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Kweld spot welder

probably 9001 soon :rofl:


I was the 9010th!

$243 well spent.

9009 would have been cool too, where ya at?


I ma try to convince myself to go for the Malectric spot welder but the difference in price seems not worth it the assle. This Kweld looks so good.


Yeah I’m dreaming of welding copper :star_struck:


It’s not. Battery hookup is legit


Kweld is rated up to 2000A then it should self protect
Recommended 1500A supply
Recommended min 1200A supply
Absolute min 800A supply

I would try 3s2p possibly 3s3p I found 1 3s1p 6000ma Turnagy graphite gave me 1200A

3s2p(paralleling a2nd battery) gave me 1800a (added 50%)

I never tried a 3rd as I dident want to exceed the maximum 2000a. Just saying 3 might exceed the units limit of 2000a.

The battery ideal internal resistance and voltage was talked about above


Thanks so much for the help I’m trying my best to understand it. I’ll definitely give these cells a shot.

Does anyone know if I should expect import duties?
To the US of A.

So 3s battry = 11.1v - 6.3v (kweld needs at 1500a)= 4.8v

So as stated above you 4.8v over voltage will alow 4.8*0.67=3.216Mohm reactance inside the battry /3= 1.072Mohm per S to stay in the optimum range of the Kweld

In the video each cell had a internal resistance of 6-44Mohm well above the recommended 1.072Mohm per a cell in a 3s configuration

2 options to rectify this higher voltage or lower internal resistance

Say you used a 3s6p each cell is 6Mohm resistance (best battry internal resistance I saw in the video if I used the 44Mohm it will be way worse)

1s 6p (1/6Mohm battry resitance)*6Series=1Mohm
1/1=1Mohm battry resistance in the parallel group.

3s6p 1(parallel Group battry Mohm resistance)*3(number of series)=3

So a 3s6p should work if you got only the most healthiest 6milly ohm cells and no bad ones. To put this in to prespective a 30q has a 20mohm internal resistance so each cell is aprox 3*30q in capacity and discharge.

Unless I’m screwing some thing up the 1000a burst rating is well over estimated and is closer to 250a burst rating

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A customer has tried these without any luck, less than 1000 when paralleling 3 of them. If a seller has to shout out his advertistment in capital letters like that one, then this is already enough for me to skip it entirely.

The order numbers don’t count like this. I’m using Wordpress/Woocommerce, and it seems that they even increment when someone creates a shopping basked which he then discards. Real numbers are approaching 2000.

Can’t tell with regards to duties, but you’ll certainly have to pay VAT as you aren’t buying from one of your country fellows, and effectively make a net purchase from me.

was just rereading this and noticed a mistake. Correct wording would be “for every volt above 6.3V that the battery has, it needs to have >>>>0.67<<<< milliOhm of internal resistance”


That would explain my confusion of 1.5v been 1ohm and 1 battry ohm was as much as 1v befor not making sense in you post above I will correct My post above in case any one reads it later and uses it to calculate

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Just out of interest I wondered what size pack you would need to run the welder of 30Q Maths below (let me know if I made a mistake so were typed it on my phone)

Working on Optimal Kweld power requirement 6.3v-30V at 1500a

For every V over 6.3 we can have 0.67mohm Battry internal resistance.

Or for every 1ohm battery internal resitance we need another 1.5V

30Q has a
internal resistance of 20mohm
Average voltage 3.7V

So working on a 3s20p

No. of Series * Average Voltage

Battry Pack Avrage Voltage - Kweld Min Required Voltage
11.1-6.3=4.8 exsees voltage

Exsees Voltage * Allowed Battery Internal Resistance = Maximum Battery resistance

Maximum Battery resistance/Series count

(1/cell internal resistance)*P Group=
1/Answer=Battery P Group internal resistance

So a Q30 3S20P (60 cells) pack is a optimal solution

What if we go fo a high voltage option up to 30V the max voltage of the Kweld

No. of Series * Average Voltage

Battry Pack Avrage Voltage - Kweld Min Required Voltage
29.6-6.3=23.3 exsees voltage

Exsees Voltage * Allowed Battery Internal Resistance = Maximum Battery resistance

Maximum Battery resistance/Series count
15.611/8=1.951 battery P Group Internal Resitance

(1/cell internal resistance)P Group=
1/Answer=Battery P Group internal resistance

So in theory a Q30 8S11P (88cells) the smallest P count pack you could use with out exceeding the Max voltage of the Unit staying at the optimal 1500A


Plus it uses much better mosfets and only 20% of their capacity

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I think that @thisguyhere tried to make a 25r spot welding battery 3s20p and it just couldnt give the current fast enough


yeh absolutely. I am looking for a car battery seems the lipo overheat easily. What would you reccomend to look for? I will just buy it locally.
I know the caps will work better but tjey are out of stock.

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I bought a 45 ah650CCA Yasua battery if I remember right and it couldnt give enough current, maybe it was because of my cables but Im not sure

I would reccomend you to get a 4Ah red graphene for 30-40$ and weld really slowly untill kcaps are in stock


Well I do not need to weld right now. I will then wait and think about it. I really thought the car battery works out better :sweat_smile:

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If you are going big amps I recommend using as150 to connect everything, I killed some nanotech lipos with a big pull using xt90 plugs in series/parallel.

Ordered some grahenes to replace


that I bought it already :blush:

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I would say green is better than red and higher capacity

I guess @Acido wanted to give an alternative to save some money to invest in the Kcaps later on. Just my guess.

Green is better for sure but 2p costs like the Kcaps

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