Make your own Crude Battery Spot Welder with a Car Battery! 

GreatScott = Potentiometer ElectroBOOM = Full bridge rectifier!!!

Finally a spot welder I might build! Thanks a lot!

I've started watching your videos because I wanted to learn some basic electrical engineering. Three years later and I actual understand what's going on! Thanks for sharing your ideas and lessons.

Fantastic job great video like always 👍

You are the hero I needed. I messed up some cells in my Esk8 battery pack because of broken parallel cconnections due to solder connections failing. I don't want to resolder new cells so I need an affordable spot welder and this is definitely a viable build. Thanks for persisting and finally designing a working spot welder. I cannot thank you enough.

I would be very interested in how that big relay is constructed, specifically the contacts. Would you do a teardown? It seems to be screwed together so the teardown shouldn't be destructive.

pro tip: don't crimp or skrew soldered wire; it will get loose after a while - after all, nicely done project! like

Hi Scott, I really enjoyed this video. It was very well made as usual, with nice drawings explaining everything. But the project(s) itself were the main star, very creative and what I liked especially was that you finished the job and didn't just call it a day after the first failed attempt, goes to show that stuff like this needs several iterations, which is very important IMO.

Hey great scott you really are "THE ELECTRONICS GOD" I hope i can make my own spot welder base on your circuit diagram. Excellent job!!!

Amazing !!! You have access to really high class accessories, tools, components and all that is needed for any projects.

Cable shoes 🤣 that must be the German Translation for ring terminal! Love the German language.

When I am thinking about building a spot welder, here you are making a video! Great video!

This would be handy for so many projects. Not just electronics. Great build!

I used a homemade spot welder 40 years ago. 120 vac to 15 vac using a 12 v octal timer and 1/4 kwatt transformer. Did flat heater wires! The most expenses part was the 1/4 kwatt transformer!

Your projects always look so clean with everything brand new. NICE😊

I build the exact same spot-welder. But I upgraded it then with mosfets instead of the relay. I also replaced the car battery with a "car starter Powerbank". It works perfectly.

Hey Scott, that's a great video to introduce spot welding and also explain in detail the whole schematic of welder circuit... Nice built up... Thanks

Thank you Great Scott. Your last designs inspired me to DIY my own spot welder first from a car audio 20V 1F capacitor. It was not powerful enough even charged to 18V. So I turned to a car starter solenoid/car battery/timer configuration back in February. Simple, consistent welds on my 13S8P bike pack from recycled laptop batteries, (don't use recycled laptop batteries for an e-bike). 880CCA car battery: have, $16 starter solenoid from autoparts store, 3D printed holder for spring loaded welding tips recycled from an actual automotive spot welder and processed in a lathe. Borrowed the auto-pulse idea from Maletric's design. No idea how many joules i'm welding with, enough would be my guess. 15mS seems a happy medium between 8mS just starting to contact and 45mS blowing holes through 3 layers of nickel strip.

I’m so glad you reviewing this spot welder, and make a different one from it

Nice project! I'd simplify it even further by replacing the Arduino with a 555 timer. Same footswitch and RC tank, but simpler trigger circuit with no need to code.

Ive made a spot welder by using microven transformer. And I control the 220v input of the transformer with my diy SSR with a triac which can easily pass 20A. And rewinded the transformer so the output is around 6-7 volts and its the cheapest spot welder with 2 pulse system

This is so great, I’m already getting the components to build my own... Thank you so much!

Hi, that project is super, and now something you can rely on! Happy days!

That idea is very helpful us to done our project related with spotwelding Thanks to you for this video

Fantastic project, keep doing I really enjoy watching your videos. Thank you!

Missed you last week. Good build, nice demonstration.

Hey Scott, Nice Move. I wanted to build it like forever. Thank you for your video and the code...

I'd love to see that relays contacts monitored with a scope. Curious what it's minimum on time is or if it has any contact bounce. Glad you got the project working well!

thanks for this idea, i actually have most of this already. saves me a bunch of money to get started.

Awesome that you were finally able to create a working DIY spot welder!

Exceptional build, good job!

Finally a proper working diy spot welder we'll need a "DIY OR BUY" video to for this one

Great video. A starter-motor relay (from a car) can be bought very cheaply (mine was free) from a car dismantler.

I never thought of using a starter solenoid. Very cool idea.

