ichiban
100 W
So, I assume that means there is no easy/straight way to attach MP4 directly into a post ?
kWeld - "Next level" DIY battery spot welder
- Thread starter tatus1969
- Start date
Crash_3174
1 µW
- Joined
- Aug 1, 2019
- Messages
- 1
tatus1969 said:
Hi, all very new here seeking expertise on the kweld. I have had mine now for over 3 years and no real issues. Now all I get is overcurrent messages. Tried 3 batteries now still the same thing. Anyone know why this would be the case. On calibration I got 1850a, 1566a and 1410a, all giving me the overcurrent message. Any ideas would be great thanks all
Do any of the FETs exhibit visual signs of being different than before? If not, you could set a multimeter to diode mode, and check from the tab with red lead to the rightmost pin with black lead, then the opposite. This should show if the FETs are damaged.
ichiban said:
No. Some time ago the forum admins removed this ability and deleted all existing such files, I think to save server space due to costs.
The best way to post a video is to put it on youtube or some other video streaming/hosting service, and link it here. YT is good because there is a button already in the forum to create an embedded video with it on the page, by putting just the alphanumerics at the end of the YT URL between the youtube tags.
ichiban
100 W
Thanks ! 
ichiban
100 W
Crash_3174 said:
Like some suggestions on this threads, try using partially discharged batt for CAL, that might help.
You said there had been no real issues before. How about what happened "before" you have this overcurrent warning AND why do you want to do calibration (CAL) ? Any mods/changes ? Pls take some pictures of your whole set-up and post here for the gurus to see better and help. Especially, very clear close-up pictures at the kWeld pcb to see whether there are some visible/physical damages. Details like wires length & gauges, batt size, how you do your CAL, etc. will help to diagnose.
Do check your kWeld per amberwolf's hints above. If there is something wrong, need to fix that first. Contact your supplier is the first way to go.
For my kWeld, I also found overcurrent warning during CAL even that the current was just a bit above 19xx A. My system has a programmable CC-CV regulators, so I just lower the voltage gradually by 0.1V at a time to feed kCap and tried CAL again until no warning. Then CAL can be completed. Do not know what your system is like ?
ichiban
100 W
*** Continue with kWeld's Mod ***
The Maxwell 3400F 2.85V *4pcs giant caps I ordered have arrived. They are used ones but in good physical shape. I do not know how to test them in terms of ESR, capacitance, etc. Anyone knows how to do that easily with basic tools, kindly enlighten us.
However, these caps are BCAP3400 P285 K05 which intended to be connected to caps ends. There are no threaded studs on either end. So need to spotweld, tightly clamp or solder, may be with dip solder tank. Anyone want to buy these, BCAP3400 P285 K04 (with threads) should be easier.
I intend to make 4S1P out of these caps to make something similar to kCAP. These supercaps module will be at 2.85*4 = 11.4 V which can boost welding current easily via kWeld. I might need a new PSU that can output 14-15V 60A or higher to sufficiently supply my programmable CC-CV regulators (+ power diodes). That should enable kWeld to inject current through the Cu-Ni(Fe) sandwich as high as kWeld's limit 2,000A quickly, t (mSec) will be shortened by as much as 3-4 times (theoretically). High amp at low t = high Q, that is exactly what we want to weld Cu effectively. Thicker copper like 0.3, 0.4 mm or more is our potential target.
When connecting these caps in series, balancing circuit is needed. I ordered these :
https://www.aliexpress.com/item/4000001731159.html?spm=a2g0o.order_detail.order_detail_item.5.d0184ecfJOplRz&gatewayAdapt=glo2tha
, for testing. There are several types of balancing boards in the market. These boards work mostly to watch overvoltage by draining current from almost-full cap strings. They do not protect short cct, low voltage protection and etc. like BMS for battery pack. But Frank mentioned that they might not work well especially when caps are off balance by much (like 2.5v // 2.7V.). The almost full string can be overcharged. May be due to its low balancing current that cannot keep up with the high-current charger. Need to try that out. May be we can DIY an easy version spot-welder (starting from kWeld+kCap) that can weld thick Cu effectively.
