kWeld - "Next level" DIY battery spot welder

Batteries, Chargers, and Battery Management Systems.
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Re: kWeld - "Next level" DIY battery spot welder

Post by Hummina Shadeeba » Jan 22 2021 12:42am

AC5ME wrote:
Jan 21 2021 8:50pm
It's not making any tones at all, and it would be nice if it did.

Thanks.
I’m surprised/scared how I misunderstood you.


How many welds is good enough?
https://www.google.com/amp/s/www.massli ... utType=amp

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Re: kWeld - "Next level" DIY battery spot welder

Post by Hummina Shadeeba » Jan 25 2021 4:05pm

if getting "timeout" does that mean the battery isnt capable of putting out the joules in the amount of time given? i need a bigger battery if getting timeout?

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Re: kWeld - "Next level" DIY battery spot welder

Post by flippy » Jan 26 2021 10:34am

Hummina Shadeeba wrote:
Jan 25 2021 4:05pm
if getting "timeout" does that mean the battery isnt capable of putting out the joules in the amount of time given? i need a bigger battery if getting timeout?
it tells you that you need a break. take a walk, stretch a bit, grab some coffee and then come back. :lol:
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Re: kWeld - "Next level" DIY battery spot welder

Post by Hummina Shadeeba » Feb 02 2021 11:01pm

i keep blowing through the 300 amp fuse if anyone has any ideas what my problem is please advise me.

why wouldnt this tool work?:

if i added electrodes. what current does it put out in comparison? im guessing it is ON too long, but if you quickly connected and disconnected maybe? i have no idea

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Re: kWeld - "Next level" DIY battery spot welder

Post by flippy » Feb 03 2021 7:10am

Hummina Shadeeba wrote:
Feb 02 2021 11:01pm
i keep blowing through the 300 amp fuse if anyone has any ideas what my problem is please advise me.

why wouldnt this tool work?:

if i added electrodes. what current does it put out in comparison? im guessing it is ON too long, but if you quickly connected and disconnected maybe? i have no idea
the fuse heats up when welding fast. i have the same issue. its simply unavoidable thanks to the nature of how a fuse works. either weld slower, harder and shorter (more amps) or do what i did...

i just replaced it with a piece of copper i had. :roll: (YOLO)
Last edited by flippy on Feb 03 2021 7:17am, edited 1 time in total.
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Re: kWeld - "Next level" DIY battery spot welder

Post by jonescg » Feb 03 2021 7:15am

Question for the kWelders out there - can you spot weld 0.15 mm thick nickel to nickel plated 1.2 mm aluminium?
How about 0.8 mm nickel plated copper?

Seems like you need all the Joules :?

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Re: kWeld - "Next level" DIY battery spot welder

Post by flippy » Feb 03 2021 7:20am

jonescg wrote:
Feb 03 2021 7:15am
Question for the kWelders out there - can you spot weld 0.15 mm thick nickel to nickel plated 1.2 mm aluminium?
How about 0.8 mm nickel plated copper?

Seems like you need all the Joules :?
i dont see why you would do something like that in the first place. just because you can does not mean you should.

it would require the shortest of leads, all the amps it can handle and very precise electrode tips and pressure. and even then i dont think it would be a good connection.
if you are going to attach strips to bus bars like that it might be more practical to just use M2(,5) or M3 nuts, bolts and washers for example. or just solder.
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Re: kWeld - "Next level" DIY battery spot welder

Post by jonescg » Feb 03 2021 7:33am

It's a build technique specific to an application. Tesla has been using it to great success with their Model S and Model X batteries, except they have million dollar wire bonding machines. For the DIY conversion, it's a great way to go, provided you can make the interconnects. I have considered mechanical clamping with screws, yeah. It would be a lot of work though.

