I got one of these... I blew the first one and did the mods on the second one... then I realized my battery is not powerfull enough. The label says its 10000mah 25c lipo.... but it is only able to spot weld 0.10mm tabs. I tried the 0.15 and 0.2 but they don't stick. So I ordered a new lipo from a more reputable brand and it arrives tomorrow. Thank you for taking time to help others.
I want to say thanks, using your tutorials I was able to fix my Bl18-2k unit. When I got it, I hooked it up to a car battery but it would not do anything. It made all the correct beeps and the display and buttons all worked correctly. I found the diode was bad so I changed it and added the inrush current limiter resistor in series with the diode and I also changed R4 to 470 ohms. Still did not work. After changing all three transistors in the push pull circuit it started to work. Thanks again.
Gladd to hear - the push pull transistors usually don't fail, so I'm surprised this happened to you. Maybe it was a defect (DOA) - did you test the transistors to see if any of the three had failed/shorted?
@@Luca_Techy It could very well have been bad from the start. it never worked from the first time I tried it. I did try to check them with a cheap Electronic component tester, but it said they were diodes. I salvaged all the replacement parts from old electronic boards I had and used the component tester to figure out what they were so it worked pretty good for that.
@@dennisallen2264so this is the exact issue i am having. It appears everything works other then the actual weld happening. I got my welder from banggood about a week ago and it is the CA20-2K. Can either one of you make a video checking the transistors? I have tried a car battery and a 3s 5000mah 60c battery with no luck I get the beeps like it is working but no welds or arks.
Thank you for the work you have done in detecting and rectifying the issues with this unit. I am not an electrical engineer but was able to get the basic understanding of what the problems were and how you fixed them so when I received my unit it needed all three modifications that you identified which I carried out quite easily before switching it on for the first time. So far it is operating well and producing good quality welds without any magic smoke being released, I hope it continues. Thank you again for your videos:-)
I have this unit. When I tried for the first time, with a lawnmower battery (U1), I killed three of the FETs. I ordered some more and replaced them and added the capacitor fix suggested by Maker Luca but when I tested again (with a 94R battery this time), each time, a FET would pop and catch fire. I was getting decent welds (at 45) but was losing a FET each time. I'm not sure what the issue is. I put a DSO on when I was down to 2 and there didn't appear to be a deep sag in the voltage. I have five unused FETS left. I have a solenoid on order and I'm going to try using this device as a control on that and get the pack I wanted welded up and then I'll investigate further with the FETS.
What thickness strips were you trying to weld? Did you shorten the original power leads? Also, when a FET shorts you would need to replace the whole batch or simply leave the ones that are left as they are matched (supposedly) in batches. 45ms is already a very long pulse window, you should be able to weld .15mm strips with less than 20ms. Attempting to weld anything over .2mms is overkill for the unit and out of specs as explained in the FAQ (it all depends then on the FET matching and general assembly of the unit).
@@Luca_TechyThe strip is 0.15 so should be OK. Other than the replaced FETS and the extra capacitor, it's all stock. I don't think the number is ms but some energy measurement. If I said that, I misspoke. I bought a pack of 10 fets but I'll replace all five anyway (I only have one left on the board right now anyway). I'm going to try the solenoid and get my pack done before I try and mess with just the fets again (or I may just stick with the solenoid if it works well).
Just keep in mind that normal solenoids aren't reliable (consistent) under the 20ms or so time frame so you need a specific power solenoid that can handle that speed and current peak (200+Amps). Solenoids can be used for thicker spot welds but if you are spot welding 18650 or 27100 cells which usually takes 20ms or so and something gets stuck you will perforate the negative side of the cell permanently damaging it. The same applies to a shorted FET(s) situation to be clear which though should not happen under normal circumstances.
@@Luca_Techy I'll definitely be doing testing to see how well it follows the inputs. Damage to the cells is not that important for this pack as I'm using used cells (actually aggregating two existing packs). I have a bunch of dead ones that I can practice on too.
I've just received mine. It has a 357T optocoupler that I don't don't what for and it has an MCP1407 mosfet driver on the control board. But no decoupling capacitor after the diode on the control board (I added one 1000uF). The power board only holds the 10000uF cap with 5 mosfets and campling diode between each gate to drain, some 30 ohm serie resitor on each gates plus one 10k pull down resistor.
Hi Harold, please check out my previous video All "Mini Spot Welder" versions, I explain all the circuits and problems there, starting from the one you have.
@@Luca_Techy Thanks for the information to the other video (very instructive). Here is a chronogram of the trigger on pin 4 (output of the MCP1407 driver) in yellow, in purple the trigger at the mosfet's gate (between the mosfet's gate and the 30 ohm resistor) and the source to drain voltage in blue. www.dropbox.com/s/rq0tz4zby3ancrl/NewFile10.png?dl=0
@@Luca_Techy It's unmarked with has white buttoms with 5 mofets Rev 0 first additon. I think I will buy another one if I can't get this one working. Which version do you would you recommend? Or maybe a different type.
Ok so if you hear the double beep when contacting the electrodes it means the detect circuit is working - what battery are you using? Is it at least a 3S 5000mAh 50C or 12V AGM 45Ah? Did you try the 12V lamp test by increasing weld time up to max to see if you are getting a pulse?
Great videos! After seeing so many welders fail on their 1st weld I used your videos to modify a welder I got before I even powered it up, works perfectly. Thanks! Some questions, is there any way to power these with one battery and use another battery to do the spot welds? Also, I have a ton of 18650 3000mah that will do 20a draw. If I made a 3s pack from them, would a 3s10p which gives me a theoretical max draw of 200a be OK?
Theoretically you could by isolating the + line from the main battery so it just goes directly to the + weld contact and power the welder with a seperate smaller 12V battery connected to the + of the welder board. You can't use anything less than 12V to power the welder as the push-pull circuit voltages are calculated for this 12-16V input range else it will fail to drive the Gates properly (unless you change the resistor divider on the base, but then other problems can arise). I wouldn't worry about powering it with a seperate battery as once you have done all the mods the whole setup works pretty reliabily within it's operation limits.