Frank is working on his next version kWeld Pro, which should be capable of 4500 amps ! Something we are really looking forward to. Prepare to fill your piggy bank quickly.
I am quite a noob for these supercaps things, any comments / tips would be greatly appreciated.
The Maxwell 3400F 2.85V *4pcs giant caps I ordered have arrived. They are used ones but in good physical shape. I do not know how to test them in terms of ESR, capacitance, etc. Anyone knows how to do that easily with basic tools, kindly enlighten us.
However, these caps are BCAP3400 P285 K05 which intended to be connected to caps ends. There are no threaded studs on either end. So need to spotweld, tightly clamp or solder, may be with dip solder tank. Anyone want to buy these, BCAP3400 P285 K04 (with threads) should be easier.
I intend to make 4S1P out of these caps to make something similar to kCAP. These supercaps module will be at 2.85*4 = 11.4 V which can boost welding current easily via kWeld. I might need a new PSU that can output 14-15V 60A or higher to sufficiently supply my programmable CC-CV regulators (+ power diodes). That should enable kWeld to inject current through the Cu-Ni(Fe) sandwich as high as kWeld's limit 2,000A quickly, t (mSec) will be shortened by as much as 3-4 times (theoretically). High amp at low t = high Q, that is exactly what we want to weld Cu effectively. Thicker copper like 0.3, 0.4 mm or more is our potential target.
When connecting these caps in series, balancing circuit is needed. I ordered these :
https://www.aliexpress.com/item/4000001731159.html?spm=a2g0o.order_detail.order_detail_item.5.d0184ecfJOplRz&gatewayAdapt=glo2tha
, for testing. There are several types of balancing boards in the market. These boards work mostly to watch overvoltage by draining current from almost-full cap strings. They do not protect short cct, low voltage protection and etc. like BMS for battery pack. But Frank mentioned that they might not work well especially when caps are off balance by much (like 2.5v // 2.7V.). The almost full string can be overcharged. May be due to its low balancing current that cannot keep up with the high-current charger. Need to try that out. May be we can DIY an easy version spot-welder (starting from kWeld+kCap) that can weld thick Cu effectively.
Frank is working on his next version kWeld Pro, which should be capable of 4500 amps ! Something we are really looking forward to. Prepare to fill your piggy bank quickly.
I am quite a noob for these supercaps things, any comments / tips would be greatly appreciated.
A-DamW
100 W
ichiban said:*** Continue with kWeld's Mod ***
I am quite a noob for these supercaps things, any comments / tips would be greatly appreciated.
@ichiban
I have been using a 6s1p supercap bank(used, 2nd hand cells) to start my 5.9litr cummins diesel pickup since 2014, NO balancing circuity.
They are the Maxwell 3000F 2.70V(slightly older generation than yours).
Open circuit voltage on my alternator(no lead acid battery in parallel) is around 15V max(usually closer to 13.8V).
So 15Volts/6series = 2.5V per capacitor, ~0.2V or 200mV headroom per cap, worst case scenario.
When I built the cap bank, I started with all cells at 0V, then charged them(as 6s1p) to the nominal voltage of my vehicle.
The reason I charged the cells from 0V, is I wanted to see the natural variation of the cells in series.
Then I checked the balance of each cell, If I recall, it was max ~0.015 or 15mV delta.
I was pretty nervous the first few days/weeks starting the truck(can easily pull 2000A starting), I would check balance every time before and after starting.
After checking regularly for months, none of the cells drifted high or low(still a few 10's mV difference, but no drifting out of range)
So after 8 plus years, I maybe check balance once a year, I just checked last month, still within a few 10's mV difference.
