Which Budget Spot Welder Should I Buy for a Few Battery Packs?

[Etienne]

Because it's a complete product and you don't need to buy batteries separately. Also it has a lot of really good reviews and if was something wrong, there is a great support behind. I also write to them before I buy, to se how fast they respond.

ok good to know what motivated your choice

 

[Diggs]

I didn't catch up on this conversation until now. There are other threads here discussing the same question -

What is a good budget spot welder?

I want to rebuild some 18650 tool battery packs. I tried one of the Amazon welders and it is a no go. Seems to be great for .15mm tabs, but the tabs on my battery pack are about .3mm and the welder will not touch them. Since I am learning, I was guessing the welder was junk. Now I think it is...

endless-sphere.com

 

[Lola]

Right, I bought a red welder in late 2021 and the simple capacitor mod worked. I hadn't seen this video and he explains it well, I remember that the Wise Maple version was said not to need any mods.

With the chinese market ,successful product gets copied, sometimes poorly. If they don't want to redesign, maybe they just use the name. That's why most of the red welders had flaws. It couldn't have been the original designer putting out variations that didn't work in the field. Lots of fakes out there,

Your option #6 is a different welder than the one that worked in 2021. Might work. Who knows. It's cheap enough to roll the dice, but you still need a battery, I suggest you listen to BlueSwordM's experience.



.

That makes sense. With so many clones and revisions, it’s hard to know which version you’re actually getting until you try it.

 

[docw009]

A BMS failed and drained one of my packs to 1.6V.cell. When I pulled it apart, I was impressed by the weld strength from my red welder. All the nickel strips (.15mm) ripped. None popped off. I'll have to re-cell it. Have several more batteries to re-cell too. including some tool packs.

I ordered an Awithz UF20B capacitor welder for $142 shipped from China.

 

[Zambam]

A BMS failed and drained one of my packs to 1.6V.cell. When I pulled it apart, I was impressed by the weld strength from my red welder. All the nickel strips (.15mm) ripped. None popped off. I'll have to re-cell it. Have several more batteries to re-cell too. including some tool packs.

I ordered an Awithz UF20B capacitor welder for $142 shipped from China.

Could have saved yourself $2 buy local from a trusted seller.

AWithZ UF20B- 10.5kW Spot Welder

Shop AWithZ UF20B- 10.5kW Spot Welder at DIY500AMP. Battery building supplies for spot welding, connectors, insulation, busbars, cells, and DIY power.

diy500amp.com

 

[docw009]

Only $14 USPS shipping plus sales tax ..maybe $165 shipped for the one from Florida? Cheaper than amazon anyway, That's $180 after sales taxes. .

The red welder would have worked, but the RC Lipo to power it is 4 years old. A new one is $60 so I decided to try the supercaps.

Could have saved yourself $2 buy local from a trusted seller.

 

[Hummina Shadeeba]

This is my favorite.

I got it from batteryhookup and was like 30$ cheaper but gone there now.

I just found this on AliExpress: | 14kw 2400A high current double super capacitor spot welding machine | 6V intelligent digital display lithium battery welding

https://a.aliexpress.com/_mtqhGA3

Can do .2mm copper under .1stainless steel easily using less than half full power. It won’t do .3mm, at least not with my attempts using .1 and .2mm ss on top

(Won’t do plain. .2mm copper and photos are misleading…if they ever show.

 

[sternwake]

The red welder would have worked, but the RC Lipo to power it is 4 years old. A new one is $60 so I decided to try the supercaps.

Nelvick @ZEUS-FL Does a lot of cell testing, and sends the latest and greatest cell samples to Mooch( and sometimes Pajda too) on his own dime which benefits us all, So spending a wee bit more for quick shipping from his store is a good thing which helps us all in the long run.


I had one of the red welder versions, and its interface among the cheap PCB welders where you supply your own weld battery, was the best, but the purple PCB welder could weld the same copper sandwich with less power/Gear from the same weld battery.