I have the moded maple welder and I used a 6500MA 60C/120C lipo and with 5ms it burned the connector. So either my connector was not good enough or maybe the battery was too powerfull? Good thing is that no mosfet are burned only the connector from the battery to the welder....
By connector do you mean the terminal which screws on the board? Probably it wasn't soldered on well - it is very important that the power lines have good solid connections to the battery when you use these welders, they contact must be solid.
I have got my cb23-4k version And I didn’t modify it but at my second test the mosfet burn 🤦🏻♂️ I used 35ah car battery If I changed the burned mosfet and do these modifications is it will work good? Another question if I removed the burned mosfet without replacing a new one what will happen?
hi i just got one, as i plug it in it just beeps , the screen wont turn on, and it doesent react to the power button , i bought a 12v 5a charger and welded it to the tip they provide, what am i doing wrong? is my power supply not the correct one?
I'm a bit confused here, what did you weld to what tip? Firstly, use a 3S 5000mAH 50C (at least) Lipo pack to power the welder when welding strips. Be sure to connect the power to the input power side of the welder, not the output/terminal weld tip side. The input is on the right side of the welder looking at the display facing you so that the 3 buttons are below the display. If you connect the pack and the welder beeps but the display doesn't turn on then there's a fault: possibly just the display or it could be the MCU, but if it beeps it means the MCU is doing something and it may just be the display which is faulty. If you have that 5A 12V PSU/charger, connect that to the power input in place of the battery for testing purposes. It should beep as usual when you power it. Try simply bridging the welding tips together and see if you get a double beep - if so the welder works but the display is faulty (maybe the flat ribbon is misplaced on the connector or is torn - you can unscrew the top 4 screws and check the display ribbon yourself if it's seated correctly in the connector - be careful not to tear it). You should also connect a 6-12V lightbulb and try to see if it briefly flashes when connecting it across the weld terminals, but you would need to increase the weld time to over 50 to see a decent flash. If you bridge the terminals and nothing happens (no double beep) then the MCU is dead or there's a major fault. If the light bulb constantly shines when bridging again there is a major fault (shorted FET for ex.).
Hi Luca. I have an original version 0 unlabelled welder. Can you tell me the values of the 2 resistors situated between the optocoupler and the fet driver.thanks.
I'm not sure which ones you mean but the one in series with the opto on pin 1 is 1K (102). The other one located on the opposite side is a 10K pullup (103) which is located beside a cap (probably a 100nF or 104K) which is near the input diode. If you check my video (and the other All Mini Spot Welder versions) there is a pic of the original Rev 0 MCU where you should make out the components.
Hello Luca, Thank you for such a great video!! I made the stupid mistake of hooking it up backwards. The mosfets are definitely shorted out. Any idea what replacement mosfets i can buy? Can't see any part numbers on the mosfets. Thanks in advance!! Aaron
Hi Aaron, if you check out my video descriptions in the playlist the main components are all listed and there are links to download the schematics. If you hooked it up backwards hopefully you just may have damaged a FET but depending on the version you have you may have damaged also the regulator and/or logic board. You can try powering just the logic board if you have a bench power supply and some alligator clips and see if it turna on (check the pinout from my schematic to see which is + and minus - you can power it from 7V to 14V with less than 200mA current). If the logic board still works then you just have a shorted FET (or 2) and should be repairable. It also depends on what board rev you have.
No, but I did shorten them and also showed how much voltage drop there is on the welder from the battery (approx 50% of the voltage drops in the best conditions) with original cables. This drop on one hand reduces the weld energy but on the other hand limits the current through the FETs and helps increase their life span. If you reduce the cable length and/or replace the cables with larger (AWG 6) copper, you can but you must always "recalibrate" your setup starting from a low time setting (5ms) to see if you are not overdriving the welder. I find that with the default cables and a good battery pack (or 12V AGM 20Ah+ battery) the welder performs very well for .15mm strips with settings around 10-15ms. Driving it over 30ms with a good battery is risky, which is why the Wise Maple has this hard limit set in software.
@@Luca_Techy I guess they ARE a wise maple haha, thanks for the info, will keep it in mind, hopefully I can design a much better setup without all of the flaws, but that project is on my free time
do you mind having a look at the BIFRC? it seems to be doing a much better job than the other cheap spotwelders. it has 8 mosfets. Im getting my unit in two weeks. I will analyze the circuit to my ability and if you want send you pictures and measurements with my oscilloscope.
I had ordered one but never received it - I also ordered one with a one cell LiPo included and that also never made it here so I gave up. If you want to take some scope shots feel free to send me them thought the circuit analysis will be more difficult without the board itself.
I ordered my DH30 (m8s) LCD touch screen one in October 2021..(£45) From the first time didn't give me any proper impulse with a parallel 2x5000mAh 45c 3s LiPo.. Then with a 110Ah 950A car battery I had one successful welding after one fet blown.. I desoldered that FET and also ordered a complete replacement FET board. I tried with that car battery and with the old board few times, but there is many adjustment, not just the 20 gears but Ah, c... So I tried increase step by step, but the impulse was (if was ) most of the time a very little click heard, nothing more. Then when arrived to the maximum gear then few times got a very huge power, burned a hole in the nickel strip.. So I was given up a bit. Than I saw this video and thought, might same way if I trace and can hacking the control board's power, might will working. But... I made a mistake. I plugged to the computer with an USB-C cable. Appeared as a USB flash drive ( named haohaodada) there have to copy the new firmware if have (but not new or old found anywhere) From that time, the control board didn't booting. Because the on/off designed as a capacitive touch, I measured that chip it's works, if I touch the on/off surface on the case, then the 5V and 3.3V are present, if touch again then they disappear. So that part works, but no beep, no screen no any sign of life. If I plug to USB, as a flash disk still appears, but looks stucked in firmware update mode. The microcontroller is an ARM Cortex 0, but labelled as "haoda USB" As I researched that's a Chinese Stem program to learn programming this chip. On they website, have olnline courses, online interface for make scripts like Arduino IDE, but no any hardware documentation.. On they developer board seems like an arduino nano and there is a reset/restart button exists. But in this spot welder board not, so I can't just simple restart without at least know the chip pins and the layout.. Their website (bifrc.com) is totally wiped, nothing available, just like a freshly installed raw webserver.. No firmware, no contact, no support anywhere. Their Facebook page also inactive, last post from 2018.. Instagram same..
