JP spot welder

fechter said:
48v is too much. 12v is about the maximum.
Consider that on mine, I measured about 3,000A during the pulse at 12v. There has been some success using gigantic capacitors and a 12v supply. The average power is not that much so the caps can get recharged with a reasonably small 12v supply.

Fletcher,

How did you measure the current of such a short pulse?
Is there a special device that does that or you rigged something up using standard testing equipment?
I want to test mine.

Thanks!
 
I used an oscilloscope across a 6" section of 10ga wire and measured the voltage drop. I got the resistance of the wire from a table and did the math to get the current.
 
NetPro said:
fechter said:
48v is too much. 12v is about the maximum.
Consider that on mine, I measured about 3,000A during the pulse at 12v. There has been some success using gigantic capacitors and a 12v supply. The average power is not that much so the caps can get recharged with a reasonably small 12v supply.

Fletcher,

How did you measure the current of such a short pulse?
Is there a special device that does that or you rigged something up using "standard" testing equipment?
I want to test mine.

Thanks!

I have done measurements using large shunt resistor and oscilloscope.
 
Just a follow up if anyone is interested. I soldered 28 AWG wire to tiny nickel strips, and then spot welded them onto the battery for the BMS.

I wanted to avoid any soldering onto the battery. Soldering also off the battery allows me to really heat everything up to guarantee a perfect solder, something you really couldn't do on the battery because you may overheat the cells.

I also wrapped the pack up in Kapton tape first to avoid residue on the nickel. Then used scotch tape to tape down the wires, then box packing tape to really tape up the pack to make sure everything is very secure.

I did notice a few wires on one side of the pack seemed to started to wear. It must have been from possible rubbing on the side cover? I used some electrical tape on the sides and used a lot of packing tape to make sure nothing wears through and the wires stay secure.

You can see the 28awg soldered wire welded to the cell.
OA08Wge.jpg


Completed pack ready to be installed in bike.
PmKnAzb.jpg


NQLkA9M.jpg
 
You can see in the pictures a couple of wires I noticed had the silicone split open or gouged out. I really have no idea how this happened. I figured if it was from rubbing it would have shown more wear marks. It almost looks like it got cut open and not worn out from rubbing.

I noticed this on only one side of the pack and maybe 4 different wires had signs of the silicone either cut open or damage marks.

For 95% of the wires they are run over the cell groups in series, so it would not have shorted anything. Only the tops of the wires seemed to be damaged in those few locations.

I didn't notice any issues when I removed the pack and believe the pack was still wrapped in tape solidly around. The thin foam I used for the sides also don't have any wear marks on them.

I also have kapton tape on my side covers, and some thin foam on the sides of my battery pack which are not worn out. Highly unlikely this would cause a short.

That all being said, using wires may come with some hazards as you can see. Why those wires split on a few locations , I have no idea?

I wrapped those wires with electrical tape, then I used lots of packing tape around the battery this time around. It is much more secure. I will also add more foam sheets to the sides of the battery.


You can see the blue wire silicone is cut open and the copper wire inside exposed. This wire sat above another group in series, as you can see it is over the black wire nickel. If this wire lost its insulation it may have touched the nickel tab on that adjacent parallel group. There may have been kapton tape under this wire also but I don't know if I added the tape below it. This time I did on those few wires run over other series cell groups.
Uik4Ugi.jpg


The orange wire has a small chunk out of it. All the other wires around it are still perfectly untouched. Maybe this wire was higher than the others? I could not tell.
yGbeIfk.jpg


This was the side of the pack when I removed it, the tape still looks in good order at those locations.
t1654sO.jpg


I used this packaging foam on the sides, there are 3 thin sheets of this fragile stuff and not a single hole or wear mark can be found. Makes me believe this didn't happen from rubbing on the side covers or there would have been a hole and wear marks on this soft foam and there was not. Something else must have caused damage on those wires.

1zDwQOZ.jpg
 
That's pretty concerning. It could be fairly disastrous if a wire shorted. In both cases it appears there is another wire directly under the spot where it rubbed through, so those must be high spots. I would recommend using fish paper or Nomex paper between the wires and the cells anyplace where a short is possible. A bunch of silicone glue around them might help too.
 