For those newer to electronics, like myself who were wanting to build something like this, there were a few components that were not included in the list of this video or in the Instructable: The red film capacitor appears to be a Würth Elektronik WCAP-FTBP Film Capacitor (which is what came up when I was finally able to get a clear shot of it at 6:10). I am not sure if this is the 470UF cap or the 220UF cap. WE does not carry a 470uf capacitor, but they do carry ones listed as 470nf (.47uf). So now I am wondering if I am looking at the schematic incorrectly, if it is mislabeled, or if the standard aluminum cap is 470uf and the film cap is 220uf. This is why it is important to label all of the components during assembly, because there is no way of telling what is what for those who are new. I tried to find the 10U capacitor, but couldn't see one on the project. Instead, there also appears to be a tiny SMD Ceramic capacitor that is soldered on the bottom of the breadboard. This was shown as a loose component next to the WCAP-FTBP at 3:41, and then shown on the underside of the board at 4:41. I am presuming this is the 10uf (not nf?), but at this point I don't know. I would appreciate some clarification from GreatScott or more electronic-savvy individuals on this channel to be able to correct me if I am wrong on these observations, or the labels of these components, but I thought I would try to help those who are confused by the omission labelling of some of these components in the video. An updated PCB trace would be amazing to help those looking to repair their 18650 battery packs without needing an electrical engineering degree in order to complete the project. As a backup to this project, since I am not confident in being able to find/layout the exact components, I plan on toying with using a 555 Timer in monostable mode with a potentiometer to control the pulse duration of the relay. EDIT: After re-examining the schematic, it would appear that the 470uf cap is the standard aluminum capacitor as it is next to the 12V, and since the red WE film cap is next to the TC4420, that would likely be a the 220nf (.22uf) - but I am not certain.

yesterday I looked for a DIY video for spot welder then I watch the old video. I was thinking when he is going to try again :D

Very professional looking project.. Amazing

seriously, this was one of your coolest videos to date 😎

Beautiful work, dude! 😃 I'm going to look for everything you used and try to make one too! 😃

Very good video and interesting project! I'm only a bit concerned about the lead acid battery misbehaving after long continued use. Maybe adding a thermistor attached to battery could help to implement a safety power off.

Nice Job! and congrats on hitting 1M SUBS!

A successful project Scott, Congrats

I am not an electronics super Student like you, but I managed to build such a simple Version 2 Years ago. The point is that often the simple Version is the best version. My Spotwelder only consists of a Car Battery, an Arduino, a Resistor, thick copper Rods and Powerful Mosfets, I control the on/off time via my Laptop, so no other complicated circuitry. This stuff is literally no Rocket Physics. I did not even made the Math for on/off Time of the Mosfets. I just tried around a little bit until I became good Results. I think it is a little bit amusing that you tried these complicated versions when the key is simplicity. But nevertheless the approach with the Supercapacitors was pretty interesting. Greetings from Hamburg.

You finaly nailed it. Now make functional welder

Great Scott what a great video I will be using this at some point to make one

Knowledge is better than love and it's only getting better everyday.

I was actually thinking to buy one from eBay but after your video, I might give this one a try.

Por fin un experto en lo que hace, gracias por compartir tus conocimientos

Very well done! I do car audio and like those battery adapters you bought.

Hi GreatScott! Thank you for your great content! I found in your code that when the "timems" reads "0ms" the welding tips can still be live/ shorted if the foot switch is pushed by accident. The code in your void weld reads as follows: void weld() { if(digitalRead(2) == LOW) { digitalWrite(9, HIGH); TCNT1 = 0; OCR1A = timems * 250; wait = 1; detachInterrupt(0); } } I have amended the following lines to make it safe. void weld() { if(analogRead(A0) == 0) digitalWrite (9, LOW); else if(digitalRead(2) == LOW) { digitalWrite(9, HIGH); TCNT1 = 0; OCR1A = timems * 250; wait = 1; detachInterrupt(0); } } Regards Charles

Great simple project. Thanks!

Very nice spot welder! Keep it up man!

for screw connection of the cable you shouldn't solder the cable... IPC-A-610 norm...

There is another very popular and relatively easy way, It's to use a rewinded transformer from the microwave oven as a power source for spot welder. It would be nice you to make the video about that.

Stay Creative and I will see you next time Love that line

I love ur videos great scout!!

Thanks a lot for this tutorial. I have tons of 18650s and I'm building a huge 25s1p pack to power a 1940s portable tube radio which requires a 90v battery and I was going to solder them the "bad" way, with a soldering iron... Anyway, some of the stuff like the relay can be found for much cheaper on ebay: Arduino Pro Mini 1.48€ TC4420 1€ IRLZ34N 1.40€ (price for 1 in packs of 2) DK238 Relay 19.68€ Foot pedal 1.15€ 0.96 Oled display 1.99€ Battery terminals 1.63€ 200A fuse holder 5.40€ 200A fuse 0.40€ (price for 1 in packs of 5) Copper nails 5.10€ (price for 5) Which makes it a total of around 40€ not accounting for thick wires, potentiometers, veroboard all that stuff. But let's suppose it's around 15€ (10€ of cables and 5€ of extra hardware) so the real total price is 55€. You could even remove the copper nails from the list and replace them with heavy duty ground wires if you can get your hands on a foot or two. If you want to go the cheaper route with a 555 monostable circuit you can shave 10€ off the price. And if you think the big chinese electronics lobby is trying to scam you with their scary "safety" gibberish simply get the relay and a foot pedal just like AvE did: Spot welder for 30€!! (anyone reading this, please don't do that, accidentally burning down your table or you house is not worth it for this price.) And again, thank you for this video! Love these useful and effective projects!

congratulations for 1M subscribers 🎉🎉

Congratulations! You did it! :)

I've seen and used an even more primitive version. Take all the timing and foot pedal off, build a holder for both electrodes so you can use one hand to hold them, and connect a momentary button switch to the relay. Of course his will be far more consistent than the one i used. Also a far cheaper high amp relay is a starter solenoid and can be found in any junk yard for $10 or less.

