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

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More project information (schematic, code, pictures, ....) on Instructables: www.instructables.com/id/Make...
Parts list (incomplete, see Instructables for more, affiliate links):
Aliexpress:
1x Arduino Pro Mini: s.click.aliexpress.com/e/_d6f...
1x TC4420 MOSFET Driver: s.click.aliexpress.com/e/_dWH...
1x IRLZ34N MOSFET: s.click.aliexpress.com/e/_dZC...
1x Power Relay: s.click.aliexpress.com/e/_dTC...
1x Foot Switch: s.click.aliexpress.com/e/_dZM...
1x OLED: s.click.aliexpress.com/e/_dV3...
2x Car Battery Terminal Adapter: s.click.aliexpress.com/e/_dTR...
1x Fuse Holder + 200A Fuse: s.click.aliexpress.com/e/_dX8...
2x Copper Nail: s.click.aliexpress.com/e/_d8a...
Ebay:
1x Arduino Pro Mini: rover.ebay.com/rover/1/711-532...
1x TC4420 MOSFET Driver: rover.ebay.com/rover/1/711-532...
1x IRLZ34N MOSFET: rover.ebay.com/rover/1/711-532...
1x Power Relay: rover.ebay.com/rover/1/711-532...
1x Foot Switch: rover.ebay.com/rover/1/711-532...
1x OLED: rover.ebay.com/rover/1/711-532...
2x Car Battery Terminal Adapter: rover.ebay.com/rover/1/711-532...
1x Fuse Holder + 200A Fuse: rover.ebay.com/rover/1/711-532...
2x Copper Nail: rover.ebay.com/rover/1/711-532...
In this project I will be showing you how to create a crude but functional battery spot welder. Its mains power source is a car battery and all of its components combined cost around 90€ which makes this setup pretty low cost. So sit back and learn how to build your own with an Arduino and a few complementary components. Let's get started!
Websites which were shown during the video:
www.keenlab.de/index.php/prod...
malectrics.eu/
www.instructables.com/id/DIY-...
Thanks to JLCPCB for sponsoring this video
Visit jlcpcb.com to get professional PCBs for low prices
Music:
2011 Lookalike by Bartlebeats
Killing Time, Kevin MacLeod
(incompetech.com)

[@arnab1804]

GreatScott = Potentiometer ElectroBOOM = Full bridge rectifier!!!

[@deadbird99]

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

[@denndy]

Your comment is 2 Days old. This Video is uploaded 2 Hours ago. KZbin?... What is going on?

[@deadbird99]

@@denndy Patreon.

[@GRBtutorials]

I might build the other, though, because the reason it didn't work was some critical mistakes when designing the PCB, not its feasibility, and I don't have a spare car battery nor a 1000 A relay (which are quite expensive).

[@TecSanento]

you may even use a 200A Battery disconect Relay - as i did - wich is cheaper

[@raiptv3393]

Old saw blade kzbin.info/www/bejne/jaWxnJKnfsiBbbM

[@loukashareangas4420]

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.

[@jkbrown5496]

Generally, they are just solenoids with a thick copper washer on the end of the plunger that is pulled into contact with the two high amp terminals when the coil is energized.

[@loukashareangas4420]

Well, yeah, I know how a relay works, I am more interested in the contacts themselves. Can they make the contact (easier) as well as break the contact under a 1000A DC load (doubtful), or is the contactor supposed to be operated under no load only. Those kinds of details.

[@loukashareangas4420]

@@mustafayasiraydin exactly!

[@Schniels65]

Ich würde auf Graphit Tippen.

[@jkbrown5496]

@@mustafayasiraydin Perhaps and I know they use alloys for high voltage contacts. But the ones I've seen generally use the large contact surface area, along with dual contacts one on each side of the disk to deal with the low voltage, 12 volt, high amp car solenoid switches. The solenoid action and the spring return ensure short make/break periods. These are expensive commercial devices with exotic alloys.

[@chewbaccarampage]

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.

[@Inventor101]

Fantastic job great video like always 👍

[@mickgibson370]

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!

[@ahmedsiddiqui9515]

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

[@hidde3064]

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.

