Spot Welder for Lithium Cells, Simple and Inexpensive

From across our Northern border, AvE explains how to assemble a simple spot welder to link cells. His YouTube channel is helpful, interesting and funny, some adult language.


Or go into YouTube and search for: “Simple and dirt cheap Spot Welder for lithium cells. Now, 100% MOT FREE!”

The video won’t play for me… :weary:

I edited the OP to add the link and the tile so you can go into YouTube and search out the video.

Pretty cool. Thank you for sharing.

Hey that’s great!! I’ve been wanting to do this for some time now. :beer:

That’s pretty cool. Now to make a proper lead holder… How is he going to do the positive side with the clamp?

I like the solenoid idea, but as he mentions there is a problem with doing the positive side.
For now I will stick to my big soldering iron and electronic solder. Gotta be fast though. The amount of heat flowing into the cell casing is what needs to minimized. A large iron and a very quick application does that.
Ironically, the positive end is the easiest to solder as the flat top button is not sinked to the cell as well as the negative.

Off the shelf battery welding machines have 2 probes, thats how they avoid “grounding” thru the battery body, one probe is + other one is - you just press them tightly to the battery and thats it, no need to peel off the battery protectiv foil either…
Google image search link <- every one of them has 2 probes…

Solenoid! How the heck did I never thought of that. Now that’s a forehead slapping moment. :stuck_out_tongue:

I’ve always wanted to try this but dare not to push the two 12V terminals manually (like some instructions on the net). If the two rods stick, which they tend to, you get explosive batteries. Or vaporizing wires. Whichever it is, not cool.

Hmmm, a thought, do you think that those high current 25R/30Q can solder themselves with this method?

BTW did he say that battery was $3.99?

Exactly right.

Also, the rod ends need to be tapered, not blunt. Check home improvement or electrical supply houses for a small amount of copper rod, most all carry it, for grounding wires.

The first automotive spot welder/dent puller I ever had was nothing more than a very large deep cycle battery and the biggest solenoid I’ve ever seen. Don’t know what they sourced it from, it was about 6-7” wide!


Think he said “$Free.99”. He mentioned replacing the battery on his sled I think, apparently he kept the old one.

Is there no Core charge on batteries in Canada?

There is a fairly recent thread here about a guy seeking advice to do just such a thing, I’ll look for it…


Google “sput welder”, I made one for my anodizing set of to securely attach aluminum lead wires to parts I was anodizing, I forgot the size capacitors I used but the information is out there

This thread convinced me to give this a shot. Thank you Pinetreebbs.

They say that pure nickel tabs are important for low resistance, but that some vendors will actually send nickel plated steel. It’s supposed to difficult to tell the difference visually and by touch. Supposedly, pure nickel tabs will not generate sparks when ground/sanded at high speed. Also, pure nickel will not rust like like steel.

I just received the below yesterday and it passes the no spark test using a belt sander. Will try the rust test tonight, but don’t expect any issue as the no sparks test was pretty convincing to me.

As stated earlier Pos & Neg should be on the same time at the tab.
Here is a later Vid from AvE

You make a persuasive case to only put the probes on the tab. I’ll heed your advice with enthusiasm.

:smiling_imp: I Solder mine together. I use a larger iron than my normal bench Weller. I have also had success soldering sub-C packs (stacked end to end) for radio controlled cars. Hard to keep them straight as once soldered you cant take apart again. I used a delrin vise jaw block with a V groove to lay cell into while heating and slide them together quickly. Kept a stack of 3 straight.

That was the last vid AvE did in his attempt to weld tabs. I don’t have the Nerve or containment facility to attempt welding Li-Ion.