JP spot-welder, FET-switched, timed adj. pulse

[Quokka]

Does this mean that amps are maintained throughout the welding pulse? Is the impact of "Avalanche" one where the power of the weld is dropping off steeply towards the end of the weld impacting on the fusion of the 2 pieces of material?

 

[okashira]

Tom

you are kidding right? People have been using 12v - 24v lead acid and coat hangers to spot tack weld for decades
[/quote]

Wow. Lol. Please show me an example of this. Last time i checked coat hangers are made of steel, which is 10x worse conductor compared to copper.[/quote]
Not gonna spoon feed you.

 

[okashira]

Does this mean that amps are maintained throughout the welding pulse? Is the impact of "Avalanche" one where the power of the weld is dropping off steeply towards the end of the weld impacting on the fusion of the 2 pieces of material?

Well, yes in a way it does. Because the battery welder maintains the current throughout the pulse, the mosfets are forced to turn off when the full current is flowing.
That current in effect has inertia, and it's not easy to stop it from flowing. In fact, it's impossible.
So, the current must continue to flow after the mosfets turn off. Thus the spike to 31V across the mosfets (the current forces itself right through the silicone)

The diode gives most of that current a way to go *around* the mosftets when they turn off, without any other negative imacts.

No, the "avalanche," has no impact on the performance of the weld itself. The avalanche is just an event that damages the mosfets over time.

 

[NetPro]

okashira,

Pretty impressive work; it is great that someone is taking the time to research and optimize the design to prevent avalanche damage.

One question for you about the white welding cable attached directly to the welder (showing in the picture before last).
Is this the crazy-flexible silicone cable you have mentioned a couple of times?
It looks like it is a 2 awg but could be a 4 awg with thick jacket. Which is it?
I am interested in buying some of this good-stuff. Would you sell a few feet or point me in the right direction, please?

 

[okashira]

okashira,

Pretty impressive work; it is great that someone is taking the time to research and optimize the design to prevent avalanche damage.

One question for you about the white welding cable attached directly to the welder (showing in the picture before last).
Is this the crazy-flexible silicone cable you have mentioned a couple of times?
It looks like it is a 2 awg but could be a 4 awg with thick jacket. Which is it?
I am interested in buying some of this good-stuff. Would you sell a few feet or point me in the right direction, please?

It is 4awg silicone
Think i found it on ebay, jumped on 150 ft after I got the first order.

 

[NetPro]

okashira,

Pretty impressive work; it is great that someone is taking the time to research and optimize the design to prevent avalanche damage.

One question for you about the white welding cable attached directly to the welder (showing in the picture before last).
Is this the crazy-flexible silicone cable you have mentioned a couple of times?
It looks like it is a 2 awg but could be a 4 awg with thick jacket. Which is it?
I am interested in buying some of this good-stuff. Would you sell a few feet or point me in the right direction, please?

It is 4awg silicone
Think i found it on ebay, jumped on 150 ft after I got the first order.

Super!
Still available on eBay and just bought 10ft.
Pretty sure it is the same product you have, based on comments you made earlier. Ships from California.

Thanks, okashira. Appreciate your help

 

[fechter]

Tom
you are kidding right? People have been using 12v - 24v lead acid and coat hangers to spot tack weld for decades

Wow. Lol. Please show me an example of this. Last time i checked coat hangers are made of steel, which is 10x worse conductor compared to copper.
Not gonna spoon feed you.

I think they mean using the coat hanger as a welding rod, like a regular arc welder. I've done it before. Flux coated rods work better but sometimes you're in the McGiver mode and have to make do with available materials. Barbed wire fence wire works too.

 

[MattyCiii]

Okashira thanks for advancing the state of the art and posting your results!

 

[Offroader]

How will length of probe cables affect welding quality?

Will it make any differences using 3 foot cables vs 5 foot cables?

Assume using 4AWG wire.

 

[Doctorbass]

Here is the progress on my J-P spotwelder.

First bank of 1.034Fadads done. It give about 0.2Wh( 750Joules) energy and have an increbly LOW ESR !! 0.4 miliohm for a single bank!
The copper sheet bus bar should help to lower inductance in teh high current circuit and help getting faster pulse raise time... but not sure it will help.. but i wioll try anyway.

total 66x panasonic 35v 47 000uF.

Max energy: 1800 Joules at 35v and about 225 joules at 12V

Enjoy!

[youtube]Gzx0tgMEo4M[/youtube]

Doc

 

[Doctorbass]

Great progress today!.. all caps assembled!

Now it's time for low inducance HIGH CURRENT BUSS BAR !!

sorry for the images upside down.. on my browser they are correct as well as when i open these with paint.. lol.. it appear that the E-S picture have image orientation detection fail!...

