EVE LF304 with welded studs. Pushing 230A through a tiny terminal?

We have a new PowerWall! Yeah, Qishou (QSO) has finally delivered. When I opened the first box, I wasn't quite sure what to think about this new design. It seemed like a bad idea: welded studs!
The contact area from the terminals to the bus bars are tiny, 60% less in fact. How is this supposed to handle high currents?
Well, here is the test you have been waiting for. 230A through a tiny terminal. How long until we see the candles again. Or, wait... is this actually working?
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[@upnorthandpersonal]

Do note in the datasheet that cycles are defined differently: the 3500 cycles are at 1C, the 6000 cycles are at 0.5C, both at 25 degrees C. As usual, temperature has a bigger influence on cycle life.

[@dc1544]

if you only push your banks at .3C or even .2C that will also give you more cycles if you are not maxing out the battery using 10%-90% finding the right voltage to charge to is key using the power curve. the specs on my batteries show 3.15-3.35 V would get me 85-90% capacity. that would keep the heat down and extend the life even further.

[@OffGridGarageAustralia]

@@dc1544 you cannot charge your batteries to 3.35V only this could be everything from 50%-80%. Voltage cannot be used for SOC with LFP cells.

[@pete2531]

You can charge at 3.35v til no more current flows and still get most of capacity but downside is that charging is slower

[@dc1544]

@@pete2531 my goal with 4 16s battery banks is use around 70-80% so I can get around 8000 plus cycles. also only charging and discharging at .1C to .3C. with both I should get over 21 years out of these batteries in theory. even 16 years would be awesome. my ttotal system will have 53,760 watts. 80% is 43,000 watts. I will have to see how much I really need in watts. I could end up buying another 32 cells if my needs require more.

[@renatomercurio4774]

@@dc1544 no. EVE has handled this 90% charge trick intside the LF280K cell, that's why it has the dimension of the 304Ah type. So you will actually get 6000 cycles as in the specification with full 1C - allowing for cheaper smaller cars to sell.

[@TheDigitalMermaid]

QSO confirmed the 280K cells I ordered are all welded studs as well. So happy to see how well my flexible bus bars are doing, even better than I originally hoped!

[@wayne8113]

Hi Madi, Your bus bars are holding up quite well. I thought it was a great idea when you first made them, much better terminals, full contact area. 👍

[@JamesEDennison]

As my battery pack is installed in a converted bus/motorhome I will be monitoring the aluminum bus bars I built and terminals for any vibration damage and if I find any will build flexible connections as you did ... wish I'd thought of that when building the battery but it was before you had done it.... hopefully I don't run into problems.... James

[@OffGridGarageAustralia]

@James, bus bars are easily being replaced if you have to... Get Madi to send you some. She makes hundreds of them (apparently) 😊

[@elmer665544]

The new welded studs are part of the contact area. So, better stud contact includes better nut contact on the top of the bus bars. Better current sharing between the top and bottom of the connection should account for the better than expected performance.

[@bbrown_sc]

I agree. Those flange nuts bite into the nickel plated copper bus bars (that's a feature) and make very good contact on top. I think that is the majority of the surface contact area. I drilled and tapped the bus bars for the balance leads so the ring terminals don't get deformed by torquing down the flange nut. I just finished a build ((2) 48v 16s, OverKill/JBD BMS) with the same LF304 cells also from QSO, thanks to Andy/Amy. I'm only running 100A and I don't have a Flir camera, but I haven't detected any heat as of yet. I think most of Andy's heat issues were from those aluminum bus bars. I think those are more of a problem than the surface area of these welded studs.

[@pau1phi11ips]

@@bbrown_sc as nice as those big Alu bus bars look, they're not very practical.

[@TrevorFraserAU]

Yeah, that's what I'm thinking, it is the nut on top that makes it work more than the small plate underneath...

[@mohamaditani6160]

only problem its galvanized steel, not aluminum nor copper, your best bet is to use soft aluminum washers between the bussbar and terminals IMO

[@ForbiddTV]

@@bbrown_sc I always wonder about the nuts supplied with the bus bars if those raised ridges actually keep 90% of the metal from contacting the busbar at the relatively low torque we are tightening these nuts down to. I would think copper nuts without the ridges would make for more surface contact. If you were worried about them backing out you could make it a jamb nut arrangement with two nuts.

[@gregcope5565]

@Off-Grid Garage / Andy, Why not measure the resistance between the Cell terminals with a good IR meter like YR1035+. If there was a lack of contact area and higher resistance from the terminal-bus-terminal connection this would give an indication. As you have both cells and the same bus bars this would make an interesting data point comparing old and new. Ray Builds Cool stuff did a good video on Bus bar connections and resistance.

[@Shep5847]

I have 32 welded stud cells. I used to use the rigid busbars that came with your cells (tin plates copper) and have had zero issues pushing just over 300amps through them with minimal to no heat up on them (confirmed with FLIR thermal camera). My issue I ran into was having the rigid busbars in a mobile RV environment and the vibrations caused the rigid busbar to break a welded stud on one cell. I switched to the copper flexible busbars with no rigidness anymore and can still push over 300amps through them with no heat up. My 4/0 cables are warming up according to the camera, but the busbars are still quite cool. 🤷🏻‍♂️

[@RolandOfGileadOnYT]

I also think that the busbars have a very large outside area compared to the volume, which means there's a lot of area that acts as cooling area.

[@OffGridGarageAustralia]

Thanks for sharing @Shep. I guess flexible bus bars are a must for all mobile applications.

[@ForbiddTV]

@Shep Which flexible copper busbars are you talking about? The open braided ones?

[@Shep5847]

@@ForbiddTV The ones on Ali express with the yellow orange insulator in the middle. YT won’t let me post a link.

