aluminium bars flat and shiny, I would suggest the glass mirror and fine grit 1000-2000 grit paper idea, and to sand the whole bar perhaps utilising a sanding block to keep each side flat, then maybe a light buff polish and immediately apply the paste with a polishing cloth one at a time. Also, I dont know how flat or stable ur battery cabinet base is, it does look good, but would a thin excercise matt type density foam base under the batteries, may (or may not!) help them sit or settle into the base allowing a certain give in the terminal area for getting a more even contact. Love ya setup & vids.
Andy, if your going to take the time to clean & polish the bus bars, I would also remove the battery studs and sand the top of the battery terminals as well
it makes sense to do that, as they will have the same issue, i just used 25mm dowel and drilled a 6.5mm hole with the drill press into the dowel and glued 800 and 1200 grit wet and dry on each end. i hare the welded stud version, but it will work the same without drilling the thread hole for andys cell studs
Hello
I'm not sure, but it seems to me the problem is that there is a small amount of material left after cutting the mounting holes. Therefore, when you moved the contact, it adjusted itself. If you have a tracing ink, try to determine what the actual contact surfaces are. And then take one contact and cut it with a knife (after the circuit) and check if something improves. Sorry for the rough translation but I'm getting to work. Regards and good luck 💪
Maybe the issue is not just variation in the terminal height but the plane of the terminals are not level and with the stiff bus bars, only part of the bus bar is making contact with the terminal.
Nice work Andy, good to see it was exactly as we expected after our conversation. I guess it goes to show that "Sunny hot Queensland" can be harsh on bare aluminium. I'll be using these learnings in my own processes from now on too. Never stop learning!
It's always surprising how many people comment before they've even watched the video. For the people who suggest to use Copper, you should go back through some of Andy's previous videos, he tried that, and the Aluminium ones have consistently performed better. However they were assembled almost immediately after receiving the bars from me. This delay wasn't expected so we can see the results. Copper is more conductive, however it's also a dissimilar metal, so that can cause issues in itself sometimes. Aluminium to Aluminium seems to be very effective, and the extra size of the aluminium bars counteracts the extra resistance. Andy also won't need to worry about vibration or expansion/contraction, because it's a stationary system and there's already a small gap between the cells to allow for this size change (explained in a previous video).
Lithium solar used a flexible copper bus bar. Might be worth ordering a few of them for a comparison test ?
Solid material, not deflected to align with the terminals. That’s why not make the perfect surface contact.
For my banks I bought flexible busbars, 300 A, from Weberpower. I think this is better than the aluminuim busbars. Maybe there is an galvanic interference between busbar and terminal, due the excessive moist weather....
Do you think that torque meter is accurate?
Extremely interesting! This is great stuff!
Thank you.
Thank you for your work. Your videos are great and so instructive.
Hi Andy, thank you for your videos, I'm learning a lot.
Have you tried flexible copper busbars? They are made with 30 layers of copper and compressed on the ends. This is perfect for good contact on the battery terminals.
Please, can you do a test and check hot spots with the thermal camera?
On aliexpress, these are the busbars with yellow plastic protection, made by Weber Power Tech
Big kiss from France
Ohh andy no me canso de ver tus videos ,eres como la Wikipedia de las baterías
When you sandpapered the busbar, there was a ridge showing around the outside and the bolt hole, see 20:23.
Is this the same on both sides ? The ridge will reduce the contact area. If not ridged on both sides then sand the flat side and put that against the terminal.
Interesting discovery in this video. I'd be going with the flexible type instead. You'll be spending many hours fussing with those rigid bus bars I think. Your shelves might be perfectly flat, but the battery terminals could be slightly off perpendicular and/or they could be at slightly different heights... either will give you headaches.
Hi i had a large lead acid battery banks 48v 1200 ah i used aluminium busbaars and also had som heet up alot i replace all my busbaars wit flexible busbaars and thet solved the problem i thought it was because of different resistance in the aluminum busbaars but don't now if that was the case
The answer might be in the slots in the bus bars in that they don't make full contact with the batteries/posts/nuts on top. Lesser contact means higher current in less space or a slight reduction in capacity. The homemade connections with lugs allow fur full contact. Also consider that aluminum doesn't flow current as well as copper does.