I need a spotwelder, I guess I'm gonna have to break down and build one! I'm thinking about using a starter solenoid,

Another video = another reason to be subscribed 👍👍👍

I love to do what you explain on the video. But I don't have elementary electronic knowledge.

I used an arduino with a potentiometer and simple timer code to pulse a 5v 30a relay to pulse a Ford starter relay. Cheap and simple. $20 if you already have an arduino.

Nice, I like the simplicity...

The flyback diode extends the set welding time, because the relay shuts off only when the magnetic field in the coil is reduced

Wow! Swap out the expensive relay for the solenoid off a car starter motor (which includes a relay in it) and this is almost free!

Simple design, Winner :DIY

Finally you have done it! 👍

Great Video!, GreatScott! :) I'm looking into creating battery packs, slowwwly ... Merry Christmas!

YES! exactly what I need!

Don't mean to spoil the fun of building spot welders to anyone, as this is a pretty awesome thing to do, but in case anyone needs something to get the welding task done, welders have now become cheaply available on Amazon for about $50, or AliExpress for about $30-$40. Probably not as great efficiency as ones we can build ourselves, and certainly less configurable, but get the job done. Sharing this only because i recently needed just that to recover a 84V battery (leaking cell). My first impression after coming across this video was that the welder would cost as much as a power cell, but thankfully it wasn't that bad. Bought myself a tiny and great looking box that gets the job done.

Great video Scott congrats

Don't forget to consider fact that relays require some time to swich on/off

Great videos man, I love your work!

I've got one great spot welder on arduino and microwave transformer. But not long ago I buy 350F 2,7V supercap (8$). I just welded to supercap terminals wires and copper electrodes, and thats all. Simple and efective spot welder :) Just I need to be fast :P

I bought a similar 18650 battery spot welder made by Malectrics. It is very nice to and was about half the price. Before getting it, I tryed making different welders myself. The last was using an friends old microwave oven transformer. Wife was nervous every time she saw me using it and made me get a good one. Night and day difference on the quality of the welds. Unless you really know what you are doing, stick with buying one.....

Nice video. I need to build myself something like this. Cheers

Nice project, GreatScott! Unrelated comment: have you ever considered doing a project with the Arduino MKR Vidor 4000? There's not a lot of useful youtube videos out there about this board, and I really like your format. Would watch several times.

Interesting idea but a few remarks on that solution: 1. Why do you use an arduino setup? Its so much easier just with a classical NE555-timer with the same precision :-) 2. I tried big solenoid switches too with a 66 Ah car battery. They wont last long as the current can easily raise over 1000 Amps for a few ms. Even below 1000 Amps the switches wear out rather quickly and tend to stick! The fuse will be your only safety measure then. 3. In my opinion an electronic switch without mechanical contacts is much better here (power mosfets). 4. A good crimp is much better for power connections than soldering. And soldering strips to put into screw terminals is generally a bad idea - as already mentioned below. But i fell into the same trap a lot of times but i had cases where these connections went very bad after a time due to mechanical stress and settling of the solder.

Excellent project 👍

Finaly ! After the hate on last video i'm glad you did it (more or less)

Thanks for teaching.

Legends straightaway proceed to end, and then rewind whole video and watch 😊

You can actually get some really beefy mosfets for not that expensive for lower voltage applications, $40 for a 330a rated mosfet! (Max 40v)

Man this was real nice .

This is good ! Thanks for sharing !

Listening to this while my eyes are closed made me super aware of your breath in before starting each sentence.. 😅

this is awesome as f, keep doing amazing stuff!!!!

Great video as always 👍

I just use 2 copper wires from a car battery. I press 1 down on the Nickel Strip Tape and then touch the other one on it. Works for me. Minimal parts.

You should not tin wires while using screw connectors. The solder can corode and the connection will come loose. The best way is to use special crimped connectors made of copper tube.

6:57 isn't it a bad idea to tin wires that you put in screw terminals?

Microwave transformer and big relay on the primary side driven by 5V arduino relay is good option I use it and it's great and muuuuch cheaper

Finally an other video

0:49 "diy crude oil refining" Great Scott the oil tycoon CONFIRMED! :D

finally a spot welder wich work and is not dangerous to use on this Channel, look great, i'm just a bit disappointed that it's not a cd one, anyway this one work and is cheap so....

Nice informative video, thanks. But the solder skills are improvable.

Awesome video, I have attempted the build. I’ve posted a question on the instructables if you have a moment to answer. Many thanks!

I think u can use tungsten electrodes from tig welding, will be better than cooper ones.