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Re: kWeld - "Next level" DIY battery spot welder

Post by flippy » Feb 03 2021 7:41am

jonescg wrote:
Feb 03 2021 7:33am
It's a build technique specific to an application. Tesla has been using it to great success with their Model S and Model X batteries, except they have million dollar wire bonding machines. For the DIY conversion, it's a great way to go, provided you can make the interconnects. I have considered mechanical clamping with screws, yeah. It would be a lot of work though.
in NO WAY the bond wire "tric" should be used or copied by DIY people thinking its "the best solution because tesla uses it".
the reason is because tesla uses bond wires is simply because its the fastest and cheapest way to connect a thousands of cells per hour on a single processing station. the simple fact that tesla's wire bonding machines uses a ultrasonic head on itself costs about a solid quarter million a pop should give clue as to why.

even tesla wont use it in their new 4680 batteries...
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Re: kWeld - "Next level" DIY battery spot welder

Post by jonescg » Feb 03 2021 7:50am

The new cells are big enough and capable enough to need more than a wire bond to complete the circuit. I mean, how long until Tesla decides to use screw terminations on prismatic cells? :wink: Anyway, the bus plate is a solid approach. The issue is how to link the cells to it. I'm left wondering if mechanical (pressure) connections are the future? No idea what they'd look like when potted though.

There is NO WAY I would try and pass the 150 amps this application is expected to demand through 0.15 mm nickel tabs. The resistance would generate some serious heat and sag the pack like crazy. The bus plates allow decent current to flow through the module, but the limitation is the connection from cell to busplate.

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Re: kWeld - "Next level" DIY battery spot welder

Post by Hummina Shadeeba » Feb 03 2021 10:02am

flippy wrote:
Feb 03 2021 7:10am
Hummina Shadeeba wrote:
Feb 02 2021 11:01pm
i keep blowing through the 300 amp fuse if anyone has any ideas what my problem is please advise me.

why wouldnt this tool work?:

if i added electrodes. what current does it put out in comparison? im guessing it is ON too long, but if you quickly connected and disconnected maybe? i have no idea
the fuse heats up when welding fast. i have the same issue. its simply unavoidable thanks to the nature of how a fuse works. either weld slower, harder and shorter (more amps) or do what i did...

i just replaced it with a piece of copper i had. :roll: (YOLO)
I blew three fuses in a row even at 8 joules. Something is wrong with the welder for sure.



Potting compression connections sounds a bad idea if the potting material is too hard. Maybe a soft potting material with thick copper and magnets would be good.

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Re: kWeld - "Next level" DIY battery spot welder

Post by flippy » Feb 03 2021 10:19am

Hummina Shadeeba wrote:
Feb 03 2021 10:02am
I blew three fuses in a row even at 8 joules. Something is wrong with the welder for sure.
no, you are welding with too low voltage so the current needs to be too high to get the joules.

harder and faster is better. the slow cooking of the fuse is simply because it gets the time to heat up as the pulses are too long to get the joules.
Lithium beats liquid dinosaurs.

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Re: kWeld - "Next level" DIY battery spot welder

Post by Hummina Shadeeba » Feb 03 2021 10:41am

I did hundreds of welds at 31 joules and 16v and even creeping down to 15v and now can’t weld at 8 without blowing the fuse immediately. I think it must be broken.
Last edited by Hummina Shadeeba on Feb 03 2021 10:44am, edited 1 time in total.

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Re: kWeld - "Next level" DIY battery spot welder

Post by flippy » Feb 03 2021 10:43am

if it takes too long you have too much resistance or not enough volts to push the amps into the weld.

too much time = glowing fuse.

dont look at the joules, look at the pulse time.

do you keep your tips clean, leads and connections tight? the magnetic currents might loosen nuts over time.
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Re: kWeld - "Next level" DIY battery spot welder

Post by Hummina Shadeeba » Feb 03 2021 10:45am

100s of welds with success with same settings and now fuses pop at what should be a 1/4th the time with only 8 joules

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Re: kWeld - "Next level" DIY battery spot welder

Post by Hummina Shadeeba » Feb 03 2021 10:48am

The pulse time being decided by the battery’s ability to put out the amps needed right? So with the same voltage and joule setting it’ll be the same pulse time. Higher voltage being shorter pulse for the same joules output. But I’ll check all my connections and make sure there’s no resistance somewhere in the circuit.
Last edited by Hummina Shadeeba on Feb 03 2021 10:51am, edited 1 time in total.

