kWeld - "Next level" DIY battery spot welder

[tatus1969]

I'm looking for the ability to change weld power without using the knob. I have a small CNC-board on which the k-weld is mounted and I'm welding 21700 cells. The amount of power needed is different when welding the minus pole vs the plus pole and I want to automate the "change".

that would require a firmware extension as kWeld does not have a proper automation interface. It has been requested many times, but I just never hav gotten to that :-/
kWeldPro will definitely have that - automation via USB, and also a digital input/output interface for use with CNC machines. For example, one input (to kWeldPro) is the trigger, one output is a ready signal and another output is pass/fail.

 

[tatus1969]

Hola How can I get the pro version of the kwed and how thick can it weld?

not yet, but we are making a first batch of 20 right now. I hope to be able to open up for preorders before Christmas. The first units will be kits, and I might have a price point in one or two weeks from now. Software will be limited when they get released, but we are and will remain working heavily on that thereafter. My plan is to reach at least kWeld status, with proper energy metering and of course capacitor voltage control.

And to your question: it has already done stress testing with full steam 13ms / 3300 ampere pulses, once every two seconds. Sock solid after 100,000 cycles That amount of current is definitely by far enough for 0.3mm nickel, and also solid copper sheets should be possible. But I havent been able to test many variants yet, rather concenrating on development. I'm curious to read what you guys will achieve with it.

 

[tatus1969]

Why would you use 11 at all?

yeah, good point. Any idea how to explain that to 10,000 customers?

 

[tatus1969]

I ordered a Kweld, but none of the recommended batteries on their website are available at Hobbyking. Can you recommend an alternative LiPo battery? Or any of these Acid batteries should work?

aarrgh, again... checking,

Turnigy Graphene Panther 6000mAh 3S 75C Battery Pack w/XT90

Introducing a new generation in premium performance. The Turnigy Graphene Panther 75C is a powerful lipoly battery with an unbeatable cycle life and durability.

hobbyking.com

Turnigy Graphene Panther 5000mAh 3S 75C Battery Pack

Introducing a new generation in premium performance. The Turnigy Graphene Panther 75C is a powerful lipoly battery with an unbeatable cycle life and durability.

hobbyking.com

are shown as 'in stock' but with just a few of them. I guess I need to make more test buys soon...

 

[riba2233]

yeah, good point. Any idea how to explain that to 10,000 customers?

haha idk, tell them it is a pure pos and not worth it, hopefully they will trust you

 

[BVH]

Check out the SMC brand of flight packs. These are currently the top of the line in quality and performance as depicted on the RCGroup forum thread by MCSGUY. This thread has been running for 12 years and MCSGUY knows his stuff. Lipo ranking table on Pg 1 is always up to date. Battery Load Test Comparisons - RC Groups

 

[DogDipstick]

Check out the SMC brand of flight packs.

I am telling you guys, use a 20$ stack of Ev lipos from such as the Chevrolet. Volt.
The pack that runs my K-Weld.... Well over 2000A, still not dead, 12 years old... 20$. They ( LGCHEM) made the cells years before this man (Frank) ( Tatus) ... amde this spot welding machine.. and I cannot kill them and they do 2x the power out aH for aH, than ANY SMC or Hobbyking junk hobby grade lipo.

In SCC you want a good current? use a 20$ stack of EV lithium polymer.
You wont kill it. I am sorry, BVH.... I know I am a broken record with what I repeat... but ... they just dont fail for me. I have even posted in Wayne giles and MCSGuy's threads telling them too. they know me certaainly, perhaps they remember me still.

....the most ( maximum) I can measure is ~3000A.


I do not like overpriced hobby grade lipos.

 

[cutlaszc]

Should we build SuperCap module out of this Maxwell 3400F, 3V/3.15Vmax. For 3S2P, we will get 2,266F with higher Vcap, much lower ESR, 10x the Farad, I expect > 3,xxx Amp output can be achieved. Or the more hard-core 4S2P, or even 4S1P with the > 3,xxxF, 2.85V (total 750F or so) this is what we can get much more headroom V (2.85V*4Serial). From V = I*R, increase V (from 3S to 4S caps = from 8.55Vmax to 11.4Vmax) and lower R (big wires), Imax will be increased and t will be decreased dramatically - that is exactly what we want for high Q (very high energy in very short time). PSU might need to be upgraded to ≈14.5V / > 60A, programmable CC-CV charger preferred. Just make sure your gears can withstand this magnitude of punch. The 3S/4S balancer board also needed. Should be able to weld thicker Cu directly to cell cap. May be 0.3-0.5mm ? Have to unlock current kWeld from its 2,000-A limit (factory default). It just looks promising. These Maxwell 3400F3V/3.15Vmax are expensive plus they are heavy and gigantic (1 pc ≈ 1 soda can). So shipping cost will be steep too. Alternatively, I found 3400F 2.85V Maxwell used ones for sales cheap at $10.- ea. But buying used ones is like buying lotto, could be a complete Crapacitor. :lol: :lol: The ESR is what matters here and they keep increasing with usage - not to mention if they are even genuine Maxwell originally. That's the trade-off. I don't know whether there is an easy way to test these SuperCaps reliably, especially the ESR. Any idea ?

