Welded stainless steel m6 studs a good solution?

Brett V

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I've come to the conclusion these studs are not stainless steel...they strip very easily. And they're too short! Stacking two busbars to top balance only leaves a few threads to work with and that's only if you skip the lock washer. I have two cells now with the top few threads pulled off and I'm only using a nut driver to snug them down for top balancing. I'll be OK once they are assembled as a series string since there will only be one busbar thickness to deal with but plan to be VERY careful! I've ordered some flange nuts and will ditch the supplied hardware in hopes I can get a respectable connection.
 

APhoton

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I've come to the conclusion these studs are not stainless steel...they strip very easily. And they're too short! Stacking two busbars to top balance only leaves a few threads to work with and that's only if you skip the lock washer. I have two cells now with the top few threads pulled off and I'm only using a nut driver to snug them down for top balancing. I'll be OK once they are assembled as a series string since there will only be one busbar thickness to deal with but plan to be VERY careful! I've ordered some flange nuts and will ditch the supplied hardware in hopes I can get a respectable connection.
what are you torquing these to?
 

12VoltInstalls

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Stainless fractures and galls, then breaks, generally. Stripping? Could be a better alloy that doesn’t have the brittleness of tractor supply bolts.
 

Stepandwolf

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Stainless fractures and galls, then breaks, generally. Stripping? Could be a better alloy that doesn’t have the brittleness of tractor supply bolts.
The issue of SS galling has come up before but I think it is non-factor. While playing around with my batteries, I have taken the studs in and out, the washers on and off, multiple times. No sign of galling. I am wondering if galling doesn't begin unless you have higher pressures.

I just ordered my second set of batteries yesterday, and went with thread holes again, like the Lishen I already have. I was undecided about thread holes, but I wanted to buy domestically, and that was what they had. I intend to use blue Loctite as it doesn't need primer to adhere to SS. I am using the longer hex head bolts with plenty of length. I will have the busbar on the bottom, then the BMS lead, then a Nord-Lock washer, and a serrated flange nut, and a bow on top.
 

jwelter99

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Hello folks,

do you think the new solution by welding stainless studs to the alloy surfaces is a good idea? Im not shure.

1. galvanic corrosion of alloy and stainless steel.

2. Electrical conductivity of stainless steel is worse than from alloy.

3. I think the surface area is smaller than with the old alloy m6 thread holes.

Im hesitating to buy EVE 280 Ah welded cells, but the vendors of Alibaba seem to only cell welded cells at the moment.

Best regards

The stud is stainless that has a hex end that is pushed into an aluminum donut that is then laser welded to the terminal.

As it is an interference fit (the stud into the AL donut) it should be air-tight so no galvanic corrosion will happen.

It can't be worse then the shitty threading in some cells, and if a problem you can saw the stud off and drill and tap to be back to where we used to be.

From my perspective these new studs are a big step forward.
 

Brett V

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The studs welded to the battery posts seem to be soft metal not stainless. Not even cheap stainless. I'm 60 years old, my hands aren't that strong, yet I was able to strip the threads on the stud with just a nut driver. I wouldn't even consider going near them with anything that has some leverage. I've worked with my hands my entire life and know what snug vs tight feels like. I still feel the tapped holes with helicoils are the best solution.
 

Stepandwolf

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The studs welded to the battery posts seem to be soft metal not stainless. Not even cheap stainless. I'm 60 years old, my hands aren't that strong, yet I was able to strip the threads on the stud with just a nut driver. I wouldn't even consider going near them with anything that has some leverage. I've worked with my hands my entire life and know what snug vs tight feels like. I still feel the tapped holes with helicoils are the best solution.
Would you take a current M6 threaded hole and add a Helicoil to that, or drill that out and put in a Helicoil?
 

Brett V

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An exiting hole would have to be drilled out for a helicoil. I've done helicoils in aluminum before, Ford had an infamous problem with the spark plugs in aluminum heads stripping out and that was the fix. They're very strong if done right. The problem isn't the merits of the welded stud, it's the typical Chinese lack of quality.
 

Short_Shot

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The issue of SS galling has come up before but I think it is non-factor.
Galling really only occurs when using metals of very similar hardness and composition.

If you have a stainless stud and matching alloy stainless nut you'll gall every time, usually occurring after just a few cycles of on/off, but if your nut and bolt are different enough it'll virtually never happen.

And depending on dumb luck you may just have two very different grades of SS at play, thus solving the issue.

I think the minimum was something like 7 or 8 rockwell B but it's been a few years.
The studs welded to the battery posts seem to be soft metal not stainless. Not even cheap stainless. I'm 60 years old, my hands aren't that strong, yet I was able to strip the threads on the stud with just a nut driver. I wouldn't even consider going near them with anything that has some leverage. I've worked with my hands my entire life and know what snug vs tight feels like. I still feel the tapped holes with helicoils are the best solution.
Stainless steel is available in many alloys with wildly variable hardness. The softer stuff strips near as easily as aluminum but as above can be beneficial when selecting a good SS nut to alleviate galling.
 
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