My new 800 watt second Capacitor Discharge Welder

First off thanks to Fritz for putting up with a new to building electronics! he is an awesome guy to develop an awesome machine for the fraction of the cost and then put up with new guys like me. Hat is off to him! http://frikkieg.blogspot.com

So after wading through all the Chinese crap and getting screwed on a deal I decided to go the build it yourself route. After many hours of searching, pondering and tire kicking I settled on Fritz's welder. All said and done I'm out somewhere between 5 and 600 bux but I feel better about this than a stab in the dark buy from China. It was this or the DN-10. From what I have read it should put out about 10,000 amps so .2 mm nickel strip look out. I got about 400 cells from Doc and I ain't afraid to weld them. So I'm 99% done but the bridge rectifier I bought is bad so I just ordered two more.

it was a really fun and easy project. Seeing how a 200 watt second Sunstone unit cost just shy of $4000 I know I've made the right choice. I have a 20' roll of .2mm nickel ready to go.

Here are some Pictures and I'll update more when my rectifier shows up.

Tom

Nice work. More details please. Like where you got all the components and how much it cost you. As well as pics of the weld. Thanks.

Dude, that's awesome! Got more details on your build? Is it capable of continuous pulse discharge welding?

The cost was somewhere between 5 to 600 bux. All the components were bought from mouser.com, digi-key.com , Amazon.com and eBay. When you buy the boards from him it comes with a complete material lost including hyperlinks to all parts. I had never done reflow soldering before and it's super easy and really cool to watch it work. The whole thing ready to go weighs in and just shy of 41 lbs that includes 2-4 foot long 1 gauge leads with 3/8" solid copper leads and 400 amp quick connects.

The voltage is adjustable up to 23.2 volts which is the key benefit that makes capacitor discharge welding better than transformer types. With the higher voltage the current can be delivered faster and more precise to minimize heat trace in delicate situations like battery building. The unit I built has 3 computer grade 25v 1 Farad capacitors and 18 75v 209 amp power MOSFETS to handle the switching. After some research I liked that this was built like a tank. Many home builts used on 6 to handle what this one does with 18. All of Fritz's directions, build materials, diagrams and testing procedures were pretty easy to follow. I'd be lieing if I said I didn't end up with extra parts but that was me not understanding or knowing what all the parts were or looked like and getting just plain confused. I have about 1/4 of the parts needed to make another...oops!

Also in the price I bought a reflow/soldering station rework unit which was super nice to have. It included a lighted magnifying glass which there is no way I could have done without. At 49 I'm at that point were I have trouble seeing small stuff more so early in the morning and late in the evening....the times I have to do this sort of stuff. I'll post some pictures from along the way....again, weld pictures will come later this week when my bridge rectifier comes in!

Drunkskunk said:

Dude, that's awesome! Got more details on your build? Is it capable of continuous pulse discharge welding?

Click to expand...

I think that depends on the materials assuming you mean one of those welding wheels for continuous seam welds? Other than that I do not know all of its capabilities yet.

Tom

Sexy looking build,will you terminate cells to sell perhaps :wink: .

beast775 said:

Sexy looking build,will you terminate cells to sell perhaps :wink: .

Click to expand...

I almost feel obligated to. For years I built custom packs out of nicad, NiMH, emoli cells (v28), a123 and just wired lipo together. I think with this and some super bad arse 18650 cells is going to me be really creative.

Tom

Great effort! How many hours are you into this project? Where did you find .2mm nickel strip? Is it nickel or nickel plated steel? Will be great to see your welds

dbaker said:

Great effort! How many hours are you into this project? Where did you find .2mm nickel strip? Is it nickel or nickel plated steel? Will be great to see your welds

Click to expand...

I'm actually pretty mechanical and I'd guess I have under 40 hours in the whole project minus the time sourcing parts and going to get them. Nor does that include the time spent reading and learning about reflow soldering, heats ranges for certain components blah, blah blah. Total time since actually getting the boards was about 2 months give or take a day or three. The boards showed up the second week of February.

The .2mm nickel I got was from electricrider.com but not sure on what it is exactly. http://www.electricrider.com/Nickel-Strip-1-4w-x-008t-1-unit-1-foot-p/nickel-36.htm It just says "high quality nickel"......

