Source for studs for Eve 280 AH cells?

[apctjb]

Ordered some replacement cells for my battery bank and the new EVE 280 cells I received have studs rather than treaded insert. Thinking I will add studs to my existing cells so all are the same.

Can anyone point me to a good source for studs that work with the EVE treaded post (6mm)

Thx

 

[sunshine_eggo]

you mean grub screws?

https://www.amazon.com/gp/product/B088FFD5CZ

 

[apctjb]

Yes, those look perfect. Thanks

 

[sunshine_eggo]

Yes, those look perfect. Thanks

They don't need to be that long, but they worked fine for me.

 

[apctjb]

I remember using 12mm cap screws so was thinking 20mm, but no harm in longer I guess.

 

[HRTKD]

If the right size/alloy grub screw can't be found, buy threaded rod and cut it to the length you need.

 

[Struc]

https://www.amazon.com/gp/product/B08C4XPJ3Z/

Edit: Oh, and nuts: https://www.amazon.com/dp/B071XHYWLW

 

[Rocketman]

McMaster-Carr has lots of metric grub screws, that’s where I got mine.

 

[hwse]

And for FWIW, Andy on Off-grid Garage has repaired several stripped-out cells by screwing a standard 1/4" NC grub screw into a stripped socket. It is just slightly larger diameter and will go in without drilling and tapping.

 

[apctjb]

Andy on Off-grid Garage has repaired several stripped-out cells by screwing a standard 1/4" NC grub screw

Good suggestions. Are folks using any type of conductive anti seize ; like copper past of just putting them in dry?

 

[hwse]

I have welded studs, so it doesn't affect my cells but... Back when I was planning on getting threaded sockets, my plan was to use red Loc-Tite (permanent) when I inserted the grub screws the one and only time I intended to turn those screws. When compared to aluminum, stainless steel is a semi-conductor at best. It has quite high resistance for a metal part so almost all current is passed from the aluminum surface to the buss bars and not through the threaded screws. Every time you turn the screw, you potentially damage the threads so lock them and forget them.
I would use a crows-foot socket on the torque wrench so that I could hold the screw with an Allan wrench to hold it stationary when tightening.

 

[Rocketman]

I used a silver epoxy. I didn’t want my studs to loosen up. Once and done.

 

[Hipster]

I used a silver epoxy. I didn’t want my studs to loosen up. Once and done.

those that hold it strong - wont come loose - is it better than red locktite ?

 

[Rocketman]

I thought so (and still think so).

Red locktite (I believe) does not conduct electricity.

The silver epoxy is supposed to conduct electricity. The main amps will not be flowing up the studs - but I figured every bit can help.

But also I liked the epoxy nature of the product.

It was easy to use - I just used a toothpick to apply and I have not had any loosen up on me - 1-1/2 years in MotorHome.

 

[hwse]

Stainless steel has significantly more resistance than does the aluminum terminal or nickel covered copper buss bar so based on Ohms Law the stainless will carry very little current. If you doubt this, put a stainless-steel washer between the terminal and the buss bar and check the heat buildup.

 

[sunshine_eggo]

Torque the studs, and they're not coming loose. No loctite or other adhesive needed.

Stud material mostly irrelevant beyond galvanic corrosion concerns. Conductivity between the terminal face and ring terminal or bus bar is what matters.

 

[https://www.syluecncmachi]

What stud do you source? Ningbo Sylue Machine can help you.

 

[hwse]

Torque the studs, and they're not coming loose. No loctite or other adhesive needed.

Stud material mostly irrelevant beyond galvanic corrosion concerns. Conductivity between the terminal face and ring terminal or bus bar is what matters.

What torque to you use on the welded studs?

 

[sunshine_eggo]

Torque limited by the terminals. The particular Eve cells I had was 8Nm max. I torqued to 6Nm

 

[hwse]

Torque limited by the terminals. The particular Eve cells I had was 8Nm max. I torqued to 6Nm

Where did you get the torque spec? I have EVE 280k cells with the M6 welded studs with the smallish ≈10mm conctact area.

 

[HRTKD]

Where did you get the torque spec? I have EVE 280k cells with the M6 welded studs with the smallish ≈10mm conctact area.

One of the EVE data sheets provides that specification for rotational torque on the terminal itself.

 

[sunshine_eggo]

Where did you get the torque spec? I have EVE 280k cells with the M6 welded studs with the smallish ≈10mm conctact area.

IIRC, it was in the cell datasheet.

I hate the new cells for that reason. It's like a built-in defect. Mine were the ones with the large flat internal threaded terminals. Massive contact area and worked great with grub screws.

 

[HRTKD]

I hate the new cells for that reason. It's like a built-in defect. Mine were the ones with the large flat internal threaded terminals. Massive contact area and worked great with grub screws.

Agreed. I would have a tough time buying another set of cells at this time because of the funky terminals. The one version that has two connection points would be OK. But that dinky contact area that you refer to really bothers me.

 

[hwse]

Agreed. I would have a tough time buying another set of cells at this time because of the funky terminals. The one version that has two connection points would be OK. But that dinky contact area that you refer to really bothers me.

I have seen several videos about the small contact area and surprisingly it doesn't seem to matter. If it is in fact not capable of carrying the required current this fact will manifest itself by the contact area getting hotter than the surrounding surfaces. When tested, the contact area remains cooler than the buss bar or the cells, so it is not a problem. Here is a video of a test with 160A for 20-minuts then 230A for an additional 10-minuts with no heating. The good stuff with a flir camera begins at 22:25. I bought my 280K's with these terminals after watching this test.

 

[sunshine_eggo]

There's a difference between "this is a good design" and "this is not a problem".

Not sure what you're looking at. I watched the video you linked and saw the opposite.



The FLIR imaging confirms it for me... it's a bad design. The fact that there's a temperature rise at all indicates a point of resistance. Those connections very nicely add 8 additional resistors.