How many amps are you pulling through welded on terminals?

[Hedges]

Here's an article on a previous method for fixing aluminum house wire. (now superseded by other techniques.)

Note the idea of applying a corrosion inhibitor and scrubbing off oxide through the inhibitor.
They also favor non-flammable corrosion inhibitor.

Scotchlok 3M Connector [now obsolete] Aluminum Wire alternative repair Method using a Specific Twist-on Connector - Details

Welded stud offers 0.111 square inches contact area? That's like 2/0 cross section.
The issue is contact patches, not overall area. For a given pressure, I don't think 0.111 in^2 is better than 0.290 in^2
Just give me more torque.

 

[ed1380]

Here's an article on a previous method for fixing aluminum house wire. (now superseded by other techniques.)

Note the idea of applying a corrosion inhibitor and scrubbing off oxide through the inhibitor.
They also favor non-flammable corrosion inhibitor.

Scotchlok 3M Connector [now obsolete] Aluminum Wire alternative repair Method using a Specific Twist-on Connector - Details

Welded stud offers 0.111 square inches contact area? That's like 2/0 cross section.
The issue is contact patches, not overall area. For a given pressure, I don't think 0.111 in^2 is better than 0.290 in^2
Just give me more torque.

issue isn't contact area on top of the welded terminal/stud. issue is contact area between the original terminal and new welded terminal. open my picture full size to get idea of what I mean. the surfaces aren't perfect so the only good connection is the weld bead

 

[HRTKD]

issue isn't contact area on top of the welded terminal/stud. issue is contact area between the original terminal and new welded terminal. open my picture full size to get idea of what I mean. the surfaces aren't perfect so the only good connection is the weld bead

If the only good connection is the weld bead, you're fooked.

 

[Hedges]

issue isn't contact area on top of the welded terminal/stud. issue is contact area between the original terminal and new welded terminal. open my picture full size to get idea of what I mean. the surfaces aren't perfect so the only good connection is the weld bead

If the only good connection is the weld bead, you're fooked.

http://copperalliance.fr/uploads/2018/03/6_jointing.pdf

"In practice, an electrical contact between the solids is formed only at discrete areas within the contact interface and these areas (known as ‘a-spots’) are the only current conducting paths. The a-spots typically occupy an area of the order of 1% of the overlap area."

I'll take a weld bead over 1% of 0.290 in^2 any day.
And if the cross section of the weld bead is larger than a wire gauge able to carry the current (according to ampacity chart), why worry at all?

 

[HRTKD]

I would want to see the welds. If these are laser welds, they may be quite small.

 

[Hedges]

https://www.wirebonddemo.com/wp-content/uploads/SMT-July2012_WedgeBondingforAutomotive.pdf

"A 20 mil diameter, 100 mil length, 99.99% Al round wire can safely carry 120 amps."
That's just 0.000314 in^2

(plausible, since it has 400x the cross section of the 1 mil wire we found could carry about 1A just before it burned out.)

That even makes the 0.002900 contact area of a bolted connection sound not so bad.
(But I still prefer the quite small laser welds.)

 

[ed1380]

That paper is a great read but it talks about materials that are too hard to deform. Hence the low contact area. The soft aluminum on the terminals is able to form to the busbars. And you'd get even better connection if you wiggle the busbars while tightening. Similar to how it works on a car battery. The soft lead terminals are able to deform to each other.

 

[Bob B]

Good report here .... https://diysolarforum.com/threads/r...ure-cells-from-shenzhen-luyuan-amy-wan.22371/