Six years later, and here I am discovering this work of art. Thank you very much.

Making use of the https://www.youtube.com/post/UgkxcJ22tnHH9l1vjdIdEIG27iOG55P7LXI8 reconditioning plan, I just saved 2 auto batteries from being completely junked. The guides were very simple to follow. I wish I would have found this years ago! You may use the guide to recondition any battery type

I built one of these today to repair a Milwaukee impact gun battery…. They can be quite aggressive on a 360ah battery… my first few clicks weren’t short enough but I got a feel for it eventually

I found the negative end of the cells welded a lot nicer than the positive ends

Went to Home Depot today and bought two lengths of heavy 1 O wire each at 2.5 ft or 763 mm. for 8.00 US. And added 1 ft or 305 mm in length of 1/8th inch or 3.175 mm solid copper wire.for  66 cents. or 60 euro cents.  I bought a battery of 280 cca for 22.00 at my local walmart. Or 19.90 euro's.  All of my parts will arrive tomorrow and I have already charged and tested my batteries for my 52 volt E-bike without a PAS sensor. Thanks for the video as it saved me a lot of money for a possible one time venture!

I was about to take apart someone electric scooter for a battery, now Ill just make one.

This is handy to know. When I had a job refurbishing starters as a lad, I made several critical welds using a copper clad carbon rod, (type that used to be used in movie theaters to produce the bright light cast upon the screen). The point I'm trying to make is that we used a car battery for the source of power to weld for that, so it will certainly do a great job for small spot welds as shown here. Thank you for the video, I'll be ordering some nickle to repack a few cordless shop tool batteries. 👍

I like your minimalist approach. The advantage of a capacitor bank is you can control how much energy is stored and the caps can be recharged from a much smaller capacity current source. Need more current? Add another parallel cap. Usually they use FETs to dump the caps but I guess you could stay with the solenoid

Yes, try a foot switch. I made a spot welder from an old microwave oven transformer modified as a step down transformer: 1.5V at 800A. No need for a solenoid.  I need to see if it will spot weld batteries.

In the US "twin and earth" wire/cable is called Romex® or its "trade name" non-metalic (NM-B) cable.  2.5 mm² is about 12 AWG and it is solid copper.

Megga! even I can do this, no more pain trying to solder to battery tops.  Many thanks.

Thanks for the video! I’m in need of a battery spot welder, think I’ll build rather than buy!

Battery spot welding machine is mainly used for 18650 cylinder call pack welding, it can weld Nickel tab thickness from 0.02-0.2 mm with good welding effect. The pneumatic model is with smaller volume and weight, easy for international shipping. click on http://www.tobmachine.com/18650-Battery-Spot-Welding-Machine_p766.html, view more.

As a ham radio operator there are many times that I need to weld batteries this would save a ton not only in money but in time as well, thanks.

It is a simple spot welder, it require 5 items, 1) 12v battery, 2) press button switch, 3) power contactor relay ( this is used for starting the starter motor or scooter, auto bike, car or truck), 4) 2.5-4 square mm 2 fluxible wire of required length, 5) two pointed solid copper round piece of 10-12 SWG, connect one wire to battery  negetive & pointed round copper piece, 2nd wire connected to positive terminal of battery then to power relay 1st terminal & form 2nd terminal to pointed solid piece, in the relay there is a coil which has 2 terminals connect them in series with push bottom switch to both the terminals of battery, keep the pointed piece 3 mm apart & insulte them, now the spot welder ready, keep the pointed solid 2 piece on strip of battery cell firmly press the button switch & release it with in 2 secs, you notice spark at strip, now it is welded, continue the number of welds you need, thanks to all, regards, Siddaramaiah. C.

Excellent explanations clear and to the point.

Must take time between weldings on the same battery to protect battery from heat

THANK YOU
I am converting my longboard to be an electric one. I still need to build the battery pack as premade ones are either sketchy or really overpriced.
Most of the spot welders out there are way to expensive for just one battery pack. I was about to give in and buy a premade pack when I saw your video. The solution is so simple that it never ocurred to me. Might spice it up with an arduino to manage the timing as I don't trust myself to nail that.

Just a 12v battery with a relay.  So I can build a bench top spot welder press for 18650s power it with my shop AC welder set on low amperage.  200 amps at 12v seems very high.

fantastic! I've been looking at buying fancy welding kits for a while now

ONE MORE TIME THANK YOU KEVIN...FOR ALL THIS EFFORT..!!
THE 600AMPS ARE WAY TO HIGH FOR WHAT WE NEED...YOU HAVE A 200AMP CCA BATTERY AND STILL YOU HAVE TO BE FLASH GORDON QUICK IN ORDER TO MAKE THE PERFECT WELDS YOU DO..
1.THIS SETUP IS PROBABLY THE BEST BALANCE...DONT GO FOR HIGHER LIKE 500-600 AMPS FOR 2 REASONS..
a.you wont find a solenoid rated for that amps...and if you find... adding the cost of the battery you are near the price of a commercial dedicated 18650 welder which is around 150-200$
b.with this amount of power you have to practice a lot the timing...you should release  the button extremely fast...
I HAVE A SOLENOID RATED AT 300 ...MAX 400AMPS...AND BOUGHT A BATTERY WITH 360 CCA...ONLY IN THE LAST ATTEMPT WHEN I PRESS THE BUTTON AS QUICK AS I COULD I MADE A GOOD WELDING THAT COULD REMOVE ONLY WITH PLIERS..I HAVE TO ADJUST THE LENGTH OF THE CABLES ...CAUSE ITS WAY TOO MUCH CREATING  FURTHER RESISTANCE.!!
I WAS THINKING ABOUT BUYING THE EXACT SAME BATTERY BUT I WENT WITH THE BOSCH 3001 BATTERY FOR 3 REASONS...IT HAS MORE THAN  TWICE THE CAPACITY OF WHAT YOU USE ...IT HAS ALMOST DOUBLE MAX AMPS...AND ITS PRICE WAS 35EURO INSTEAD OF 55 EURO THAT I COULD FIND YOURS!!
IF YOU WATCH THE FIRST AND THE LAST VIDEO YOU WILL SEE THE RESULT OF YOUR PRACTICE...NOW YOUR HANDS ARE SUPER QUICK ON THE BUTTON....AND WITH AN ALMOST CONSISTENT TIMING!!!
HAPPY NEW YEAR AND ONE MORE TIME THANK YOU FOR ALL...!!!!