Spot welder / spotwelder choosing the right one

Issac

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Jan 19, 2018
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Hey Guys !

As many people before me, and after sooner or later think about buying (or making) one for them self to proper build their pack.

I checked forum and did't find a proper topic about this.

So there's many Sonkko one, but not much more.

I'm too stupid to build one myself (tried already, failed and get electrocuted - so I'll better stick to low DC voltage :s ), so I figure just buy one.

Could you please advise on purchase:
Is it worth 120$ for SUNKO 737G or it's mandatory to 190-230$ for 709A/AD or kweld ?
 

bournevexed

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Jan 21, 2019
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Hey Isaac,

I'm using the malectrics arduino spot welderhttps://malectrics.eu/ with a 3S 5000mAh 65-130C Lipo
which I bought seperate. I've had it for about 10 days & just recently put it together which is very easy.
Pretty straight forward! Though I'm not using the foot switch(personal choice as the welder has auto detect).
Its an awesome piece of kit.

Just so you can see:

here are the Lipo Battery assembly instructions:

https://malectrics.eu/lipo-battery-bundle-assembly-instructions/


And the Car Battery assembly instructions:

https://malectrics.eu/car-battery-bundle-assembly-instructions/

here is a photo of what i didyesterday on some cells i have.


image_apmflb.jpg

image_nzsekh.jpg
 

daromer

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Im using the Suunko 709A. Do not go with smaller than that one if you plan for the AC powered version. I like that version since it just works and I dont have to bother with batteries. BUT it demands 16A slow blow fuse and 230VAC system.
 

Issac

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Jan 19, 2018
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@bournevexed

That's looks interesting. Did you consider kweld before buiyng ?
What convinced you ?

@daromer
I could have problem with proper ameperage on 230VAC - fast fuse box in house.
But as there's more possibility with DC, so I'll think better go this way, especially for me when I have 12x350F ultracaps conected in 6S2P with can deliver in 16,2V max of 1680A in short circut !!! (slowly charging from any DC source via converter, with BMS of course - cost of build~80$)
 

daromer

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DC source is easy if you have the supply for it. Some more intital work only :)
 

Issac

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@daromer I can easily change supply for the supercaps if needed.

So for now: (current price incl. shipping)

EUR215 kWeld VS EUR145 Arduino Battery Spot Welder Kit V3.3 145EUR

I prefer kWeld but 70EUR difference is just enormous, do you have some justify to cover the price difference ?
 

higher_wire

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Aug 30, 2017
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I'm using the 110v version of the 709a. Haven't had any issues.
 

jonyjoe505

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Feb 28, 2018
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I prefer kWeld but 70EUR difference is just enormous, do you have some justify to cover the price difference ?

I researched as best as I could but also went with the cheapest tab welder. I got the older version 2 maletrics which only runs on car battery (no lipo) and had a primitive lcd screen. But using 6 gauge pure copper welding cables for the probes gave me very good performance, excellent weld at number 4 power setting on 0.15 nickle strip, it goes up to 9 power setting so the welder is very powerful even at the lower settings.You need to do the welds at the lowest setting that gets good results, the higher the power level the hotter your cables get, they can becometoo hot to hold very quickly if the wiregauge is too low which require higher power. The newerversion 3 that came out is very similar to the kweld and it was cheaper then theversion 2.

Many people think the AC units because of the 120 volts it uses is more powerful, but if anything I read many reviews of them blowing house fuses. That is something to check before buying a plug in model.

I beenusing the maletrics with a small 28ah agm battery, works fine with that, you can probably use it with a lead acid jump pack a long as you use thick gauge pure copper cable everywhere. The small tab welders are alsoeasy to store when not in use.
 

Mikethezipper

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Jul 7, 2018
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I have the malectrics welder as well - I bought it a year ago before the Kwelder was all the rage. It's so easy to use you kinda feel stupid about it, because what it does and how it works is just so simple.
Definitely don't use a huge car battery though. I have mine hooked up to the only "free" car battery I had laying around, at at 1000cranking amps, the thing nearly melts holes through everything even on the lowest possible setting. The only thing I don't like about it is that there really isn't that much info I could find about the malectrics one - on what settings to use etc. You can do auto pulse (it detects when both are touching, waits a for an adjustable delay, then just zaps) and you can adjust pre-pulse and overall pulse duration. That's pretty much it. So when I watch Daromer's excellent videos, none of his settings or methods really translate at all to what I'm doing.

However, if you stick to a battery that isn't massive and has a cranking amps of closer to the 600 ish range, then you should be good from what I can see. Since it's based on mosfets, I don't see why it would "wear out" over time. And I can tell you from someone who has put over 1000amps through it, that it has held up fine so far.
 

Issac

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Jan 19, 2018
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Thank you guys for a help.

I'm surprise that even 28Ah AGM could deliver enough current to spot weld weld, but when you think about it, when dropping the wrench on even 7Ah battery sparks are flying, and somtimes even grab and weld to electrodes.

@Mikethezipper
"The only thing I don't like about it is that there really isn't that much info I could find about the malectrics one - on what settings to use etc"

It's because weleder, just allows current to pass throug the electrodes. Simple AF.
Constant are the limitation of welder (resistance on cables and max allowed current that can mosfets pass thorugh)all the wariables are depends on the user, so they need to adapt basing on three wariables and learn on own mistakes.
1. Time (ms)
2. Source of supply (battery/transformer) Current that strictly depends on Voltage, and so on..
3. Material that we use to connect
 

Overmind

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Jan 16, 2019
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I find spot welders to be quite expensive so I think I'll design my own at a point.
 