@@Luca_Techy I got the bifrc and an updated red one. they listened to everything you said in your videos. the bifrc is garbage. pulses every second or manual trigger. no auto trigger. the red one is amazibgly pwerful everything is reinforced now.
The bifrc guy unavailable.. I find out he is a very young FPV racing drone enthusiast and hobbyist. He or his friend also call as LantianRC, what was late brand name of his or their project, but BIFRC abandoned since 2018 LantianRC also since 2019... They instagram pages still available, but no new posts and no answers for messages on any of those accounts.. I couldn't find any at least archived webpage of them or the firmware or anything else..
I've got a purple spot welder, i use it about 5 times and worked fine, but when i tried to use i thers no spark with the same battery, the button, sound and LED works fine, i checked the continuity with the mosfets, no continuity, whats wrong?
Hi, if you hear the weld beep confirmation but get no weld, either the battery is not supplying sufficient power or they FETs are not being triggered for some reason. You should try the lightbulb test using a 12V (or even 6V) normal filament light bulb - I explain how to in a video in my playlist.
@@Luca_Techy i saw your video with 12v bulb test, i am not trying but i think the mosfets because i bought the same k99 spot welder and weld firmly with the same battery before I used. I thicken the traces to supply more power to the traces maybe oberheat the board
What kind of hack would it be necessary to source 12v to the driver from a separate power supply? Doing so there wouldn't be a problem with the dropping voltage. At the same time, the spot welding current is to be independent from the one needed by the driver. In my case, I am interested in hacking the "Wise Maple" version.
You would need to isolate the +V to the MCU and feeding it a seperate +12. However this is unnecessary once the inrush current limiter resistor has been added in series with the cap, but is less critical on the Wise Maple, or use one of those XT90 connectors with anti spark resistor (same thing but directly in the connector). The Wise Maple needs only this mod - you don't need to source a seperate voltage. The other models need the R4 mod as even with a seperate voltage source they would fail due to incorrect Gate drive.
No it's not appropriate. You need a good 12V battery (40Ah car battery) or a 3S 5000mAh Lipo with 50C at least. You need a peak current of 200 Amps at least to spot weld.
It is a possibility but it's increased hassle as you need then 2 power sources. The current limiting resistor + diode is a one time, future proof mod and the large 10000uF cap is plenty to keep the logic going for that short time pulse.
THat's fine, your FETs are OK. You need to verify if your battery is in good working order. You need a good 12V 20Ah AGM battery or a 3S 5000mAh 50C LiPo at least to get good welds. Do not use Gel-acid or old UPS batteries if you are not certain of their internal resistance.
@@TheFlyingKiwiNZ If you are sure the connections with the battery a sound, you may try to shorten the input cables by about 10cms to see if you get better welds. Keep in mind that you shouldn't pass the 40ms range - if you have a good battery and the welder is properly driing the FETs you should get good welds with .12mm strips at max 20ms.
Best is a 3S 5000mAh 50C, I don't advise a 4S. You need at least 50C 4000mAh for this to work properly and the more cells you put in series the more you increase internal resistance. Also you risk overdriving the pushpull driver. It is still within operation limits but very borderline so do this at your own risk.
@@Luca_Techy thanks man I have 14s100P i hope this mini welder will help me to fuse the 1400 cells i think i will just remove my care battery lol thanks agin
Can i use a 12v 60amp SMPS. As the retailer suggested that i can use this spot welder with 12v 40 amp SMPS. Should i use an smps? Should i just go with a car battery. The retailer made me buy the 12v 60 amp smps costing 40 USD. Can i use this test method with smps before i put the welder to use?
@@Luca_Techy thank you so much Luca. Also in your quick test i saw you attach the positive probe of the multimeter to the negative polarity of the board for contuinity. While i do this i see reading and when i change the probe polarity it shows 1. Why does this happen? Are my mosfets fried already? I just beefed up the tracks with solder.
If you apply the 2 basic and mandatory mods for these models and you have a good battery pack then it will work fine for the hobbyist making some packs. If you need to do hundreds of welds a day consistently then this is not the product for you.
just got one of these with no version on the main board, going to add the mods before i even attempt to use it, but was wondering if you knew why it wouldnt have a version id on it?
If you have a good enough battery you needn't change the basic cables, maybe shorten the ones going to the battery about 10cms/3inches like I did. If you need to have long (50cms/20 inches) power cables for some reason then I'd suggest a good copper quality AWG6 or 8 cable to keep the losses at minimum. In all cases whenever you change the cables always start testing/calibrating the weld from 5ms upwards.
Can i use a 12v 60amp SMPS. As the retailer suggested that i can use this spot weldet with 12v 40 amp SMPS. Should i use an smps? Please please please reply sir
no probaly not unless you look at the smoothing capacitors of it (the ones that smooth the dc at the end) if they are too small it can blow something up.
That mainly depends on how many spot welds you want to achieve: but consider that the electrodes will need to cool down in any case. It won't really help in saving the FETs from failure, that's a different story. If your FETs are matched and driven correctly, you will burn your hands holding the electrodes before they fail due to overheating.
Hello. I want to use my 12.6 volt 200 amp deep cycle solar battery as the power source since it sits next to my work table ... is that over kill ?????? Have all my mod parts and expect welder delivery today. Thanks for the Vid.
Don't worry, no 12V battery is ever overkill for these spot welders - just be sure to hook up the connectors with good screw on clamps and *start testing from 5ms* upwards (after applying the mods). You should never exceed 20-35ms with a good battery on .12mm strips.
3 года назад+1
Hi Luca thanks for the great videos, do you have a recommended seller we could but the spot welder from?
Hi Pedro, I don't have any preferred ones, I bought mine from Aliexpress from random sellers and they all arrived within a month. I know that there are sellers on Amazon or Banggood who sell the "Rev 0" ones still so you might check there as from AliExpress I have only sourced the BK/BL versions without the MCP driver. If you can source this model I suggest it as once modded with the additional Cap it's a better version than the bk/bl "cheaper" ones. You can't really tell which version it is by the photo, however I know that they are slightly more expensive (around 25-30 Euros) respect to the bk/bl versions.
