After the failure of my $16 battery tab spot welder, I saw Kevin Dark’s DIY version.
But it wasn’t exactly what I needed, so I decided to build a modified version.
The Modified Dark Welder, or Dark Welder 2.0, has a foot switch that triggers a precise welding current pulse that is always the same length of time – no matter how long you hold down the button.
And in my new version, the button is now a foot pedal to keep your hands free.
The best part is: IT WORKS!
Off we go:
Stuff mentioned in the video:
- Check out Kevin Dark’s original welder
- Kevin Dark’s YT channel
- Capacitor Charge calculator
- Capacitor Discharge calculator
Also, don’t miss his nifty 18650-powered DIY electric skateboards!
Schematic
Click to view larger version:
Parts List (some affiliate links):
- Gebildet Pedal Switch
- 4700 uF 63V electrolytic capacitors
- Schottky 5A 100V diodes
- 150 ohm 2W resistors
- Copper nails
- Lighted pushbutton switch
- 12V, 10Ah, 150CCA lead acid battery
- 16mm^2 wire
- Large domino (screw terminals to hold welding cables + copper nails)
That’s all, folks!
Dark Welder 2: My DIY battery tab spot welder
Hi Scottie.
Although your design for the spot welder is a slight improvement on Kevins,it falls short in as much as you have not addressed that over time the contacts will get pitted and weld themselves together.the addition of a capacitor and a resistor across the contactor terminals will do much to aliviate the arcing much the same as a condenser was used in a car distributor to help protect the points back in the day.
also it would be very easy to add a visible or audible device to indicate the fact the contacts were welded
together.
Hope thats given you something to think about.
Have a nice day.
Hello,
Thank you to share the modification for the Kevin’s spot welder.
Is it mandatory to have a 4700uF 63v? I have one on 25v is it enough?
Thank you in advance for your answer.
Happy new year.
Maurice
That should be just fine. I just went a bit nuts with the 63V rating – I like to over-design things!
Thank you very much for your answer.
Best regards.
Maurice