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Boss level custom spot welder


A single pack will not be noticeable - long term could be dangerous however and right now it feels like a false advertisement. Be careful!


I will be. Safety is important to me


The welder has been widely used for years and this is already harassment and defamation.


please have a look into this - I am just concerned and would like confirmation on the claims that this welder is any safer than the other versions out there. Using it with Lipos is potentially very dangerous and people should be aware.
My posts got flagged even though I am just stating legitimate concerns.
I am open to be proven wrong with some actual measurements.


Please @moderators pay attention to this guy. Has been trying to bomb this thread since his first post with inflamatory comments. Claiming that it is dangerous because it uses lipo is plain absurd. Lipo is always dangerous.
This device has ben widely used in Korea for the last two years. Every lipo user knows that the bricks start bulging when something is wrong. And that didn’t happen. His defamatory attitude makes me think he is related to another brand and wants to ruin sales on purpose.
This is not a sales thread as I stated. Is a thread to talk about this welder.


Lipos are not always dangerous. They are dangerous in some situations for example when shorting them.
Probably this kind of pulsed short does not cause damage to the battery but we need more time to confirm that.


I disagree. Lipo is always lipo. Is the most dangerous chemistry available for batteries. Overcharge, pierce, hits. …can make it burn.
Must be taken with respect and care. I have been a lipo user for many years and I never ever lost respect and care for it.
There’s Nothing to worry about if you treat it properly. That’s all.


I don’t have enough knowledge to give an answer but the question on how the spot welder is working seems legitimate.
Is the welder shorting the lipo or is there a buffer between the Lipo and the weld (capacitors for example) ?
Maybe shorting the Lipo directlry is fine but the question is still valid.

In the first post you say that :
YES! lipo hates being shorted but he managed to make the short beyond the lipo so no damage at all.
Can you elaborate a bit more for us to understand how it works ?

I also already have a lipo from KaptaynBalu but I am curious how this one work.


That says capacitors to me…


Sorry pal. I can’t give you an accurate answer. Aulakiria said at the youtube comments something about ne555 timer circuit. I don’t really know how it works. What I know for sure after so many years using huge lipo packs for my ebikes is how to detect a damaged lipo. I never hesitated to dispose of a bulged brick. None of my packs (by the way have been many) have been Allowed to have a suspicious brick.
The lipos I use with this machine are in perfect shape so far.
I guess my opinion is meaningless but this machine has been sold in Korea for years for a reason.
I apologize if I get conspiracy theorist here but all these inflamatory comments do not look legit to me.
Using cheap bms with lipo is dangerous. I never advice to do it. A lot of people here do it though. I do not see that dude caring for them but he is super duper worried for the safety of the boss users all of a sudden.
Microwave transformers M.O.T. Can be lethal, yes I didn’t say dangerous I said lethal if treated carelessly.


Car batteries can be very dangerous too:


Let’s not play the dumbass game here. Spot welding has some risks.
Batteries have some risks.
Lipo is dangerous if not treated properly.
No one should buy a device like this if is an irresponsible person, reckless, procrastinator or is just afraid of lipo.
I have no personal interest on any of you buying this thing and the creator is not making a noticeable profit out of this. As I already stated this is his hobby no more no Less.
Do not buy it if you are scared. Period.


Hello, I am the creator of this device.
I do not speak english well.
so I do not read all the posts of this forum.

Seems some of you are worried about safety.
I used the lipo as the power source of the welder.
Of course, you can also use deep cycle lead batteries with sufficient capacity.
Lead batteries are also used in Korea.

Lipo fires are well known all over the world.
Lipo must be treated carefully.

This device is a timer that controls the flow of electricity.
Electricity should only flow for as short a time as possible.

when the spot welding is completed (nugget is formed), the battery will be in a shorted state.
Continued electricity will damage the battery.
So I limited the time to 16ms (16/1000 sec).

Do not lengthen the time enough for the nickel to discolor.
Your battery is slightly damaged.
Likewise, lead batteries are also damaged. It’s just invisible.

Lead batteries are not 100% safe.
Will there be a fire if the lead battery is short-circuited?

This is just my hobby.
I hope you use it safely.
If you are afraid of Lipo, you can use lead batteries.

If you have difficulty managing the lithium-polimer battery, the 18650 lithium-ion battery management will be more difficult.
The balance of the battery cells of the RC, the electric board and the like should be diligent.
Rather than purchasing a spot welder, please use a regularly sold product.

Thank you. ^^


The machine in video does not seem to have a time controller.
AC controls are harder than DC controls.

Spot welders, such as the Sunkko 709 in China, fail if the AC frequency is different.
Korea is a neighboring country of China.
So Chinese products come in easily.

I also made an AC spot welding controller.
See http://blog.naver.com/aulakiria/221004397424.
Recognize the AC frequency and find the right timing.

Like the DC spot, it has an automatic spot weld function.
It sold more than 200ea in Korea. ^^;


Thank you for the explanation.
The device seems to be very polished.
Please understand that my comments are in no way meant to discredit your product - it seems to be working very well and people are happy with it.
You obviously did a very good job designing and manufacturing it.
My point of concern was only regarding the initial post in this thread that said that this particular spot welder is safer than others when using Lipo batteries.
This is not true.
It is based on the same time controlled mosfet switching principle than the others we know of.
This claim is therefor wrong.

The good thing about this is though, that apparently using Lipos in spot welding seems to be working well with no damage to the batteries so far.
That would allow others to confidently use Lipos with their alternative spot welders as well.

I am in no way affiliated with any spot welder (not commercial nor open source variants) and hope that others do not see me as being defamatory.
I was just trying to understand the technology behind and asked for proof of the claims.


"It’s powered by a 3s lipo, YES! lipo hates being shorted but he managed to limit the short to 16ms so no damage at all. The size is minimal 4x3x8 cm."
Description updated.
Half of my family lives in Barcelona and I am not in the mood to waste another minute on this matter. Let’s call it a day.


^^ I understand your worries.
In my experience, MOSFETs are more vulnerable than batteries.
I’ve tested up to a 0.2T nickel strip.
More greed can damage the MOSFET. ^^;


This is a stupid question and will probably be fruitless when it comes to having a positive answer…but I was wondering if it was even possible to power the spot welder part of this with a 3sXp pack built with A123 26650 LiFePo4 cells. And yes I know it’s a much more costlier alternative…but for some of us who are iffy about keeping lipos…is it even REMOTELY possible?


Why shouldn’t it work? This spot welder just shorts a battery - no rocket science. You can use whatever battery you want. Apparently Lipos don’t mind so lifepo should be fine. You could also use a 12V car battery


The welder requires a lot of amps. The performance depends on it. It can be powered without lipo in case your battery provides a decent ammount of amps. “Any” car battery will not work properly. The creator said this at his blog:
“About using car battery :
I have never done spot welding using a car battery.
I was told that a person used the 100A deep cycle.
Batteries vary by manufacturer.
In spot welding, the peak discharge amount is more important than the ordinary discharge amount.
The battery only indicates the normal discharge amount.
You can use two or more batteries in parallel.”

How many amps do your battery deliver?
Someone asked time ago If 3 18650 in series would work and the answer was no.
If your pack has a high C it should work.


If you had 18650s such as the Sony Konion US18650VTC5A which puts out 35A and made a 3s10p pack with them it would work.
I weld with a 200A ATV battery so 350A will be enough.


Yes. I guess 350a+ should be enough.