Agreed, I think it also was probably a high spot and the pressure just separated the silicone.

Lucky 95% of the wires are above the series group they connect so it would not short anything.

I'm going to try and put some extra foam strips in areas where there are no wires so they hopefully take pressure off the other high spots.

The battery is surrounded by steel and aluminum, so I'm not too worried about a fire. I also keep the bike in my detached garage so not worried about smoke.
 
Why build this way?
https://i.imgur.com/yGbeIfk.jpg
 
Some kind of rubbery potting stuff or just plain silicone glue would help protect things if it could completely cover the wires. Any side loading would be carried by the potting.
 
I got rid of the foam sheets at the sides of the battery and decided to cut dense foam insulation and stick it at the places where there were no wires. There shouldn't be much sideways forces so this should hold the battery firmly in place and not pressure on the wires. It should also allow for better cooling then using foam sheets on the sides.

The only issue is I'm not sure if I made the foam thick enough as I cut each piece to size and stuck it on. The side panels were elevated when I put them on.

The battery sits extremely tight in foam and it embeds itself into the foam so there should really be practically no side ways movements.

AQBPcSr.jpg


vzuncAk.jpg


The other side
w9mLl8B.jpg



This is what I used before on the sides of the battery, multiple sheets of foam. This also probably insulated the battery from shedding heat. It also pushed mainly on the wires to hold the battery in place.
q4Dccq1.jpg
 
I'm currently building an 18S14P pack from Sanyo GAs's. I found my old SLA was lacking punch and I was having to crank the knob all the way up to get decent welds.
So I made a little 4S2P pack from old/spare 18650's and wired it in parallel with my SLA. It seems to be enough and now I don't need to crank the welder to the max to get good welds. :)

Cheers
 
How big was your SLA battery? I use a large one that was intended for a large SUV or ford expedition. It welds .15 nickel very easily.
 
Offroader said:
How big was your SLA battery? I use a large one that was intended for a large SUV or ford expedition. It welds .15 nickel very easily.
It's the old battery from my SUV, 750CCA, but is about 7-8 years old and was removed from my SUV after it was drained from an interior light being left on overnight. It's the age of the battery, not it's capacity that's the issue.
I didn't want to spend any money on a new SLA...especially when I'm surrounded by unused lithium...hence why I put some of it to use. :D
The cells I used were 4 x Sanyo GA's that accidentally went to 1.5V once and 4 x old laptop battery pack cells. I know not to normally mix old/new or diff capacity cells, etc, but in this case I don't care what happens to these cells anyway and checking the cell voltages and temps to make sure it's ok during use.
So far this little booster pack is not even getting warm to the touch even though ambient temps are high (40C+) here currently cause of a big heatwave.

My JP is certainly proving to be a worthwhile investment...this ~3.2Kwhr (252 cell) pack is already sold, and I have several more smaller packs planned for my new LMX once it arrives. :)

Cheers
 
Here's my setup and the in-progress battery build :)

DSC_5209.JPG
DSC_5211.JPG

As can be seen here, I have my 750CCA SLA, PSU (set to 15V), and 4S2P booster pack. Before I added the booster pack the PSU would jump to 15A charge to the SLA immediately following each weld and then taper off. Now with the booster the PSU only jumps to 6-7A after each weld and I can turn the welder time down half a turn compared to before. :)

Cheers
 
I have 3 welders. I bought the JP first. I was enticed by all the progress made on the second welder I bought, also here on ES. BUT I have to send it back, unused for a fix. SO, I bought a second JP as my backup. The first still works fine. This JP welder seems to get the least attention, and yet in my experience (yes limited) it's more reliable.

As Always YMMV
 
Cowardlyduck said:
My JP is certainly proving to be a worthwhile investment...this ~3.2Kwhr (252 cell) pack is already sold, and I have several more smaller packs planned for my new LMX once it arrives. :)

Cheers

Thanks, I 'm really glad to hear that! :)

tomjasz said:
I have 3 welders. I bought the JP first. I was enticed by all the progress made on the second welder I bought, also here on ES. BUT I have to send it back, unused for a fix. SO, I bought a second JP as my backup. The first still works fine. This JP welder seems to get the least attention, and yet in my experience (yes limited) it's more reliable.