Hi Adrian, if the battery is new and in working order then it will work (I have used a similar AGM battery for tests). However the weld power may be limited to a .12mm strip and insufficient for a .15mm strip. I could weld .12mm at around a 20-30ms setting with my battery whereas with a 3S 50C 5000mAh Lipo I can weld the same strip with a 8-10ms setting. Be sure to have applied the mods indicated for your type of welder (the driver resistor MOD and the in series resistor diode mod).
I use a similar 12V 10Ah motorcycle battery and it works well but not as powerful as my 3S 5500mAh 50C lipo - same weld with less time. You can shorted the power leads to improve welds once you see how it performs as is. Start from 5ms and go up.
I really appreciate the kind of analysis you're giving for these spot welders, do you think you could do the same for the BMS boards out there? I haven't found any real good and deep technical evaluation on them and I'm a bit concerned as you don't really have that much choice in the market.
Hi, unfortunately I don't think I can do this any time soon as I would need several samples of different BMS models to compare. The usual word of advice is don't save money on these types of products as it is very important to the life of the battery pack to have a valid management (firmware) system to avoid malfuntcion, damage and fire hazard.
Hi Luca I just bought one of these the wise maple the newest one with the displayed towards the right hand side. It works ok on fine strips but on thicker does not weld. Is it possible to change the time duration maximum between 1 and 30 it would be good to go Close 50q any suggestions on a hack
Hi, unfortunately there is no hack apart from reprogramming the mcu with a modified firmware. The more simpler solution is to shorten the leads and get a beefier battery. With a good 3S 5000mAh 50C LiPo or 20+Ah 12V AGM battery you can weld with 20ms .15mm strips.
@@Luca_TechyThanks for getting back to me with the info. I did short the leads as short as possible directly to the battery it's a lipo about 300 amps peak. It works very well with standard nickel strip that you get from laptop batteries. Not so good with nickel strip .15mm. I would definitely try with a bigger amp battery. If I did want to change the firmware do you have any recommendation on a firmware. And do you think will it help by changing the duration of the time slightly.
I haven't any modified firmware for that specific mcu (Nuvoton) but I made an Arduino pro mini version. However that requires heavily modding the board removing the original mcu which I don't suggest. Increasing the weld time over 30 of course will help but keep in mind that this version is 4 FETs so you may be overdriving it with .15mm if doing many welds. Maybe you should consider getting a Rev 0 and apply the cap mod if you really need .15mm strips.
Luca, I have the BL18-2K and mine will not light the bulb like yours does. I've checked what I know for continuity and mofset shorting, it all seems to check out. I've bumped to 99 still nothing. Where/what else and how can I further troubleshoot this welder? BTW, your reviews and mods and explanations are awesome!
Hi Jeff, if you have already done the R4 470 Ohm resistor mod (and the series 20 Ohm resistor current limiting mod) then your next step is to check the 3 transistors for problems (shorts) and connections between them and the FET Gates through the 30 Ohm resistors. First give them a reflux as maybe there is no contact with the pad. Also spray some deoxit on the 5 pin connector as I've had problems with continuity andmax sure they are nice and clean. You can find all the schematics linked in the description of my previous video (all mini spot welders) to see how the PNP-NPN pushpull tranistors are connected.
Very bad luck I had! While I was screwing the power cables onto the device one of the cables slashed out and hit the connectors between the screen board and the base board very shortly but enough to blow the microcontroller. No sparks, just a soft tick, no magic smoke but a sweet smell..... I can see now a tiny hole in the middle of the microcontroller. :( Moral of the story: shield the contacts with some tape before playing with the device. I have ordered a new unit... :/
That's a bummer - I suggest though to connect and screw on the power wires on the welder side always *before* connecting them to the battery in order to avoid any shorts o mishaps such as this one. Battery is always connected at the end of the cabling.
Hello, I have trouble getting it to weld a 0.15mm nickel strip. Tested it with 44aH car battery but not enough power. Maybe the leads are too long, I don't know (around 40cm from the battery). Any idea would help.
40cms is definitely long if you don't have proper AWG 6 wire. I'd suggest to try with the original leads or shorten the ones you're using (what AWG are they?). Always start from a low value (5ms) after you have shortened or made any changes and go up from there. Be sure you have good contacts with the battery terminals (use screw on connectors, avoid spring clamps). Also be sure you do these (or any) tests *after* the suggested Resistor mods.
Sure, if you are handy with one that's fine - but that wasn't the point here. The method described is an easy, quick and safe way to know if your spot welder is functioning correctly without any multimeter.
I appreciate your video, I don't think this red mini spot welder is good. My advice is not to buy it.I hope you do the same. I have several videos on the red mini spot welder. They just broke for no reason.
I agree. Mine was blown the first time I used it with a 5000 mAh 3S 75C lipo. Replaced the blown fet but it refuses to weld. It is rubbish. I'm gonna buy something else like the BIFRC DH20. It seems pretty trouble free to me and it has an internal battery. However, nice testing method with a regular bulb!
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I got one of these... I blew the first one and did the mods on the second one... then I realized my battery is not powerfull enough. The label says its 10000mah 25c lipo.... but it is only able to spot weld 0.10mm tabs. I tried the 0.15 and 0.2 but they don't stick. So I ordered a new lipo from a more reputable brand and it arrives tomorrow. Thank you for taking time to help others.
I want to say thanks, using your tutorials I was able to fix my Bl18-2k unit. When I got it, I hooked it up to a car battery but it would not do anything. It made all the correct beeps and the display and buttons all worked correctly. I found the diode was bad so I changed it and added the inrush current limiter resistor in series with the diode and I also changed R4 to 470 ohms. Still did not work. After changing all three transistors in the push pull circuit it started to work. Thanks again.
Gladd to hear - the push pull transistors usually don't fail, so I'm surprised this happened to you. Maybe it was a defect (DOA) - did you test the transistors to see if any of the three had failed/shorted?
@@Luca_Techy It could very well have been bad from the start. it never worked from the first time I tried it. I did try to check them with a cheap Electronic component tester, but it said they were diodes.
I salvaged all the replacement parts from old electronic boards I had and used the component tester to figure out what they were so it worked pretty good for that.
