spotwelder?

[Dixonk]

Hi there

I would like to buy a decent spotwelder with a recommended battery / power supply to go with it.

I've heard kWeld being mentioned little bit here and there, can someone here recommend where to grab one? with a decent battery / power supply?

Do you need anything else when you start? battery chargers / balancer or the like?

Hit me up

Thanks in advance,
Best regards

 

[DoraTheExplorer]

I have the malectrics for some years now and it just works for me. I also loan it to people, never had any complains (other than human error, like using a low amperage Lipo pack). Battery recommendations are in the FAQ on its website.

However I would -maybe- go for the kweld today. Years ago IIRC the kweld was quite a lot more expensive than the malectrics. Nowadays there is no real difference in price.

edit: disregard my posting, I just figured you already *want* the kweld. At first I though you are asking for WELDER recommendations.

 

[spinningmagnets]

it would be helpful if you could state what you plan to weld. 0.10mm thick nickel ribbon is very different than a 0.15 copper/nickel sandwich.

 

[Dixonk]

it would be helpful if you could state what you plan to weld. 0.10mm thick nickel ribbon is very different than a 0.15 copper/nickel sandwich.

Hey, I have no experience in battery assembly so I dont know. But ive seen pictures of high discharge batteries having copper and nickle so thats want I eventually want to do aswell.
I just dont want to buy more than one spot welder. Heard kWeld is capable but I dont know where to buy one.

Best regards

 

[spinningmagnets]

Both the Malectrics and kWeld are precision timers on an on/off switch.

The mistake many new builders make is assuming all pulse batteries are all the same. You can scan the kWeld thread and list the battery used, and the timing used [*in milliseconds, or...thousandths of a second].

The strength if the pulse comes from the battery, measured in amps, not from the timer.

Although, if you use a car battery or LiPo battery that has lower amps than ideal, then...you can make up for it by using a longer pulse.

The Malectrics costs less, and I think it can handle up to 1,000A...but you should double check that. It might be 800A, and that means 1,000A would fry it.

The benefit of the kWeld is that it measures the energy passing through it, and it automatically adjusts the pulse length to compensate for the slowly lowering voltage from the battery pack.

If you use a large car battery that is fairly new, the voltage and amps will not change much from start to finish. Many have gotten good results with the Malectrics.

That being said, a used kWeld that still works fine can be sold on the used market for 80% of the new purchase price, since they are in demand.

If you use thinner copper and thin "nickel-plated" steel strips, you can get a solid weld with the lowest possible amount of welding energy.

Again, it is best to find a successful combination and copy it, a set of specs that weld the type and thickness of buses you plan on using.

Copper is four times more conductive than nickel, so 0.10mm copper is as good as 0.40mm nickel. How many amps will your pack provide? Which cell will you use?

 

[Dixonk]

Both the Malectrics and kWeld are precision timers on an on/off switch.

The mistake many new builders make is assuming all pulse batteries are all the same. You can scan the kWeld thread and list the battery used, and the timing used [*in milliseconds, or...thousandths of a second].

The strength if the pulse comes from the battery, measured in amps, not from the timer.

Although, if you use a car battery or LiPo battery that has lower amps than ideal, then...you can make up for it by using a longer pulse.

The Malectrics costs less, and I think it can handle up to 1,000A...but you should double check that. It might be 800A, and that means 1,000A would fry it.

The benefit of the kWeld is that it measures the energy passing through it, and it automatically adjusts the pulse length to compensate for the slowly lowering voltage from the battery pack.

If you use a large car battery that is fairly new, the voltage and amps will not change much from start to finish. Many have gotten good results with the Malectrics.

That being said, a used kWeld that still works fine can be sold on the used market for 80% of the new purchase price, since they are in demand.

If you use thinner copper and thin "nickel-plated" steel strips, you can get a solid weld with the lowest possible amount of welding energy.

Again, it is best to find a successful combination and copy it, a set of specs that weld the type and thickness of buses you plan on using.

Copper is four times more conductive than nickel, so 0.10mm copper is as good as 0.40mm nickel. How many amps will your pack provide? Which cell will you use?

Hi again,

This is a very informative posts, thanks alot for putting time into replying and helping me.