As Always YMMV



Thanks for nice words! :)
 
litespeed said:

Hi Tom,

I read your post of the reply from Bryce Bytheway from Sunstone Engineering on welding copper and you seem to be in the know. So when I was looking at other posts of yours I saw the side pulls on the above battery and I always wanted to ask some one in the know about the correct way to pull off a long line of parallel cells.

So you have a 15P and you although you have a good bus bar running down those 15 cells your pulling your NEG and POS wires off on the side, like from the last 2 cells. This appears to be a very poor design but that may because of my lack of understanding. As current travels in series wouldn't it be better to have 15 jacketed wires of equal length twisted fitted into a connector (yes perhaps an overkill). Or you could use 8 jacketed wires and pull them off in between each 1.875 cells give or take a little. Or perhaps even 4 jacketed wires from from each 3.75 cells.

I'm not sure you build the above battery but what is your take on this issue please.

Bob
London.Ontario.Canada
 
Can you draw a picture to convey your thoughts?

As far as soldering the wire from the middle or the end of the run I call bull shit on that. Both ways draw current and voltage. Without sophisticated equipment you WILL not be able to tell the difference and even there would be the equivalent of slicing hairs.

Tom
 
Has anyone found a good supplier of "pure" nickel strips (not the nickel-plated steel kind) 0.20 mm thick X 8 or 10 mm wide?
I bought some through aliexpress but I am afraid they are made of some alloy that causes the electrodes to stick big time.
I have tried different electrodes material and thickness and even bought the Glidcop type from Sunstone but the stickiness continue.
Played with different settings (welding time, electrode pressure, voltage) to no avail.
This is happening with four different welders: A 800 W/S CD , JP and kWeld as well as MOT and I have run out of things to try.

Because the 0.15 trips don't stick to the electrodes, by the process of elimination I am blaming the thicker strips' alloy as the culprit.

Anybody have acquired 0.20 thick nickel that does not stick to the electrodes?

Thanks.
 
It sounds like you don't have enough current. You might try a stronger battery as a supply. The other thing to try is slotting the nickel so the electrodes are on opposite sides of the slot.
 
That's what I originally thought and figured that by buying this battery (brand-new) for the JP welder, I would be all-set:

OptimaYellow Top Deep Cycle Battery, Group Size 31T, 900 CC.
https://www.optimabatteries.com/en-us/yellowtop-deep-cycle-battery
Manufacturer claims an Internal Resistance of 0.0025

But no cigar: electrodes continued to stick when using the 0.20 nickel.

Then, I built my first MOT using this transformer:
SAMSUNG DE26-00126B MICROWAVE TRANSFORMER SHV-U1870D *B01
https://tinyurl.com/yy566dr7
Then, added a second MOT with secondaries in parallel, then a third one (all 3 identical, of course) and still no difference.
Even tried a Harbor Freight 220 volt spot welder transformer (tested 3, 4, 5 and 6 turns on the secondary) then two of them in parallel.

All along, the powerful CD 800 Watts/sec, with plenty of juice, was doing the same thing.
http://frikkieg.blogspot.com/
Mind you, this unit was built with three 1.070 Farad with a 0.001 ESR at up to 25V. (And I confirmed these specs when I received them)
Enough power to blow a big hole through the nickel and the battery can if cranked high enough.
I also tried all-copper 2 AWG cable to wire my setups but saw no change :(

The slotted nickel strip? I tried that with no luck, unfortunately.

So, recently, I bought one kWeld unit and though, electrodes are sticking a little less, I can't say I have resolved the issue.

In summary, I can get a darn good nugget with all my welders using the 0.20 mm nickel, but the doggone electrodes stick big time.
Not so with the 0.15 mm thick one and I find hard to believe the difference of .005 ONLY is the reason for all this trouble.

Given all the things I have tried, buying a known-good nickel material is the next logical step.
At least, it would eliminate this as the problem's source.

Hopefully, someone can point me to a trusted vendor. I have tried 2 on Aliexpress (a while back) and those strips have kept me busy for a long time, trying to eliminate the stickiness.

Thanks for reading this mini-book :)
 
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