[@ForbiddTV]

@@Shep5847 Hmm, having a hard time picturing them.

[@markdavidson6321]

Great test, as always, and impressive performance from those cells. Thanks for the great videos!

[@OffGridGarageAustralia]

Thanks a lot Mark!

[@theoff-gridhouseinrome3598]

Hi Andy great video, I was skeptical about the surface of the connection, but is incredible how the connection stay cool.

[@newscoulomb3705]

3:00 I wonder whether they moved the terminals farther out so that a standard length busbar can work with all cell configurations (i.e., side-to-side, end-to-end, and end-to-side).

[@Dirt-Diggler]

Came on to say the same 😁👍

[@chrisdavies6110]

Hallelujah 😍

[@wayne8113]

Was thinking the same thing 👍

[@OffGridGarageAustralia]

Has anyone tested it?

[@newscoulomb3705]

@@OffGridGarageAustralia I don't have the new cell configuration, so I can't. I was kind of hoping you could do a video on it. 🙂

[@ssoffshore5111]

I just bought some new LF280K batteries, they have TWO screw-in studs on EACH terminal... with a larger flat base for the busbar! I think it's a huge improvement over all the previous designs!!!

[@OffGridGarageAustralia]

Yes, seen them on Mike's channel (Lithiumsolar). They look great.

[@hansmichaelreitz2551]

You have two contact-areas , one from the cell to the busbar and the second from the screw/nut to the top side of the same busbar ! !

[@russveinot5754]

I am now convinced and should have told you in your last battery test, my thoughts on why the heating up at the terminals. The high resistance inside the battery connection could be the culprit. That may be why they changed the battery terminals! Great video, Andy.

[@OffGridGarageAustralia]

Thanks Russ!

[@kswis]

Those are very nice batteries. Excited to see them all lined up on the shelf. We'll done Andy!

[@OffGridGarageAustralia]

Thank you!

[@jamesmason7124]

Thank you Andy for doing this test on the new cells

[@OffGridGarageAustralia]

No problem 👍

[@kirovoleg]

Hi Andy. Great test. I think your idea of separating the cells would also increase the surface area. Looking forward to the completed battery.

[@RolandOfGileadOnYT]

Thanks for this test, I was wondering about this as well. As said before, I do use ring lugs on the studs instead of busbars with slots. I did a quick test, but not with 230A. Thanks again.

[@OffGridGarageAustralia]

That should be totally fine. I could not test any heat building up around the flexible bus bars with ring lugs on mine. The contact area is even larger and 4Nm seems to be enough.

[@newscoulomb3705]

10:30 I do have a set of batteries with these welded terminals. I wasn't planning on pushing more than 100 A through them, so I'm not very concerned. Something worth considering is buying some aluminum washers with the same diameter hole that can create a larger, flush contact surface.

[@OffGridGarageAustralia]

They seem to work well as they are. I'm not bothered with any further washers to increase contact area. I will push barely 40A under full load once all three banks are installed.

[@Rocky-52]

Hi Andy. Yet another well put together test set up. Most excellent. Your videos have helped me out, no end of times. By the way, I'm having trouble locating a "Cucumber to Celsious/Fahrenheit" conversion chart

[@OffGridGarageAustralia]

Thanks Rocky. We need to do our own conversion calculator. similar to the 'Amp to Celsius' one 😉

[@williamhustonrn6160]

Great video Andy, Thank you again on informing me about the flexible braided busbars, i replaced all of the crushed copper pipe busbars last night and today with the new flexible ones i made. I made them with Copper braided grounding strap and crushed sections of copper pipe on the ends as a DIY crimp, then i punched a hole through the copper pipe and braided ends. They are working great and give me the flex i wanted that the ridgit crushed copper pipe busbars didn't give me.

[@OffGridGarageAustralia]

Is that crimping force of your copper pipe enough to make good contact to the braided mesh though?

[@williamhustonrn6160]

@@OffGridGarageAustralia yup its no different than a crimped ferral end. I just found copper pipe that was just snug enough to go over the end of braided copper, then crimped it with the same hydraulic crimper you use for putting your cable ends on. Then since my hydraulic crimper came with attachment for punch pressing holes in things, i used those in my bench vise to press holes through the copper pipe and braided wire. I did it in the bench vise because it was to awkward doing it in the crimper. If i didn't have the punch parts, i would have just simply drilled out the holes.

[@raystone4673]

Hi, I modified some braided copper battery cables which were too long for in between cell distance, on a group of 460 Ah cells I got through AEVA about 5 yrs ago. They were approx 100 mm2 area and had hard copper ends already. I cut off to length, and got some not so common 5/8" pipe from plumbing supply place. Not 1/2" or 3/4" or metric equivalent. I squeezed short piece onto end of braided cable using big vice with angle alum jaw inserts so it wouldn't leave teeth marks. The inside dimensions of the crushed pipe, was very close to width of orig cable, and 2-3 mm of thickness.. The battery posts were m8, so I used an exact 8mm drill. (The braided cable had some free length for expansion). Drilling thru crushed pipe copper caught the thin wires inside and tried to spin and break them. So I used big soldering Iron and filled airspace of crushed pipe end, with 60/40 solder. I then filed both sides of new link end with good file, and tinned with solder and wiped excess while liquid, to leave nice surface. A nice copper stud and terminal would be good to see on a battery. Iron's conductivity is about 16% of copper, brass is about 28%, and stainless is less than 3% I believe. I'd like to buy a version of the cells, with the original big aluminium internally threaded posts if ever available. The pulsed discharge rating of the latest EVE/Gobel cells is 2C. So an EV wants to pull 600A. intermittently. I can't find a pdf drawing of these cells with the welded studs on the net.