When My Cheap Zee 3s 5.2Ah weld battery started stinking like electrolyte at the end of my third battery build with it, well, its performance had already tanked and I kept having to use higher and higher gear levels and keep it above 11.9 volts and keep the welder relatively cool, and the battery from getting too hot.

I wanted to be able to weld thicker than 0.1mm copper, and Didn't want to buy another Lipo battery.

I got the AwithZ P20b, and have successfully welded 0.3mm copper under 0.2mm Nickel plated steel, when both these busbars had the slit to weld across, AND using the Special welding flux at near max available power.

I have a 1 meter roll of 100 Mm wide 0.25mm copper. That under 0.1mm stainless steel using flux at gear 729 with my P20B yields incredibly strong and low resistance welds. But without the Flux gear 940 is not enough to get two strong equal strength equal size welds.

I dont have any experience with battery based welders outside the cheapo 25$ red or Purple PCb welders, but the Super capacitor based spot welders are a game changer.

I have seen battery build YT videos by TYEboi, using my same welder and 0.2mm copper under stainless and he was able to use gear 450 where I needed gear 550, and this can be because he uses a different electrode tip profile and uses more downward pressure, or it could be slight variances in the actual output power of the specific welder with same model name and number, or a combination of factors.

He does have a Video with a general guide for settings required for the 14.6kw AwithZ P20B, and you can extrapolate those to your 10.2kw AF20B.

Do note your uf20B will have only 99 gears not 999, but just knock off that last number and do some math to translate his 999 gears at 14.6kwmax to your 99 and 10.2kw max .

If you don't have a bunch of extra test cells to learn what power levels you need to use for the material you plan to weld, a trapezoidal razor blade can get you to within 15-20%. The razor blade also allows you to see the underside. When not enough power is used only one of the welds will be visible on the bottom of the razor. Keep bumping up the power until they get closer in size, and the strength of those welds when you rip the welded strip off using the tips of needle nose plyers will be far more symmetrical. When too little power is used one of the welds of a pair will look perfect, tearing the material and leaving it on the cell, but the other will pop off with little to no force. This One strong weld, one weak weld when too little power was used was not nearly as obvious on battery based spot welders in my experience. The battery based welders the weak welds when too little power was used, both of the pair of welds would be nearly equally weak.

The underpowered PCB welders one had to make sure to NOT press down too hard with the electrodes, but this is not required with the more powerful supercapacitor based spot welders.
So there is a learning curve, and I'd urge a good amount of practice on the razor blade and then old discharged cells to develop the technique with repeatability, before committing to using fresh cells.

You will NOT find any instructions as to what power level to start with any given material thickness, with the AwithZ welders.

The specific cell one is welding to, can also change the settings required, as the nickel plating can be a different thickness and surface texture which change resistance at the weld points and thus the welder settings.

If one is welding over and over to the same cell and dremeling off the Nubs and the cell's nickel plating, the power level required to achieve strong welds will not be exactly representative of the power required to weld the same strip thickness to a Virgin cell.

Some cells also require more power on anode than they do cathode, so Buy an extra cell.

 

[docw009]

I did OK figuring out the red welders, although I blew up my purple one on the first weld. Have done thousands of welds with them. I am not planning to do nickel copper. The Awithz shipped today, SHould see it in two weeks.

 

[sternwake]

I did OK figuring out the red welders, although I blew up my purple one on the first weld. Have done thousands of welds with them. I am not planning to do nickel copper. The Awithz shipped today, SHould see it in two weeks.

I blew up my red welder with flames shooting out one of the mosfets but My purple was/ is still working. I have cannibalized some of its 10 and 8 awg beefed up cabling.

I will be using as thick of copper conductors as I can regardless if I can get away with much thinner pure nickel for any specific application. I refuse to waste battery capacity heating conductors when it is easily avoidable.