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Re: kWeld - "Next level" DIY battery spot welder

Post by flippy » Feb 03 2021 10:51am

Hummina Shadeeba wrote:
Feb 03 2021 10:45am
100s of welds with success with same settings and now fuses pop at what should be a 1/4th the time with only 8 joules
like i said: the joules dont matter. you can pop a fuse with 1 joule. a fuse is rated at "amps over time".

a fuse works by MELTING the thin wire inside. just like the welder works. if you want to prevent the fuse from blowing you need to have the time of the pulse to be so short that the fuse will not melt. currenty you are popping the fuse wich means the pulses are too long or you are using a fuse that is too "fast". you must use a slow blow fuse. the slower the better. if you got a random replacement fuse its likly you got a "fast" fuse instead of a slow blow type.
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Re: kWeld - "Next level" DIY battery spot welder

Post by Hummina Shadeeba » Feb 03 2021 10:57am

I got a 300 amp fuse. Didn’t say slow or fast and haven’t heard of that distinction.

But if the same voltage and same battery it will put out those amps at the same speed and adjusting the joules would change the speed no? Going from 31 joules no problem to 8 and popping fuses repeatedly now. Nothing changed.

The fuse is there to protect the tool when something is wrong. I think something is wrong. Other than tightening everything and maybe going up in voltage I’m out of ideas. I can get another fuse and try with higher voltage. What voltage u think is good?

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Re: kWeld - "Next level" DIY battery spot welder

Post by Hummina Shadeeba » Feb 03 2021 11:17am

flippy wrote:
Feb 03 2021 10:51am
Hummina Shadeeba wrote:
Feb 03 2021 10:45am
100s of welds with success with same settings and now fuses pop at what should be a 1/4th the time with only 8 joules
like i said: the joules dont matter. you can pop a fuse with 1 joule. a fuse is rated at "amps over time".

a fuse works by MELTING the thin wire inside. just like the welder works. if you want to prevent the fuse from blowing you need to have the time of the pulse to be so short that the fuse will not melt. currenty you are popping the fuse wich means the pulses are too long or you are using a fuse that is too "fast". you must use a slow blow fuse. the slower the better. if you got a random replacement fuse its likly you got a "fast" fuse instead of a slow blow type.
I put what looks to be the same style fuse in it it had. Looking on Amazon all the slow fuses seem a different style. Don’t think they’ll fit in the case.

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Re: kWeld - "Next level" DIY battery spot welder

Post by john61ct » Feb 03 2021 11:19am

Fuses are most certainly faster and slower, soon as you get past the V&A thoseare the most fundamental specs

datasheets represent the time relationships with plotted graph curves.

Have you tried using afresh new source pack? LFP will last much longer than li-ion chemistries, less energy dense (Ah) but have plenty of c-rate power oomph, but bigger Ah will aways mean less V sagging in use.

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Re: kWeld - "Next level" DIY battery spot welder

Post by john61ct » Feb 03 2021 11:24am

And cheap-chinese fuses hardly ever live up to their specs, can be wildly off, each batch completely different performance when bench tested

Good quality like non-counterfeit Cooper Bussmann (vet suppliers, avoid eBay, Amazon, China)

rated for DC at those kind of amps

(obviously AC circuit protection is irrelevant here)

cost lots more than the welder


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Re: kWeld -

Post by Hummina Shadeeba » Feb 03 2021 11:25am

john61ct wrote:
Feb 03 2021 11:19am
Fuses are most certainly faster and slower, soon as you get past the V&A thoseare the most fundamental specs

datasheets represent the time relationships with plotted graph curves.

