kWeld - "Next level" DIY battery spot welder

garolittle said:
tatus1969 said:
tomjasz said:
My POS dead Sunnko was $250. My new KWeld will be $234.

The real question is will they perform better?
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Never owned a Sunkko, but I can tell that I have quite a few customers who told me that they have dumped their Sunkko after having used kWeld 8)
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I am one of those who dumped the Sunkko after using the kWeld. 8)
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Sunnko = POS
KWeld = awesome!

I've owned a Sunnko for a couple of years now and have done a few battery projects with it, but it was always problematic and worked poorly. I was never happy with the welds it did. I'm cheap if I can be, but this was one time that being cheap was a bad idea. Once I decided to buy a KWeld and then tried it out...there was no comparison. Now I wonder why I lived with the shitastic Sunnko for so long!
 
Mine did a cute of welds and blew.They finally sent a new PCB but I cut my losses and sold it all off for pennies on the dollar.

Not happy with my first KWeld but that speaks to my own failure and lack of skill. Using my two JP welders and adding the KWeld later this winter. Just holding back this time to see how it improves and develops. A pretty amazing thread and story!
 
spinningmagnets said:
"...would you mind commenting on probes. I imagine somewhere in the thread you have, but I''m at a loss finding that. Are any of these materials a potential improvement?..."

The kWeld electrode holders are ...
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Thanks Ron, I was about to answer but nothing to add to this :D
 
garolittle said:
flippy said:
garolittle said:
I am one of those who dumped the Sunkko after using the kWeld. 8)
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i stopped using after the transformer blew up all over the workbench.
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Wow. Glad you were not hurt!
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I was wondering how an open air transformer explodes. I can see arcing and therefore burning and charring, but not exploding.

To explode you need a transformer in an enclosed can...like the stuff you see on a typical telephone pole or the big ones on the ground. The transformer is completely immersed in oil. Temps inside the closed can increase dramatically, cause the oil to expand and start to boil and then the can bursts or explodes.

Sort of like what happens when you decide to over volt super caps a smidge too much. =)

You need to exceed the capability of the sealed container to hold back more pressure to get an explosion. An open air transformer like inside the Sunnko's will just vent off any gasses as fast as they form.
 
ElectricGod said:
I was wondering how an open air transformer explodes. I can see arcing and therefore burning and charring, but not exploding.
To explode you need a transformer in an enclosed can...like the stuff you see on a typical telephone pole or the big ones on the ground. The transformer is completely immersed in oil. Temps inside the closed can increase dramatically, cause the oil to expand and start to boil and then the can bursts or explodes.
Sort of like what happens when you decide to over volt super caps a smidge too much. =)
You need to exceed the capability of the sealed container to hold back more pressure to get an explosion. An open air transformer like inside the Sunnko's will just vent off any gasses as fast as they form.
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the transformer windings on the inside failed due to overheating as the ouside was only aircooled with a couple fans and due to the fact its on a 247V supply with a D class 32A breaker it could generate a LOT of energy there with nowhere to go. it blew out the windings and got a really nice plasma arc explosion covering the back wall and ceiling with vaporized copper.

violent transformer explosions are not that rare, i worked in utillity for getting my electrical degree and industrial transformers (not oil cooled) as used in industrial complexes would fail quite violently, sometimes even moving the concrete roof that was placed over the top of the little house they are set in.
 
spinningmagnets said:
Interesting, thanks for sharing. How could I avoid this when using a transformer?
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not running it at its "chinese" ratings for starters would be a good way. those sucko transformers are running at 3~500% of its actual rating.
also get a transformer that is physically rated for its task and have enough cooling and prehaps a temp sensor at the core to turn off the transofrmer so you dont melt the insulation laquer off the windings and create a massive short as i did.
heat soak is the main cause of problems, the center of the transformer is WAY hotter then the outside in a aircooled transformer. so its very easy to hit the laquer temp limits. same goes with motors, its the laquer that dictates the max temp the motor can handle.

or dump the transofrmer in a oil bath....

that said: once you had a suckko or its clones and then work on a piece of kit like the kweld that is -properly- designed to handle its actual ratings -reliably- you realize what level of bank those suckko makers are making on those crappy things. anyone doubting the cost of a kweld should just look up the prices of the -genuine- fets that are used.
 
flippy said:
spinningmagnets said:
Interesting, thanks for sharing. How could I avoid this when using a transformer?
Click to expand...

not running it at its "chinese" ratings for starters would be a good way. those sucko transformers are running at 3~500% of its actual rating.
also get a transformer that is physically rated for its task and have enough cooling and prehaps a temp sensor at the core to turn off the transofrmer so you dont melt the insulation laquer off the windings and create a massive short as i did.
heat soak is the main cause of problems, the center of the transformer is WAY hotter then the outside in a aircooled transformer. so its very easy to hit the laquer temp limits. same goes with motors, its the laquer that dictates the max temp the motor can handle.

or dump the transofrmer in a oil bath....

that said: once you had a suckko or its clones and then work on a piece of kit like the kweld that is -properly- designed to handle its actual ratings -reliably- you realize what level of bank those suckko makers are making on those crappy things. anyone doubting the cost of a kweld should just look up the prices of the -genuine- fets that are used.
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That's a good way to put it..."Chinese ratings"...which are always inflated.