My advice would be, spend the money on additional supercaps, run the pack with minimum 200-500mV headroom per cell(check balance regularly of course), and don't waste money on balancers. Plus, more caps just means easier upgrading to kWeld Pro!
I have a spot welder I am planning on using with my supercap bank.
With a 1,000,000 charge/discharge rating, you will be handing these caps to your grandchildren.
Hi. After I tested cheap Sequre SW2 spot welder I decided to switch to kweld which will be more suitable for my needs. But now I have question about what Lipo battery to be used. From keenlab website recommendation that this https://hobbyking.com/en_us/turnigy-battery-nano-tech-5000mah-3s-65-130c-lipo-pack-xt-90.html is good one. But now it is out of stock. I found another one on hobbyking website https://hobbyking.com/en_us/turnigy-nano-tech-plus-5000mah-3s-70c-lipo-pack-w-xt90.html which is the cheaper but on paper have better specs compared to almost twice expensive one. Also I can obtain that battery easily from local shop in my country. But I can't understood difference between them. Maybe nano-tech non plus have better battery life? I see also that there is sign "matched" on battery. I didn't know what that's mean on Turnigy batteries?
ichiban
100 W
Great to read your sharing A-DamW. Yours is actual proven usage from experience. :thumb: :thumb:
That's a good safety margin for the supercaps charging, especially from fluctuated alternator. Your cap cells seem very well balanced even for used ones at 15mV diff. Considering your 8+ yrs of actual usage for engine starting application, it well passs most standard for daily uses.
The critical part with serial supercaps is that they can be overcharged, which will shorten their lives and can even lead to explosion. We all heard that but I have not personally seen any serious damages of overcharged supercaps, except that they got very hot (no explosions ??). The supercaps manufacturer use the term "V absolute maximum" that should tell us something. So, I assume that we might get away with it for slightly overcharges and once in a while, but prolong/frequent overcharge is to strictly avoid. However, reversed polarity supplied to supercaps or even regular small caps that is guanranteed to cause serious explosion. Similarly, a batt pack without a good BMS will never give me a peaceful sleep at night. Lithium batt is even more sensitve to mistreats than supercaps, particularly when they aged.
I do have some questions/opinion re supercaps bank for kWeld :
1) Your case is for engine starting, which are just several starts/stops on a daily basis. That means supercaps will be charged/discharged only several times per day. But for spot-welders, we use it to weld our batt pack hundreds or even thousands of welds to be made per day(or per pack). So, there are inevitable hundreds / thousands of charges / discharges per day. The risks of these heavy uses spotwelding should be much higher than your case ? So, good balance boards for serial supercaps should be money well spent ?
2) Most supercaps modules commercially availble in the market do have balance boards equipped as a standard, even the cheap ones for car audio buffering from China. kCap 3S2P is also included. That also tell us something.
3) For used supercaps, we do not know how much aging, "off" and mismatch are they from spec. They might have been through only some perfect cycles or severely abused before reaching our hands - difficult to check. These mismatches among individual caps will cause them to charged diffrently, some caps V will rise and reach Vabsolute max sooner than the rest. In such case, the balance boards can be a big help here. If they are new or well matched caps, you probably do not need balancing, at least for a while before they aged.
These expressions are intended for exchanging wisdom of the community through discussions/sharing. All productive comments / experiences are welcome here.
Look forward to doing that !! By that time, their new toys might be some hard-core levitating bikes !
A-DamW said:
That's a good safety margin for the supercaps charging, especially from fluctuated alternator. Your cap cells seem very well balanced even for used ones at 15mV diff. Considering your 8+ yrs of actual usage for engine starting application, it well passs most standard for daily uses.
