Suggestions wanted for a spot welder for battery tabbing

[Ampera]

Greetings, I'm going to be working on a few projects that will require rebuilding long since out of production battery packs, which would preferably involve tabbing batteries with spot welds.

I'm in the US, so something that easily ships here would be nice. It doesn't have to be particularly fancy, just enough to get strips of metal onto battery terminals. Cheaper is better until it becomes a fire hazard (well, /more/ of a fire hazard).

Any tips or pointers would be appreciated. (I'm aware of pre-tabbed batteries, and I'm aware of the dangers of batteries in general, especially lithium ion batteries, I intend to have measures in place to mitigate these risks)

[Gyro]

The one in this thread apparently works ok with the tweaks either fitted or pre-installed (has list of things to look for)...

https://www.eevblog.com/forum/reviews/mini-spot-welder-from-aliexpress/

[voltsandjolts]

I haven't used any of these short-circuit-the-battery type spot welders, and not sure that I'd buy one, but some folks seem to have success with them.
This self-contained type which includes two LiPo cells seems to work. Would the battery explode some day? Hmm, not sure.

https://youtu.be/rHTsKArz6HI

I think they are using a bunch of parralled FETs similar to Infineon IPLU300N04S4-R8 as the switch.

[Ampera]

I've seen ones like those and they just make me nervous. Something that plugs into the wall might be a better idea. I don't mind if I have to spend a hundred bucks or so to get one that isn't sketchy (sketchy + batteries != good time, imo)

Suggestions nevertheless appreciated, and I'll keep them in mind.

[enz]

There is also kWeld https://www.keenlab.de/index.php/product-category/kspot-welder-kit/
It's done by a member of this forum: https://www.eevblog.com/forum/projects/guesses-on-what-i-am-attempting-here/


Seems to me like the best solution for battery welding at home.

[voltsandjolts]

The idea behind battery tab welding is to produce a very short high energy current pulse, which provides a strong weld with very localised heat.
Whatever welder you choose, make sure not to heat the cell up, that is dangerous.

This video shows how NOT to do it. If he has used this on lithium cells he is risking serious injury. Crazy.

https://youtu.be/al45MXMp7e0

[voltsandjolts]

I don't mind if I have to spend a hundred bucks or so to get one that isn't sketchy

Since you're in America, you might be able to pickup a Hughes/Palomar/Micro-Join/Miyachi HCD125 for a few hundred bucks.
More outlay but you'd very likely get (at least) your money back when selling.

https://www.eevblog.com/forum/projects/homemade-spot-welder-keeps-blowing-mosfets/msg3580031/#msg3580031

[mastershake]

i have a few i use 2 are mot types i built with transformers i have to say they do work very well once you get them dialed in properly. i tried the red one on the first post and imo it was junk. it was fine for a few welds but didnt last long. i tried then getting one of the newer versions of the same model and it killed a couple of the fets within a few uses. the kweld is pretty awesome i know someone who owns one and i have had a chance to use it. i also built another unit myself that i honestly dont remember where i got the plans for it i think it may have been something o modified off a you tube video but its made somewhat like the kweld and it works great. just depends which way you want to go. i know some people who use the short type with a car battery and they have done so for years and they are still working fine and using them. as said they major thing is you want to get in and out quickly with as little heat as you can.