I've never thought of this before, but transformers work at all sorts of frequencies. They also use laminations to build up the iron core. I wonder if the transformer suffers iron losses like a motor does? Is that reduced by using thinner lams or different materials?

I have tried to use Chinese components many times. I'll be cheap if I can get away with it, but this invariably bites me in the butt from time to time. I think it was Spinning Magnets that suggested to me several years ago that I shouldn't use Chinese halls. I got to the point where this made excellent sense and now I no longer use Chinese electronic components anywhere. I have yet to see an example where they are as good as legit electronic components. Invariably the cost benefit of the Chinese part is vastly outweighed by the performance and reliability of a legit component. This is true for halls, mosfets, capacitors, resistors, inductors, probably transformers too.

It's not that China can't make good stuff, they can, but too often there's one place that does good work and 30 copies that are crap. Buy at your own risk if you buy copies. I stick with known companies like QSmotor and avoid the rest.

I did have a good laugh at the "Sucko" comment!
 
yes, basically transformers and motors are the same thing. they work on the same princples, so thinner laminations is better and higher fequencies means you can push more power into them. and cheap chinese transformers means thicker laminations so more heat.
this is also why 50/60hz transfomers for utillities so huge. and this is partly why the millitary uses a LOT of 400hz equipment, especially near planes and comms, you can push a LOT more power with much higher efficnecy.

the problem is not china, its the fake china stuff.

random video showing what i mean: https://youtu.be/wVYMyExlJpU?t=109

imagine if you used fake mosfets on the kweld. it would probably vaporize the board.
 
flippy said:
yes, basically transformers and motors are the same thing. they work on the same princples, so thinner laminations is better and higher fequencies means you can push more power into them. and cheap chinese transformers means thicker laminations so more heat.
this is also why 50/60hz transfomers for utillities so huge. and this is partly why the millitary uses a LOT of 400hz equipment, especially near planes and comms, you can push a LOT more power with much higher efficnecy.

the problem is not china, its the fake china stuff.

random video showing what i mean: https://youtu.be/wVYMyExlJpU?t=109

imagine if you used fake mosfets on the kweld. it would probably vaporize the board.
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I bet our Sucko spot welders run direct on 60hz, 120v AC. I haven't looked inside very closely, but I don't remember there being any kind of a large rectifier bridge or high current oscillator circuit right off the AC side and right before the transformer to create a switcher. I'm thinking the transformer is just a straight up 50-60hz step down device with a larger secondary winding. I saw a TO-247 device inside. I bet that's a triac and switches AC power in and out to fake PWM. I didn't see any large capacitors of any quantity so that explains the dimming of the house lights when I make a weld with the Sucko. It's just a very poor grade AC arc welder with some very simplistic AC input control to fake actual sophistication and quality.
 
Succko
 

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Thanks for those pics!

Or more specifically...

Sunnko:

Big%20Pile%20of%20Turds.jpg


KWeld:

pile-gold-bars-17073426.jpg
 
I've been practicing with my kWeld on some bad, recycled batteries I salvaged before I make my real pack out of the new batteries I received last week (Samsung 30Q's). Quick question on the "Nickel/Copper Sandwich" and arranging my pack:

I'm putting together a small 4S2P pack. Each row of batteries will be in series (4S) and each column will have a parallel connection top and bottom (2P).

My current thinking (no pun intended) is to weld a copper series connection along with a nickel parallel connection on top of it at the same time but with the two tabs running 90 degrees to each other (i.e., the copper bar in the series row and the nickel bar in the parallel row). When I get to the second cell, I would slip a copper series bar under the other half of each nickel bar and simultaneously weld them both to each battery in the second cell. In this fashion I think I get best practice conductivity with the copper on the series connections and without a superfluous layer of nickel on top of the series connections.

Yes? Am I missing something? Any thoughts would be appreciated before I start in on my first real battery pack. Thanks.
 
tatus1969 said:
ElectricGod said:
pile-gold-bars-17073426.jpg
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Ahemm... can I get this reward paid out cash instead? 8) 8)
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Yes you can, but I get half the $$!

After seeing that elephant and pile of poo picture, I'm wondering how that elephant did that in one "squatting". I mean that pile is 1/3rd the size of the elephant! I've heard of people being full of shite...but geez...it's a figure of speech, not literally true!
 