The rain washed the solar panels. You will be gaining about 20% extra power. LOL
Already before watching this Video I decided to make my own busbars same as Digital Mermaid, to provide breathing of the batteries, which are compressed in my case, with 4mm rubber sheets in between and tensed together with four round 4mm steel rods which are bended into a slight zig zag crooked line, so they act as a spring. At the ends I threaded them. The M4 nuts at the ends of the rods must be tighten with 0,565Nm (not oiled) to reach the 300Kg compression (with 4 rods).
Just for comparison M4 standardized strength classes reach from 3,3Nm till 5,6Nm tighting force, which results in 438Kg up to 754Kg contact pressure with ONE tiny M4 bolt! I guess many others overdue the compression, when i see all this thick threaded rods others have.
Nothing against your friend, but aluminum has at least 35% less conductivity compaired to copper. The contact surface will never cover 100% of the electrode, so theres a bottleneck for sure. Not to mention additional problems with movement, alignment and corrosion will occour.
The solvation of all this Problems: Flexible busbars as them Digital Mermaid made - cheap and good!
I was watching another video about those batteries and he said you don't want the bolt all the way down touching. needs a gap. You might want to check into that and the quality of the bus bars. I see others also making pure copper bus bars to avoid issues like what you are seeing.
Great video Andy
Thank you.
If you use aluminium busbars, you definitely should not use washers (at least not alone. The prevent the nut from scratching through the oxide layer.
Better/best solution: You should use spreaded washers (don't know if it is the right name) e.g. DIN 6796 together with a washer and a spring ring e.g. DIN7980. This is what you learn in germany, when you are an electrician trainee. The spreaded washer will cut through oxides, the spring ring will keep the force mostly equal and the contact gas tight when temperatures change (at least the ones of copper) and the washer uncouples the spring from the spread washer. So, the screw stack is: Busbar -> spreaded washer ->standard washer -> spring ring -> nut.
Aluminium oxide is one of the hardest and most isolating materials and only some atom thick layers of aluminium oxide will lower your conductivity reasonably.
There is one quite new material on the market (CUPONAL), that has an aluminium core and a thin copper layer on the outside, combining best of both worlds. In my opinion, it could be improved by a tin layer to protect the copper from oxidizing, but the copper oxide is quite weak and easily can be scrached away by the screw.
Sand paper will only be a short term solution. Temperature differences will change forces, oxidation will find it's way in and the resitance will increase again.
Could it be that alcohol does not remove Aluminum Oxide.
Directions for using No-A-Lox compound on aluminum at the public utility I worked at before retirement required applying the anti-oxide, brushing thru the compound with a stainless steel brush to remove AL Oxide, and leaving the No-A-Lox compound in place to stop oxidation of Al (apparently it happens real fast if the raw Al is exposed to the atmosphere for any length of time). Make the bolted termination, wipe off excess NO-A-Lox compound and test. It might fix your problem.
Also depending on how thick Al buss were fabricated, by sheer and Whitney punch for holes, the bus conducting surface may not be flat one one end and may not be parallel end to end.
I did something similar in the next video. Thanks for sharing your knowledge.
I've been following your channel for sometime..
I am encouraged by your experience of connecting 2 banks in parallel do not matter even if discharge states are not same.
I plan (dream) to connect 2 indentical 48v 100ah packs with individual BMS (Active & Passive) in series (96v, 100Ahr) then charge it at 96v and run an EV. However, inan emergency I will reconnect them in parallel making a 48v, 200Ah power pack to supply my home solar inverter. My doubt is, if there will be issues and might damage anything when alternating between 96v & 48v?
Your advise would give me a direction on how to proceed.
Watching here from the Philippines.
Raw aluminium will oxidise instantly and form most of its oxide layer in about a minute, then its full layer of oxide stabilises around 10 minutes.
Not sure how to get around this besides the crushable stainless ridged washers, or a spring washer, to break through the oxide.
I'm lucky to have copper terminals and bus bars.
I wonder if lead-based bars would be better (since more flexible). Then again maddie's cable-based ones seem to be a good option.
Allium bus bars?
Annodised?
I've solar bus bars on my feed in. If I put the multimeter on them sometime I get a reading others not. However I have bare allium. That's no problem.
Check the bus bar is actually flat.
Scratch the surface. Sand them down more than you have. The bars come coated to stop the oxidation.
Use copper compression washers under the bus bars.(not the gapped type but solid)
Hey buddy maybe the end of the buss bar needs double thickness to increase contact area to the bolts. 🤔 I really like the way you solve problems…
Keep up the good work, proud of your effort in this project...