@@dennisallen2264so this is the exact issue i am having. It appears everything works other then the actual weld happening. I got my welder from banggood about a week ago and it is the CA20-2K. Can either one of you make a video checking the transistors? I have tried a car battery and a 3s 5000mah 60c battery with no luck I get the beeps like it is working but no welds or arks.
@@Luca_Techy See my comment below PLEASE
Luca is the fucking spot welders master
Thank you for the work you have done in detecting and rectifying the issues with this unit. I am not an electrical engineer but was able to get the basic understanding of what the problems were and how you fixed them so when I received my unit it needed all three modifications that you identified which I carried out quite easily before switching it on for the first time. So far it is operating well and producing good quality welds without any magic smoke being released, I hope it continues. Thank you again for your videos:-)
You're welcome!
I have this unit. When I tried for the first time, with a lawnmower battery (U1), I killed three of the FETs. I ordered some more and replaced them and added the capacitor fix suggested by Maker Luca but when I tested again (with a 94R battery this time), each time, a FET would pop and catch fire. I was getting decent welds (at 45) but was losing a FET each time. I'm not sure what the issue is. I put a DSO on when I was down to 2 and there didn't appear to be a deep sag in the voltage. I have five unused FETS left. I have a solenoid on order and I'm going to try using this device as a control on that and get the pack I wanted welded up and then I'll investigate further with the FETS.
What thickness strips were you trying to weld? Did you shorten the original power leads? Also, when a FET shorts you would need to replace the whole batch or simply leave the ones that are left as they are matched (supposedly) in batches. 45ms is already a very long pulse window, you should be able to weld .15mm strips with less than 20ms. Attempting to weld anything over .2mms is overkill for the unit and out of specs as explained in the FAQ (it all depends then on the FET matching and general assembly of the unit).
@@Luca_TechyThe strip is 0.15 so should be OK. Other than the replaced FETS and the extra capacitor, it's all stock. I don't think the number is ms but some energy measurement. If I said that, I misspoke. I bought a pack of 10 fets but I'll replace all five anyway (I only have one left on the board right now anyway). I'm going to try the solenoid and get my pack done before I try and mess with just the fets again (or I may just stick with the solenoid if it works well).
Just keep in mind that normal solenoids aren't reliable (consistent) under the 20ms or so time frame so you need a specific power solenoid that can handle that speed and current peak (200+Amps). Solenoids can be used for thicker spot welds but if you are spot welding 18650 or 27100 cells which usually takes 20ms or so and something gets stuck you will perforate the negative side of the cell permanently damaging it. The same applies to a shorted FET(s) situation to be clear which though should not happen under normal circumstances.
@@Luca_Techy I'll definitely be doing testing to see how well it follows the inputs. Damage to the cells is not that important for this pack as I'm using used cells (actually aggregating two existing packs). I have a bunch of dead ones that I can practice on too.
@@Luca_Techy Which FAQ are you referencing, by the way?
I've just received mine.
It has a 357T optocoupler that I don't don't what for and it has an MCP1407 mosfet driver on the control board. But no decoupling capacitor after the diode on the control board (I added one 1000uF).
The power board only holds the 10000uF cap with 5 mosfets and campling diode between each gate to drain, some 30 ohm serie resitor on each gates plus one 10k pull down resistor.
Hi Harold, please check out my previous video All "Mini Spot Welder" versions, I explain all the circuits and problems there, starting from the one you have.
@@Luca_Techy Thanks for the information to the other video (very instructive).
Here is a chronogram of the trigger on pin 4 (output of the MCP1407 driver) in yellow, in purple the trigger at the mosfet's gate (between the mosfet's gate and the 30 ohm resistor) and the source to drain voltage in blue. www.dropbox.com/s/rq0tz4zby3ancrl/NewFile10.png?dl=0
Hi, thanks for the trace. Yes as you can see in less than 4us the Gates are fully driven - much better performance than the pushpull solution.
Thank You very much for sharing all this information!! My M7's came in today so tomorrow I'll be able to see if I've finally fixed this thing!!
Thanks for the great videos. I have a unit that never worked out the box. It goes thru the stages of welding but doesn't weld on any setting.
Hi, based on your welder model, have you applied the R4 mod? Did you check my other videos about this mod?
@@Luca_Techy I watch many videos. This is the version without the R4 resistor. There are no components under the capacitor.. Thanks for the reply.
What model is it exactly? The old Rev 0 with the FET driver or the new rev-0 with the voltage booster described in my latest video?
@@Luca_Techy It's unmarked with has white buttoms with 5 mofets Rev 0 first additon. I think I will buy another one if I can't get this one working. Which version do you would you recommend? Or maybe a different type.
Ok so if you hear the double beep when contacting the electrodes it means the detect circuit is working - what battery are you using? Is it at least a 3S 5000mAh 50C or 12V AGM 45Ah? Did you try the 12V lamp test by increasing weld time up to max to see if you are getting a pulse?
Great videos! After seeing so many welders fail on their 1st weld I used your videos to modify a welder I got before I even powered it up, works perfectly. Thanks!
Some questions, is there any way to power these with one battery and use another battery to do the spot welds?
Also, I have a ton of 18650 3000mah that will do 20a draw. If I made a 3s pack from them, would a 3s10p which gives me a theoretical max draw of 200a be OK?
Theoretically you could by isolating the + line from the main battery so it just goes directly to the + weld contact and power the welder with a seperate smaller 12V battery connected to the + of the welder board. You can't use anything less than 12V to power the welder as the push-pull circuit voltages are calculated for this 12-16V input range else it will fail to drive the Gates properly (unless you change the resistor divider on the base, but then other problems can arise). I wouldn't worry about powering it with a seperate battery as once you have done all the mods the whole setup works pretty reliabily within it's operation limits.
I tried this with a bulb from my twilight and it blew up. Darn LED bulbs, lol. Just kidding. Nice test method.
I have the moded maple welder and I used a 6500MA 60C/120C lipo and with 5ms it burned the connector. So either my connector was not good enough or maybe the battery was too powerfull? Good thing is that no mosfet are burned only the connector from the battery to the welder....
By connector do you mean the terminal which screws on the board? Probably it wasn't soldered on well - it is very important that the power lines have good solid connections to the battery when you use these welders, they contact must be solid.