Tom

1So I finally got my Sunstone Engineering probes that they recommend for 18650 and Nickel. They work perfect and was all I needed to unleash the power of this thing. Nickel is un removable at 13.3 volts with a 2/11.6 millisecond pulse using .2 mm nickel. I finally got my packs glued up, cleaned the ends and started welding. One pack down and two to go. I used a double strip on the lead ends to connect the wires to so I should be in pretty good shape current wise. I built 3--8s15p Konion cell packs out of recycled Makita 18v packs. Total cost will be about $550 all said and done for batteries, wire, connectors, nickel and shrink wrap for. 24s15p pack which will be 100.8 volts and 22.5 amps. It took a while to dissect the packs, charge, let sit to make sure they were ok but at under $1.54 cents per cell finished in a pack is cheap by anyone's measurement. Next pack will be made out of 3 amp cells but this one will be fine for now. See pictures below,

All in all this has been a super cool build, a huge learning experience and a perfect end to all the work.

Tom

Congratulations, Tom

Thanks!!!

Finished spotwelding now just have to add balance connectors and plugs then wrap them up......

Getting close to EVelbike time!

Tom

Tom,

Thanks for posting your welder build. I have gone ahead and purchased Fritz's plans, control pcb, and ver2.1 microprocessor. He doesn't have any mosfet pcb's right now, but hopefully will have some in a month or two.

You mentioned that you bought an extra 1/4 of parts. Please PM me if you want to sell them.

I also have an issue finding high grade 25v capacitors. I may have to go with the 20v audio type. Hopefully that will still work out ok for building battery packs.

Looking at using a pelican case.

Joost

Joost,

Your more than welcome to buy the extra parts I have if you would like them. I'll get them out and take a picture sometime this weekend.

I know on the caps there was only one place in the USA to get them from a guy on eBay. I'll try and find his info. Slipping all this in a pelican case sounds awesome except for the cost of one. I had a budget only because I do things like that.

Have fun with the build.

Tom

Tom,
Thanks, much appreciated.

I'm also trying to do this on a shoe string budget. The pelican case I already have lying around. Fritz told me that the capacitors he recommends are now hard to find.

He offered to sell me one of his completed machines, but $2k is way to much for me. I plan on doing the circuit boards first....then in the unlikely event that I'm successful, I'll get the pricey parts (transformer/capacitors).

The pictures of your battery packs look nice and clean, I'm inspired!

subscribed

Need to get some more batteries to weld. This thing just sits on the shelf. The pack I made is holding up well. I did have a cell or two go bad and took out the whole 15p in that row. Hard to tell what went wrong since the whole row was dead by the time I noticed. This was over the time period of about a week with the battery just sitting from a storage charge.
Dicecting a pack sucks but it was simple enough. Next pack I'd like to make from 25R cells or better for more capacity with less weight/cells. This one will push over 200 amps continuously but I really have never gone over 75 amps with the MXUS 6T. Maybe I will with a QS 205?

Tom

qs205 likely will

samsung 30Q is the best at the mo in my opinion. can be had for around 3.6usd/cell plus shipping from evva.
i have recently finished my 22s12p pack, have pulled 13+kw peak to date(new personal record 8) )

iv dicected a pack or 2 to get dud out aswell. its a mystery why some cells die.
so far for me it was only 1 or 2 cells out of 200+ in a pack. not having to solder makes it less painful.
i had 1 30Q out of 264 that was dodgy on arrival
and 1 or 2(?) lg mg1 from tumich out of 220.

im curious as to what your welder can do, ie, how thick material in what pulse length?
could it do 0.16 copper for example?
can it do 0.3 nickel cleanly without excess heat?
to do copper would need hi power, short pulse and tungsten tip electrodes to create the resistence/heat at the tip to make the weld.
easy to diy, use peice of tungsten/zirconium tig welding electrode for aluminium welding, press fitted into copper shank.

edit- i just read back there, thats a bargain pack you got there!
i hope the cells are still in good enough condition to have good lifespan...

As far as what it will do I still don't exactly know. It's actually more powerful than 90% of the machines on the market at 10,000 amps but I haven't really tried to stretch its legs yet.

I guess I should get some different metals and tips then give it a try. I have at least 50 bad cells to experiment with.

Tom

best spot welder