A-DamW said:
The critical part with serial supercaps is that they can be overcharged, which will shorten their lives and can even lead to explosion. We all heard that but I have not personally seen any serious damages of overcharged supercaps, except that they got very hot (no explosions ??). The supercaps manufacturer use the term "V absolute maximum" that should tell us something. So, I assume that we might get away with it for slightly overcharges and once in a while, but prolong/frequent overcharge is to strictly avoid. However, reversed polarity supplied to supercaps or even regular small caps that is guanranteed to cause serious explosion. Similarly, a batt pack without a good BMS will never give me a peaceful sleep at night. Lithium batt is even more sensitve to mistreats than supercaps, particularly when they aged.
I do have some questions/opinion re supercaps bank for kWeld :
1) Your case is for engine starting, which are just several starts/stops on a daily basis. That means supercaps will be charged/discharged only several times per day. But for spot-welders, we use it to weld our batt pack hundreds or even thousands of welds to be made per day(or per pack). So, there are inevitable hundreds / thousands of charges / discharges per day. The risks of these heavy uses spotwelding should be much higher than your case ? So, good balance boards for serial supercaps should be money well spent ?
2) Most supercaps modules commercially availble in the market do have balance boards equipped as a standard, even the cheap ones for car audio buffering from China. kCap 3S2P is also included. That also tell us something.
3) For used supercaps, we do not know how much aging, "off" and mismatch are they from spec. They might have been through only some perfect cycles or severely abused before reaching our hands - difficult to check. These mismatches among individual caps will cause them to charged diffrently, some caps V will rise and reach Vabsolute max sooner than the rest. In such case, the balance boards can be a big help here. If they are new or well matched caps, you probably do not need balancing, at least for a while before they aged.
These expressions are intended for exchanging wisdom of the community through discussions/sharing. All productive comments / experiences are welcome here.
A-DamW said:
Look forward to doing that !! By that time, their new toys might be some hard-core levitating bikes !
Deadrabbit
10 mW
- Joined
- May 26, 2019
- Messages
- 24
Hi,
I have some A123 anr26650m1a cells leftover. I want to build a 12s3p power supply for my kweld.
This is my design, I ended up with:
The H-Nickel strips are 10 mm x 0.15 and the bus bar strips out of 8 mm x 0.3.
I want to solder a AWG8 cabel to the bus bars.
Are there any recommendations?
Thanks!
Maximilian
I have some A123 anr26650m1a cells leftover. I want to build a 12s3p power supply for my kweld.
This is my design, I ended up with:
The H-Nickel strips are 10 mm x 0.15 and the bus bar strips out of 8 mm x 0.3.
I want to solder a AWG8 cabel to the bus bars.
Are there any recommendations?
Thanks!
Maximilian
Search "resistance soldering unit" / RSU
Deadrabbit
10 mW
- Joined
- May 26, 2019
- Messages
- 24
spinningmagnets said:
You mean I should use copper sandwiches?
I found your blog article according to RSU.
Thick cables are very hard to solder with conventional soldering irons. For fat copper cable I prefer crimping with a hydraulic crimper, but I think an RSU is cheaper and easier to get or make.
If you end up having a spot-welder, it's surprisingly handy to have around.
Deadrabbit
10 mW
- Joined
- May 26, 2019
- Messages
- 24
I also have a heat gun and I think, this might be no problem to solder the cable to the nickel strip.
I didn't understand your comment, the pack should be a power supply for my kweld instead of the heavy lead acid battery.
BW
I didn't understand your comment, the pack should be a power supply for my kweld instead of the heavy lead acid battery.
BW
Oscillator Ocelot
100 µW
- Joined
- Dec 25, 2022
- Messages
- 9
Hi everyone!
(Full details of what happened are at the bottom of my post) The lipo I was using was a Turnigy Graphene 5.0 4S 75C lipo
I have a question about using two batteries vs. one battery to power my Kweld. I hope posting it in this thread is okay.
I’ve been a long time lurker, and built a Kweld system using your generous contributions of data gathered from your experimentation, and I thank you greatly for that.
In short, my lithium polymer battery died while powering my Kweld, and I’d like to know:
1) Is using two identical lipo batteries in parallel a good way to reduce current stress on the battery while powering a spot weld?