[@fritzw9156]

Hi Andy greetings from sunny cold Austria, I also got the new 280AH/K batteries and was amazed at the changed connection. You have now tested this (I have not yet come to it), thank you very much now I can sleep peacefully. Stay safe and drink a beer (i will do so)

[@OffGridGarageAustralia]

Thanks for sharing Fritz and greetings from Australia to Austria 😊🍺

[@rustytoronto]

you can get over sized washers to make the full surface area covered. 🙂

[@davegeorge7094]

Best wishes for all of us with these new type terminals!

[@OffGridGarageAustralia]

They just work, Dave!

[@nigelcharles511]

I also have the new studs. As I made my own busbars I drilled them to 1/4" (6.35mm) which allows an easy fit whilst maximising contact area. The greater torque should help with conduction between busbar and terminal post. I don't intend going above 100A so we'll within the quoted 160A.

[@SuperRockmonkey]

Great stuff Andy. Thank you!

[@OffGridGarageAustralia]

My pleasure!

[@beebop9808]

Just ordered 48 304 cells yesterday with newer dual post terminals. Nice looking connections with piles of contact area with the buss bars.

[@randylenart9674]

Good video Andy I built a 12volt 560ah system for my camper last year using the same cells and ended up using them to power my cabin up north and could run my well pump lights microwave and all my power tool's went throu one 300amp circuit breaker but worked very well using stock buss bar's

[@OffGridGarageAustralia]

Great set up, Randy. Thanks for sharing. So you're using the standard fixed busbars in your camper with all this vibrations, rattling and moving?

[@Toasta-Builds]

Great test Andy thanks for sharing. I use the welded stud 304 cells in my 30kwh pack, no heat, about 2 cumbers! but only drawing 133amp max.. something to be said about crimped cables though huh.

[@repairman2be250]

How much did it cost you for 30Kwh, if I may ask?

[@andig69]

Hi Andy, again a cool Video! I get the same battery cells a few months ago and had the same concerns like you. I used the original busbars for mounting together with this paste from Wago I posted a few videos ago (cleaned the studs before with abrasive fabric). And it works perfect! No candles to see… even at high currents (in my case about 120A only) I talked to a mechanic designer about this and he said: When screwing busbars together only the small area below the nut defines the contact area between the 2 busbars because only in this area there is a high contact force to get a good metal to metal contact. It seems a good solution to me at the end…😉

[@OffGridGarageAustralia]

Thanks a lot for sharing. As other stated here as well, there seems to be no problem with this connection. I will set up the two new battery banks with this method and see how this plays out over time.

[@LarryL619]

YAY! I just received 304ah with welded studs as well. I was concerned seeing much less contact area when compared to my other cells. I’ve been putting my current batteries anywhere between 1800w to 3000w. I’ll likely never use above 160A constant draw. Good to know I don’t need to add washers or anything - just use the stock busbars. Great test!!

[@OffGridGarageAustralia]

It almost is too easy, right?

[@edwardvanhazendonk]

Great test, good to know!

[@OffGridGarageAustralia]

Thank you!

[@davidmills2266]

This was on my mind then boom, Andy comes up with a video.....nice one Andy great video

[@OffGridGarageAustralia]

We're all connected! 😁

[@glastron9988]

Hello my friend. Glad to see you posted this as I was in the same conundrum. I am currently running a 24v system getting ready to graduate to 48v. I have been using Amazon, and bought a set of 8 -280ah prismatic cells initially. The cells looked great upon arrival, nice and square on most sides, and with nicely nickel plated bus bars. The topside connections had large square pads for the bus bar to set on like the first ones you showed. So I ordered a second set, hit the order again button, and when ordering I noticed the same 280ah cells for $100 less. So I bought these, and upon arrival I had the same reaction as you, trying to figure out how these would ever pass the same current. They were not as square as the first set I bought, slightly larger, and had those welded on terminals. Wanting to combine these for 48v, it raised questions as just how different these are. Have no real complaints so far on either set. Both work fine with 24volt daly BMS's , but I'm not loading this system either. I'm still not sure what the difference is supposed to be between these cells. Both listed as grade A, 280 AH cells on Amazon, some further research is needed I believe.

[@OffGridGarageAustralia]

If you have different orders, you probably end up with different batches of batteries. In my first battery, I have 3 different orders and even they are all supposed to be LF280, they already vary and cause some challenges... As long as they all have the same capacity I would not bother too much. Probably do a capacity test on one or two to confirm this.

[@kenlillia]

I have 200 ah cells. Battery is 2P 4s configuration 400ah 12 volts. My studs are welded. I have copper bus bars made from copper pipe. I have tested discharging 250amp continuously for 30 minutes. Temperature of bus bars and studs are around 2 degrees Celsius above ambient temperature. I hav e no problems with contact. I tighten to the same torque I would for a Phillips head screw. Cheers Andy enjoy your vids.

[@OffGridGarageAustralia]

Thanks for sharing, Ken! That is great.

[@gumpster6]

Great high current performance on those new batteries. I hope the capacity meets the rating. Looking forward to you getting them installed on the shelves. Time for a new clamp meter that can go 300A+.

[@OffGridGarageAustralia]

Thank you. The capacity test seems really good with these cells (next video). My instant thought was getting a new clamp meter with a higher range... 😊

[@marcoarpago]

I just got my 304Ah cells yesterday from Amy and was a little concerned about the welded studs, but this video took my worries away , thanks

[@OffGridGarageAustralia]

Thank you. Go for it, it works great as it is!

[@loucinci3922]

Solid test. I thought you would need a bushing to fill in the gap and bring surface up to steel washer. thanks for sharing.

[@silverleapers]

Perfect testing and thanks, from foggy cool Newfoundland Canada

[@OffGridGarageAustralia]

Oh, wow, from Newfoundland. Thanks for watching and saying hello!

