kWeld DIY Spot Welder - Custom Battery & Enclosure

What is the verdict 6 months in? Is 9.4V nominal enough for the kWeld? It has about 6.3V static overhead so not a lot of headroom to work with. Surprised the cells have a low enough impedance to get to 1500A. (11.0V - 6.3V) / 1500A = 3mR for the 4P3S battery. (3 / 3S * 4P = 4mR per cell, that' s exactly what the datasheet says!

That enclosure design is so well thought through, nice job. How long did that take you?
Are you doing cad at work as well?

Just saw the battery build and couldn't get over how trick looking that kweld case was and was thrilled to find a video for it too. And overjoyed to find that you also released the files for it. Will have to check if I have enough headway cells to make one. I don't think I have copper laying around so might have to just spring for the case from battery hookup. Probably be best to retire the old poor lipo.

Your Headways only test at 7000mAh? They likely don't have anything near their stated C rating then. 4 in parallel should be enough to compensate for that but any idea what their AC IR is? I have some old cells that didn't see many cycles and their IR (all 8 but I killed one) is 1.9mΩ

This is the cleanest and most indepth video I came across about kweld.

I have a couple of questions.

1. Is it possible to get a good weld 0.2mm copper sheets with this setup? If yes, how many joules should it be set to do that and if it's even capable of doing that.

2. You said it's capable of 2000A but wouldn't a 4p make it only 960A pulse? Or are there capacitors inside to make it go up to 2000a

Thank you for this. I am currently building this exact setup. Areyou running 3s4p or 4s3p? I am going to be incorporating a daly bms on mine.

New subscriber here, I love your design, is there anyway you can print out one for me, I don't have a 3d printer

battery stuff is a pain in the arse lol .thank the lord for what we have now all be not made as good as it could be .headways are a nice cell ill agree with that good jump boxs

Would like to see someone test/use the batteryhook up spot welder they have/had.. If they ever come back in stock.. Looked very interesting when I saw it.

This is a nice enclosure and nice battery tab welder good job I also buy a lot of batteries from Battery Hookup

Thanks so much for this awesome design! I just put one together for myself and want to avoid this issue with the switch creating too much resistance but still want to weigh to be able to turn the spot welder on and off. What did you end up doing for a solution?

Excellent video as always. I wonder if it would have been safer to go with glass or Kevlar/aramid reinforced plastic for the case. I vaguely remember something about battery enclosures in Formula Student having to be made from Kevlar because of Carbon Fiber's conductivity.

all you had to do with your old welder was clean the tips and sharpen the points or just replace the battery not hard very easy to open

The amps listed during the "overcurrent" test was LESS than the next successful test shown on the video... which is odd. Also I looked up the datasheet on those mosfets and with 6 in parallel, a drain to source voltage of 9.6V, and and on time of 32 milliseconds (lowercase t value shown in video) would get you outside of the safe operating area chart... which is odd. Am I seeing missing something?

Very nice and clean build! I love it and what I can’t believe is the fact you made it free!

Can you please share the 3d printer you use
Thank you

Have u tried copper nickle sandwich with that set up?

It could be tested but carbon infused filament could be conductive?

Be careful

Great

Really nice job!

Price please

beautiful

Takeaway: Respect the k-weld. Acquire the k-weld.
I think this is the best build i’ve seen on a portable battery-powered, full-function spot welder.
I’ve been using a beefed-up inexpensive spot-weld pcb on a 4s2p headway pack for a few months & it works great, but I’d like to do a similar build to this ultimately. Sweet build!

It would be great if I had one like that

Overall, i like your set-up. Couple suggestions:
1. polish the electrode tips with sand paper. You want highest resistance to be between nickel strip and battery, not somewhere else in the circuit.
2. You may want to consider a 4s instead of 3s configuration. Been using 3s set-up for a long time, but sometimes it just does not have enough voltage to drive the amps.
3. With 100J and 1200A i welded through 7, yes 7 strips of 0.15mm nickel, but i did have one electrode on the longer bottom strip and another on a shorter top strip. Point being is, you can do allot more than is reasonable with this welder if you prep for it just right. Having a blunt tip electrode as a ground on the bottom piece is a good way to force all current through weld spot without marking up bottom piece; but this is a unique case.

I do see a problem with your design. I build a ton of batteries and the kweld is an amazingunit. I've been abusing mine for over 3 years. If you're doing a ton of back-to-back Welds you know how hot the electrodes get. The kweld unit itself gets very hot. Most of us incorporate a fan into the design of the case.

좋네

I love India 🇮🇳

Beautiful implementation, extremely well thought out!

$240 for the kit that is crazy I'm sure it's good and I guess they are using name brand components but something closer to $100 sounds more like it to me

Is it possible to use such a battery for an electric surfboard or foilboard

Are those wires moving cause of the high current?

Я не даже добре розумію англійської мови, та ваша робота чудова, якість на вищому рівні! 🤗👍👍👍👍

If you punch or cut a slot or hole in the pure nickel strip, you disrupt the path of least electrical resistance for the spot weld. This forces more electricity down and across the cell. More energy is used for the weld than arc across the nickel. Requires less energy

Why do a battery powered welder at all?

Regarding the old spot welder: Did you tried to clean the ends of the copper welder pins with sand paper?

I would love to see you try to spot weld pure copper instead of pure nickel, I saw some people be successful with a K-weld but your design would be perfect if it does that too!

Awesome work James, as usual. Watch out for puncturing the battery (especially on the negative terminals). That can be a nasty emergency to deal with (I recommend a metal trash bin while making the battery). I'm looking forward to the rest of the bike build. Take care!

This is an awesome design! Did you have a lot of trouble print carbon fiber on an Ender 3? What kind/size nozzle did you use?

Зачем ты удалил мой комментарий? Или ты решил заработать на этом кривом продукте?

bigger buggy battery bundle bonder booster battery?
(and a buggy battery bundle bonder booster battery box)

edit: bottom balanced and brass bus bars? Are you just messing with me now?

Great job, James! Can't wait to see it finished, I'm building one myself, did you sort out these Headway cells problems?

Похоже, что слишком большая длительность импульса, никелевая полоса поменяла цвет в местах сварки.

James. Another great video! Do you recommend a particular brand of 3D printer for a newbie to 3D printing? Maybe get an affiliate link to a brand you recommend? Thanks. Keep up the great work.

As usual, you get what you paid for...
There does not seem to be any provision for ventilation/cooling. Should one be concerned?

WOW... Love it.. Really great job...

Can you explain to me how a bms would monitor an individual cells voltage when they are all connected together as one?

I’ve seen this Kweld DIY kit mentioned several times on endless sphere.
Is there a decent spot welder that one can buy ready to use?

Yes, I do want a KWELD. Bad.