Ive used an hour each day (what kids allowed me and energy) to read up abit but im no more wiser today than when I first decided I want to buy a spotwelder.
Ive decided on a new spotwelder whichever is capable and thats one thing I dont know yet.
I dont know what cells to use either I dont go into this with a great plan or anything but more or less if I find some decent cells at a decent price I'll go at it, I'll probably start with some less costly ones to try and give my son a better pack for his ebike.

If both Malecteics and kWeld is capable of spotwelding copper / nickle for say something that can handle 300amps or so I dont really care which one, as I wrote before. I dont know much.
By googling I dont know where to buy from either, theres more than one website selling.

Best regards

 

[amberwolf]

I dont know what cells to use either I dont go into this with a great plan or anything but more or less if I find some decent cells at a decent price I'll go at it, I'll probably start with some less costly ones to try and give my son a better pack for his ebike.

Some things that will help us help you determine what cells to use, and the rest of the specs the battery must meet to be able to do what you want.

Do you already have a system (motor, controller, battery) on the bike?

If so, does this system already do what you want it to?
If it doesn't, what specifically does it not do that you want it to do, under what specific conditions and riding style, and what specific motor, controller, and battery do you already have? (links to the purchase pages may be helpful)

If you have no system on there already, thenwhat specifically do you need the bike to do for you (or him), under what specific conditions and riding style?

 

[Dixonk]

I dont know what cells to use either I dont go into this with a great plan or anything but more or less if I find some decent cells at a decent price I'll go at it, I'll probably start with some less costly ones to try and give my son a better pack for his ebike.

Some things that will help us help you determine what cells to use, and the rest of the specs the battery must meet to be able to do what you want.

Do you already have a system (motor, controller, battery) on the bike?

If so, does this system already do what you want it to?
If it doesn't, what specifically does it not do that you want it to do, under what specific conditions and riding style, and what specific motor, controller, and battery do you already have? (links to the purchase pages may be helpful)

If you have no system on there already, thenwhat specifically do you need the bike to do for you (or him), under what specific conditions and riding style?

Hi there!

Well for my son I want to be able to make him a battery able to discarge 60amps ~ with around 15ah~ at 72v (20s) he has a fardriver72300 I believe its name is.. can handle 110A cont I believe.

For myself I have this urge later down the line to buy qs138v3 along with a capable fardriver or votol controller and more or less buy cells when I find something suitable in my price range and go from there

I don't really see myself using the spotwelder much more than for these two projects above but you never know.. if not, I can always resell it but either way.. could be a fun thing to spend some time on.

Best regards

 

[tomjasz]

If you use thinner copper and thin "nickel-plated" steel strips, you can get a solid weld with the lowest possible amount of welding energy.

Again, it is best to find a successful combination and copy it, a set of specs that weld the type and thickness of buses you plan on using.

Copper is four times more conductive than nickel, so 0.10mm copper is as good as 0.40mm nickel. How many amps will your pack provide? Which cell will you use?

Are some of the successful combinations of nickel coated steel and copper already charted in a thread?

I’ve not really paid attention and had always used nickel strips. But the first welder I bought was a Sunnko and a complete fail. But a kilo of nickel coated steel came with it and I’d surely like to use it rather then send it to the recycler. My recovered stroke brain struggles wading through some of the long threads.

I need to measure the kilo thickness. Off the search threads again too…

I sold my first version KWeld, I bought to soon in its version cycles. I think it was a first release. @JohnCT got it, never heard if he fired it up

, but still have powerful sealed trolling motor battery and the welder from the Croatian member. Name eludes me at the moment. Edit. Jakov, that’s the fellows name… I thought I had two but digging through my parts and back ups I had 3. One needs a minor repair and going to the AU moderator. First one was sold but having found the third I’m back and interested in messing with it again.

Great thread and I’m once again inspired.
A couple of 100W solar panels left over from my sun powered compost tea brewer and sprayer will be finally be repurposed for garage lighting.

 

[spinningmagnets]

The welding of two metals occurs in a tiny spot when it get hot enough to partially melt.

Copper is so conductive that it takes a very large amount of amps to get a spot hot enough. Industry uses a laser, which is horribly expensive.

However, if you make a sandwich with copper between the cell-tip and a nickel strip, the nickel and cell-tip both have enough resistance to convert the amp-pulse into enough heat.

