JP spot welder

[bigbore]

I've been using LiPos with success with this spot welder.
First I built this:
https://endless-sphere.com/forums/viewt ... 4#p1169774

Then I improved to this:
https://endless-sphere.com/forums/viewt ... 0#p1172206

[riba2233]

For lithium cells max is 3s but 2s should be enough if cells are strong.

Unfortunately I can't give any hard recommendations for various lithuim batteries, I don't have any personal experience. But I can say that you are probably better of just buying new or used car battery, unless you already have some lipo you don't need. You'll be safer, it will probably be cheaper than buying new lipo, and if you spend time assembling many 18650 or other cells that time will cost you more than the value of car battery.

But that's only my opinion, I could be wrong, and maybe someone else has first hand experience.

[wini]

Yes it would be easier, i'll will proably start my first weld with my van lead battery

But as i will create a 2nd stationary battery, i would like to use it with the welder.

Am i right when i think that if i can achieve the same internal resistance with a 3s li-ion battery than a 90Ah 800cca lead battery, the welder will work the same?

[riba2233]

Yes, if you match that it would be fine.

Maybe somene has one of those miliohm-meters and car battery, and can find out it's IR? Thanks!

IR data for 18650 cells known, so there shouldn't be any problems.

[wini]

I am thinking of adding 100w car bulb light in // let say 20 of them and mesure the volt sag of my lead battery.

And then doing the same with the 18650 in 3s configuration and ad cells in // as long as i reach the same resistance.

Is this method seems correct to you guys?

[riba2233]

Sure, you can try. Although bulbs can be little tricky for short term load, since they have substantial inrush, so measuring IR which should be as short as possible to aviod dropping voltage would be better using resistors.

[Offroader]

Riba, with those Electrodes, are they hollow through the whole electrode so I can fit a wire in it?

Would it be possible to cut the crimped top part so I can fit a new wire in and recrimp it?

[riba2233]

No, they are hollow only on ends, but you can drill an new hole, just make sure it's in center.

[JumperJackFlash]

Glad to see you're back! Hope you're feeling better.

I pm'd you for a welder.

[riba2233]

Yes I'm feeling well now and I got help from my brother, thank you for asking!

PM replied.

[macribs]

Welcome back Riba. Happy to see you well and about.

[riba2233]

Thanks

[brumbrum]

All set up with my 100ah battery that will eventually takes its place in my camper van once welding jobs have been completed. Lots of initial testing going on at present with nickel/copper and a bunch of old laptop cells that have sat in my garage for a few years.

[riba2233]

Nice, tell us the results once you finish your testing!

[Cowardlyduck]

I received my JP spot welder yesterday. Thanks Jakov!

I have a 12V wall wart ready to go, however I noticed the PCB has 12V 500ma printed on it. My wall wart is only 200ma. Will that matter?
It seems to power on ok, but I haven't tested it yet.

Cheers

[tomjasz]

Welcome back!

Is the how to use/weld manual still available?

can't find and haven't welded since spring. Now that it's bitter cold I'll build again!

[brumbrum]

Welcome back!

Is the how to use/weld manual still available?

can't find and haven't welded since spring. Now that it's bitter cold I'll build again!

Sounds interesting, where do i get one?

[riba2233]

I received my JP spot welder yesterday. Thanks Jakov!

I have a 12V wall wart ready to go, however I noticed the PCB has 12V 500ma printed on it. My wall wart is only 200ma. Will that matter?
It seems to power on ok, but I haven't tested it yet.

Cheers

Hi, I think it should be fine.

Welcome back!

Is the how to use/weld manual still available?

can't find and haven't welded since spring. Now that it's bitter cold I'll build again!

Well, the "manual" is youtube video. I'll make the paper version when I finish up some other projects.

[fechter]

Since my old lead-acid batteries were pretty much shot and I had to crank the weld time up almost to the max, I decided to find something better.

I tried a 6s, 10Ahr LTO battery, running around 15v. This worked reasonably well, but still required a pretty high weld time. A larger Ahr one might work quite well, and these are very safe and last nearly forever.

Then I looked at some Lipo packs. People had reported good results with Turnigy 5.0 Ahr high rate packs. I noticed the 5.0 uses 10ga wires, but there was a smaller 2.2Ahr that also used 10ga wires. I decided to get two 2.2 so I could put them in parallel. These were slightly more than a single 5.0, but I was in the experimenting mood. I got the 3s "Graphene" 65/130C rated ones.

Img_0569.jpg (77.78 KiB) Viewed 2780 times

Img_0571.jpg (67.4 KiB) Viewed 2780 times

Tiny little buggers. So they shouldn't make too big of a fire if they go off. I cut off the RC plugs they came with and put the wires from both into a single large crimp ring terminal, then used bolts to connect them.

I initially tried a low setting, about 1/4 power. Pow!, got a nice big spark and blew a hole through the nickel. Probe contact was poor on one side (my fault). I dialed it down to about 1/8, which I guess is around 5ms and got nice welds. I was very impressed. These things can belt out some serious amps. I think it might work well with a single one.

I need to work on my electrode setup more, and I also plan to use a wall wart to keep the cells right at some constant voltage (I'm thinking 12.2V).
The whole works could fit into a fairly small case, which would be next.

[brumbrum]

Thanks for sharing your setup.
It looks like my campervan battery has died in the recent cold weather so my new 100ah pb will have to tkae its place. I think i will go down the lipo route too.

Any ideas how long a 5ah 3s lipo will last during welding?

[jimwebo]

I continue with my capacitors and luxury.
Although I changed from spot welder

IMG-20171118-WA0008.jpg (168.26 KiB) Viewed 2682 times

[fechter]

Any ideas how long a 5ah 3s lipo will last during welding?

Not really, but from what others have reported, quite a few welds. I plan to keep a steady 12v supply on them to keep them up to 4.1v/cell or so.

[riba2233]

Thanks for this fechter, now others have some good recommendations on what lipo to use!

@jimwebo - that looks sick, total overkill

[riba2233]

We are taking a restock/holiday break until 15 jan 2018! Happy New Year to everybody!

[Cowardlyduck]

Just had a scary moment building my monster 2.5KW pack for my Stealth Fighter.
I had turned the pot up pretty high and getting some decent strong welds, probably a bit on the strong side, but not too extreme. I was on my first layer of nickel which is possibly where I went wrong turning it up this high.
Anyway, I welded the negative terminal of an 18650 and it instantly sizzled (but only for a fraction of a second) with some clear liquid coming out of where I had just welded. At first I thought it could just be some left over alcohol from the cleaning I do with isopropyl alcohol wipes just prior to welding, but after wiping it away, more reappeared and I could see it very slowly seeping out from underneath the point I had just welded!
After wiping it away a few more times, and smelling it, I realised it was the batteries electrolyte leaking out
The cell wasn't getting hot and it was one row in from the edge, so I carefully, but quickly cut the already connected nickel and pulled apart just enough cells to pull that one out. Replaced it now and re-welded in some more nickel and everything seems ok.

Anyway, I hope that serves as a warning to all, not to crank up the power too high with your spot welder just cause you can. I think especially when welding the first nickel layer that directly contacts the cell and especially on the negative side, you want to only give it the power it needs...nothing more.

Cheers