2) Would using a lipo battery with fewer cells (3S instead of 4s) be more hardy for the kinds of current draw seen in a spot weld (less points of failure, etc.); assuming the 3S and 4S battery both have a 75C continuous rating, and 150C peak rating?
My reasoning (please correct me if I’m wrong) is that the weld (generation of heat) mostly depends on current to generate that heat, so adding voltage to increase total power doesn’t help much with the weld. Correct?
3) What should I do with my dead lipo? It’s fully charged, but cell #3 shows zero voltage through the balance wire. The main power connector shows zero voltage (I assume cell #3 failed as an open circuit). There’s no swelling apparent. My current plan is to carefully cut off the heat shrink and use my balancing battery charger/discharger to bring the individual cells down to a safe storage voltage and then… I don’t know. Are the other cells still good? Is the whole thing dangerous now? The battery is currently being stored outside on concrete in case it vigorously vents with flame.
For anybody interested, here are the full details:
I’m using the sandwich method with 0.2mm copper and 0.15mm pure nickel strip. I cut the nickel strip into two thin strips to help direct the current down through the copper instead of across through the nickel.
I had to increase the joules setting on the Kweld to at least 100 joules before I started getting welds that I couldn’t easily pry off the battery cap. The weld was pulling around 1800 amps. I only got a couple welds finished at that setting before I heard a click from the lipo powering the Kwelder, at which point the Kwelder started displaying an undercurrent message and refused to weld. I unplugged the welder and plugged it back in and started a calibration process. The short required for the calibration finished off the lipo. The Kwelder wouldn’t even power up at that point.
I’m assuming (hoping) the battery dying has nothing to do with a failing component on the Kweld, and the battery died because the thickness of the copper I used for the sandwich method required too much current from the lipo to make a good weld. That’s why I’m contemplating using two lipos so the current demand on the battery is cut in half.
Maybe something else is going on? Maybe the battery I was using should be able to handle those tiny moments of 1800amps just fine and I just encountered a freak accident?
Any help would be greatly appreciated!
Thanks!
(Full details of what happened are at the bottom of my post) The lipo I was using was a Turnigy Graphene 5.0 4S 75C lipo
I have a question about using two batteries vs. one battery to power my Kweld. I hope posting it in this thread is okay.
I’ve been a long time lurker, and built a Kweld system using your generous contributions of data gathered from your experimentation, and I thank you greatly for that.
In short, my lithium polymer battery died while powering my Kweld, and I’d like to know:
1) Is using two identical lipo batteries in parallel a good way to reduce current stress on the battery while powering a spot weld?
2) Would using a lipo battery with fewer cells (3S instead of 4s) be more hardy for the kinds of current draw seen in a spot weld (less points of failure, etc.); assuming the 3S and 4S battery both have a 75C continuous rating, and 150C peak rating?
My reasoning (please correct me if I’m wrong) is that the weld (generation of heat) mostly depends on current to generate that heat, so adding voltage to increase total power doesn’t help much with the weld. Correct?
3) What should I do with my dead lipo? It’s fully charged, but cell #3 shows zero voltage through the balance wire. The main power connector shows zero voltage (I assume cell #3 failed as an open circuit). There’s no swelling apparent. My current plan is to carefully cut off the heat shrink and use my balancing battery charger/discharger to bring the individual cells down to a safe storage voltage and then… I don’t know. Are the other cells still good? Is the whole thing dangerous now? The battery is currently being stored outside on concrete in case it vigorously vents with flame.
For anybody interested, here are the full details:
I’m using the sandwich method with 0.2mm copper and 0.15mm pure nickel strip. I cut the nickel strip into two thin strips to help direct the current down through the copper instead of across through the nickel.