I have got my cb23-4k version
And I didn’t modify it but at my second test the mosfet burn 🤦🏻♂️
I used 35ah car battery
If I changed the burned mosfet and do these modifications is it will work good?
Another question if I removed the burned mosfet without replacing a new one what will happen?
Locate and remove the shorted FET - you can use the welder with just 4 FETs it will work fine if you don't overdrive it just apply the mods.
Great stuff thank
hi i just got one, as i plug it in it just beeps , the screen wont turn on, and it doesent react to the power button , i bought a 12v 5a charger and welded it to the tip they provide, what am i doing wrong? is my power supply not the correct one?
I'm a bit confused here, what did you weld to what tip? Firstly, use a 3S 5000mAH 50C (at least) Lipo pack to power the welder when welding strips. Be sure to connect the power to the input power side of the welder, not the output/terminal weld tip side. The input is on the right side of the welder looking at the display facing you so that the 3 buttons are below the display. If you connect the pack and the welder beeps but the display doesn't turn on then there's a fault: possibly just the display or it could be the MCU, but if it beeps it means the MCU is doing something and it may just be the display which is faulty. If you have that 5A 12V PSU/charger, connect that to the power input in place of the battery for testing purposes. It should beep as usual when you power it. Try simply bridging the welding tips together and see if you get a double beep - if so the welder works but the display is faulty (maybe the flat ribbon is misplaced on the connector or is torn - you can unscrew the top 4 screws and check the display ribbon yourself if it's seated correctly in the connector - be careful not to tear it). You should also connect a 6-12V lightbulb and try to see if it briefly flashes when connecting it across the weld terminals, but you would need to increase the weld time to over 50 to see a decent flash. If you bridge the terminals and nothing happens (no double beep) then the MCU is dead or there's a major fault. If the light bulb constantly shines when bridging again there is a major fault (shorted FET for ex.).
tx for your sharing,
Hi Luca. I have an original version 0 unlabelled welder. Can you tell me the values of the 2 resistors situated between the optocoupler and the fet driver.thanks.
I'm not sure which ones you mean but the one in series with the opto on pin 1 is 1K (102). The other one located on the opposite side is a 10K pullup (103) which is located beside a cap (probably a 100nF or 104K) which is near the input diode. If you check my video (and the other All Mini Spot Welder versions) there is a pic of the original Rev 0 MCU where you should make out the components.
Many thanks for the information that’s helped me.
Hello Luca, Thank you for such a great video!! I made the stupid mistake of hooking it up backwards. The mosfets are definitely shorted out. Any idea what replacement mosfets i can buy? Can't see any part numbers on the mosfets. Thanks in advance!!
Aaron
Hi Aaron, if you check out my video descriptions in the playlist the main components are all listed and there are links to download the schematics. If you hooked it up backwards hopefully you just may have damaged a FET but depending on the version you have you may have damaged also the regulator and/or logic board. You can try powering just the logic board if you have a bench power supply and some alligator clips and see if it turna on (check the pinout from my schematic to see which is + and minus - you can power it from 7V to 14V with less than 200mA current). If the logic board still works then you just have a shorted FET (or 2) and should be repairable. It also depends on what board rev you have.
you showed on another video that the cables are aluminum cables, have you tried replacing them with copper cables?
No, but I did shorten them and also showed how much voltage drop there is on the welder from the battery (approx 50% of the voltage drops in the best conditions) with original cables. This drop on one hand reduces the weld energy but on the other hand limits the current through the FETs and helps increase their life span. If you reduce the cable length and/or replace the cables with larger (AWG 6) copper, you can but you must always "recalibrate" your setup starting from a low time setting (5ms) to see if you are not overdriving the welder. I find that with the default cables and a good battery pack (or 12V AGM 20Ah+ battery) the welder performs very well for .15mm strips with settings around 10-15ms. Driving it over 30ms with a good battery is risky, which is why the Wise Maple has this hard limit set in software.
@@Luca_Techy I guess they ARE a wise maple haha, thanks for the info, will keep it in mind, hopefully I can design a much better setup without all of the flaws, but that project is on my free time
do you mind having a look at the BIFRC? it seems to be doing a much better job than the other cheap spotwelders. it has 8 mosfets. Im getting my unit in two weeks. I will analyze the circuit to my ability and if you want send you pictures and measurements with my oscilloscope.
I had ordered one but never received it - I also ordered one with a one cell LiPo included and that also never made it here so I gave up. If you want to take some scope shots feel free to send me them thought the circuit analysis will be more difficult without the board itself.
I ordered my DH30 (m8s) LCD touch screen one in October 2021..(£45)
From the first time didn't give me any proper impulse with a parallel 2x5000mAh 45c 3s LiPo.. Then with a 110Ah 950A car battery I had one successful welding after one fet blown.. I desoldered that FET and also ordered a complete replacement FET board.
I tried with that car battery and with the old board few times, but there is many adjustment, not just the 20 gears but Ah, c...
So I tried increase step by step, but the impulse was (if was ) most of the time a very little click heard, nothing more. Then when arrived to the maximum gear then few times got a very huge power, burned a hole in the nickel strip.. So I was given up a bit. Than I saw this video and thought, might same way if I trace and can hacking the control board's power, might will working.
But... I made a mistake. I plugged to the computer with an USB-C cable. Appeared as a USB flash drive ( named haohaodada) there have to copy the new firmware if have (but not new or old found anywhere)
From that time, the control board didn't booting. Because the on/off designed as a capacitive touch, I measured that chip it's works, if I touch the on/off surface on the case, then the 5V and 3.3V are present, if touch again then they disappear. So that part works, but no beep, no screen no any sign of life. If I plug to USB, as a flash disk still appears, but looks stucked in firmware update mode.
The microcontroller is an ARM Cortex 0, but labelled as "haoda USB"
As I researched that's a Chinese Stem program to learn programming this chip. On they website, have olnline courses, online interface for make scripts like Arduino IDE, but no any hardware documentation..
On they developer board seems like an arduino nano and there is a reset/restart button exists. But in this spot welder board not, so I can't just simple restart without at least know the chip pins and the layout..