My current thinking (no pun intended) is to weld a copper series connection along with a nickel parallel connection on top of it at the same time but with the two tabs running 90 degrees to each other (i.e., the copper bar in the series row and the nickel bar in the parallel row).
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View attachment 1

Trying to find time to finish desired experiments. I think there's a benefit to having the copper split, so the welding current is forced to pass down through the cell, rather than most of the current just passing across the copper due to its high conductivity.



I just threw these pictures together for an illustration. The copper is 0.20mm, and the nickel is 0.15mm. Both are quite easy to cut with scissors. Since copper is four times as conductive as nickel, 0.20 copper would be the equivalent of 0.80 nickel. but nickel that thick would just be a resistor at high current.
 
ElectricGod said:
After seeing that elephant and pile of poo picture, I'm wondering how that elephant did that in one "squatting".
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Deduct 20% of that mass to account for that poor guy underneath :wink:

spinningmagnets said:
Trying to find time to finish desired experiments.
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Exciting! :bigthumb:
 
ElectricGod said:
tatus1969 said:
ElectricGod said:
pile-gold-bars-17073426.jpg
Click to expand...
Ahemm... can I get this reward paid out cash instead? 8) 8)
Click to expand...


After seeing that elephant and pile of poo picture, I'm wondering how that elephant did that in one "squatting". I mean that pile is 1/3rd the size of the elephant! I've heard of people being full of shite...but geez...it's a figure of speech, not literally true!
Click to expand...

Chinese elephant, running 300 - 500% overrated.
 
Taswegian said:
ElectricGod said:
tatus1969 said:
ElectricGod said:
pile-gold-bars-17073426.jpg
Click to expand...
Ahemm... can I get this reward paid out cash instead? 8) 8)
Click to expand...


After seeing that elephant and pile of poo picture, I'm wondering how that elephant did that in one "squatting". I mean that pile is 1/3rd the size of the elephant! I've heard of people being full of shite...but geez...it's a figure of speech, not literally true!
Click to expand...

Chinese elephant, running 300 - 500% overrated.
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Got it...
It's not real elephant poo. It just looks like elephant poo on the outside, but inside there's really a single dog turd inside a hollow pile.
You know...sort of like those 9000mah Chinese 18650's we are all so "fond" of that have a 1000mah lion cell inside them.
Just gotta LOVE the Chinese for their knock-offs!

It makes me wonder if a real Sunnko is really that horrible or if most of us have clone knock-offs.

Xiaomi is a well known Chinese manufacturer. I'd put them right up there with Samsung for quality, refinement and functional electronics. I've been using their phones for years. They have gained a lot of popularity in the USA and folks like Lineage and other ROM suppliers have been supporting the Xiaomi phones for years now. Xiaomi makes really nice hardware that costs a lot less than Samsung or well known western brands. I also have a pair of earbuds from them and a fake pair. The fakes look almost identical to the real ones. There are very tiny differnces. The sound quality however is like the $2 earbuds you get at the gas station. The real earbuds cost me $40 and they are every bit as good as my much more expensive BOSE earbuds.

China can make really good stuff that doesn't cost a lot, but then all the Chinese cloners ruin it with their very low grade crap.
 
ElectricGod said:
It makes me wonder if a real Sunnko is really that horrible or if most of us have clone knock-offs.
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no, these are the "real" deal. so its just that shitty.
 
flippy said:
ElectricGod said:
It makes me wonder if a real Sunnko is really that horrible or if most of us have clone knock-offs.
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no, these are the "real" deal. so its just that shitty.
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I laughed for a good minute...thanks for the amusement!
 
ElectricGod said:
I laughed for a good minute...thanks for the amusement!
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good thing you had a laugh, my wife did not when the transformer exploded in my old workshop in my home and the smell lingerd for days on end in the entire house....
 
flippy said:
ElectricGod said:
I laughed for a good minute...thanks for the amusement!
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good thing you had a laugh, my wife did not when the transformer exploded in my old workshop in my home and the smell lingerd for days on end in the entire house....
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I bet! burning electronics stinks.

I was thinking about this transformer issue. There had to be symptoms and other things happening. Yes it's a Chinese over rated transformer, but still...

1. Burning smell and smoke coming from the transformer.
2. Zapping or arcing sounds coming from the transformer
3. Possibly blown breaker on the AC input.
4. Blown fuse in the Sunnko welder that was bypassed or replaced with a much larger one.
5. To get molten copper requires 1083C. AKA REALLY HOT! The transformer had to be arcing for a while for this to happen.
6. For the copper to spray everywhere, the cover was not on the spot welder. Otherwise it would be nearly 100% contained inside the metal shell.
7. The triac was a dead short inside or bypassed or the control electronics would not shut it off. This allowed the transformer to stay powered continuously.

My suspicion is that all of these or most of these happened.
 
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