[@davegeorge7094]

They must have improved the internal res. of these new terminals. I received the new terms. on my 280AH cells and was worried until this post, thanks again man! I am using copper washers under them though, so nut torque and res. stays in range.

[@OffGridGarageAustralia]

Thanks Dave. The surface of the lower ring around the terminals seems very rough on mine from the welding process. Not sure if this is meant to be as a contact area.

[@isfanromeo]

Thanks for the great videos, you help me alot!

[@OffGridGarageAustralia]

Thanks, Isfan. Great to have you here.

[@naomihalliday-cox6614]

Hi Andy. Again, thanks for all the great videos with unmatched detail. I have learned so much from you and your videos. I do have a suggestion/thought. Perhaps you could "countersink" your thicker bus bars so that there are two contact areas using a flat headed drill bit so that the modified/countersunk bus bar would contact both the higher smaller area and the lower area of these new welded terminals on your later model K-Series batteries. Or even having/stacking two bus bars, one with a larger opening that would contact the lower larger terminal area and then one with a smaller opening that would contact the smaller upper terminal area.

[@OffGridGarageAustralia]

Thanks a lot Naomi, great to have you here! The lower part of the terminals is not as smooth due to the welding process. You will see this in one of the next videos, so I don't think it is actually designed or meant to be used as a busbar connection.

[@rahsomali]

Cool Stuff Andy, thank you.

[@OffGridGarageAustralia]

Thank you 😉

[@whitey321]

Love the videos👌

[@OffGridGarageAustralia]

Thanks, Tim, much appreciated!

[@JamesEDennison]

Hi Andy.... Greetings from the Great White North (Canada)...🤪🤪.. I have been using the welded stud version as well since last September.... no issues so far.... they are installed in a bus conversion running the entire bus so pulling up to 250 amps at times.... the only issue I have is cell 8 goes a little out of balance once in a while.... a little loosen of the nut and re-tighten and all good again.... I made my own aluminum busbars so may be running into a little corrosion issue as you did... not sure.... keep up the testing.... it's helped me a lot.... James

[@OffGridGarageAustralia]

Thanks a lot for sharing, James. That is great to hear. Wow, all these projects around the world with batteries, that is incredible to read and learn about. Yeah, aluminium bus bars are quite different. I will install the two new batteries with the original copper bars and see how they perform over time in comparison to the aluminium bars . Thanks again and all the best to Canada!

[@renatomercurio4774]

Thanks for that great video. I got those as well recently and had the exact same concerns and wanted to do the same test. I have already ordered the conductive copper paste and was looking for M6 bridge washers. But the bridge might just be worse and not needed.

[@michaeldudley7840]

I've been running an 8S2P pack of these terminal type for a year now with no problem. However, I rarely exceed 100-110 amps discharge, and even lower charge rates. I made my own bus bars from aluminum angle stock. I put holes in the vertical leg of the bars for my balancing and test leads. That way I never touch the terminal connetions once they're installed. The angle shape also doubles the cross sectional area of the bars. I also use only the serrated flanged nuts with no washer on the terminal to increase the contact area.

[@OffGridGarageAustralia]

Hi Michael. Thanks for sharing. Seems like a lot of people are using aluminium bus bars. That's a great idea using an angled bar for that purpose.

[@farqend]

Hey Andy, to keep the amount of area you need in perspective just look at the actual Fuse element, I am always amazed at how much current passes through the tiny fuse wire.

[@OffGridGarageAustralia]

That is true and they also heat up quite a lot when going over 70% of their rated current. I guess that's the purpose, so they will melt in case of an over current 😁

[@dan2304]

Andy, batteries look great. Clean the surface of the terminal and bus bars with a little fine wet and dry abrasive paper and use terminal grease and all should be good. As an engineer I don't like flange nuts either, plain nut and washer or washer and nylock nuts are my go to.

Well, this video puts my mind a bit at ease after seeing the small contact area and steel studs on the 36 EVE LF280K cells I bought.. Placing dual #2 copper cables on these along with the copper flexible buss bars.. Plan is that the 2x 17 cell batteries will provide 75 amps or less maximum each or 150 amp maximum or les if one battery is offline so it should never get above .5c charge/discharge.. You pushed a 12v setup to over 200 without much heat so 50+ volts at 200+ amps should be far lower resistance ampacity heating just like wire size vs voltage.. Thanks again for real world testing and sharing this with all of us.. That being said I still would rather have larger contact area and silver or copper anodized studs and nuts.. The cable heating you have might be a resistive mismatch of the 2 separate cables acting as one if there is a slight difference in their length or slightly oxidized inner surface of the crimp providing some resistance.. I am going to use dual #2 cable but I plan to clean the inside of the crimp pocket and solder them after crimping using some liquid flux applied before assembling and crimping.. Overkill can keep you from getting killed.......

[@OffGridGarageAustralia]

Thanks for your feedback. The contact area is not the problem, but the force you connect the two areas together. Here, we have a very small area, but torqued with 4Nm the force is very high pushing onto this contact area. I have several batteries with these cells and terminals and never had any problem. 150A is certainly not an issue. Some manufacturers have included small copper washers to increase the contact area. But tbh, they make the situation worse as you have more resistance between the different materials of aluminium-copper-copper than just aluminium to copper.

@@OffGridGarageAustralia Thanks for the testing videos and the reply Andy

[@teardowndan5364]

I'm not too surprised: half to a third of the surface area means 2-3X as much pressure squishing the imperfect surfaces together so you get closer to ideal metal-to-metal contact across the remaining contact patch without needing perfectly flat surfaces. You also don't need to worry about that pesky aluminum oxide on the bare battery terminals anymore.