Since current takes the path of least resistance, the nickel has almost no current flowing through it when you are using the finished battery. The nickel is used for the sole purpose of converting the welding current into a tiny bead of heat.

Steel has even more resistance than nickel, but it rusts easily. However, nickel-plated steel is ideal for our purposes. A thick ribbon of "nickel-plated-steel" would take a higher current to get a spot hot enough, so you want something relatively thin. 0.10mm seems to work well for this.

I dont know if its possible to find thinner steel, or if it would be better or worse in some way.

However, the standard of using a 12V car battery for a short pulse of welding current is something that is readily available everywhere, and 0.10 nickel-plated-steel is a good cap material, because it accomplishes the job with fairly low current. If you use pure nickel ribbon, that also works, but its more expensive and it requires more current to weld.

I am unable to test dozens of combinations, so I have been waiting to collect the data from others.

The kWeld reads out how much energy passed through it, and it also automatically adjusts the pulse length to compensate for minor variations in the voltage from the welding battery.

If using 0.10mm nickel plated steel ribbon over 0.10mm copper sheet, that should work quite well for any common electric bike, and can be accomplished by the Malectrics [which costs less].

If I was building a motorcycle battery which needs 200A or more from the pack, I would start with the kWeld, and experiment to see how thick I can make the copper.

We can discuss ampacity of copper conductors endlessly, but the fact remains that many high-amp batteries are still being made with nickel buses, which cause high resistance, and convert many battery watts into heat when they are running..

 

[lnanek]

I was under the impression people avoided steel due to the rust factor. Like if you are building a battery to last 6 years, and expect to be caught in the rain twice a year, you wouldn't want to open the battery up to atomize it and reuse any good cells on year 6 and have a bunch of rusty connections. I've even seen a rusty charge connection burn out on one battery.

Nickel isn't ideal for conductivity, but can't you just double up on the thickness rather than resort to nickel plated steel?
Even if you only have thin .10 ribbon laying around, you can spot weld a second set on top.

 

[hemo]

From my last small build of p42a's as a simple 12s2p pack, I used ni/steel & cu sandwich with good results via the malectrics. 0.15 slitted ni/steel H strip and 0.08mm cu sheet, pulse rate of about 44 or 46. One has to test on old cells or use craft knife blades to determine the best pulse rate for effective weld strength and weld burn thru on the opposing face.

 

[amberwolf]

Well for my son I want to be able to make him a battery able to discarge 60amps ~ with around 15ah~ at 72v (20s) he has a fardriver72300 I believe its name is.. can handle 110A cont I believe.

If your battery is only going to be able to supply 60A, you'll need to use the fardriver setup program (or app if it has one) to change the fardriver's current limit so it cannot draw more than 60A, or else it will damage the battery by drawing more current than the battery can handle.

If you're certain that 15Ah (1kWh) is enough for the range it needs under the circumstances, then:

if you need 60A out of it (continuously? if not, for how long at a time and how often?), and it's only 15Ah, then 60 / 15 = 4, so the cells will need to be able to handle 4c, or 4x their capacity in current.

Let's say you used 3Ah 18650 cells, 5 of them in parallel, and 20 of those 5p groups in series. That would give you 15Ah at 72v nominal.

Each 3Ah cell would need to be able to supply 1/5 of the total current, or 60 / 5 = 12A.

There's plenty of other ways to divvy up the requirements to pick cells.

 

[tomjasz]

I was under the impression people avoided steel due to the rust factor. Like if you are building a battery to last 6 years, and expect to be caught in the rain twice a year, you wouldn't want to open the battery up to atomize it and reuse any good cells on year 6 and have a bunch of rusty connections. I've even seen a rusty charge connection burn out on one battery.

Nickel isn't ideal for conductivity, but can't you just double up on the thickness rather than resort to nickel plated steel?
Even if you only have thin .10 ribbon laying around, you can spot weld a second set on top.

I think it was Damien Rene that I saw posted some value indicating steel required thicker ribbon. But not being very well versed in the details I can’t make any definitive comments. As to rust, ACF50 and Boeshield treatments have worked incredibly well for me. Here in tropical Minnesnowta summers and salty winters they save the day. I now open new packs and give them a good spraying. Good enough for avionics makes them good enough for me.