What is a good budget spot welder?

[B. Mann2]

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 just too weak for what I want. I would like to stay in the budget area and not a kit. Plug and play would be great. 110 volt good. Rechargeable ok.

Amazon one if anyone wants to check it out. https://www.amazon.com/dp/B0CB3KWD24 Specs say good for .3 metal, but no way.

I can't seem to find any power tool battery rebuilder forums. Here seems to be one of the better battery forums.

I hate to solder them. Looking to step up to a decent spot welder. A lot of welders posted seem to get phased out quick.

 

[A-DamW]

Kweld seems to be highly rated: (no personal experience)
kWeld – Next level battery spot welder

Malectrics is what I bought (full disclosure, I have not actually used it yet)
DIY Arduino Battery Spot Welder Prebuilt Kit V4 - Malectrics

Straight DIY: (I want to try this)
1989 Kawasaki EX500 (Ninja) - EV conversion, finished but still refining

 

[gromike]

I burnt up a couple of cheap spot welders then bought a kweld. I could of bought ten cheapos for the price of a kweld and could do probably just as many spot welds, but it's the kweld's setable consistency in the power it delivers to the welds where I think it shines.
I'm on my third battery build so I don't have all that much experience, but if you don't have a reliable and controllable welder you are wasting your time and money.

 

[Diggs]

I would like to stay in the budget area

I just finished a pack (280 welds at one sitting) with one of these (same as this). They have been improved several times over the years and worked wonderfully for me using an AGM car batteryas a power source. There are quite a few YouTube videos for mods to improve it but many of those improvements have already been incorporated into the newer versions by the maker. Some YouTube videos says its sister welder (Wise Maple) has had all the issues resolved and is the one to choose. Which ever it is there must be a very strong and stable power source or there will be problems with either the unit or the welds. (I'm sorry but a Kweld just isn't worth the money to me....)

 

[4πr^2]

I burnt up a couple of cheap spot welders then bought a kweld. I could of bought ten cheapos for the price of a kweld and could do probably just as many spot welds, but it's the kweld's setable consistency in the power it delivers to the welds where I think it shines.
I'm on my third battery build so I don't have all that much experience, but if you don't have a reliable and controllable welder you are wasting your time and money.

Burning up the cheap spot welders (and even some 'good' spot welders) is often a result of not providing high enough input current. You need large gauge wires, short wire runs, and ideally a high current LiPo battery or very large lead acid starting battery on the input side.

If the welder can't get the high input current it needs, when it fires the welding shot, the voltage and current on the input sag very low and the welder can't "snap" the mosfets to the off state in a quick and efficient manner. Instead, they turn off slowly which leads to a lot of heat and often times, burning up.

I had this happen to one cheap welder due to a slightly loose connection at the battery. Unfortunately, it was cheaper to buy a whole new spot welder than to replace the block of mosfets alone!

Either way, keep your spot welder fed with lots of low resistance / high current input and it will be happy!

 

[wiredsim]

Starting off with the recommendation for a type (not necessarily the seller, I didn't buy from this one):

6.5V-16V 99 Gears Adjustable Spot Welder

This has been the best I've tested so far. I am using with a 16AH SPIM08HP 3S pack. With that pack I have successfully welded .2 quality nickel strips and offset .15 strips for 21700 cells. It can get hot after a large number of welds. I plan to upgrade the weld pens / leads and add a better heatsink / fan. My voltage sag on that pack is low enough that I haven't done it, but you can easily provide controller power to it via a separate power supply to ensure proper MOSFET operation in the event of excessive voltage sag. The UI is a bit odd, but it will provide 3 separate pulses and you can adjust the timing between them and the power level of each pulse.

This particular type has a small OLED display, not the segmented LED display. Note that the unit I purchased is one of the newer board revisions which has 6 MOSFETs on each side of the PCB. The older style had all 12 on the front side of the PCB, which would make cooling easier for sure. There is also another style that looks similar, but it has a much larger color screen and a dial interface. I'm interested in testing one of those, but I really don't have any reason to spend the money on it right now. Plus, the only listings I've seen only have 5 MOSFETs and likely can't handle as much current. Funny thing is the pads are on the back of the board- it should be possible to add them if you can get the right ones.

Why am I qualified to recommend this? Well, I'm not, but I have tried lots of different spot welders.

I went through a couple of different cheap spot welders, first an AC triac based unit, because of my own stupidity it died. I then tried one like A-DamW linked to- it still powers on, but some of the FETs have blown. I also purchased a MiniSpotA from Lee a few years ago, it works but not as strong as I'd like, it gets hot quick and my Lipo battey started to swell. Plus, the form factor isn't great to be honest, pretty awkward to use.

I then bought a SeeSii 11000mAh from Amazon, it seemed great with my initial testing. I let it sit in the box for a few months and it self-discharged. Since then, after fully charging, it will power on, but has no-where near the spot-welding power I need, it will barely weld .10 nickel.

