harvested 18650 cells, connected metal strips, etc.

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harvested 18650 cells, connected metal strips, etc.

I harvested some ncr cells from laptop batteries I had a few years back. Since they weren’t button tops I left a little bit of the soldered metal strips that connected the batteries in series on the top and bottom to use in place of button tops or as a connection point.

Is that appropriate?

Should it be removed?

Barkuti
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Personally I would have removed all the nickel strip remains, I believe that's unnecessary. Flat top is usually fine. A good physical connection is one with ample contact surface and high conductivity (oxidation free). However a not too big and properly polished piece of nickel strip remain should not be a problem.

Solder blobbing cells can be done quite easily, take a look at this video:

 

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jeff51
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Depending on the application, the strip could be helpful.
As long as it does not extend past the edges of the center post.
Smooth out the edges so it won’t cut stuff up.

Some lights have a rubber washer thingie around the positive connection to prevent backwards cells from making a connection.
As long as your strip remnant fits, you’re good to go.

If your application needs a taller button top, the a solder blob is the way to go.
I wish I had left a bit of strip behind when I harvested a pile of laptop 18650s a few years ago.
Easier to remove if not needed than to add something back.
All the Best,
Jeff

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If I could use flattops, I’d file ‘em down flush.

But since a lot of lights require button-tops, you can file off the sides of the flash so you don’t go poking holes in your thumbs, but leave a bit of a bump to make contact.

One benefit of that is that while the pinhead-sized bump isn’t much contact area, where it does make contact it’s under immense pressure, which would be a definite plus.

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Zappaman
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Like the video, I just grab my old lead electrical solder and run it against the side of the tip after dropping a light bit of resin on the contact first. But I have an additional step afterward.

After you have the “blobs” soldered in place, often they are not uniform. And having a round contact point is also causing a bit of resistance making contact on other flat surfaces (like with my new Sofirn IF25a which has no forward spring behind the driver- just a flat, wide brass contact).

So, you can take a finer file and file down the blob a touch… squaring it off like a standard button top. Do be careful with some cells as it’s east to file the wrap and you do not want to do that! I go for about a 2-3 mm wide flat spot- again… about like a normal, button top’s width. Easy last step, better conductivity, and best done in batches where they come out more uniform…In my case anyway Wink

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jeff51
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I flatten the tops of my solder blobs for better contact too.
I like to scratch up the tops of the battery with some 200-400 grit wet/dry paper, then clean them before putting on some rosin before soldering.
This seems to make the solder “Wet” better than the shiny metal.
All the Best,
Jeff

wle
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i would eliminate sharp edges and points, for sure
if you just rip the strips off with pliers, there can be ridges and edges and points left over
those can;t be doing any good

get a file after them
do not short to negative

or a grinding wheel

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Zappaman
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I usually can peel up the strips with needle nose pliers- rolling them up on the tip. Then just solder the blob over any small shards leftover. But if one really doesn’t want to let go- I grab the dremmel tool Blushing

ZappaMan