[@OffGridGarageAustralia]

It seems to work flawlessly with this method. No hot spots, no contact problems any more. 4Nm is all it needs now...

[@bigshotdadz]

I've had these cells for almost four (4) months and regularly (as in almost daily) push and pull 100+ amps thru them with no issues.

[@OffGridGarageAustralia]

Great, thanks you for sharing.

[@Ryan-hn3vd]

I have the EVE 305ah batteries with the welded studs for 4 months. I started with aluminum busbars and had lots of trouble with heating even with cleaning sanding. I put the tined copper busbars that came with them and it works perfect. No cleaning paste nothing.

[@OffGridGarageAustralia]

Great, thanks for sharing. I will do the same with my banks, just using the copper bars and see how we go over time.

[@JimmyLLL]

I made a pack with the 280k and standard busbars that come with them. Pulled 200 amps for 15-20 minutes and everything was still cold to touch. No issues at all. The Jaibaida 200a BMS handled it great.

[@OffGridGarageAustralia]

Thanks for sharing. So 5 cucumbers for your test then 😁

[@JimmyLLL]

@@OffGridGarageAustralia 5 for the busbars and 3 for the BMS

[@evil17]

Very interesting Andy! I would have had the same issues as yourself about these busbars and contact area, but I wonder if with the smaller contact area, you are actually getting a much higher force on that reduced area, and also the busbar can possibly flex or force into a better seating position. Another comment was about the busbar size helps to possibly conduct heat, but then they didn’t even really get hot did they under these conditions, so. Yay! Looks good!

[@newscoulomb3705]

14:29 I've been using flat washers with the lock nuts to prevent scarring on the busbars, especially on projects where I'm fiddling around a lot.

[@deanjones3239]

I thought about that but washers can introduce additional resistance. Are your washers aluminium or copper? If alu, are they treated for oxide corrosion? If copper, how do you deal with galvanic corrosion with alu?

[@newscoulomb3705]

@@deanjones3239 Sorry, I thought this was a different comment. The washers are soft steel. The washers and nuts do not increase resistance because that's primarily traveling through the terminal and the busbar. The nuts and washers are only securing/pressing the busbar into place. Also, the busbars I'm using are nickel-plated copper.

[@chevrofreak]

I think the busbar being clamped from both sides by steel that is somewhat penetrating it is providing a very solid connection.

[@LupoDIY]

regarding the surface area it is even less: 10mm diameter - M6 stud it is around 50mm2. considering that it is steel you could also argue that you can add the same surface of around 50mm2 on the upper side where the washer sits. but even than it is just 100mm2 in total. 100mm2 copper at around 60-80°C should be able to handle up to 300 amps iff the contact resistance is low, but I would also consider it as borderline, especially if you think about the degradation over time of the contact itself by e.g. expansion/contraction (as it happened with Andy's old battery)

[@OffGridGarageAustralia]

We will see how this plays out over time. Many have reported having this set up for a few months now without issues. I guess, we will test it out 😉

[@mdazizulislampdb4790]

Thank you too, I saw your full video

[@ForbiddTV]

I just bought 32 of the EVE 304's with the welded studs last week and was concerned myself (mine were the same as yours). If you were to drill out the hole size of the bus bar or terminal lug to 12mm then it could make contact with the larger surface area on the lower shoulder which has about three times the surface area. The problem is this shoulder is 2.2mm lower, so a 2mm thick bus bar wouldn't be tightened down with the standard nut without an additional copper washer as a spacer.

[@OffGridGarageAustralia]

That's a lot of additional resistance you create with all these washers. I'll leave mine as they are and see how they go over time.

[@mirorava3296]

The cells I ordered are exactly like yours (304 ah) and I'm happy that the welded studs didn't give any problems To reduce even more the little heat that generates at the contact point, you could try to use 6 Nm instead of 4 The 4 Nm are correct for the old tipe if you don't want to strip the threads, I've seen some tests and I've done some too on an old batch of 200 ah eve cells (that where at the end of their life), and the terminal starts rotating inside the cell at 16 Nm more or less, I obviously won't go that far, but 6 Nm would give a really good contact pressure without ruining the cells

[@OffGridGarageAustralia]

Thanks Miro. I'll keep this in mind. I will go with the 4Nm to start with and if problems occur, I know, I can go higher. As I will only pull 30-40Ah per battery bank, I'm not expecting any problems anyway.

[@excillisbank2611]

Vraiment incroyable constat ! je suis resté dubitatif jusqu'à la fin du test..., car j'étais moi aussi très surpris de la nouvelle conception des cosses de ces nouvelles batteries de 280AH d'EVE. cela nous amène a voir différemment les supports et connecteurs de batteries en terme de surface de connection !? très bien Merci ANDY.

[@ThePhotobiz]

I have the same welded studs. I figured the smaller contact area is still double the 35m2 cables. Mine is running cold with a max of 160A drawn.

[@OffGridGarageAustralia]

Perfect, thanks a lot for sharing, Steve. So 5 cucumbers for your setup then 😁

[@mikecorrea3845]

The 280AH cells I got last summer had the welded stubs but also came with copper flat washers with a big hole so they would sit on the base of the terminal and they were thick enough to come flush with the higher part. The washers were not a perfect fit but still it resulted in a bigger contact area, like the old terminals. I normally don't push big currents, but I was concerned so I tested the batteries with a 150 amp load and the terminals did not get hot. From your testing it looks like I really don't need the copper washers, but I'll keep them and treat them (NO-OX-ID) to prevent dissimilar metal issues.

[@OffGridGarageAustralia]

Thanks for sharing, Mike. These copper washers would make sense if the underlying ring is clean and even. Mine are not so smooth and have a lot of metal 'debris' from the welding process. They probably found it it's not necessary any more 🤷‍♂️

[@aday1637]

Andy, they probably started welding the stud so that folks would not try sanding or polishing the top of the terminal:) Now I'm not mentioning names, here, but there are those that get the sandpaper and files out when they get these. I once knew a guy who used an angle grinder on his.