Issac

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Thank you all guys.
I decided to buy Malectrics spot welder and pair it with 6S1P or 2P 350F maxwell supercaps (with proper BMS Vmax 13,5V max and 840A short current, can be doubled if needed - but welder may not hold it)
 

duwdu

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Apr 17, 2018
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Issac said:
Thank you all guys.
I decided to buy Malectrics spot welder and pair it with 6S1P or 2P 350F maxwell supercaps (with proper BMS Vmax 13,5V max and 840A short current, can be doubled if needed - but welder may not hold it)

Congrats on your purchase of the Maletrics unit; looking forward to reading your user experience. I'm still torn between the Maletrics and KWeld.

In the meantime, could you please share the full components purchasedetails of your Maxwell supercaps build including the BMS/balancing boards? I've been wanting to gothat route but have not been able to locate how to build such a packfor the $80 (or thereabout) that you stated earlier yours cost you. Thanks.

........
P34c3
.....
...
 

Issac

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@duwdu

Working very well, but I do not have comparision to k-weld.
As I remember I choose malectrics because they have confirmed working history with supercaps.

But I switched to lead-acid carbattery, because caps didnt work.
I think because they were old (2007 manufakture date ~10 yearslifespan), even when charged to max they cannot give proper current, and welds were very weak. (with 6S2P configuration of 350F 2.5V charged to 13.5V it sucs..)

BMS board i bought on ebay, from seller that no longer exists. I did connect it later with extra copper wires blobed with solder, no change.

I found on ali the same one:
https://pl.aliexpress.com/item/32813057355.html
 

chuckp

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Jul 29, 2018
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I took the home brew MOT spot welder route.

Works very well, over 5000 welds in so far and still going strong.


image_jhfvdv.jpg

image_nojpyk.jpg

image_hevxxf.jpg


image_ufasba.jpg

image_rrwpjc.jpg
 

Oz18650

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Joined
Oct 2, 2017
Messages
200
chuckp said:
I took the home brew MOT spot welder route.

Works very well, over 5000 welds in so far and still going strong.


image_jhfvdv.jpg

image_nojpyk.jpg

image_hevxxf.jpg


image_ufasba.jpg

image_rrwpjc.jpg

That looks really good.
Can you tell us more about the spot welder you made?
 

chuckp

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Messages
376
Oz18650 said:
chuckp said:
I took the home brew MOT spot welder route.

Works very well, over 5000 welds in so far and still going strong.


image_jhfvdv.jpg

image_nojpyk.jpg

image_hevxxf.jpg


image_ufasba.jpg

image_rrwpjc.jpg

That looks really good.
Can you tell us more about the spot welder you made?

Sorry I didn't take any photos at the time, but here goes.

I had an old UPS for a PC that was no longer useful. I stripped it out just for the case as I thought it would make a good housing for the electronics.

I used a JST41-1200 Battery spot welding control board, 16 single chip microcomputer control, 1602 MCU LCD, encoder double pulse pcb to control the pulse duration. https://www.aliexpress.com/item/32810563725.html

Striped out an old 230V 850W microwave oven i had kicking around to salvage the transformer, cut out the secondary windings and removed the magnetic shims i replaced the windings with two turns of 16mm2 flexible battery cable with approx 1M of spare cable to exit through the case for each of the spark electrodes.

I mounted the MOT in the case along with the pcb and used a small 230V to 12V transformer for the pcb power supply. Cut the end of the case out and fitted an old PC fan on the end to keep everything cool, not that anything gets hot, I probably didn't need the fan. Pushed the battery cable out through a couple of holes drilled into the front of the case and cut holes for the display board and adjustment knob.

I soldered a couple of soldering iron tips into the ends of the battery cable for the electrodes and covered the ends with a few layers of heat shrink.

Used an old sewing machine peddle switch to operate the welder.

It works very well for welding fuses to cells with pulse power set to about 80% but I do need to have the pulse power set to 100% if I'm welding nickel strip otherwise the weld isn't strong enough.

I have now obtained a 1000W MOT that I'm going to fit in at some stage. I will take a few build photos when I get around to doing it.

I haven't measured the output amperage but I would imagine it's around the 450A mark, the voltage at the electrodes around 1.8V

I found that a two pulse weld works well on the fuses, P1 set to 65% for 70ms (to pre-warm the metal) a 25ms delay and P2 set to 80% for 90ms (for the weld).

The only purchases i made was for the JST41-1200, 230V-12V transformer and 2.5m of 16mm2 battery cable, the build cost was around 35 and a few hours of my time.
 

Oz18650

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Oct 2, 2017
Messages
200
chuckp said:
The only purchases i made was for the JST41-1200, 230V-12V transformer and 2.5m of 16mm2 battery cable, the build cost was around 35 and a few hours of my time.

Thanks for elaborating on your build.

That is another option which I did not know before.
 

duwdu

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Apr 17, 2018
Messages
15
Issac said:
@duwdu

Working very well, but I do not have comparision to k-weld.
As I remember I choose malectrics because they have confirmed working history with supercaps.

But I switched to lead-acid carbattery, because caps didnt work.
I think because they were old (2007 manufakture date ~10 yearslifespan), even when charged to max they cannot give proper current, and welds were very weak. (with 6S2P configuration of 350F 2.5V charged to 13.5V it sucs..)

BMS board i bought on ebay, from seller that no longer exists. I did connect it later with extra copper wires blobed with solder, no change.

I found on ali the same one:
https://pl.aliexpress.com/item/32813057355.html

Thanks for the insight on your user experience, Isaac, particularlythe caps. Enjoy.

........
P34c3
.....
...
 
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