okashira
10 kW
I think fetcher's mosfet method should work fine. diode was only like $20 though ..dssguy1 said:
JP spot-welder, FET-switched, timed adj. pulse
- Thread starter okashira
- Start date
okashira
10 kW
Smart way to do it then!
I should have done it that way, I got plenty of FET's. lol
I should have done it that way, I got plenty of FET's. lol
Lurkin
100 kW
My spot welder has arrived! Exciting!
Is anyone likely to make a FET unit for sale for this modification?
Is anyone likely to make a FET unit for sale for this modification?
Offroader said:
If the diode rating is similar to the FETs, it should work just as well. I think the FETs will be cheaper though. Much cheaper in my case since I had a bunch lying around. I was real impressed by the pulse current rating of the body diode. In use, mine does not even get slightly warm, but I have short cables.
Firing the welder into a coil is sort of the acid test. I think it would make a good coil gun driver.
If you use the supplied cables, you probably don't need the diode as many have used the welder without one. If you want to use longer cables, you probably need it. It won't hurt to add it for sure.
If you're using a large car battery, you can do quite a few welds without the charger, but I would recommend leaving the charger on all the time so the battery voltage remains constant.
If you're using a large car battery, you can do quite a few welds without the charger, but I would recommend leaving the charger on all the time so the battery voltage remains constant.
vicens
100 W
I have already tried the spot welder.
Here the cells to be tested.
All assembled here. The battery purchased from scrap vehicles does not work. It does not have enough strength to maximum time. Bad buy. I used the battery of my car.
Nikel strip 0.15 mm. Setting 10 ms. It seems that the weld is good.
Nikel strip 0.15 mm. setting 20 ms. It seems that the weld is good. the darkened strip of brown color looks.
Nikel iron strip 0.2 mm. 5ms setting. It seems that the weld is good.
Nikel iron strip 0.2 mm. 10ms setting. Welding is bad. Cispas out. Out fireworks. No picture.
Here the cells to be tested.
All assembled here. The battery purchased from scrap vehicles does not work. It does not have enough strength to maximum time. Bad buy. I used the battery of my car.
Nikel strip 0.15 mm. Setting 10 ms. It seems that the weld is good.
Nikel strip 0.15 mm. setting 20 ms. It seems that the weld is good. the darkened strip of brown color looks.
Nikel iron strip 0.2 mm. 5ms setting. It seems that the weld is good.
Nikel iron strip 0.2 mm. 10ms setting. Welding is bad. Cispas out. Out fireworks. No picture.
randyc1 said:
yes of course, I use AA batteries and C. Just about any battery should work. Once you pull the weld off just file down the cell flat again, takes maybe 5-10 passes with the file. I use the same cell over 50+ times with test welds.
mistercrash
10 kW
I used AAs to make new battery packs for the house's cordless phones. I used my JP welder to make new battery packs with Hobby King 2550mah nimh AAs to replace the original and tired 900mah battery packs. The phones can stay off the charger for two weeks now lol
okashira
10 kW
I have a few bare boards and components to make a few welders. maybe 3-5. I can also make nice leads with 4awg silicone wire and supply the diode for improve high current.
Might go ahead and assemble them since I have solved my mosfet exploding problem.
Perhaps I can supply to a few who are in need in Riba's absence, but my prices will be higher then his and limited quantity. (although - I will include extra long 4awg silicone super soft wire leads and diode mod)
Shit, I have batteries too. Can supply 3p3s A123 20Ah pouch cell packs good for 3000+ amps.
For those who are afraid of hooking things up wrong, I can include whole kit with battery since the A123 LiFePO4 battery will weigh only 10 lbs. Cost will be like $500 for whole kit though...
Might go ahead and assemble them since I have solved my mosfet exploding problem.
Perhaps I can supply to a few who are in need in Riba's absence, but my prices will be higher then his and limited quantity. (although - I will include extra long 4awg silicone super soft wire leads and diode mod)
Shit, I have batteries too. Can supply 3p3s A123 20Ah pouch cell packs good for 3000+ amps.
For those who are afraid of hooking things up wrong, I can include whole kit with battery since the A123 LiFePO4 battery will weigh only 10 lbs. Cost will be like $500 for whole kit though...
Doctorbass
100 GW
I see most of you guys seem to use battery as power source.. so maybe we should remane it as :J Portable spotwelder!" :lol:
Doc
Doc
I tried to weld .3 nickel and added two 3s 20c 5000 turnigy packs. I also added the diode.
My recommendation is do not try and weld .3 99% nickel. It is too thick for consistent welds, the welds are very burned. I can usually get only 1 side to weld properly. I don't think it is worth using because of too many inconsistencies. .3 99% nickel is simply too thick.
The way to probably weld .3 nickel is if you can get a really high amount of amps and use higher pressure on the probes.
To top it all off, after about 15 test welds, I turned my pulse time to around 15-18ms and when I welded I heard a noise from my JP welder, saw some smoke, some burning smell and now voltage between the probes is constant 12 volts. I obviously blew my fets.
SO even with this diode modification, you can still easily blow your fets with too much battery power.
.2 99% nickel is probably the max I believe for spot welding.
If you want thicker nickel for more amps, then get wider nickel. Like .15x12mm .
These are just my thoughts here and you obviously will have to experiment.
