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Improving Contact Area on Welded Stud Pads

Putting your own studs in, is better but you can still easily over torque. You also need primer for the loctite and it's hard to find and expensive.
Have you tried Loctite 2760 vs. 283 and primer?

Rather than a Loctite product, and since 283 and 2760 are meant to be permanent, wouldn't JB Weld work as well?
 
Does anyone know what the torque specification for these welded studs, M6 and M8 is? What kind of n-m or in-lb should I be aiming for?
 
Does anyone know what the torque specification for these welded studs, M6 and M8 is? What kind of n-m or in-lb should I be aiming for?
I think for M6 you want 4 Newtons, and about 7 for M8. I know I calculated 40 in lb for my m6 as I don't have a newton meter, but I can do sq inch
 
It's still better than those set screw lugs.

Set screw lugs are UL listed. That means they passed testing for performance over environmental conditions.
They are tin-plated aluminum. Plating, performed after aluminum oxide has been removed, makes all the difference.

But used on cell terminals, you still have the problem of terminal metalization. I think those ought to be tinned, but most likely aren't.
 
Set screw lugs are UL listed. That means they passed testing for performance over environmental conditions.
They are tin-plated aluminum. Plating, performed after aluminum oxide has been removed, makes all the difference.

But used on cell terminals, you still have the problem of terminal metalization. I think those ought to be tinned, but most likely aren't.
On the whole I am inclined to agree with you. If you get them from a reputable supplier then go for it.

But keep in mind those standards also tend to be much lower current applications than what some of us might do. Especially if you're not trying to pull hundreds of amps.

At least based on US "standards" for a 4/0 wire (no reason for this size, just example) is only good for 230 amps. 260 for 90c wire. A UL lug would be designed for that, plus some safety factor of course.

However, chassis current rating for 4/0 is 380a and you can go higher with very short runs. A UL lug would probably be fine but a $1.50 Chinese mystery brand one would be concerning.

Hell. These ones I don't believe are UL listed and I see them used all the time with poor results even though they should be more or less fine. But clowns like me put 300+ amps through these wires.

 
@Horsefly So what was the final outcome on the aluminum jewelry washers?
Yeah, as @MasnPip said, the jewelry washers are not a good idea. They are too thin, so if you can manage to get them over the first 11mm pad and get them to make contact with the next pad down, they are too low for the bus bar to make contact.

The very first oil pan gasket rings that I gave the link to (https://www.amazon.com/gp/product/B01ER3U3XY) work pretty well. Someone here suggested Gardner Bender OX-100B to enhance the electrical contact on the aluminum. The Gardner Bender website describes what it does "Ox-Gard Anti-Oxidant Compound contains prime grade zinc and is formulated with metallic zinc to create a compound that enhances electrical and thermal conductivity which is used on high power crimp connections and stud bolt mountings." Anyway, I assembled my pack with the OX-100B on both sides of the washer and on the top pad. I used some different bus bars that were meant for M6 studs rather than the ones that came with the cells, which had holes meant for M8. I've only tested it under a 9A load (it's all I have here right now), and the cell voltages all kept steady and the bus bars and studs stayed cool.
 
I found drilling the bus bars we were shipped to 7/16 makes for a nice fit to collar of the welded stud. The base diameter of the weld measured out to 15 mm. These Copper Washers would be a perfect fit in both diameter and thickness to fill the space between the aluminum battery contact and bottom of the bus bar but I take it copper to aluminum, even with no-ox, is not considered a good practice?

Don't judge the quality of the drilled out bus bar. I haven't deburred it properly, just a quick scrape with a coarse file.
 

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I think you have even less material contact now.
The top shoulder of that stud is steel, I'm trying to get the Bus bar down to the aluminum somehow...unless the steel is considered good enough.
 
The top shoulder of that stud is steel, I'm trying to get the Bus bar down to the aluminum somehow...unless the steel is considered good enough.
I thought it was steel as well, but someone posted somewhere that the stud itself is steel but they were pretty sure that the top shoulder is aluminum. I check in a minute.
I found drilling the bus bars we were shipped to 7/16 makes for a nice fit to collar of the welded stud. The base diameter of the weld measured out to 15 mm. These Copper Washers would be a perfect fit in both diameter and thickness to fill the space between the aluminum battery contact and bottom of the bus bar but I take it copper to aluminum, even with no-ox, is not considered a good practice?
I think the problem is both your drilled out hole and the washer is copper, so you are definitely going to have some galvanic issues.
 
If you succeed in having the busbar bearing down on aluminum cell terminal when tightening nut on stud, you will be applying pulling force to the weld.
 
The stud itself is stainless, pressed into an aluminum "housing" that is welded to the existing terminal.

The bus bar sits on aluminum no matter what. But now you are relying on an uneven weld to for your contact surface and a very small amount from the shoulder. I think that would be way worse than the original way.
 
Heres a close up of the weld that was pretty consistent on all of my cells. Very uneven. This is also why I opted to cut the washers out of "dead soft" 1000 series aluminum, in hopes that it would "conform" to the unevenness of the weld.

20210412_133427.jpg
 
So this shoulder is aluminum? Ok, that makes things easier.
 

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The top shoulder of that stud is steel, I'm trying to get the Bus bar down to the aluminum somehow...unless the steel is considered good enough.
I assumed, based on the picture pre-weld, that they merely molded aluminum around a standard bolt. If so, other than the head of the bolt on the bottom, and the threaded bolt, all the rest would be aluminum?
 
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