DIY Spot Welder MOSFET easy to build and cheap

[akkuman126]

I made a tutorial to build a cheap spot welder.

https://www.youtube.com/watch?v=VSGhcC35Z6Q&t=16s


What do you say about it?

 

[spinningmagnets]

Please do not make multiple threads about this. I will allow this post because it is in the proper section (the others were deleted).

I do like how well the video is made. It's a 6-minute video about assembling a very simple spot-welder, single-pulse, no timing adjustment. It uses a large one-farad capacitor as the power source, which must be recharged between welds by any 12V source.

Since the architecture of the FET on/off portion of this is spread out, I would even recommend watching this video before the others, even if you like the features of the other spot-welders for the type of jobs you do....

 

[Alan B]

First of all, welcome to ES.

Nice video, and a straightforward project.

Technical Comments:

1) The energy of the single-pulse welder shown here is adjusted by changing the charging voltage of the cap (within its ratings). So it is in some sense adjustable. Adjustment is important to get a good weld.

2) Double-pulse welding is generally used for batteries, not single-pulse.

3) The primary risk to success is the large capacitor. Many of the available capacitors are counterfeit or inadequately rated for this application and will fail to meet the current and energy needs of the welding pulse.

4) Static control is recommended when working with FETs to avoid damaging the sensitive devices.

Further information on the capacitors and double vs single pulse welding can be found on ES and elsewhere on the internet.

 

[akkuman126]

Part II shows how to load the cap and first test.

Need some exercise but now I´m ready to build my 700Wh Li-ion battery pack with my new spot welding machine.
Yesterday I ordered 60 Panasonic NCR18650B batterys, so I hope they will arrive soon.

Stay tuned!

[youtube]o6OafhgeK_U[/youtube]
https://www.youtube.com/watch?v=o6OafhgeK_U

 

[akkuman126]

I got my new battery case for my lithium-ion cells.

https://www.youtube.com/watch?v=nqxY-899Rb8

 

[akkuman126]

I got my NCR1860B cells. Yesterday i started a life cycle test with one of them. Charge with 1.5A up to 4.2V. Discharge with 3A down to 3V.
Want to compare with the Panasonic datasheet. After 100 cycles i will stop the test to compare. But that takes 3 Weeks.