kWeld – fuse
kWeld – firmware update tool

kWeld – complete kit


(3 customer reviews)

NOTE: variant “cables assembled” current only available for pre-order as we are out of stock of cable assemblies. Our supplier plans to send us new material by July 6th.

NOTE: if you purchase this article together with a pre-order article, they will be shipped together.

To U.S. customers: our domestic reseller offers a selection of keenlab products, please contact: or go here

To Australian customers: our local reseller is building up stock and accepts preorders here

New design featuring C14500 (tellurium copper) CNC’ed electrode system for better heat handling capacity and improved handling:


The assembly and operating manuals are available on this website for download ( – Please make sure to study them carefully in order to ensure safe and reliable operation.

Purchase this item if you want to receive everything that is needed to build a kWeld unit. Complete the kit using basic tools, add a suitable power source, and start welding.

If you want to source some parts from e.g. your local hardware store, then this article may not give you the necessary flexibility and options; in this case, you can order the individual components from the shop instead, and use the description below for an overview of what is needed to build a complete kit.

The kit includes:

Electronics This is the brain of the kWeld battery spot welder. You purchase a professionally reflow soldered, tested and programmed electronic module. See for more details.
Cables, electrode holders, and electrodes All bits and pieces that are required to fully assemble the kWeld cabling, including a pair of electrode holders and a pair of electrodes. (See and for details.) The power input connection consists of loose cable ends, you need to add a connector that matches your power source. Suitable XT150 power connectors are available in the shop.

Choose the supplied loose option if you have the time and tools do do the necessary assembly steps yourself, saving some money. Check out the assembly manual for an overview of the involved work. If you are in doubt, choose the assembled option here.

Fuse A 300A high current fuse (type ANL) that needs to be mounted on the kWeld electronic module and protects the system from the consequences of unlikely catastrophic failures.
Foot switch The pulse trigger switch of the kWeld system. It has a rugged construction, and uses a real micro switch that is also easy to service. The cable length is 2.0m.
CNC machined bus bars These need to be bolted to the electronics module and provide a low impedance path between the switch transistors and the cable system.
Mechanical parts All bits and pieces that are required to fully assemble the kWeld electronics module with the LCD, the cabling, the fuse, and the bus bars. See for more details.

Please note that a power supply is not part of the kit. The following high current power supplies have been tested with the kWeld system and can be recommended:

  • Turnigy nano-tech 3S/5000mAh/130C Lithium Polymer battery (link). I have stress tested one of them for several complete discharge cycles, and it shows no visible swell thereafter. The measured current is 1300-1500 amperes.
  • Turnigy graphene 3S/6000mAh/65C Lithium Polymer battery (link). These do not show any swell after a few full power discharge cycles, but I have no data on their life span yet. The current level is comparable with the nano-tech model.
  • Ultracell UXL65-12 (link). According to feedback from a user, the current reported by kWeld is approx 1000A when tested with 0.15mm nickel strips.
  • Bosch SMT 31-100 (link). According to feedback from a user, the welding current reported by kWeld is approx 1400A.
  • The power supply must be able to deliver at least 800A (recommended: at least 1000A) to ensure proper functionality of the device.

IMPORTANT: Lithium Polymer batteries are potentially dangerous. If they fail internally, they can spontaneously self-ignite. It is therefore strongly advised to permanently supervise them during use and also while charging them, and to store them in a fire safe container when not using them.


You are dealing with very high energy levels when using this system, which may result in personal injury or fire when handled improperly. Take appropriate safety measures and use this system with caution. Never leave it unattended while being powered.

This product contains small parts, keep out of reach of children!

This system produces significant magnet fields, do not use it when you have a cardiac pacemaker!


This kit is provided as is without any guarantees or warranty, except where obliged by national law. In association with the product, makes no warranties of any kind, either express or implied, including but not limited to warranties of merchantability, fitness for a particular purpose, of title, or of noninfringement of third party rights. Use of the kit by a user is at the user’s risk.

In no event shall be liable for any direct, indirect, punitive, incidental, special, or consequential damages whatsoever arising out of or connected with the use or misuse of any product purchased herein. You agree and acknowledge that any product purchased should be used at your own risk and you should assess the risks before purchasing any product or using any product. You agree that in the event that is deemed liable for any harm caused, the amount which it shall be liable to you shall be limited to the cost of the product.