Their website (bifrc.com) is totally wiped, nothing available, just like a freshly installed raw webserver.. No firmware, no contact, no support anywhere.
Their Facebook page also inactive, last post from 2018.. Instagram same..
@@Luca_Techy I got the bifrc and an updated red one. they listened to everything you said in your videos. the bifrc is garbage. pulses every second or manual trigger. no auto trigger. the red one is amazibgly pwerful everything is reinforced now.
The bifrc guy unavailable.. I find out he is a very young FPV racing drone enthusiast and hobbyist. He or his friend also call as LantianRC, what was late brand name of his or their project, but BIFRC abandoned since 2018 LantianRC also since 2019...
They instagram pages still available, but no new posts and no answers for messages on any of those accounts..
I couldn't find any at least archived webpage of them or the firmware or anything else..
I've got a purple spot welder, i use it about 5 times and worked fine, but when i tried to use i thers no spark with the same battery, the button, sound and LED works fine, i checked the continuity with the mosfets, no continuity, whats wrong?
Hi, if you hear the weld beep confirmation but get no weld, either the battery is not supplying sufficient power or they FETs are not being triggered for some reason. You should try the lightbulb test using a 12V (or even 6V) normal filament light bulb - I explain how to in a video in my playlist.
@@Luca_Techy i saw your video with 12v bulb test, i am not trying but i think the mosfets because i bought the same k99 spot welder and weld firmly with the same battery before I used. I thicken the traces to supply more power to the traces maybe oberheat the board
What kind of hack would it be necessary to source 12v to the driver from a separate power supply? Doing so there wouldn't be a problem with the dropping voltage. At the same time, the spot welding current is to be independent from the one needed by the driver. In my case, I am interested in hacking the "Wise Maple" version.
You would need to isolate the +V to the MCU and feeding it a seperate +12. However this is unnecessary once the inrush current limiter resistor has been added in series with the cap, but is less critical on the Wise Maple, or use one of those XT90 connectors with anti spark resistor (same thing but directly in the connector). The Wise Maple needs only this mod - you don't need to source a seperate voltage. The other models need the R4 mod as even with a seperate voltage source they would fail due to incorrect Gate drive.
Please someone should educate me if 12V/65amps adapter (power supply) can power this spot welding machine effectively.
No it's not appropriate. You need a good 12V battery (40Ah car battery) or a 3S 5000mAh Lipo with 50C at least. You need a peak current of 200 Amps at least to spot weld.
It looks like it is easier to remove the diod and connect separate power supply for controller/driver.
It is a possibility but it's increased hassle as you need then 2 power sources. The current limiting resistor + diode is a one time, future proof mod and the large 10000uF cap is plenty to keep the logic going for that short time pulse.
I did your mods but I don't get good welds. Just tested between source and drain and I get 2.1 megohm. I guess that means it's bad?
THat's fine, your FETs are OK. You need to verify if your battery is in good working order. You need a good 12V 20Ah AGM battery or a 3S 5000mAh 50C LiPo at least to get good welds. Do not use Gel-acid or old UPS batteries if you are not certain of their internal resistance.
@@Luca_Techy yes I used my diesel car battery 600CCA fully charged. Still no good.
@@TheFlyingKiwiNZ If you are sure the connections with the battery a sound, you may try to shorten the input cables by about 10cms to see if you get better welds. Keep in mind that you shouldn't pass the 40ms range - if you have a good battery and the welder is properly driing the FETs you should get good welds with .12mm strips at max 20ms.
its good way to test ,,, suggest a for batteries vedio if u got time
can i use 16V diy 18650 pack as battery for the mini welder ?
Best is a 3S 5000mAh 50C, I don't advise a 4S. You need at least 50C 4000mAh for this to work properly and the more cells you put in series the more you increase internal resistance. Also you risk overdriving the pushpull driver. It is still within operation limits but very borderline so do this at your own risk.
@@Luca_Techy thanks man I have 14s100P i hope this mini welder will help me to fuse the 1400 cells i think i will just remove my care battery lol thanks agin
Can i use a 12v 60amp SMPS. As the retailer suggested that i can use this spot welder with 12v 40 amp SMPS. Should i use an smps? Should i just go with a car battery. The retailer made me buy the 12v 60 amp smps costing 40 USD. Can i use this test method with smps before i put the welder to use?
Go with a 12V 20Ah+ AGM battery, or 3S 5000mAh 50C LiPo. Switching PSUs are not appropriate for this application.
@@Luca_Techy thank you so much Luca. Also in your quick test i saw you attach the positive probe of the multimeter to the negative polarity of the board for contuinity. While i do this i see reading and when i change the probe polarity it shows 1. Why does this happen? Are my mosfets fried already? I just beefed up the tracks with solder.
Good
Do you suggest this spot welder for making battery packs
Thanks
If you apply the 2 basic and mandatory mods for these models and you have a good battery pack then it will work fine for the hobbyist making some packs. If you need to do hundreds of welds a day consistently then this is not the product for you.
@@Luca_Techy
What you will suggest
Thanks
K-Weld or Arduino welder project are good products.
just got one of these with no version on the main board, going to add the mods before i even attempt to use it, but was wondering if you knew why it wouldnt have a version id on it?
just saw rev 0 , unlabeled :) nvm
If it has all the major components on the MCU board with the MCP1407 driver then you just need to add a 470-1000uF 25V cap after the diode and gnd.
would you recommend changing the wires on this to better quality ones. If yes, what gauge should we go for.
If you have a good enough battery you needn't change the basic cables, maybe shorten the ones going to the battery about 10cms/3inches like I did. If you need to have long (50cms/20 inches) power cables for some reason then I'd suggest a good copper quality AWG6 or 8 cable to keep the losses at minimum. In all cases whenever you change the cables always start testing/calibrating the weld from 5ms upwards.
@@Luca_Techy Thank you for the info. Much Appreciated.
Can i use a 12v 60amp SMPS. As the retailer suggested that i can use this spot weldet with 12v 40 amp SMPS. Should i use an smps? Please please please reply sir
no probaly not unless you look at the smoothing capacitors of it (the ones that smooth the dc at the end) if they are too small it can blow something up.
@Luca What do you think of adding aluminium radiators on top of the MOSFETs?
