I did it on 30q’s and all of them adhered through except when my battery ran low
P42a might be harder because I hear sometimes you need more power because of the cell
1 Like
Two old lead acid batteries totalling 120 Ah seems to be on the very edge of over current, but it welds 0.3mm pure nickel very well at 80J.
Will probably move over to some thicker leads as they heat up after a few welds. And 0.3mm thick nickel is hard to work with as it is so damn rigid.
1 Like
The standard setting on K-Weld is 800amp burst or something i have adjusted down to 500amp. and still welds solid.
i dont like 0.3 material its just too stiff… i prefer twice layers if it comes to higher discharging challenges.
1 Like
Update:
Nah nvm even at 1923A when calibrating the welder having two massive batteries and optimising the cable length to be just above 1m. Running at 100J I can’t get the negative side to have the nickel rip before the weld fails even though the weld looks hot. I guess it’s because of the heat dissipation of the cell l. The heat generated also melts the pvc wrapping on the cell which obviously sucks.
On the positive side the weld is good as low as 60J same with running it on some razor blades. I guess unless you have slits in the nickel you wanna stay at 0.2mm or below.
1 Like
Having slits in the nickel works, can do the negative side at 90J. But the amount of force you need to jam the probes into the nickel to get a good contact with cell makes it easy to actually slightly dent the cell.
So for me it’s a no go for sure!
1 Like
I dont think there is an application where 0.3 is required, 21mm wide .2 already exceeds the current capabilities of basically every 21700 (and 18mm for 18650) so if the pack is designed properly .3 is unessesary. Copper foil on .2 would be a better solution imo.
3 Likes
What h want for this
Happy New Year! 
Yup, I am working on a new device “kWeldPro”. Parts are already piling up here (chip crisis means that you need to buy a part at the moment you are putting it into your schematics…), and I should have first prototypes by mid of this year. Some key specs:
- ready to use desktop unit with AC input
- supports welding copper (3000 amps minimum)
- 450W power supply (200 joule pulse, once per second, at device output terminal)
- water cooled electrode system (option)
- pneumatic actuator (option)
- 4.3’’ touch screen
- USB, RS232, PLC interface, dual trigger
- folded steel enclosure
- price tag around 1000€ (base unit, probes and power supply will be extra)
Cheers Frank
19 Likes
Sounds very cool - if you manage to hit that price point with everything working perfectly that will be a super impressive unit!
Not sure I’ll ever build enough batteries to justify that cost but I’m sure some people will
1 Like
Definitely pro. I expect any pro getting this will be 
the copper welding ability for thic super-high discharge parallel packs 3000A wow the leads must fly upwards
4 Likes
Holy capacitor
5 Likes
I don’t even need one of these but it’s gonna be hard for me to resist the temptation once they are ready
6 Likes
glares at 2 overheated kwelds 
6 Likes
I wonder if you could mineral oil cool both of them.
a pump, radiator, ice, oil, and buckets should be all you need.
1 Like
I’m sure it can be done. But i’m also sure that i can’t be fucked doing it
1 Like
I’m very interested in the AC input and water cooled tips on the new units! I’ve been mentally modeling some kind of electrode cooling system for a while.
On power supplies though, I noticed some people are having great success on lipos and others are not.
For those who are not, Try lead acid deep cycle marine batteries. 800CCA (or MCA on this silly label) or better. And put a battery tender on it and leave it there. I’ve been doing this for a couple years now on the same battery and I love it. I got mine at Autozone for about $120, it’s 840 cranking amps. I can weld all day. Which makes me wish I had some of that water cooling in the tips.
2 Likes