Weight 0.8 kg
Dimensions 20 × 20 × 15 cm

cables supplied loose, cables assembled

3 reviews for kWeld – complete kit

  1. jimmyhammar1 (verified owner)

    Really a total newb here so cannot get technical, but that also part of why this little beauty is so great, someone like me can just get one and start putting together battery packs. A China welder based on a transformer is not really that much cheaper if going low end China welders but with this one there is no worries and learning period, perfect result each time.

    Highly recommend, ohh also the seller is also perfect and fast with all mail contact so far, could not be happier and money well spent.

  2. Werner Hopf (verified owner)

    Als Besitzer eines Akkupunktschweißers vom chinesischen Quasimonopolisten für Hobbyisten war ich mit dessen Gerät im Gegensatz zu anderen gar nicht so unzufrieden. Die gebauten Akkupacks erfüllten meine Erwartungen. Es gab jedoch Einschränkungen:

    1. Mit 0.2mm Nickelband war das Gerät am Anschlag
    2. Bei voluminöseren Akkupacks, deren Form vorgegeben war (z. B. Erneuerung Werkzeugakku, Notebookakku) erwies sich die Elektrodenbefestigung als 5 cm vom Gerät entfernter “Haken” als hinderlich. Manchmal wären trotz Fußpedal 3 oder 4 Hände zum Halten nötig gewesen.
    3. Der FI meiner Hausinstallation verträgt den induktiven Einschaltimplus des 220V-Geräts nicht und löst aus, lange bevor man überhaupt ans Schweißen denken kann. Zum Glück wohne ich in einem Mehrgenerationenhaus, dessen erste Installation noch aus der Vor-FI-Zeit stammt. Also keine Sorge. Ich habe nichts überbrückt und betreibe bzw. betrieb den Punktschweißer zusätzlich an einer aufgesetzten Sicherheitssteckdose. Doch insgesamt deckt sich das mit den Erfahrungen von Makern aus den USA. Mit deren 110V-Netz geht mit diesen Punktschweißgeräten auf Transformatorbasis fast gar nichts mehr. Und für mich war das Hin- und Hergespringe lästig.

    Trotzdem wollte ich erst für den Punktschweißer eine flexible Elektrode vergleichbar mit der des kWeld erwerben. Doch das wäre für mein Modell eine Bastellösung geworden, da nicht vorgesehen (wenn auch im Inet angeboten mit “Bauanleitung”). Bei der Recherche stieß ich auf den kWeld und ließ mich überzeugen mehr Geld in die Hand zu nehmen. Vor allem die Aussicht den kWeld mit ohnehin vorhandenen Akkupacks betreiben zu können gab letztlich den Ausschlag.

    Das Kit musste wegen fehlenden Bestands vorbestellt werden. Von da an gab es dann allerdings nur noch positive Überraschungen:

    – Der angegebene “WiederAufLagerTermin” wurde eingehalten.
    – Die Abwicklung ging schnell (6.7.19 bestellt, ab 9.7.19 wieder auf Lager, Ankunft 12.7.19) und professionell.
    – Der Zusammenbau ist mit vorbildlicher Anleitung kein Problem.
    – An meine mittlerweile etwas betagte “24V- Ladestation” bestehend aus 8x A123 LiFePO4 (AMP20M1HD-A) 20Ah mit EC5-Stecker angeschlossen, kWeld kalibriert, und die Probeschweißungen mit 0,1 – 0,3mm (Rein-)Nickelband waren unglaublich gleichmäßig und bombenfest.
    – Einstell- und vor allem Analysemöglichkeiten von denen ich bisher nur träumen konnte. Trotzdem intuitiv bedienbar.
    – Erster “wirklicher” Akkupack (Rasenmäherakku) funktioniert einwandfrei und wäre schon mechanisch mit dem alten Punktschweißer kaum relasierbar gewesen.

    Fazit: Ich kann das Gerät jedem der in diese Richtung Ambitionen hat nur wärmstens empfehlen.

  3. razor_sparks (verified owner)

    This thing is so easy to use once set up and calibrated properly. You do need a few tools to get things assembled properly, like a good soldering iron, some metric wrenches, some metric Allen keys, a hex lug crimping tool (and some spare lugs for practice, because you get ONE SHOT with crimping the probes!), some extra heat shrink, and patience. But this thing can WELD! I’m running mine off of a pouch lithium pack meant for RC cars and it actually Overcurrent’d the first time trying to calibrate it, I had to add extra wire to REDUCE the current! (Seriously, this whole system is so overbuilt for performance it’s ridiculous.) [Maryland, USA]

Add a review