I had to increase the joules setting on the Kweld to at least 100 joules before I started getting welds that I couldn’t easily pry off the battery cap. The weld was pulling around 1800 amps. I only got a couple welds finished at that setting before I heard a click from the lipo powering the Kwelder, at which point the Kwelder started displaying an undercurrent message and refused to weld. I unplugged the welder and plugged it back in and started a calibration process. The short required for the calibration finished off the lipo. The Kwelder wouldn’t even power up at that point.
I’m assuming (hoping) the battery dying has nothing to do with a failing component on the Kweld, and the battery died because the thickness of the copper I used for the sandwich method required too much current from the lipo to make a good weld. That’s why I’m contemplating using two lipos so the current demand on the battery is cut in half.
Maybe something else is going on? Maybe the battery I was using should be able to handle those tiny moments of 1800amps just fine and I just encountered a freak accident?
Any help would be greatly appreciated!
Thanks!
Once a battery has experienced a stress event, (overcharge, overdischarge, overheat, etc) it has changed from it's original composition (a little, a lot, almost impossible to know exactly even if you knew it's exact characteristics before the event to compare with testing those characteristics after, since the change could be microscopic in nature).
the change may not be problematic in a dangerous sense, it might just affect (however minutely) it's ability to supply current, or increase voltage sag, or decrease capacity, etc.
Liveforphysics has posts with more info on this for various kinds of stresses, based on his battery testing and RnD.
For this case, you'd need to test what the actual per-cell voltages are to see what each cell actually is, at the cell tabs for each individual cell (not just the balance wires).
There is a possibility that an interconnect between cells has failed (unsoldered, or blown like a fuse), and that the balance wire for the cell that reads 0v is on the wrong side of that interconnect, so it's no longer connected to the cell. In this case, it's likely that none of the cells have stress damage, and the only problem is the interconnect(s) being unable to handle the current being drawn from the pack.
As for using multiple packs in parallel; it's virtually always going to be "better" in regards to lessening cell stress to do this, unless you can get cells that are directly capable of handling the required currents while staying near the median of their capabilities. (or at least, not coming near the extremes of those capabilities).
the change may not be problematic in a dangerous sense, it might just affect (however minutely) it's ability to supply current, or increase voltage sag, or decrease capacity, etc.
Liveforphysics has posts with more info on this for various kinds of stresses, based on his battery testing and RnD.
For this case, you'd need to test what the actual per-cell voltages are to see what each cell actually is, at the cell tabs for each individual cell (not just the balance wires).
There is a possibility that an interconnect between cells has failed (unsoldered, or blown like a fuse), and that the balance wire for the cell that reads 0v is on the wrong side of that interconnect, so it's no longer connected to the cell. In this case, it's likely that none of the cells have stress damage, and the only problem is the interconnect(s) being unable to handle the current being drawn from the pack.
As for using multiple packs in parallel; it's virtually always going to be "better" in regards to lessening cell stress to do this, unless you can get cells that are directly capable of handling the required currents while staying near the median of their capabilities. (or at least, not coming near the extremes of those capabilities).
BVH
1 kW
- Joined
- Mar 26, 2009
- Messages
- 411
I use two, 3S/6000 Graphenes with no trouble. During calibration, I can use only one because I will get an over-current error with too much current available with two in Parallel. Calibrate with one, then put two in parallel. IIRC, way back in the thread, it was recommended to use 3S v 4S for a higher current flow to meet the Joules setting, since the Kweld is basically a finely calibrated "short circuit" device. Raise Voltage, reduce current and vice-versa.
Hi guys, just wanted to give a sign of life here - Happy New Year! Somehow my topic notifications go into the spam folder and therefore I wasn't notified a long time...
