Sometimes it is great need to weld some metal sheets together. Sometimes they are very small, like nickel plated battery connectors. There are special industrial devices for spot welding, but for DIY and hobbyist user it is very easy to build this welder at home.
All you need is few very big capacitors, thick wire and DC power supply. Sometimes you need to put some resistance in such device, and automotive headlight lamp is very good alternative. The PSU must be as powerful as possible. Output voltage must be less than maximum voltage of capacitor and safe to handle.
Circuit diagram of the spot welder is something like this:
In my experiment I used 3 capacitors 100 000µF at 16V each. It is recommended to use variable output power supply to change the welding power. Too much power may make holes in your battery pack. Before welding useful device make some practice on some bad cells.
Here is my experiment with steel tape-like detail from digital photo camera. It is about 0.25mm thickness nickel plated steel. Double spots made connection quite durable. Never use single spot- it tears of very easy. For battery packs prepare special nickel plated or pure nicker foil. As simple steel or copper will corrode in time.
Magnified welding spots:
Dear
today i was looking for a diagram of spot welding then i saw your web page
if you get my email would you please contact me to ask you more information about spot wire welder please
regards aali
Good day,
pls show me a complete circuit diagram of a spot weld
thank you very much
This is Full circuit. Any PSU and these components. This spot welder is for welding small components- like battery cells. This is not welder for industry. Industry welder is a bit other configuration.
Please share the video of how to use this diagram of spot welder.
i want to learning from you. i saw circuit have a resistor on it ( R 1 ) ,so pls tell me what value resistor did you use ?
THX 4 RESPONDING.
The purpose of this resistor is to limit current from PSU to welding point and to limit capacitor charge current. This is very simpliefied circuit. In real world it is advised to disconnect PSU from cap battery during discharge. This spot welder is only for very tiny details welding: like attaching nicker foil to rechargable battery cell.
Very interesting and congratulations. I would like to have a contact. Unfortunatly I couldn’t read the technical details. I’m interested in a welding equipment at 40 to 60 DC volts and this spot welder shown here seems to be the answer I was looking for.
R1 is a automobile bulb of voltage equal to source voltage.
The capacitors are hard to find items.
Reportedly 33000uf 16V capacitors work with a laptop 20 volt charger.
In this setup when bulb extinguish means capacitors are charged and ready to
spotweld. For next weld , wait until bulb extinguishes again.