DIY Capacitive discharge welder (1 Viewer)

[Betteron2wheels]

EMORTH showed some interest in this at the last meeting. Another one of my partially completed projects. I pulled it out and started getting reacquainted with the progress I had made and what was left to do so I could try my 1st weld.

The point of a capacitive discharge welder (CDW) is to spot weld batteries together with strip if metal. My initial plan was to make batteries for motorcycles, now I'm also thinking about ditching the lead acid 2nd battery in my cruiser and replacing it with a few banks of 18650 LIFePO4 batteries.

Why? Because why not? And, the battery in there now is for my trolling motor...

 

[Betteron2wheels]

The hard part is gathering enough capacitors without braking the bank. I found someone selling a batch of these 10v, 220000uF caps on ebay for a good price

 

[Betteron2wheels]

So now I have my capacitors, now to wire them all together, contain them all, wire up a trigger and come up with the actual weld tips/handle

 

[Betteron2wheels]

For the weld tips, I picked up some copper wire from the local home improvement store. It might actually be grounding rod, I can’t remember for sure. I cut two pieces and sharpened the tips with a lathe then 3D printed holder, a tube handle and trigger switch handle

 

[Betteron2wheels]

Wiring was easy enough, a bunch of ring terminals from Cycle Terminal and a crimper and soldering iron made short work of connecting them in parallel


Next came the 3d printed 6 pack holders to hold them all together. The print bed isn’t big enough to do 3x4 in one go so 3 per level did the trick

 

[Betteron2wheels]

A high current Silicon-Controlled Rectifier (SCR) from Mouser will handle the capacitor-to-weld tip switching

 

[Betteron2wheels]

A LM2596 DC-DC Adjustable Converter coupled to a lap top power supply and a couple of switches will be used for an on/off/charge control.

 

[Betteron2wheels]

Here's what the batteries look like

 

[davesax36]

Man, I wish I was an engineer.

 

[Betteron2wheels]

Me too! I'm copying one I found on the web

 

[emorth]

Fantastic! Curious to see how long it takes to charge the capacitors.

 

[Von Hayek]

Nifty.

 

[jcj_78FJ40]

Why? Because why not?

Excellent attitude (and use of a 3D printer)

 

[DirtNap]

Very impressive indeed. You be a good friend to have in a post-apocalypse world.

P.S. I knew there was a reason I needed a 3D printer!

 

[Betteron2wheels]

I got mine from for less than $300. Comes as a kit, assembly required

Folger Tech RepRap Prusa i3 Clear Frame Full 3D Printer Kit

 

[Crusha]

I got mine from for less than $300. Comes as a kit, assembly required

Folger Tech RepRap Prusa i3 Clear Frame Full 3D Printer Kit

What kind of time was involved in assembly?

 

[Jakes40]

What kind of time was involved in assembly?

I was thinking the same thing.

 

[Betteron2wheels]

What kind of time was involved in assembly?

I cant remember for sure, a long evening for the hardware. Then there's the software, this one uses an Arduino attached to a Ramps 1.4 and Folger Tech has pretty good instructions. I'd say 10 hours by the time you done tweaking. Then there's a lot of mods you can do...

 

[shmukster]

Very interesting and kudos on your workmanship!

 

[76FJ40]

Can we see some video of it in action?