18650 spot welding -how to- ULTIMATE REPOSITORY

[DasDouble]

Spoiler: quote="DVDRW"

Didn't understand price either.
Gave up and just soldered wires directly to transformer output. Two hand operation but works perfectly.

Could you not just put these cables to there where these summits are? Then you wouldnt have to open the whole thing.

 

[DVDRW]

788 Welding voltage is very low ~3V AC. Inch or more longer cable and welding performance decreases dramatically.
Been there done that, see holes on front.

 

[flippy]

can you show a picture of how you made the connection? of did you just replace the wire in the transformer?

 

[DVDRW]

Just soldered to transformer wire.
http://i.imgur.com/QjQFjij.jpg

 

[vex_zg]

Just soldered to transformer wire.
http://i.imgur.com/QjQFjij.jpg

the transformer is still triggered/turned on by the original control electronics of the welder?

 

[DasDouble]

I still dont get it. Why soldering the AWG wires inside, when you also could put them outside, where the original nipples of the welder are???

PS: What AWG wires are these? 12AWG? 10AWG? 8AWG?

 

[vex_zg]

I still dont get it. Why soldering the AWG wires inside, when you also could put them outside, where the original nipples of the welder are???

PS: What AWG wires are these? 12AWG? 10AWG? 8AWG?

the new wires are much bigger and lower resistance so by soldering them directly to the output of transformer you bypass some of the thinner higher resistance wires inside.

every miliohm matters at these high currents. 1 miliohm causes voltage drop of 1V at 1000A. If you have only 3V to start with this matters quite a lot.

 

[DVDRW]

Jep, resistance is critical.
Dont know AWG exactly. Found about 0 or 1AWG silicone wire lying around.

How these overpriced quite long extension probes work? 709A welder has higher voltage?

 

[flippy]

709 is identical as far as i can tell. and with the external leads (wich get effing hot!) it is impossible to weld even .3 strips.

 

[DasDouble]

Could someone please tell me what temperature acceptable and poor/hot means in °C?

 

[DasDouble]

Didn't understand price either.
Gave up and just soldered wires directly to transformer output. Two hand operation but works perfectly.

Will a 10 awg wire be enough for this modification?

 

[flippy]

never, you will burn those out in 10 minutes. 4 AWG would be minimum IMHO.

 

[vex_zg]

never, you will burn those out in 10 minutes. 4 AWG would be minimum IMHO.

I am using AWG 1/0, AWG 2/0 was too big and heavy, but 1/0 is OK.

 

[DasDouble]

Could I theoretically use 3 times 10awg wires and combine them to one? Because I won´t get a 1/0 wire at the moment that fast.

 

[parabellum]

Could I theoretically use 3 times 10awg wires and combine them to one? Because I won´t get a 1/0 wire at the moment that fast.

Is there any hardware shop with welding supply near you? They will have flexible, rubber coated, arc welding wire, it comes in number of monstrous gauges and is not expensive.
You definitively can get enough parallel 10awg wires to conduct same current as 1/0 wire, but I do not know how they handle inductance in this case.

 

[vex_zg]

Could I theoretically use 3 times 10awg wires and combine them to one? Because I won´t get a 1/0 wire at the moment that fast.

Is there any hardware shop with welding supply near you? They will have flexible, rubber coated, arc welding wire, it comes in number of monstrous gauges and is not expensive.
You definitively can get enough parallel 10awg wires to conduct same current as 1/0 wire, but I do not know how they handle inductance in this case.

inductance will be less when paralleled. But capacitance will be higher. Should not be an issue though.

If you are in a hurry you can use car jumper cables. You can get them very cheap in local big supermarket stores, they will most likely be CCA (copper clad aluminum) but should work. Worked for me when I was starting this project.

 

[DasDouble]

Could I theoretically use 3 times 10awg wires and combine them to one? Because I won´t get a 1/0 wire at the moment that fast.