Also the TVS diodes might need mods to cope with the new much higher oomphs ?

Frank, do these sound OK to you ? Is it possible to unlock this kWeld's 2,000-A limit ? Pls advise.

Hello, how can I unlock the current kWeld from its limit of 2000?

 

[Merlin]

not yet, but we are making a first batch of 20 right now. I hope to be able to open up for preorders before Christmas. The first units will be kits, and I might have a price point in one or two weeks from now. Software will be limited when they get released, but we are and will remain working heavily on that thereafter. My plan is to reach at least kWeld status, with proper energy metering and of course capacitor voltage control.

And to your question: it has already done stress testing with full steam 13ms / 3300 ampere pulses, once every two seconds. Sock solid after 100,000 cycles That amount of current is definitely by far enough for 0.3mm nickel, and also solid copper sheets should be possible. But I havent been able to test many variants yet, rather concenrating on development. I'm curious to read what you guys will achieve with it.

any news Frank? still waiting

 

[leffex]

I have some kind of problem now.

I exchanged the kweld original sticks to another branded one and after that. All the same the welder pushes alot of current through piecring the cells.

50 Jouls feels like maybe 150-200 J and max setting is 150 right?

Putting down the Joule down to 8-10 is rather normal area and around 50-70 jouls of power.

The only thing I did was add some alcohol on the nut and tightened it up on the fuse side output as I feelt the lower nut, as this has two was a little lose.

It has been through an event of a loss of a small screw on the copper bar on on negative input most to the right which triggered a flash or a surge / short circuit somewhere put it didn't trigger the big fuse. After a new screw and tightening of bolts it started up and worked as normal. - this was a year ago in my kwelders history.

Please what can be the issue this time?

Can I do a reset or factory reset somehow and have it back to standard power or has this happened to someone else and can I then use new Joulse levels calculated from the new values that seems to be lower for higher power.

It seems the problem allows current to pass for longer than it just did before and as such this current heats up and pierces through the cell instead of welding it.

I guess it would be powerful enough for copper and I will try but this is seriosly something I need to fix.

I use 0.15mm pure nickel and 50 J is very good power for this. Maybe too much and now I put settings to 8-10 I think. I will continue to try and see.

I have since then also put back the original kweld cables and copper rods. They don't seem to cause the issue. Input battery power is 4s 35ah lipo rated to about 1780A current on my kweld.

 

[eee291]

Maybe recalibrate the resistance and wire length like when you first bought it.

 

[leffex]

Wire length in the settings is 1.0 Meter so the lowest I can do on my firmware and boardversion 3

I will do a new calibration CAL as I didn't short the copper rods to themselves but to a metsllic tool and I didn't receive all the info that I should. ms and resistance and the okeys.

I hope it will work as I can't do any work with a piecering 18650 welder hehe.

I did a test with two 1cm square nickel pieces with 0,15mm pure nickel.The 1 joule didn't do much, the 1,5J did a little movment and 2J it jumped, power was though normal setting for this should be 10 to 20J

 

[leffex]

Maybe recalibrate the resistance and wire length like when you first bought it.

Yes. Now it works. I'm happy.

One small issue that can be adressed is when using the small M4 screws to hold the rods. Either use a checker to just tighten it up to the small torque requirments or redo this somehow as my threads has been damaged and so I can't fasten my rod.

Now I fixed it with a new hole and new theads and a new nut but its not the easiest and fastest fix.

We have a new kweld coming in soon as backup.

Reliability is high on kweld. I only didn't know this CAL was very important. Todays test gave out 1590A and low resistance like 2,56ohm or something with original cable. Now the welder is working again and I can work.

 

[rsh]

Hello to this forum

I just finished my KWELD and ran into calibration problem.
Searching this thread does not show a solution for me.
Thread #1,503 was not helpful.

Setup is KWELD with attached new (and charged) Turnigy graphene 3s 5000mAh and XT150.
Systems starts up to "CAL" prompt
Pushing knob brings (very fast) "open" and "OK" then falls into a
loop: Offs= 64 Std= 1.9. OK
Values of Std= are different each time restart
neither knob nor pedal ends the loop

When not selecting CAL by pushing knob it is possible to cycle through menu points and selecting them.
Changing menu values is also possible.

I just contacted Keenlab but its weekend ....
maybe someone here has a hint what to check?