Yes, I've spent a fair amount over several years this way, but at the start I never could have justifed the expense of something like KWeld and I've learned a lot along the way. I understand kWeld is the "spend good money on good product" solution. But claiming that is the one and only valid choice is anti-thetical to this very forum. Imagine if anytime someone wanted to build their own e-bike the answer was always "go to the Bike shop and buy a Trek or Juiced". No shade against kWeld, at some point if I had more serious spot-welding needs, I might purchase one, but seems they've been resting on their (expensive) laurels for quite some time now.

 

[wiredsim]

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 just too weak for what I want. I would like to stay in the budget area and not a kit. Plug and play would be great. 110 volt good. Rechargeable ok.

Amazon one if anyone wants to check it out. https://www.amazon.com/dp/B0CB3KWD24 Specs say good for .3 metal, but no way.

I can't seem to find any power tool battery rebuilder forums. Here seems to be one of the better battery forums.

I hate to solder them. Looking to step up to a decent spot welder. A lot of welders posted seem to get phased out quick.

Ahh I missed the fact that you are looking for something that can handle .3 nickel or nickel/steel. I suspect you'll have to move up to something like the kWeld or one of the more "professional" Capacitor based spot-welders. Such as this one from Seesii:

Amazon.com

Or this:

https://a.co/d/2nNguRC

Another interesting product that out there are the relay based spot welders, they claim 1500-2000amps and supposedly good for .3 nickel:

https://www.aliexpress.us/item/3256806926481471.html

I'm skeptical, but intrigued.

 

[B. Mann2]

Ahh I missed the fact that you are looking for something that can handle .3 nickel or nickel/steel. I suspect you'll have to move up to something like the kWeld or one of the more "professional" Capacitor based spot-welders. Such as this one from Seesii:

Amazon.com

That one looks pretty nice as long as I am sure it can weld the heavy tab. A little pricey but do able. The one I posted above said it was rated 8000 but would not work at all. https://www.amazon.com/Seesii-Adjustable-Capacitor-Portable-0-1-0-3mm/dp/B0CY4KVTF1/

I am not sure on the ratings of this one. Then this one "looks" stronger, but lists as only .2mm If I read it correctly. It is hard to get an accurate description from the page, since I question the accuracy's.

https://www.amazon.com/U-S-Solid-USS-BSW04-Capacitor-Equipment/dp/B0D1B5CLPD/

 

[B. Mann2]

Doing more looking and the Kweld looks nice. If you buy from UK? it looks like about $180 US + shipping. But the US seller is about $350. Ouch. You still have to get a power supply.

 

[docw009]

For your purposes, you say you want something that can do .3mm stock. You might measure those nickel strips anyway. If you can get the Kweld for $180 and maybe 50 dollars shipping, then good. I believe people run them on the larger 12 V car batteries. That's $140.

 

[wiredsim]

For your purposes, you say you want something that can do .3mm stock. You might measure those nickel strips anyway. If you can get the Kweld for $180 and maybe 50 dollars shipping, then good. I believe people run them on the larger 12 V car batteries. That's $140.

Not in the US you can't. The kWeld full kit from Grid Rewired is $246 plus shipping plus the ultracap module is another $195, kSupply kit is $125. Oh, if you want a housing for it that is another $26 and $29. So, $621 plus shipping and tax.

That "AWithZ" 14-kilowatt unit that I linked above is $289 and comparable to kWeld power output and the 29-Kilowatt unit (the most powerful one) is $569 shipped on Amazon and claims it can do .6mm nickel, 1mm stainless and .3mm copper. The reviews on Amazon say the 14Kw unit will handle .25 cordless drill tabs and .3mm strips just fine.

I don't begrudge someone their intellectual property. But it gets my goat when something is clearly not a true income and career for someone and what was once a great idea just kind of languishes. I think what is frustrating is when you see example after example of how making something open source can pay so many dividends down the road, innovation after innovation building on top of the initial efforts. So, either provide the value of true commercial operation and both continue to develop product improvements and offer great support or get out of the way and let the community take it much further than you ever thought possible.

 

[B. Mann2]

That "AWithZ" 14-kilowatt unit that I linked above is $289 and comparable to kWeld power output and the 29-Kilowatt unit (the most powerful one) is $569 shipped on Amazon and claims it can do .6mm nickel, 1mm stainless and .3mm copper. The reviews on Amazon say the 14Kw unit will handle .25 cordless drill tabs and .3mm strips just fine.

Back to these 2 you mentioned. Seesi https://a.co/d/h4v84XM Or the AWithZ https://a.co/d/2nNguRC

It looks like you have done a lot of research. Thanks!!!

The Seesi is about maxxed out to do the job. AWithZ looks more than capable but at $120 more. The Kweld looks even better, but like you said it is getting close to double the cost of the AWithZ by the time you apply the probes.

I only tried one pack so far, So not in a hurry. Kind of boogered it up with the low power welder.

Not a lot of reviews on either, but after a lot of searching, I missed the reviews on the AWithZ until you pointed them out. (very good reviews, but only a few) The tool battery packs have some really thick connecting tabs. Not something that can be replaced easy, because they are integrated with the circuit board.