My recommendation is do not try and weld .3 99% nickel. It is too thick for consistent welds, the welds are very burned. I can usually get only 1 side to weld properly. I don't think it is worth using because of too many inconsistencies. .3 99% nickel is simply too thick.
The way to probably weld .3 nickel is if you can get a really high amount of amps and use higher pressure on the probes.
To top it all off, after about 15 test welds, I turned my pulse time to around 15-18ms and when I welded I heard a noise from my JP welder, saw some smoke, some burning smell and now voltage between the probes is constant 12 volts. I obviously blew my fets.
SO even with this diode modification, you can still easily blow your fets with too much battery power.
.2 99% nickel is probably the max I believe for spot welding.
If you want thicker nickel for more amps, then get wider nickel. Like .15x12mm .
These are just my thoughts here and you obviously will have to experiment.
okashira, since you mentioned blowing a lot of your fets. Do you have any tips for finding which fets are bad? Or do I have to desolder and remove them out of the welder?
I do notice one fet has continuity between drain and source.
But it looks like there could be burn marks on others, but very slight.
Should I just pull them all out and replace them all?
Thanks.
I do notice one fet has continuity between drain and source.
But it looks like there could be burn marks on others, but very slight.
Should I just pull them all out and replace them all?
Thanks.
Lurkin
100 kW
Any thoughts on using multiple layers of .15 rather than single thicker nickel?
Lurkin said:
I'm using this technique to create heavier busbars for my >100Amps packs.
By using multiple .2x12mm or 0.2*15mm strips combined into a 1.0*12 or 1.2*15mm busbar.
Since i can weld upto 2000Amps i guess using 0.3 strips would be possible also but havent tried that yet.
The FETs will generally fail shorted. Since they're all in parallel, it may be hard to tell which one(s) are shorted without removing them. If not shorted, I'd assume they are good, though it's good practice to replace all of them with ones from the same batch for consistency.
For those traces that need to carry more current, I just weld a .15mm tab onto the cell then solder some copper wire to it.
For those traces that need to carry more current, I just weld a .15mm tab onto the cell then solder some copper wire to it.
Which fets should I buy here? My fets say AUIRF1324, but most others welder say just IRF1324 as shown in the pictures below?
Other's in pictures say IRF1324
Digikey and mouser has only the following in IRF1324 that I can buy. But I can't seem to tell the difference between them?
http://www.mouser.com/ProductDetail/International-Rectifier/IRF1324PBF/?qs=sGAEpiMZZMshyDBzk1%2fWi5%252bqVgN3%252bWS8HgR2N8hhep8%3d
IRF1324PBF $3.30
http://www.mouser.com/ProductDetail/International-Rectifier/AUIRF1324/?qs=sGAEpiMZZMshyDBzk1%2fWi4%252be7FLSKd%2fqdSOy0xmwGG8%3d
AUIRF1324 $2.68
I read through the specs and can't really see the difference here. Do you know which ones I should buy?
Is there maybe a better alternative?
Thanks.
Below in the picture are my fets:
The picture below seems to be what other people have, and what is also used in the JP Manual
Other's in pictures say IRF1324
Digikey and mouser has only the following in IRF1324 that I can buy. But I can't seem to tell the difference between them?
http://www.mouser.com/ProductDetail/International-Rectifier/IRF1324PBF/?qs=sGAEpiMZZMshyDBzk1%2fWi5%252bqVgN3%252bWS8HgR2N8hhep8%3d
IRF1324PBF $3.30
http://www.mouser.com/ProductDetail/International-Rectifier/AUIRF1324/?qs=sGAEpiMZZMshyDBzk1%2fWi4%252be7FLSKd%2fqdSOy0xmwGG8%3d
AUIRF1324 $2.68
I read through the specs and can't really see the difference here. Do you know which ones I should buy?
Is there maybe a better alternative?
Thanks.
Below in the picture are my fets:
The picture below seems to be what other people have, and what is also used in the JP Manual
Hwy89
10 kW
I have a welder on order that should arrive in a few days. I have also purchased a spool of nickel strip from http://www.sunstoneengineering.com. The strip is .375" by .005". I've determined that .005" = .127mm.
I admit to being dumb about metric measurements but I would like confirmation that the .3 nickel that Offroader had problems with is .3mm not .003".
Also where does one find the current carrying capacity of different strips?
Thanks Riba for all that you have done and I hope you get well soon.
I admit to being dumb about metric measurements but I would like confirmation that the .3 nickel that Offroader had problems with is .3mm not .003".
Also where does one find the current carrying capacity of different strips?
Thanks Riba for all that you have done and I hope you get well soon.
okashira
10 kW
They are the same fets. Just choose the cheaper/ avail one.
You need 3000 amps and up to weld .3 nickel well. Anything less and you still get a solid electrical bond, not not strong mechanically
Only way to determine current is with a scope. Or a resistance model with careful measurements of your connection resistances and battery resistance.
If you blow a FET, replace all of them. Throw all 6 out.
You need 3000 amps and up to weld .3 nickel well. Anything less and you still get a solid electrical bond, not not strong mechanically
Only way to determine current is with a scope. Or a resistance model with careful measurements of your connection resistances and battery resistance.
If you blow a FET, replace all of them. Throw all 6 out.
Hwy89 said:
Yeah, that's 0.3 mm, and thank you!
I don't know why AU version is cheaper, it should be even more expensive. They are electrically 100% the same, and sometimes I had to buy AU version because regular version was out of stock.