[@cfzone8685]

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

[@michikipsy1951]

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

[@emersonsrandomvideos248]

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!!!

[@keithking1985]

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

[@reallyiffy]

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

[@jaras1969]

Well here in Denmark we call those "Ringkabelsko" (Ring cable shoes), as opposed to Spade connectors (spadekabelsko) or Pin terminals (stiftkabelsko).

[@supercunthunt7756]

Yes, your right🤣 🤣

[@andreidicu2882]

In Romania we call them "papuci" and it means shoe so nothing out of the ordinary here.

[@reallyiffy]

@@jaras1969That's really interesting! Does that mean that "shoes"(sko, and Schuh for that matter) has a meaning that is more broad than shoe in English? Possibly something like distal appendage cover?

[@FlyingShotsman]

@@reallyiffy The word shoe is used for electrical contacts in English also. The sliding contact on an electrically powered trolley, for example, is called a shoe.

[@8867348]

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

[@djruido1]

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

[@ninadtaralekar]

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

[@Jajaho2]

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.

[@budandbean1]

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

[@VKRenato]

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

[@warrengray610]

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

[@xoblyxanier]

Exceptional build, good job!

[@tonythediyer8537]

Missed you last week. Good build, nice demonstration.

[@technicallearneronlysaarth2097]

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

[@TheAshish60]

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

[@johannes5219]

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

[@greatscottlab]

thanks :-)

[@lukas7626]

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.

[@MrBlackFiction]

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

[@Unmannedair]

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

[@AlCapwndYou]

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.

[@vivi-fe5rj]

Thanks for the write-up. Apart from playing around with assembly projects, I'm an absolute beginner at this kind of thing, but I came to the same conclusion that the red film capacitor is 220nf, and that the 470uf is a standard electrolyric capacitor. Hopefully that's correct, because waiting another 2 months for Aliexpress will kill me haha. I wish he made the parts list a little clearer, but the schematic certainly helped. Like you said, I'm just some guy with limited electrical experience trying to make a cheap spot welder but for what it's worth, I think what you're saying is correct.

[@N0Xa880iUL]

Very professional looking project.. Amazing

[@philxcskier]

Nice Job! and congrats on hitting 1M SUBS!

[@long-timelistenerfirst-t-us2yy]

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

[@shhh7698]

I love ur videos great scout!!

[@ChristianJoyAzucenas]

A successful project Scott, Congrats

[@itsmilan4069]

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

[@theelevatorguyreviews4479]

Very nice spot welder! Keep it up man!

[@MCsCreations]

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

[@grins047]

Great simple project. Thanks!

[@JS-kv8ey]

Congratulations! You did it! :)

[@greatscottlab]

Thanks :-)

[@chanakasat1]

Finally you have done it! 👍

[@JamesPotts]

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

[@RinksRides]

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.

[@paco_rider]

Another video = another reason to be subscribed 👍👍👍

[@anthonyvolkman2338]

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

[@warpighammer3760]

Man this was real nice .

[@electronic7979]

Excellent project 👍

[@HometownUnicorn]

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

[@ankitjha8413]

congratulations for 1M subscribers 🎉🎉

[@snaj9989]

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

[@johnkg702]

Great video Scott congrats

[@sebaestschenr]

Great video as always 👍

[@Gabriel2.0]

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

[@petersage5157]

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.

[@jessearrazola4283]

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

[@TusharGaurav]

Great videos man, I love your work!

[@greatscottlab]

Thank you :-)

[@johnfarris6152]

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

[@wavegreen]

YES! exactly what I need!

[@zaidmughal9772]

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

[@danibiomedicalengineer860]

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

[@Kurumi_6_10th]

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

[@mxcollin95]

Great video man! 🤙

[@HeimoVN]

Nice, I like the simplicity...

[@gerrymcerlean8432]

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

[@michak8029]

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

[@yereverluvinuncleber]

The high surface area in the copper in the cables exposes to oxygen which eventually tarnishes and causes increased resistance, generating heat in the cable and reducing the current. Soldering it as one mass reduces that corrosion and keeps the current flowing. If it was higher voltage (240v) and continuous current flow then I would have said not to solder but for 12v it is fine as long as that screw connection is good and the solder is soft.

