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).
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.
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.
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.
@@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.
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!
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.
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.
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.
@@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.
@@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.
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.
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.
If you go to the instructables page it has the schematic. Capacitors are mostly generic and interchangable. As long as you use the right values and voltage ratings then you should be fine. If you can't build this from the schematic then you likely shouldn't be thinking about building something like this and should instead just buy a spot welder.
@conorstewart2214 What a helpful and insightful reply to a genuinely curious inquiry 3 years ago, which may or may not be relevant today! I am so glad you took the time to read what I posted and decided to have a trite smug gatekeeping response instead of taking the time to actually educate others, like the purpose of this channel is for. I am also grateful that you said, "as long as they are the same value, it doesn't matter" because heaven forbid RIFA capacitors were a thing. There is a reason why Replace Immediately Fire Ahead is the joke acronym. So yeah, no, you're wrong. Components matter. But hey, if you are not able to have a basic sense of time, you probably have no business replying to infer that someone wanting to verify a tutorial lines up with the schematic and proper component selection is too stupid and should just, "buy the thing". When, in fact, at the time of this posting, there were serious deltas between them. It's not like a schematic has EVER been wrong or anything... Have a great day.
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.
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.
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.
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.
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.
@@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?
@@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.
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!
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.
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
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
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.
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.
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.
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.
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....
how about the accuracy of the relay? Because of the mechanics there will be time needed to turn the relay on, and the energy in the coil will flow thru the diode and keep the relay longer on.
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.
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.
It's always nice to find people I know from other comment sections under videos from another RUclipsr... Gives me the feeling that there's people out there that think the same way I do Sadly it's Sunday today so your catch phrase doesn't work
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!
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.
@@closure4791 Yes. Relay is in the 230V side so it can be smaller and much cheaper. It is also faster because those big ass relays capable of hundreds of amps have to move large contacts and it takes time. Only down side of this relay is that it is using 230V to switch. But 5V arduino relay module is well enough for switching relay that powers the transformer.
@@closure4791 There are modules available on Ali-Express which do exactly that. They offer precise timing control and zero-crossing-detection. Some of these modules even offer double-pulse welding and they come with a powerfull SSR allready soldered in.
Great Scott !!! I have check your code, and think that it is better to declare volatile the "wait" variable, as you are changing it inside a interrupt, aren't you ? Thanks a lot.
My question too. But then, I realized that when we use any machine we learn what settings to use through experimentation. That said adding a variable for solenoid delay in the code could make it really close. If he does do that I wonder how consistent the solenoid is?
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.
I only experienced it one time during my testing that the relay got stuck. But by "hitting" it a bit, it worked without a problem during the following hour of testing.
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.....
instead of that huge relay can i use several relays in parallel to reduce the current rush on each one. will the timing of switiching be accurate enough?
I've always wondered why you use fuses in your projects. Wouldn't a circuit breaker be cheaper over the long term, as you don't have to buy new fuses whenever they blow?
GreatScott = Potentiometer
ElectroBOOM = Full bridge rectifier!!!
Finally a spot welder I might build! Thanks a lot!
Your comment is 2 Days old. This Video is uploaded 2 Hours ago. RUclips?... What is going on?
@@denndy Patreon.
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).
you may even use a 200A Battery disconect Relay - as i did - wich is cheaper
Old saw blade
ruclips.net/video/WtNk_qIcN7Q/видео.html
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.
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.
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.
@@mustafayasiraydin exactly!
Ich würde auf Graphit Tippen.
@@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.
pro tip: don't crimp or skrew soldered wire; it will get loose after a while - after all, nicely done project! like
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!
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.
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.
6:57 isn't it a bad idea to tin wires that you put in screw terminals?
No, you have a better and stronger connection thats is also protected from corrosion
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.
@@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.
Yes it is, definitely do not solder wires to use them in screw terminals.
@@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.
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.
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.
If you go to the instructables page it has the schematic. Capacitors are mostly generic and interchangable. As long as you use the right values and voltage ratings then you should be fine. If you can't build this from the schematic then you likely shouldn't be thinking about building something like this and should instead just buy a spot welder.