Hatte auch das Problem mit Wärme Entwicklung und driftende Spannungen.
Ich habe mir von WAGO die Alu Kontaktpaste besorgt, alle Verbindungen davor noch geschliffen, dünne Schicht Paste drauf, seitdem ist Ruhe.
Auch die einzelnen Zellenspannungen sind seitdem stabil.
Vraiment surprenant cette surchauffe...🤔 aller je regarde la prochaine vidéo pour le suspens et la solutions 🙃
Hello Andy. I’ve read the cells specification from Quishou. I can read. This. The pole is a double aluminum pole structure. The internal screw with size M6 is used in the poles. The anti-torsion of pole is 8Nm. The torsion should be less than 8Nm when used. The effective thread hole depth is 6mm. I suppose you far from the normal fork required? Thanks to yours vidéo I’ve ordered 32 cells yesterday! Big job is coming. 🤪
Did you order cells with or without welded studs?
A week ago, I was asking to QSO for a quote and for now they have cells only with welded studs and i don't like it
@@zarbonida you’re correct. I did not like also but I prefer to order them. They was cheaper and much better quality return i saw on internet compared to the others company. I’m worry about the total surface for connection. It’s smaller but million of persons use them. Seems it’s not a big issu! Perhaps Andy have an idea on this point ?
I am a bit surprised you did not need to sand or wire brush the terminals!!!
Just as an aside, you demonstrated one of the big dangers of Aluminum wiring vs Copper wiring. Copper oxide is conductive but aluminum oxide is an insulator. Consequently, it is much easier to get a bad connection with aluminum.
You can see the reason why most electrical connections in computers are gold plated, no oxidation ... mmmm ....Gold Plated Busbars.
Next workshop for the garage is electro plating Busbars in the off-grid garage
I am on battery 4 of 10 using tin plated copper bus bars from Dongguan Lightning and Shenzen Luyuan. 90 Amps flowing per battery from two Sol-Arks. All running cool. Cleaned aluminum terminals with scotch brite/acetone, applied carbon conductive paste (MG 847) and torqued 6mm nuts guttentight (>35.4 in-lbs!). We told you before about aluminum's crappy conductance properties.
I predict you will have endless issues with those aluminum links. I'd ditch them yesterday!! Use the great flexible ones Mermaid sent you. Besides the thermal cycling your batteries will experience from the ambient and operating losses will cyclically try to move the batteries back and forth thru the terminals due to thermal expansion.
Are those stainless washers on the terminals, I don't recall if you've mentioned that? Stainless and aluminium will always corrode.
Get some of this:
Jointing Compound Grey Aluminium Crimps
Aluminium joints (bolted and crimped) should have jointing compound applied to joint where it is not pre-loaded in the barrels of lugs or links,
Grease acts as a corrosion inhibitor, Used after scratch brushing 30% suspended zinc particles and 10% fumed silica fill voids - Zinc and silica assists with current bridges in joint
Thank you.
The solar farmers complain when it's raining and the food farmers complain when it's not raining.
Yeah, pretty much! You can't win.
Which FLIR cam do you use?
Havs the bus bar material or other aluminium components been anodised / naturally anodised over a period of time (oxidised surface to the aluminium). Can be used to create colours on Spat devices. all the best.
By the way, in addition to insulating layers in integrated circuits (ICs), aluminum oxide is used as abrasive on sandpaper, nail files, and etc.
Still raining?
In Holland and Germany we have nice warm weather
Just came to this video, after testing 250A load on copper busbars with 2S4P setup (12V > ~3000W of power on inverter). The temperature on some terminals was around 70-80C.... Turns out I had to tighten them to ~5Nm, afterwards they were room temperature. So I can confirm, that copper busbars (I got elastic ones from Ali, rated for 300A) are the way to go.
Sometimes I think you should better go with a water turbine then solar panels. :-D
Great findings with your Battery Candles.
Keep going!
The water is very inconsistent here. Too much or nothing at all...
@@OffGridGarageAustralia You "store" sunshine, why not doing the same with water? ;-)
Add some ventilation. Aluminium oxidezes really really easily. Basically if it's not shiny it's oxidized. But even with copper I think there will be some heat.
Do you think they need more torque than the manufacturer recommendations
I guess you tried that
There is no manufacturer recommendation. They say 8Nm is the max the terminal can withstand before it starts twisting.