Is there any hardware shop with welding supply near you? They will have flexible, rubber coated, arc welding wire, it comes in number of monstrous gauges and is not expensive.
You definitively can get enough parallel 10awg wires to conduct same current as 1/0 wire, but I do not know how they handle inductance in this case.

inductance will be less when paralleled. But capacitance will be higher. Should not be an issue though.

If you are in a hurry you can use car jumper cables. You can get them very cheap in local big supermarket stores, they will most likely be CCA (copper clad aluminum) but should work. Worked for me when I was starting this project.

Hey, thats a great idea!!! Thanks!

 

[DasDouble]

I have just got a 2/0 AWG wire for free. 1 meter Yey, let the weld beginn!

 

[DasDouble]

Didn't understand price either.
Gave up and just soldered wires directly to transformer output. Two hand operation but works perfectly.

[/spoiler]
[/quote]

I have now just done the same modification like you DVDRW, but with 2/0 AWG. Well. Took me about 2-3 houres because the wires took a day and two to get warm enough for soldering . This will make things way easyer

 

[tomjasz]

Has anyone built this welder with an Arduino timer? Also a display option?
http://www.avdweb.nl/tech-tips/spot-welder.html
http://www.avdweb.nl/arduino/hardware-interfacing/spot-welder-controller.html

click to enlarge.

 

[vex_zg]

Has anyone built this welder with an Arduino timer? Also a display option?
http://www.avdweb.nl/tech-tips/spot-welder.html
http://www.avdweb.nl/arduino/hardware-interfacing/spot-welder-controller.html

click to enlarge.

I started with something like that as goal but ended up building a 600ws 3F/20V CD welder myself, arduino controlled and configurable. I wanted something to weld .2mm copper and .3mm nickel, powerful reliable and customizable. Could not exactly find it so built it myself. Spent hundreds of hours, bought oscilloscope and learned a lot about transients, mosfets, arduino, and welding. Really happy with the result but I seriously overdid it

what do you want to weld? what thickness? how often do you want to weld? what's your skill level in mechanics, electronics and software development (arduino/c) ?

 

[tomjasz]

what do you want to weld? what thickness? how often do you want to weld? what's your skill level in mechanics, electronics and software development (arduino/c) ?

I have a couple of arduino 12V SLA welders. I like the one I posted an was wondering if someone did that build. I'm not all that talented. I'm just interested in welding nickel strip, and the welder with the stationary weld tips. I originally bought a Sunkko to have the dual tips. I sold it and the replacement parts at a loss. I think I might be able to do this build I just wanted to hear how others did with it. OR if someone had may partially completed the PVB timer for sale. Your's sounds well beyond me, but THANK YOU.

 

[ridethelightning]

quote [I started with something like that as goal but ended up building a 600ws 3F/20V CD welder myself, arduino controlled and configurable. I wanted something to weld .2mm copper and .3mm nickel, powerful reliable and customizable. Could not exactly find it so built it myself. Spent hundreds of hours, bought oscilloscope and learned a lot about transients, mosfets, arduino, and welding. Really happy with the result but I seriously overdid it quote]



I would be really interested in any details you might be able to share regarding building a welder like that

 

[DasDouble]

I have a question: I have got now 2 times 0,15mm x 6mm Nickel strips on my cells. Following Nobuo´s diagram, Im able to let flow 12,4 amps throught that.. But not all strips are that thick. For example on one 4s15p pack there come 3 times individual 0,15mm x 6mm strips to one ultra thick one together.. But still there goes 12,4 Ampere (times 15) through these 3 individual 0,15mm x 6mm wide strips... How is that possible, without getting them warm??? I mean in the end thats 186 Amps on these 3 strips! How do they not burn???

Thanks for sharing your knowledge..

 

[flippy]

strip length is very short reducing resistance (and thus heat) and the current duration is very short so the strip does not get time to heat up and blow out. lit's basically a REALLY slow fuse with such currents.