@conorstewart2214 What a helpful and insightful reply to a genuinely curious inquiry 3 years ago, which may or may not be relevant today!
I am so glad you took the time to read what I posted and decided to have a trite smug gatekeeping response instead of taking the time to actually educate others, like the purpose of this channel is for.
I am also grateful that you said, "as long as they are the same value, it doesn't matter" because heaven forbid RIFA capacitors were a thing. There is a reason why Replace Immediately Fire Ahead is the joke acronym. So yeah, no, you're wrong. Components matter.
But hey, if you are not able to have a basic sense of time, you probably have no business replying to infer that someone wanting to verify a tutorial lines up with the schematic and proper component selection is too stupid and should just, "buy the thing". When, in fact, at the time of this posting, there were serious deltas between them. It's not like a schematic has EVER been wrong or anything...
Have a great day.
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.
When I am thinking about building a spot welder, here you are making a video! Great video!
for screw connection of the cable you shouldn't solder the cable... IPC-A-610 norm...
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.
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.
Agreed, always difficult to decide what to do. For an application like this, with only occasional usage it should be fine.
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.
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!!!
Cable shoes 🤣 that must be the German Translation for ring terminal! Love the German language.
Well here in Denmark we call those "Ringkabelsko" (Ring cable shoes), as opposed to Spade connectors (spadekabelsko) or Pin terminals (stiftkabelsko).
Yes, your right🤣 🤣
In Romania we call them "papuci" and it means shoe so nothing out of the ordinary here.
@@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?
@@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.
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!
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.
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
Knowledge is better than love and it's only getting better everyday.
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.
Fantastic job great video like always 👍
Awesome that you were finally able to create a working DIY spot welder!
thanks :-)
This would be handy for so many projects. Not just electronics. Great build!
Finally a proper working diy spot welder we'll need a "DIY OR BUY" video to for this one
So.. whats the hysteresis time of that big relay/contactor? There should be a minimum on time specified in the datasheet somewhere
@@Mr.Leeroy bouncing can actually be a good thing here since it simulates dual pulse spot welding :)
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
Another video = another reason to be subscribed 👍👍👍
seriously, this was one of your coolest videos to date 😎
Great video. A starter-motor relay (from a car) can be bought very cheaply (mine was free) from a car dismantler.
Legends straightaway proceed to end, and then rewind whole video and watch 😊
Listening to this while my eyes are closed made me super aware of your breath in before starting each sentence.. 😅
I’m so glad you reviewing this spot welder, and make a different one from it
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.
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.
Your projects always look so clean with everything brand new. NICE😊
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.
For cheaper option just use car starter solenoid :)
Cheap option if you want to make holes on the battery...
Just get a microwave transformer and a cheap controller from aliexpress.
You finaly nailed it. Now make functional welder
Amazing !!! You have access to really high class accessories, tools, components and all that is needed for any projects.
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.
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....
Glad you like it :-)
@@greatscottlab sure
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
How long before the weld occurs at the relay contacts?
When using a relay, the 'mosfet signal' time will not always translate to weld pulse time
how about the accuracy of the relay?
Because of the mechanics there will be time needed to turn the relay on, and the energy in the coil will flow thru the diode and keep the relay longer on.
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.
Excellent project 👍
Instead of using the arduino to control the pulse time, could you use a 555 timer in Monostable mode?
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
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.
Connecting batteries with batteries...
Batteryception.
It's always nice to find people I know from other comment sections under videos from another RUclipsr... Gives me the feeling that there's people out there that think the same way I do
Sadly it's Sunday today so your catch phrase doesn't work
how did you get over here, i always see you on Wintergatan Wednesday
@@davidrubio8673 that's why I was talking about his catch phrase...
You're a long way from home :P
Hope you're well :D
It's great to know there are Wintergatan fans all across the internet. Have a great Sunday my dudes.
I don't understand how any of this works but I still enjoy these videos.
Why did you used the big relay instead of the mosfet? Isn’t the relay lower and less precise in term of time? Thanks
Congratulations! You did it! :)
Thanks :-)
Hi, that project is super, and now something you can rely on!
Happy days!
Missed you last week. Good build, nice demonstration.
