Li-ion Battery Spot Weld Training Request


Would anyone who knows how to use the electronics battery spot welder be around this Friday afternoon/evening? I’d like to learn how to use it to weld up a pack I need, and I could teach my self by reading the manual, but I figured I’d ask in case someone will be up there.


I believe @Lampy has experience on this unit. I’ve tried using it on some old/dead batteries, but the results were iffy.


Maybe I’ll just TIG weld them.

(for anyone else, this is a joke and would most likely be dangerous due to over-penetration igniting the lithium)


It is a bit fiddly but I did eventually find some settings that worked. Instead of practicing on the batteries I just welded the nickle strip on to itself untill I got it right.


Any pointers, or should I just experiment?

If you happen to be around Friday evening that would be wonderful.


The only things from memory are, very clean tips about 1/8" apart. This seemed to improve things more than pushing the buttons.

Not sure about Friday but I can try to get up there, about what time were you thinking?


5PM until 10PM sometime. I figured I’d 3D print a battery holder for the first part and then weld the cells towards the end. I’m flexible.


I’ve had good luck with the 2s version of these drop in holders that way I don’t have to worry about welding the strips and can steal the batteries for other projects and just use a nice drop in charger.


I’ve been thinking about buying these to avoid having to weld them:

Has anybody else tried these?


Does anyone know how the contact between the head end of the screw and the battery end is made? Any view of the battery contact end of the screw is conspicuously absent from all of their pics.

Doesn’t there have to be a spring or other compression mechanism pushing the contact against the battery end to make a low resistance connection?


Here’s the best I found for version 1.5:
Taken from here on this video

Later in the same video, he’s talking about the then-prototype v2.0, and shows these

Here is where he actually starts talking about the improvements made to the contacts/bus bar connectors for v2.0:

tl:dnr: looks like they use (in v 2.0, so v 1.x is probably similar concept, but different material from what I gather) a bent metal strip to provide the spring and connection, with a threaded fastener attached to it for the bus bar connections.


I’ll be there 6:30-7:00 hopefully we can refigure it out. :wink:


How did the spot welding work out? Did you find some settings that worked reliably? Anything worth publishing here?


The welder has reduced functionality in that the remote leads are about useless (probably faulty).

Using the spot weld contacts in the front of the machine and the foot pedal with it set to 8P and about 5 for current seemed to function just fine.


Yeah, we need to open her up and see what is going on with the Jack’s/leads. Seems the power is less than a third of the probes power.


I opened it up, didn’t see anything funky. Maybe I missed something, but I’m thinking it’s the actual leads themselves.


That explains a lot, but not everything. The spring force is from the stamped contacts being bent in half. What I’m still unclear on is how the holder clamps onto the battery after the battery has been inserted into the holder and the spring contact compressed.

Seems like are read somewhere in the Vruzend description that tightening the nut on the battery contact caused tightening of the plastic around the battery somewhat. This almost has to be the case, else the battery would just get pushed out of the holder by the spring contact restoring force. Is this your understanding of how it works?


Based on that same video, no. My understanding is that friction holds the end on the battery. But I am likely way off…