 

[leffex]

Cal is this

1: use knob and klick CAL
it says something, use the pedal and klick once

2: Now it will say "short"
short the copper rods together without anything between and klick the pedal

3: now it should be calibrated

I used a metallic tool because I had a 3d printed handle keeping rods apart but my weld settings became weird and too strong destroying cells, timing was of leading to overheating at low Joule settings. (Se my post before this one here in the thread.) It is solved because I did the calibration the wrong way. There should be nothing in between but the copper rods shorting together when doing the calibration, CAL.

 

[deepsea53]

Hello,

I have a few questions, that might have been answered already.

1.) Can I use two of these: Turnigy Graphene Panther 6000mAh 3S 75C Battery Pack w/XT90 in parallel on a T90 connector? I need to weld 0.3mm strips on 0.3mm strips and a single battery just didn't cut it - it maxed out at 1200 amps and I didn't want to push the joules higher than 110, with the cables getting hot after two welds already. I know the T90 connector isn't rated for that load, but neither are the battery cables, so what gives.

2.) More of a question for @tatus1969, I already wrote an email about a week ago, but didn't get a reply (not sure if my request was just annoying, didn't get through or sth. else): On the copper electrodes: Can I source them anywhere else? Because, while I do support fellow DIY people, a pair of electrodes costs 30€ including tax and shipping. That's a bit steep for me, given that the listing price is only 8€.

If there's any chance to mail them without tracking, etc. for cheap, I'd happily buy them, otherwise I'd make my own if possible

 

[leffex]

I have 4s 40ah of 12c turnigy maxing out at 1700 somewhat. (4s10ah x 4 turnigy green multistar)

However I think the connector and parallel connection between batteries are important as I have had trouble with these parts melting after usage so I have had to make many repairs around the connectors and finally it seems to work good enough for the usage I'm using it for.

Maximum for my batteries is 0,3mm pure nickel at around 100J and I use 0,15- for main usage at. 40-50J. depending on negative or positive electrode side.

 

[deepsea53]

I have 4s 40ah of 12c turnigy maxing out at 1700 somewhat. (4s10ah x 4 turnigy green multistar)

However I think the connector and parallel connection between batteries are important as I have had trouble with these parts melting after usage so I have had to make many repairs around the connectors and finally it seems to work good enough for the usage I'm using it for.

Maximum for my batteries is 0,3mm pure nickel at around 100J and I use 0,15- for main usage at. 40-50J. depending on negative or positive electrode side.

Interesting. I got a second one of those batteries for free, which is why I would like to try the 3s2p configuration. Would the kWeld be dead during configuraton phase if the current is too high?

 

[leffex]

Interesting. I got a second one of those batteries for free, which is why I would like to try the 3s2p configuration. Would the kWeld be dead during configuraton phase if the current is too high?

I don't think so. Minimum is something about 7v or 2s life4po or Li-ion/lipo. This is were the Kweld should be at its best power level according to the creator as I understand it.

I do have a 2s lifep4po but it only gives around exactly 800 so but maybe I can change some setting sand use it if I only use less joules on each weld but question is if more power and amps from the batteries gives better welds I would prefer that over my battery setup.

If current at testing is over 2000 then it will not save those settings so you should be just below. If you have a powerfull battery setup at 10% capacity and gets almost 2000, saves, or finish the CAL. test then you can charge the battery and get some more power or so to say "hack it".

The kweld can handle it as it is a EU and product made by a smart person thinking about these things ahead.

 

[leffex]

Using the KWeld

If anyone know and want to push me in the right direction. I need information what power level in Joule I need for 0,12 and 0,15 pure nickel strip as I get puncture on some cells.

Or has this happend to anyone else and may it also be if the nickel is not pushed all the way down so that the nickel touches the cell hard?

It has only happened to the lower negative part of the cells leading to a breach and leakage of the cell. That cell is then tossed and removed and goes to the recyling.

This problem is not related to when my kweld was not "calibrated" as it is calibrated correctly now.

 

[Schultz]

Hello,

I get puncture on some cells

Different cells may have different material thickness thus requiring more or less energy. The amount of energy needed to weld the positive tab is higher.

it also be if the nickel is not pushed all the way down so that the nickel touches the cell hard?

It has to touch the cell. If you need to press it hard I recommend you clean the strip and the cell tabs with alcohol and use gloves after.

It has only happened to the lower negative part of the cells

yes because this tab is thinner and easier to puncture.


You should start with 15-20j on each tab and then pull the strip with some pliers. You are good once the strip rips appart from where the welding points are and the welding points don’t come appart.

Because not all the systems are equal the answer is at you, after you will do some tries as above.

 

[eee291]

For years I have used 30J for .2mm nickel and have never had a problem.
I was naive and also used 30J for .15mm nickel and it blew a hole just before I finished the pack, since then I only use 20J for .15mm Nickel. This has worked for me so far without any issues.