Never tin wires clamped in screw terminals!
how come? Just wondering
@@The231447LucidDevTeam The solder cold flows under pressure. It will lead to a bad contact, heat and fire in the end. It's a big NO-NO.
@@zaprodk makes sense. thanks for explaining
@@The231447LucidDevTeam solder gets kind of weak over time and connectors heat up because of higher resistance. you have to crimp those connectors.
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!
A Bulletproof plate for only $2 dollars, now that's what I call a good promotion :]
Don't forget to consider fact that relays require some time to swich on/off
Arduino plus display or 555 and some writing on the pot panel? That is the question.
I was immediately thinking the same! :-)
The flyback diode extends the set welding time, because the relay shuts off only when the magnetic field in the coil is reduced
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.
Whats the on time at the relay end/electrodes , I'm sure that adds a few ms to total because of its mechanical nature. - Thanks
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
@@closure4791 Yes. Relay is in the 230V side so it can be smaller and much cheaper. It is also faster because those big ass relays capable of hundreds of amps have to move large contacts and it takes time. Only down side of this relay is that it is using 230V to switch. But 5V arduino relay module is well enough for switching relay that powers the transformer.
@@closure4791 There are modules available on Ali-Express which do exactly that. They offer precise timing control and zero-crossing-detection. Some of these modules even offer double-pulse welding and they come with a powerfull SSR allready soldered in.
Least someone got good idea lol
Por fin un experto en lo que hace, gracias por compartir tus conocimientos
Great Scott !!! I have check your code, and think that it is better to declare volatile the "wait" variable, as you are changing it inside a interrupt, aren't you ?
Thanks a lot.
Finally an other video
The relay will have a slow response time, making the timing a bit off. Did you allow for that?
My question too. But then, I realized that when we use any machine we learn what settings to use through experimentation. That said adding a variable for solenoid delay in the code could make it really close. If he does do that I wonder how consistent the solenoid is?
I wonder if the on-time and off-time of the relay is the same thus cancelling out? though an oscilloscope test wouldn't be hard to verify.
@@bilzoo20001 yeah
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.
congratulations for 1M subscribers 🎉🎉
Nice informative video, thanks. But the solder skills are improvable.
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.
Time on/off of this big relay could be much longer than ms that You set on arduino. Did You check that?
thanks for this idea, i actually have most of this already. saves me a bunch of money to get started.
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!
I was actually thinking to buy one from eBay but after your video, I might give this one a try.
Wouldn't the relay wear quite a lot with this high current switching?
I only experienced it one time during my testing that the relay got stuck. But by "hitting" it a bit, it worked without a problem during the following hour of testing.
Did you measure the mechanical delay off the relay?
Why didn't you use your favorite N-channel MOSFET, the IRLZ44N?
would you plz make a video on the loss in battery 18650 for diy beginners comparing spot weld to solder ?
Can i use another power source, like transformer from microwave ???
Fantastic project, keep doing I really enjoy watching your videos.
Thank you!
Finally you have done it! 👍
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.....
Simple design,
Winner :DIY
instead of that huge relay can i use several relays in parallel to reduce the current rush on each one. will the timing of switiching be accurate enough?
I never thought of using a starter solenoid. Very cool idea.
Can you make a video about ac induction motor, how to control them and how to speed them up please??
I've always wondered why you use fuses in your projects. Wouldn't a circuit breaker be cheaper over the long term, as you don't have to buy new fuses whenever they blow?
4:10 Why do you need a mosfet driver in addition to the mosfet? (Why not just use a logic level mosfet?)
Exceptional build, good job!
Stay Creative and I will see you next time
Love that line
A successful project Scott, Congrats
You are an awesome engineer. You could get a job anywhere doing anything! There must be more good money making RUclips videos?
I love ur videos great scout!!
Finaly ! After the hate on last video i'm glad you did it (more or less)
3:15 basically it's a contactor... Right?
Scott, do you think that the copper nails should have an insulating wrap for most of their length to help prevent shorts?
*Greatscott Lovers Like here*
Hey Scott, Nice Move.
I wanted to build it like forever. Thank you for your video and the code...
The terrifying videos are the best videos
You are best teacher.
I always wait for your Awesome video.
Thanks :-)