[@gertvanwerven6355]

You are forgetting the contact area of the Nuts

[@OffGridGarageAustralia]

Not much current will travel to this path though.

[@luisaviles6066]

Hi Andy. You are right loose contact are in the bottom, but the nut compensate in the top.

[@OffGridGarageAustralia]

By how much you would think?

[@corborst4872]

If one is pulling even higher amperage, fill out the welded stud with a soft(ish) copper ring to make an even bigger contact area possible, or just put a M6 copper ring under the battery connectors, both methods will work, as current will also flow through the M6 welded studs and the flanged nut to the cell connectors.

[@realvanman1]

Ultimate contact resistance is actually more a function of contact pressure than contact area, within reasonable limits of course. So, greater area with the same clamping force can actually result in greater resistance as the contact pressure is too low. The fact that the welded studs allow for a higher torque, and thus a higher clamping force, should result in a better connection as well. I love how really and truly put all this stuff to the test. No guesswork, no conjecture, real tests! By the way, the cucumber temperature measurement must go way back. I remember it from when I was kid. Something running nice and cool was said to be "As cool as a cucumber". ;)

[@OffGridGarageAustralia]

Yeah, I have two battery banks with these welded studs and they work great with no issues at all, all using the supplied bus bars. 🥒🥒🥒

[@jsmetalcraft2001]

When I got my welded stud cells I had the same first impression. I was concerned because of the videos posted by you and Ray. I went ahead and built the battery using the included buss bars. Two things I did different. 1. I used an aluminum washer under the buss bar. 2. I used Deoxit and a Scotch pad on all the parts. Yesterday the battery was at 15% SOC due to rain day. Sun cam out and the charger was charging at 140 amps. Two weeks now and I have yet seen any heat on the buss bars. My breaker, 2awg cables, and cells were 7C above ambient.

[@jsmetalcraft2001]

BTW, I am not sure that torque is all that much of issue in making a good connection. Only to ensure you don't over tighten. I turn wrenches so didn't bother with a torque wrench. After years you get a feel for when a nut is tight.

[@OffGridGarageAustralia]

Thanks for sharing your experience. That is great to hear. We will see how this works out over time but I think we will have much less problems than in the past with battery #1

[@jsmetalcraft2001]

@@OffGridGarageAustralia One note on your follow up video. My washers are 1/4" and fit on top of the shiny or smooth area where the buss bar would sit. You mentioned about folks that put a larger washer that fits down on the welded area. I agree with you that is is too rough and not a good place to make a low resistant connection.

[@zxrjimmy1]

I have these 304ah from Amy also, no problems whatsoever with the contact area, tried washers to make the area bigger but removed them again, all seems good, no hot spots

[@OffGridGarageAustralia]

Thanks Jimmy, that good to hear. These connections seem to work just fine without any washers or even conductive paste.

[@chuxxsss]

Time to adjust your busbars, mate. I built my own, watch that one, on my channel. I do them at the men shed. That was crazy, Andy.

[@OffGridGarageAustralia]

I think the standard bars are perfectly fine after this test...

[@danielglang6312]

Very interesting, I had mentioned a few times in earlier posts the contact problems with the slotted bus bars in that they don't have a full contact area which restricts the flow of electrons causing a possible heat buildup. It appears that the new design makes the problem even worse. I did like the woven bus bars you showed a few episodes ago since their circular holes allow for a full contact while the woven strands all the flexibility to lie flat on the terminal.. I think it is important to also consider the nut fastener on top which also conducts current through the stud. The bottom plate isn't the only current path. In regards to the texture on the bottom of the nut, I believe that it helps make a better connection by digging into the bus bar.

[@OffGridGarageAustralia]

This test is against anything I was believing before. Large contact area, clean, straight... But this here is insane. Yeah, I also believe that now a good portion of the current goes actually through the stud and nut. More testing coming...

[@wayne8113]

@@OffGridGarageAustralia That would be a great test, hope you come up with a way to insulate the terminal stud

[@danielglang6312]

@@OffGridGarageAustralia Perhaps the current going through the stud and nut makes up for the smaller contact area on the base of the terminal. The nut seems to have a larger contact area than the base and the texture helps dig into the bus bar.

[@wg6215]

I believe that the increased compression of the reduced contact area of the welded stud to the buss bar surfaces would slightly deform under the greater PSI at a givin torque causing greater contact area between the two surfaces. Almost like a crimp, or close to it.

[@rikujkoivisto]

Hi Andy! I would put a big hole washer around upper terminal (step) to make proper contact surface. 🤗

[@OffGridGarageAustralia]

It's not really necessary as I will hardly ever push more than 70A through these terminals. And as the test showed, it works quite well without.

[@piotrsobolewski5886]

Dziękujemy.

[@OffGridGarageAustralia]

Thank you very much!

[@stephsoltesz6731]

I run 24V Multiple packs. Some EVE-280AH (N) with studs & (K) welded terminals. Have run 225A Load & 140A charge using Single Packs (part of my thrash tests). No issues delivering or recieving charge, everything was fine. The "Welded studs" did get "warm" but NOT HOT. I did have TWO HOT SPOTS but as usual, a small ridge on the busbars had to be cleaned off and Voilam solved.

[@OffGridGarageAustralia]

Great, thanks a lot for sharing!

[@rossallen738]

The threaded stud itself is carrying the current which means as long as the nut gets good contact with the stud, and then good contact with the bus bar, then it isn't an issue.

[@OffGridGarageAustralia]

If I use a nylon nut on the top, what would you expect to happen?