A lot has happened in this forum since, if there is anything where I should respond then I'd be happy if that user repeats his question here
I also have some news to spread: I am working on a new device "kWeldPro". Parts are already piling up here (chip crisis means that you need to buy a part at the moment you are putting it into your schematics...), and I should have first prototypes by mid of this year. Some key specs:
- ready to use desktop unit with AC input
- supports welding copper (3000 amps minimum)
- 450W power supply (200 joule pulse, once per second, at device output terminal)
- water cooled electrode system (option)
- pneumatic actuator (option)
- 4.3'' touch screen
- USB, RS232, PLC interface, dual trigger
- folded steel enclosure
- price tag around 1000€ (base unit, probes and power supply will be extra)
Cheers Frank
Somehow my topic notifications go into the spam folder and therefore I wasn't notified a long time...A lot has happened in this forum since, if there is anything where I should respond then I'd be happy if that user repeats his question here
I also have some news to spread: I am working on a new device "kWeldPro". Parts are already piling up here (chip crisis means that you need to buy a part at the moment you are putting it into your schematics...), and I should have first prototypes by mid of this year. Some key specs:
- ready to use desktop unit with AC input
- supports welding copper (3000 amps minimum)
- 450W power supply (200 joule pulse, once per second, at device output terminal)
- water cooled electrode system (option)
- pneumatic actuator (option)
- 4.3'' touch screen
- USB, RS232, PLC interface, dual trigger
- folded steel enclosure
- price tag around 1000€ (base unit, probes and power supply will be extra)
Cheers Frank
ichiban
100 W
Great News !! Look forward to seeing its performance by welding thick copper directly. 
hallkbrdz
100 W
That sounds great - look forward to it.
@tatus (Frank):
For me it would be interesting to know the differences between the old kCap-board (Maxwell) and the new one (SkelCap). From the posts here it looks like that you can't overcharge the new board, because the charging automatically stops and so there is also no need for increasing at 0.1V steps to get more juice out of it correct?
Check post here and the following ones:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=89039&p=1711445#p1711434
Thanks
For me it would be interesting to know the differences between the old kCap-board (Maxwell) and the new one (SkelCap). From the posts here it looks like that you can't overcharge the new board, because the charging automatically stops and so there is also no need for increasing at 0.1V steps to get more juice out of it correct?
Check post here and the following ones:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=89039&p=1711445#p1711434
Thanks
The overcharge protection is not directly related to the capacitor type, as there are multiple revisions with Maxwell, some without and some with the protection. You can tell that the board has protection by the presence of a small black heatsink in the control section. The protection cuts off the charger when reaching 8.4 ... 8.5V, and periodically reconnects keep the caps topped up. I recommend to limit the charger voltage to 8.5V in order to have double protection, but 12V is also ok. The unprotected boards need to be limited to 8.1V externally. I haven't tested the old Maxwells at 2.85V per cell, so I can't truly recommend using 8.5V on these modules. But generally, going close to the max will produce the most welding current.Eraser-1 said:
The protection circuit allows 70 amps of current max, and therefore can be damaged from too high inrush current. Some people have tried to use batteries to charge the caps, or have used power supplies without current regulation. An ATX power supply is such a case. The caps represent a dead short when empty, and these power supplies try to push as much current as they can before shutting down.
The new SkelCaps are also electrically better and produce roughly 100 amps more current.
Hello guys,
I use a kwelder for a few years and recently bought for it a welding pen from aliexpress and some electrodes that come with the pen.
Now the problem is that the electrodes stick to the nickel strip after the welding and they even melted(this happened when I calibrated the system and pushed the electrodes into a chunk of copper).
I get 1400-1500a from my power source so don’t think this is a problem.
I cleaned everything with isopropyl alcohol but the result is still the same.
What should I try in this case?
I use a kwelder for a few years and recently bought for it a welding pen from aliexpress and some electrodes that come with the pen.
Now the problem is that the electrodes stick to the nickel strip after the welding and they even melted(this happened when I calibrated the system and pushed the electrodes into a chunk of copper).
I get 1400-1500a from my power source so don’t think this is a problem.
I cleaned everything with isopropyl alcohol but the result is still the same.
What should I try in this case?