Have you tried using afresh new source pack? LFP will last much longer than li-ion chemistries, less energy dense (Ah) but have plenty of c-rate power oomph, but bigger Ah will aways mean less V sagging in use.
I’ll look for a slow fuse then. I can see it turn red and it takes maybe a second till blows and I imagine much longer than the welder should be turned on. The battery has been good and it’s new. It’s iron cells. 16p5s a123 26650 cells.

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Re: kWeld -

Post by Hummina Shadeeba » Feb 03 2021 11:27am

john61ct wrote:
Feb 03 2021 11:24am
And cheap-chinese fuses hardly ever live up to their specs, can be wildly off, each batch completely different performance when bench tested

cost lots more than the welder
??!!! U have a link? Cost more than the welder for the fuse?! Fuuuuck.

I got these and good reviews: https://www.amazon.com/dp/B072QBF31Y/re ... NrPXRydWU=

I’m doing 16 volts. I guess could charge up to18 for 5s iron cells. But why you two don’t think there’s a problem w the welder? Set to 8 joules at 16v w a good battery it blows and the time on seems extra long

I’ve also had “timeout” happen when the battery drops close to 14v but not before. The timeout warning telling if the battery isn’t strong enough to put out the joules within the time period. When it does do a timeout there’s a lot more current going through snd the wires get much hotter, but no fuse blown

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Re: kWeld - "Next level" DIY battery spot welder

Post by flippy » Feb 03 2021 3:52pm

even the offical bussman fuses are well under a tenner,

https://www.amazon.com/Cooper-Bussmann- ... B000WSWXDC
Hummina Shadeeba wrote:
Feb 03 2021 11:27am
I’m doing 16 volts. I guess could charge up to18 for 5s iron cells. But why you two don’t think there’s a problem w the welder? Set to 8 joules at 16v w a good battery it blows and the time on seems extra long I’ve also had “timeout” happen when the battery drops close to 14v but not before. The timeout warning telling if the battery isn’t strong enough to put out the joules within the time period. When it does do a timeout there’s a lot more current going through snd the wires get much hotter, but no fuse blown
your battery cant get the amps fast enough so it takes longer wich results in a popped fuse.
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Re: kWeld - "Next level" DIY battery spot welder

Post by Hummina Shadeeba » Feb 03 2021 4:16pm

flippy wrote:
Feb 03 2021 3:52pm
even the offical bussman fuses are well under a tenner,

https://www.amazon.com/Cooper-Bussmann- ... B000WSWXDC
Hummina Shadeeba wrote:
Feb 03 2021 11:27am
I’m doing 16 volts. I guess could charge up to18 for 5s iron cells. But why you two don’t think there’s a problem w the welder? Set to 8 joules at 16v w a good battery it blows and the time on seems extra long I’ve also had “timeout” happen when the battery drops close to 14v but not before. The timeout warning telling if the battery isn’t strong enough to put out the joules within the time period. When it does do a timeout there’s a lot more current going through snd the wires get much hotter, but no fuse blown
your battery cant get the amps fast enough so it takes longer wich results in a popped fuse.
Thanks for the link and I’ll order those

But the welder “timeout” should happen if the amount of time that the welder uses isn’t enough to get out what joules it’s set to. 31joules in my case. I’ve had that happen lots of times in the past when the battery was going down to 14v. But this happens on the 16v full charge every time and when down to even 8joules.

What other things could it be or how do I test to find out? I don’t think the timing is adjustable on it right? Just the joules. It records and I could look at what energy passed through but I’ll look again snd think nothing related to time.

How do u summon someone on here? Trying to get
tatus1969 wrote:
Feb 03 2021 3:34am
?
Or someone who might know.
Last edited by Hummina Shadeeba on Feb 03 2021 4:18pm, edited 2 times in total.

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