[@rossallen738]

@@OffGridGarageAustralia I had thought about that, and chose not to use them because I wasn't sure how they would handle heat if there was a problem. After watching your more recent video where you explain the resistance differences I agree with you that most of the current is probably going directly from terminal to bus bar. I was surprised to see such a large resistance differential between the bottom of the terminal and the top of the stud.

[@centerrightproudamerican5727]

I have not worked with the welded studs but I have had the same concerns as you. Many folks on the DIY Solar channel have used the cells with welded studs and so far I have not seen anyone indicate it is a problem and some folks have said it is no problem. Having said that, it seems to me that they could design a welded stud that provides a lot more contact area than that.

[@ssoffshore5111]

I just bought some new LF280K batteries, they have TWO screw-in studs on EACH terminal... with a larger flat base for the busbar! I think it's a huge improvement over all the previous designs!!!

[@OffGridGarageAustralia]

I think this connection works very well here... Seen the other new terminals you're talking about.

[@bramsoff-grid]

I have the LF280K's from Basen Technology. They have fixed M6 studs, but not the extra material on the bottom.. My busbars are touching the alu from the cell.

[@OffGridGarageAustralia]

So just glued in studs?

[@marianilie7321]

you can test with a plastic between busbar and smal rim of the battery. All the curent transfer current is from pin to rimlock and busbbar 🤟

[@johnmajewski1065]

I'm learning so much, thanks Andy, for your effort and ability. Though, the 160 Amp bench test passed with no issues. The small contact area needs a solution, for a better contact area to be larger, Why? In real-life use in a vibration environment. As an example, I would like to change my 860 AGM battery bank in the future on my ocean-going sailboat to a lithium system. I would not make an installation with such a small Buzz Bar contact area as it is not only about the amps contact area, it is also about the mechanical contact area required to ensure the buzz bar's system does not become loose with the pounding in rough weather conditions (it's about reducing the weak link possibilities in sailboats).

[@OffGridGarageAustralia]

Thanks a lot John. For a mobile solution, I would definitely go with flexible busbars. The ones Madi made seem to be really good and work well even under extreme conditions. She also used this sticky heat shrink which seals the cable and protects it from moisture. You have seen her video?

[@johnmajewski1065]

@@OffGridGarageAustralia Hi Andy, Thank you for your reply...please send me the details I'm most interested in. My fear in buying a drop-in Lithium battery bank is the BMS needs to be tailored to your boat's charging assets. If not, do you risk losing them? If you are sailing to the pacific islands, and you lose power, there is no one to get you out of your fix. For this reason, Your channel is most helpful for a layman like me. I installed 4 x 215 Ah, charged by 720-watt solar panels with a Victron smart 150/70 controller - and 400 watts (at best) wind generator, and a 120 Ah alternator. I have no generator. If I had a Lithium battery bank, I suspect I would need a custom BMS to control the charging and discharging? I'm interested in building my own system batteries are fine, the problem is a reliable BMS. I thought you gave great reviews on Neek BMS, but I notice you do not use them? Why is that?? Keep up the good work. I'm having a most enjoyable learning experience. Thank you.

[@RenaatG]

Consider also that there is current flowing through the stut and nut to the top of the bus bar. What is the intersection of the bus bar? Rough deformable metals forced into each other have maybe a better conductivity.

[@OffGridGarageAustralia]

I assume, less than 5% of the current will go through the stud and nut to the top of the bus bars. Main contact is terminal and underside of the bus bar.

[@madsskovhansen4840]

Very interesting - good test! Have you tried measuring the voltage drop from stud to stud or over the fuse? Multiply by amps and you can put the watt loss / cost on each connection (at that load). Could be interesting 😊 Cheers

[@OffGridGarageAustralia]

Thanks, more tests to come 😉

[@markobotz2890]

I have heard from that in a German forum, and they say that there are some used cells on the market 😳 with this welded studs on it. Hopefully it is only a new style, good luck

[@fathergratwick]

not sure if it was mentioned but an advantage of these welded studs is you can torque them to 10nm which is recommended.

[@BeastMovies]

I love the welded lugs. I have no problems. 250amp daly bms but set at 200amp. No fancy meter, just hand tighten. The nut acts as a better point of contact.

[@OffGridGarageAustralia]

Thanks for sharing. You're using the original bus bars as well?

[@1981dasimpson]

i think drill a washer out to fit around the raised bit of the lug so you could gain more contact area or maybe larger holes in the buss bars that join them

[@mrmagoo4897]

This in incredible! I had the same reaction when i opened the box on my 280ah cells. Only frustrating thing is I may have torqued them down to 10nm as thats what the recommendation was in some forums. Rookie error sigh. They seem to be ok atm....

[@OffGridGarageAustralia]

Wow, 10Nm!!!!😬Good to know you can without damaging the cells.

[@kyba74]

Do you have any heating problems at high loads? Wonder if not enough torque is my issue.

[@robertkosovich1232]

I was just getting into the tunes,...........nonsense?.....shhhhhh class has started!

[@OffGridGarageAustralia]

Hahaha, thanks, Rob! 👏

[@rtw8972]

I would mill out the holes in the buscar to the diameter of the seat of the stud. This will give maximum contact ares.

[@OffGridGarageAustralia]

It won't. The lower ring is not plain and has a lot of rough leftovers form the welding process.

[@EddywaKenya]

Hi. I had the same issue with welded studs. My cable holes were wide. I sourced for copper washers which were tight fit on the outer sides of the welded base and flush to the top.

[@OffGridGarageAustralia]

Is you lower area around the stud not rough? Mine is from the welding... so not a great contact area. And more washers make more points of resistance?

