Kweld spot welder

Have you noticed the positive probe producing weaker welds with your kWeld? It seems like it plagues everyone eventually.

I don’t think I’ve noticed that really, I’ve had it stick a couple times but a quick file fixes that

Only a couple thousand welds on mine though not a ton

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Yes, that’s my problem exactly.

In the beginning i didn’t notice anything strange, but i was using steel strip or thin nickel 0.1mm.

I remember that i did rip tests everytime i was using a new nickel strip and i don’t remember anything like one spot not sticking on 0.2 nickel. That was a long time ago and i barely had like 1k welds total. Nowadays i have anywhere between 10k-20k welds and this problem doesn’t let me sleep at night.

So it could be that the welder is the problem and not the 1300A power supply ?

@ShutterShock what is your welding current with Lipo?

I machined the tips (they we’re looking like new) , i checked every screw inside the welder and tightened them accordingly, i looked inside the probes (no corrosion), did many calibration, but i just cannot figure out why it’s not welding correctly.

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No idea, I don’t think I’ve ever looked

I think we need to do some experiments and figure this one out… it’s really annoying.

In the mean time, have you used the double positive method?

I didn’t hear about the double positive method. How it can be done?

We have to find out if the unit is really degrading with use and what causes it. Maybe even send one welder to @tatus1969 for inspection. I think he knows better to diagnose something like this.

We need more opinions from users who regularly use their kwelds with +10k welds. I don’t really know the guys who builds batteries but maybe you can tag them.

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You move the positive probe once for every two negative welds. For me it makes the positive probe weld about the same as the negative.

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If it’s not sticking
up the jules
Clean the nickel and cell (could be contaminated with residue in the surface)
More pressure on the positive probe
Eatch layer will require a difrent jules value from exsperiance same with +and - of the cell can.

Need more information 1300a at 50j how long is the weld etc ( if you holed the peddle down after a weld it will cycle thro som stats of the weld)

1300A is enough with the systems that I have on my bench. What pulse durations does the welder report? This should not exceed 50 milliseconds. Also making the tips sharper for better heat concentration usually helps. I’m afraid but I don’t have these ultracaps anymore, that was a one-off buy. Another question: does the welder occasionally abort pulses (double beep)?

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At 50J I have a pulse around 27ms.
At 55j ~ 30ms.
Spot R ~ 1.04

The welder apparently is working right and I don’t have missed welds with the double beep sound.

I made rip tests again and the annoying thing is that I cannot reproduce the problem everytime. Sometimes both spots stick well even with 40j, sometimes only one spot is sticking even with 50J. I don’t really want to go higher than 50j for single layer 0.2 nickel because probes burn after 30-40welds. I usually bump J setting with +5 for every new layer added.



This was made at 50J and i’ve seen worse.

Looking from above the welds look good, reported welding parameters also look good and consistent, it’s only when i rip off nickel some of the spots are not cooked.

I don’t know how could i improve the welding consistency, maybe overcome this problem with more current ? Or i just throw money out the window and nothing will be improved. Is it true that higher currents make the probes less hot at same J settings ?

Dumb question but are you cleaning your cells and nickel with isopropyl before you weld?

Not dumb at all, I was thinking if sweaty hands can impact weld quality.
I don’t clean cells with alcohol, I just keep washing my hands if I feel them sweaty.
Could be that cleaning cells with alcohol will improve weld consistency?

I think it’s certainly recommended, to avoid finger oil. I know I do it.

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We know that doing so won’t degrade the weld quality/consistency. :slightly_smiling_face:

It’s just part of “best practices” that can help prevent possible issues that make you spend time trying to figure things out. If the cells, tips, your hands, and the nickel are always clean then, most likely, any issues are due to inconsistency in pressure/position of the tips or a hardware issue.

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Hello, i’m Sergio i own KWeld, i assemblied it well.
But, when i turn the dial knob Clock Wise (CW), the value in the display decreases. /

What i did wrong?
From the beginning this is occuring.
I hope you can help.
Thank you in advance
Sergio

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I’m setting up my KWeld I recently received and assembled. I want to get some use out of my old 30C 3S packs. I know that I will be able to charge them safely by paralleling up all connections and each cell and charging it as a unit with a balance charger.

I just want to make sure that it would actually be safe to run 3 of them in parallel. In particular what if I have 2x 5Ah packs and 1x 2650mAh pack, all are LiPo 3S of course. I think if they are parallelled up they will drain together, I just have to periodically check when they are near depleted that individual cells do not get overdischarged.

im weary of that 2Ah pack but the other 2 should be a ok, long as they can handle the current

In the menu, select “Encoder” which will fix this.

Please calibrate the welder with only one of the 3S/5Ah packs to see how much current they develop. From that number, I can judge whether it is safe to add the next pack in parallel. You don’t want to overdo the battery either, or you can damage the welder.

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Thanks! I’ll test once I get leads/XT150s soldered

What’s the latest news regarding 0.3mm thick nickel on the kweld?