 

[greenno]

I have made probably 20+ battery’s over the last 5 years or so and I use the K-weld and use a lipo battery pack ( Turnigy N/Tech 3s/5000ahr/ 130c for a reliable power source.
Typically use .2mm pure nickel belt material and only set the dial to 25j and doubling up I raise the setting to 30j.
Never has a weld failed and I occasionally check the battery’s for any defects when my buddy’s have any voltage issues.
95% of the time it’s the older BMS’s I was getting from Vruzend and when I switched to Daly all has been good.

Knowing What I know now I would still go with the K-weld.
Started off with a sundko from amazon total waste of money.
For $300 you can make professional builds as good as the majority of the battery’s out on the market.

I have contacted Ken over in the UK a couple of times on questions or issues and he’s always really helpful.

Just a real world experience from someone who uses one.

 

[bikestickmonkey]

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 just too weak for what I want. I would like to stay in the budget area and not a kit. Plug and play would be great. 110 volt good. Rechargeable ok.

Amazon one if anyone wants to check it out. Amazon.com Specs say good for .3 metal, but no way.

I can't seem to find any power tool battery rebuilder forums. Here seems to be one of the better battery forums.

I hate to solder them. Looking to step up to a decent spot welder. A lot of welders posted seem to get phased out quick.

For rebuilding 18650 tool battery packs, I'd recommend looking into the Mophorn 737G Battery Welding Machine. It’s well-regarded for handling thicker tabs up to 0.15mm with precision, making it a solid choice for more demanding welding tasks [3].

Additionally, you might want to explore upgraded portable spot welders like the one mentioned here; these offer more power and flexibility for heavier welding jobs.

 

[Gruesome]

Ahh I missed the fact that you are looking for something that can handle .3 nickel or nickel/steel. I suspect you'll have to move up to something like the kWeld or one of the more "professional" Capacitor based spot-welders. Such as this one from Seesii:

Amazon.com

Or this:

https://a.co/d/2nNguRC

Another interesting product that out there are the relay based spot welders, they claim 1500-2000amps and supposedly good for .3 nickel:

https://www.aliexpress.us/item/3256806926481471.html

I'm skeptical, but intrigued.

I posted a few inside pics of the first SeeSii you linked to in another thread. Seems to work ok for quadruple layers of 0.1mm strips.

 

[Rapido]

Ahh I missed the fact that you are looking for something that can handle .3 nickel or nickel/steel. I suspect you'll have to move up to something like the kWeld or one of the more "professional" Capacitor based spot-welders. Such as this one from Seesii:

Amazon.com

Or this:

https://a.co/d/2nNguRC

Another interesting product that out there are the relay based spot welders, they claim 1500-2000amps and supposedly good for .3 nickel:

https://www.aliexpress.us/item/3256806926481471.html

I'm skeptical, but intrigued.

I'm looking to purchase the Seesii one, however I'm in the UK. Can anybody speak to whether using a 110-230v step up transformer would work? / detremental to device performance? / Are they available in different input voltage?

 

[Zambam]

I just finished a pack (280 welds at one sitting) with one of these (same as this). They have been improved several times over the years and worked wonderfully for me using an AGM car batteryas a power source. There are quite a few YouTube videos for mods to improve it but many of those improvements have already been incorporated into the newer versions by the maker. Some YouTube videos says its sister welder (Wise Maple) has had all the issues resolved and is the one to choose. Which ever it is there must be a very strong and stable power source or there will be problems with either the unit or the welds. (I'm sorry but a Kweld just isn't worth the money to me....)

View attachment 356833

Are the welds in your pic done with this https://www.amazon.com/ApplianPar-Portable-Machine-Equipment-Battery/dp/B0BKL5TVY2/ref=sr_1_4?crid $30 unit from Amazon? They look good (to my untrained eyes), very consistent from weld to weld. I may buy one to play with. No desire on building a pack yet.

 

[Diggs]

Are the welds in your pic done with this https://www.amazon.com/ApplianPar-Portable-Machine-Equipment-Battery/dp/B0BKL5TVY2/ref=sr_1_4?crid $30 unit from Amazon? They look good (to my untrained eyes), very consistent from weld to weld. I may buy one to play with. No desire on building a pack yet.

Yes! Quite a few videos on YouTube with that welder but most done with old welders from 3-4+ years ago. Much has been improved on the current versions. As I mentioned, after doing my due diligence on what welder I should buy, the version labeled "Wise Maple" appeared best but seems hard to find. I'm very happy with the one I have though. Inexpensive, easy to use, reliable, and repeatable. Eventually I bought an inexpensive foot-switch for it to help on some of the welds that required precision placement.

@add - I did find the Wise Maple welder on Ebay but now I take back what I learned earlier. The version on Ebay is not the improved one and does not have the solid buss bars feeding the mosfets and the positive lead-out. It also doesn't seem to support foot-pedal operations. Hmmm......