[@EddywaKenya]

@@OffGridGarageAustralia I had to reuse the original cable (forklift) with big lugs. The hole diameter was wide and had to find a way to pinch them. And yes the stud welded area was rough. Pure copper washers and star lock washers did the trick. The motor draws 600 to 1200 amps according to the load. I have no issue with thermal on the studs.

[@sreekumarUSA]

040622/0321h PST 🇺🇸. 040622/2021h Brisbane 🇦🇺… hello Herr Andy, thanks for the presentation. I don’t thing this is a matter of concern. The supplied bus bar is 2mm thick and this is the exact difference between the top of the step and the bottom of the welded plate. The diameter of the step is 10.88mm. If the hole of the busbar is enlarged to 10.90 it will fit snuggly around it. The serrated SS nut will take care of the tightness and current. But do the experiment outside the box and check the fitment and current loss, if any. You may smear the MG Chemicals conductive Carbon grease or the No OX grease on all connections. This is my thought, it may differ from people to people. Let me know. Take care und 73s…

[@OffGridGarageAustralia]

Thanks Sree. I covered this in the next video...

[@SinKillerJ]

Ill have to check later, but I do not recall my welded ones from last year being anywhere near as tall or slim at the base.

[@OffGridGarageAustralia]

I would not be surprised if other suppliers use different studs and weld them on.

[@SinKillerJ]

@@OffGridGarageAustralia My surprise comes from using the same supplier.

[@todoxe]

hello, greetings, here I already have about two weeks enjoying these very educational and entertaining videos, thank you. I have a question. Why is the famous Renogy inverter with UPS function only available in Australia? that is, it does not appear on any other webpage from another country. I live in Venezuela and I would like to buy one. Thank you.

[@frankieboy302]

If it bugs you that much, put some washers over the ‘stepped’ terminals to increase the contact area. On the plus side, the contact area where the stud screws into the terminal in now much thicker….

[@OffGridGarageAustralia]

It seems to work fine as it is, so I will go with this. It's a bit of a long term experiment, I guess 😉

[@petertaylor5614]

Hi Andy, I hope you are well. Love your videos, super informative. I wonder if you could advise the current cost (approx would be fine) of the cells, I live in Brisbane. I am looking at a purchase of 4 of either the 280 or 304 to use as a 12v power supply for camping. All the best Peter.

[@OffGridGarageAustralia]

Thanks Peter. I ordered the cells back in December and paid for them at the time. Prices have gone up like 20%-25% since then. It's best to get in contact with QSO and get a quote as it includes shipping to your place as well then. Links to these cells are here: off-grid-garage.com/batteries/

[@petertaylor5614]

@@OffGridGarageAustralia Thanks Andy😊

[@jwm1020]

i would be tempted to get some sort of sleeve made to go over them to give you a larger contract area it's the only way that I can think of to increase the area so that you can get kind of power through that kind of stud

[@OffGridGarageAustralia]

It throws everything we know over board a bit. I feel the same and look for solutions to increase contact area. But it seems it is not necessary...

[@christophec252]

I’m so happy after the test. I’m waiting 36 cells from them! Perhaps the screws iron can carry more amps? Also the studs carry and wan be considerate for surface contact too?

[@OffGridGarageAustralia]

36 cells? not 32?

[@christophec252]

@@OffGridGarageAustralia yep sorry. Keyboard bug.

[@simonguest1890]

Hi Andy, yes I have 230ah EVE with welded studs. Work absolutely perfect since month. Just let you know that you can customize your cell orders. You can order with and without welded studs. But with studs it's a very big difference in a positive way. My older 280ah EVE with drilled holes was a shame, I torgue them with just 3 nm and 4 threads of 16 cells are broke out of the terminal. Now with welded studs a difference from frustration to satisfaction at all. Cheers

[@OffGridGarageAustralia]

Thanks for the info, I wasn't aware of that you have a choice when ordering.

[@ForbiddTV]

Are you able to repair the cells with the stripped holes? Tap a larger flat bottom hole perhaps?

[@simonguest1890]

@@OffGridGarageAustralia Sure You are welcome, i don't know if its depending on the seller, but in my case, BASEN and Donguan Lighting did that. But I prefer Donguan Lighting. James Mo is know promoted to a manager position, he do always the best for customer. They just sell Grade A cells. Doing good business in long term. 202ah cells delivered 210ah, and 230ah do 240ah.

[@simonguest1890]

@@ForbiddTV yes I just took a bigger thread bolt in it and 5/16 not m8. Because had a different thread to bite in the aluminium. I did that because the whole was bigger anyway cause of the outbroken thread in the terminal. the whole thread broke out. So the hole was clean around without any thread anymore. Hope my English was good enough to explain that. 🤔🙂

[@ForbiddTV]

@@simonguest1890 Sounds unstable if you didn't re-tap the hole, but if it worked then that's all that matters.

[@mediocre_moto]

I suppose that by moving to an all steel bolt, they have greatly reduced the risk of stripping the thread or permanently damaging the terminal on the battery (as opposed to a steel/stainless steel stud screwed into the aluminium terminal). As a "fix" for this, you could get some simple stepped washers or rings machined up (hobby lathe?) that will slip over the bolt and contact the bolt base as well as the lower part of the terminal.

[@adon8672]

Shouldn't the studs and flange nuts be factored into the contact areas?

[@OffGridGarageAustralia]

My guess is that a very small amount goes through the stud, nut and top of the busbar?

[@mikeeverett4987]

The flange nut serrations, I think even though they dig in some do actually provide a good connection through the studs to either a bar or to a terminal crimp end, I am getting the same cells soon, 32, probably on a ship right now. We will see!!..Why not try the serrated nuts on the old style cells, re compare.

[@OffGridGarageAustralia]

We will have some different bus bars set up on the three battery banks soon, so this will give us a bit of a 'long term study'.