Doc

 

[whereswally606]

intrigued Doc, was going to do a similar thing a while back an still have the caps in my loft but mine are 16v ones I think and a lot less farads as there but a lot of them none the less. I like your Teflon bus bars idea, I may have to copy that.

Lets have some videos of the welder in action.

 

[ridethelightning]

Hey Doc
Tungsten is the best electrode tip for welding copper, from what i have read and tried.
set a piece of tungsten zirconium(non radioactive) tig welding electrode, 8-1mm long, press fit into the end of some~8mm copper rods.

the tungsten creates the heat from its relatively high resistance, that makes the weld,( cause the copper wont...)
the tips stay very hard even though they get red hot. the welds on 0.1mm copper stay cool.
once you get the right setting, the welds are very consistent. i use moded dn10, but would like to try my jpwelder some day too.

if i wanted my pack conductors to be strong, not conductive, id use steel packing stap :lol:

i reley on other materials to do the job of keeping the pack physically strong.

RTL

 

[Quokka]

Here are my tungsten tips of my dn-5. Keeps tripping my circuit breaker though.

 

[okashira]

I made this calculator for a mosfet type welder and for batteries (specifically JP welder + battery source)
I put a good amount of work into it, so please give credit and keep my contact on there if you modify it. And distribute this read only link.
https://onedrive.live.com/redir?resid=6A929FF99605B0EA!12003&authkey=!ABMgmXsIdQapFfw&ithint=file%2cxlsx

Make sure you update the blue values to match your setup. Green values i carefully tweaked based on lots of testing and data... but if your setup is different keep that in mind

One could tweak it to work with a cap welder (hint, major change in the % peak current column is needed - you need to account for the falling voltage of the capacitors based on coulombs discharged) let me know if you need help with that. I spent about 15 minutes giving it a start... added calculated voltage drop @ the cap, now you need to use this to compensate for new voltage and how it will affect the current slew rate and peak current ...

 

[ridethelightning]

Here are my tungsten tips of my dn-5. Keeps tripping my circuit breaker though.

nice one Quokka.
i gotta get me a drill press vice like that. got a good supplier?

i just made do with a normal vice and handheld drill....

 

[Samd]

Some awesome engineering going on here.
Quokka would shortening the tungsten section give your circuit breakers more of a chance?

 

[Quokka]

I have had a dedicated line installed with a 20amp breaker- that's the max an electrician would install given our power outlets are rated to a max of 20amps. It cuts out with standard copper tips as well. This to me highlights the true beauty of the JP welder. You are independent of your household wiring which struggles to power any commercially available spot welder.

 

[ridethelightning]

I have had a dedicated line installed with a 20amp breaker- that's the max an electrician would install given our power outlets are rated to a max of 20amps. It cuts out with standard copper tips as well. This to me highlights the true beauty of the JP welder. You are independent of your household wiring which struggles to power any commercially available spot welder.

thats funny. i have never had any issues with the dn10 welder on the mains supply(?)

 

[Quokka]

Mine tripped the minute I plugged it in. Then I got the dedicated line and breaker. It worked great for around 3-4 hrs, welded anything I through at it. Then the tripping started. Bit suspicious that the sparky installed an rcbo instead of a normal unprotected breaker. Maybe that's the issue. But fiddling around in a fuse box is where I draw the line and call it quits. Time to get a battery powered welder :lol:

 

[ridethelightning]

sixpack swap for extension cord access to the neighbours? :wink:

 

[WrinklyWink]

I'm a little sad because I've done so much research to spot weld which got me here, but the JP welder is out of stock and the topic seems to be drifting away from sales. Can anyone advise me a good spot welder to buy? Or do I really have to go with this?

 

[macribs]

The JP spotwelder will be released as a DIY kit/open source kit. I have no idea about when tough.
Okashira will make a batch of his modified version of JP welder with some changes, AFAIK no set date for release for that one either.
You could try the Item Wanted section of the forum, maybe you are lucky and someone here are done building batteries and wishes to relocate funds.

 

[Lurkin]

I'm a little sad because I've done so much research to spot weld which got me here, but the JP welder is out of stock and the topic seems to be drifting away from sales. Can anyone advise me a good spot welder to buy? Or do I really have to go with this?

If you update your avatar with where you are, you may be able to find a member close to you with a kit/willing to help you out?

 

[Lurkin]

Mine tripped the minute I plugged it in. Then I got the dedicated line and breaker. It worked great for around 3-4 hrs, welded anything I through at it. Then the tripping started. Bit suspicious that the sparky installed an rcbo instead of a normal unprotected breaker. Maybe that's the issue. But fiddling around in a fuse box is where I draw the line and call it quits. Time to get a battery powered welder :lol:

I have been debating testing whether I could transport everything in a bike trailer to spot weld a pack together at the beach.... new office? 8)