OK, so I read about the crushed washers idea and like it.
I just received my new cells from Amy, they look very fine
The stud pads welded on my cells, have a circle around the stud, with 11mm diameter, the circle below that is 15,5mm. I'm trying to see how they're welded, there is residue on that 15,5mm pad. Seems like instead of welding around the post, they welded through it and then ground down the weld?
Here's a photo, hope you can make it out:
View attachment 77757
You can feel some small ridges with your nail, so that's not perfectly flat. This worries me, with regard to contact with a spacer crush ring and increased resistance. Are the studs strong enough to actually crush the ring properly? At what torque?
I don't use a busbar with a large slot, but ring lugs and (braided)cable between posts.
Then again... the circle around the 6mm post, has a surface area of:
pi * (11/2)^2 = 95mm2
but minus the 6mm post, which
pi * (6/2)^2 = 28mm2
ends up being 67mm2 for that small circle, which should work for about 200A, right?
Am I missing something? What would be the wise decision here?
Well, now I'm confused. I found this busbar calculator (
https://www.electrical4u.net/calculator/busbar-current-calculator-online/ ) - a 50mm2 busbar can carry 60A according to this, while a copper 50mm2 cable can carry 150A according to various tables.
Why the difference?