[@mich29sm]

Yes, it is recommended to use ferrules instead. The solder become brittle under mechanical stress (and with time) and the termination becomes very unreliable, causing high resistance/hot spots.

[@yereverluvinuncleber]

Agreed, always difficult to decide what to do. For an application like this, with only occasional usage it should be fine.

[@NL00iemand00NL]

I did a test on this and after about half a year the wire was lose and didn't make contact anymore. With these connectors it could work since the screw itself pushes the wire together if you screw it tight enough altho I wouldn't recommend it.

[@brainfornothing]

This is good ! Thanks for sharing !

[@rolandmeiner4970]

Finally an other video

[@danielspastars5298]

You finaly nailed it. Now make functional welder

[@mickgatz214]

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

[@Allan-mf1he]

Thanks for teaching.

[@GapRecordingsNamibia]

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

[@sultan7679]

Simple design, Winner :DIY

[@mid9ightwalker]

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.

[@AdamWelchUK]

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

[@Ulrich_5000]

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

[@TheChemicalWorkshop]

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

[@electronique_et_creation]

Great video, thank you

[@micharogalewicz6249]

Great stuff.

[@pranjalideshmukh5808]

You're a genius!

[@melissacoleman9633]

Your the best !!

[@cameron20020]

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!

[@hatemaiman6885]

Continue you are the best

[@twistedshadowsaf]

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

[@PhG1961]

Excellent !

[@stickz9871]

Nice Job!

[@spacemini24]

Well done !

[@awesomefacepalm]

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

[@Nedeles]

No, you have a better and stronger connection thats is also protected from corrosion

[@nrdesign1991]

It is not recommended, since the solder will settle after a while, leading to a loose screw connection. It is better to crimp the wire with a ferrule to cold-weld the strands together, and also provide a grip for the screw holding it in place. Tinning the wires is forbidden in the electrical wiring of houses, and in manufacturing of switching cabinets.

[@awesomefacepalm]

@@nrdesign1991 that's what I was thinking. I have a 3D printer and I remember the biggest nono was to solder the leads for the bed. Apparently it was a reason for loose contact and melted terminals.

[@mat.phillips]

Yes it is, definitely do not solder wires to use them in screw terminals.

[@Djhg2000]

@@Nedeles It actually gets a weaker connection because the solder has a creeping effect over time. It's a common mistake for newcomers because you intuitively think the solder makes it into one large conductor, but then you don't account for the odd microscopic properties of solder.

[@mr.diyventor8925]

*Nice video*

[@ipissed]

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.

[@TomaszWiszkowski]

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.

[@tjappie8860]

thank you man!!

[@richardnanis]

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.

[@messermachen]

I liked the idea of GreatScott and I build the same circuit with the same solenoid and had a similar problem with a 54 Ah (about 500 A CCA) car battery. After welding about 150 cells of 18650 the welding properties were getting more and more worse. In the beginning i could weld with 30 ms. At the moment i had to increase the timer up to 65 ms to have a connection which is also not as good as when doing the first welds with 30 ms. I also think that the solenoid does not like the use for many welds. Therefore i will try to use the circuit for driving some MOSFETs instead of the solenoid.

[@unknownsauce3768]

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!

[@voldenuit1706]

bravo ! très intéressant ! bonne continuation

[@jamest.5001]

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

[@shiftyjesusfish]

I gave just come from the other video and this is a much better idea! Too bad I'm a year late to this party.

[@nathanmobbs5755]

The terrifying videos are the best videos

[@ralfblumhoff7930]

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

[@BillySugger1965]

Ralf Blumhoff V = L x dI/dt. If relay current is 100mA and inductance is 1mH and mean voltage across relay during decay is 6V, then inductive hold time is around 16us. Negligible for a device operating in tens of milliseconds.

[@cxmmax4265]

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....

[@greatscottlab]

Glad you like it :-)

[@cxmmax4265]

@@greatscottlab sure

[@harukoyama9515]

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

[@blackwingmaster141]

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