That mainly depends on how many spot welds you want to achieve: but consider that the electrodes will need to cool down in any case. It won't really help in saving the FETs from failure, that's a different story. If your FETs are matched and driven correctly, you will burn your hands holding the electrodes before they fail due to overheating.
@@Luca_Techy Thank you Luca. You are of great help!
Hello. I want to use my 12.6 volt 200 amp deep cycle solar battery as the power source since it sits next to my work table ... is that over kill ?????? Have all my mod parts and expect welder delivery today. Thanks for the Vid.
Don't worry, no 12V battery is ever overkill for these spot welders - just be sure to hook up the connectors with good screw on clamps and *start testing from 5ms* upwards (after applying the mods). You should never exceed 20-35ms with a good battery on .12mm strips.
Hi Luca thanks for the great videos, do you have a recommended seller we could but the spot welder from?
Hi Pedro, I don't have any preferred ones, I bought mine from Aliexpress from random sellers and they all arrived within a month. I know that there are sellers on Amazon or Banggood who sell the "Rev 0" ones still so you might check there as from AliExpress I have only sourced the BK/BL versions without the MCP driver. If you can source this model I suggest it as once modded with the additional Cap it's a better version than the bk/bl "cheaper" ones. You can't really tell which version it is by the photo, however I know that they are slightly more expensive (around 25-30 Euros) respect to the bk/bl versions.
Did you find any rev. 0 model?
Not yet but I know Banggood has them and I am trying to source one.
@@Luca_Techy Looking at the photos provided by buyers it has the MOSFET driver.
The motorcycle battery 12V 12Ah 150A will be suitable for welding ?
Hi Adrian, if the battery is new and in working order then it will work (I have used a similar AGM battery for tests). However the weld power may be limited to a .12mm strip and insufficient for a .15mm strip. I could weld .12mm at around a 20-30ms setting with my battery whereas with a 3S 50C 5000mAh Lipo I can weld the same strip with a 8-10ms setting. Be sure to have applied the mods indicated for your type of welder (the driver resistor MOD and the in series resistor diode mod).
@@Luca_Techy Thank You!
@@Luca_Techy I found an AGM 8 Ah CA 280A battery and I think it will be better. Thanks again for the answer.
I use a similar 12V 10Ah motorcycle battery and it works well but not as powerful as my 3S 5500mAh 50C lipo - same weld with less time. You can shorted the power leads to improve welds once you see how it performs as is. Start from 5ms and go up.
@@Luca_Techy Ok thanks.
I really appreciate the kind of analysis you're giving for these spot welders, do you think you could do the same for the BMS boards out there? I haven't found any real good and deep technical evaluation on them and I'm a bit concerned as you don't really have that much choice in the market.
Hi, unfortunately I don't think I can do this any time soon as I would need several samples of different BMS models to compare. The usual word of advice is don't save money on these types of products as it is very important to the life of the battery pack to have a valid management (firmware) system to avoid malfuntcion, damage and fire hazard.
Hi Luca I just bought one of these the wise maple the newest one with the displayed towards the right hand side. It works ok on fine strips but on thicker does not weld. Is it possible to change the time duration maximum between 1 and 30 it would be good to go Close 50q any suggestions on a hack
Hi, unfortunately there is no hack apart from reprogramming the mcu with a modified firmware. The more simpler solution is to shorten the leads and get a beefier battery. With a good 3S 5000mAh 50C LiPo or 20+Ah 12V AGM battery you can weld with 20ms .15mm strips.
@@Luca_TechyThanks for getting back to me with the info. I did short the leads as short as possible directly to the battery it's a lipo about 300 amps peak. It works very well with standard nickel strip that you get from laptop batteries. Not so good with nickel strip .15mm. I would definitely try with a bigger amp battery. If I did want to change the firmware do you have any recommendation on a firmware. And do you think will it help by changing the duration of the time slightly.
I haven't any modified firmware for that specific mcu (Nuvoton) but I made an Arduino pro mini version. However that requires heavily modding the board removing the original mcu which I don't suggest. Increasing the weld time over 30 of course will help but keep in mind that this version is 4 FETs so you may be overdriving it with .15mm if doing many welds. Maybe you should consider getting a Rev 0 and apply the cap mod if you really need .15mm strips.
I just received mine and the text it has on it is CA20-2k, does this one need the same upgrades as the ca04?
Yes apply the same fixes.
Where did you buy yours?
Luca, I have the BL18-2K and mine will not light the bulb like yours does. I've checked what I know for continuity and mofset shorting, it all seems to check out. I've bumped to 99 still nothing. Where/what else and how can I further troubleshoot this welder? BTW, your reviews and mods and explanations are awesome!
Hi Jeff, if you have already done the R4 470 Ohm resistor mod (and the series 20 Ohm resistor current limiting mod) then your next step is to check the 3 transistors for problems (shorts) and connections between them and the FET Gates through the 30 Ohm resistors. First give them a reflux as maybe there is no contact with the pad. Also spray some deoxit on the 5 pin connector as I've had problems with continuity andmax sure they are nice and clean. You can find all the schematics linked in the description of my previous video (all mini spot welders) to see how the PNP-NPN pushpull tranistors are connected.
21volt bulb?
12V 21Watt (or 10Watt)
Very bad luck I had! While I was screwing the power cables onto the device one of the cables slashed out and hit the connectors between the screen board and the base board very shortly but enough to blow the microcontroller. No sparks, just a soft tick, no magic smoke but a sweet smell..... I can see now a tiny hole in the middle of the microcontroller. :(
Moral of the story: shield the contacts with some tape before playing with the device.
I have ordered a new unit... :/
That's a bummer - I suggest though to connect and screw on the power wires on the welder side always *before* connecting them to the battery in order to avoid any shorts o mishaps such as this one. Battery is always connected at the end of the cabling.
Hello, I have trouble getting it to weld a 0.15mm nickel strip. Tested it with 44aH car battery but not enough power. Maybe the leads are too long, I don't know (around 40cm from the battery). Any idea would help.
40cms is definitely long if you don't have proper AWG 6 wire. I'd suggest to try with the original leads or shorten the ones you're using (what AWG are they?). Always start from a low value (5ms) after you have shortened or made any changes and go up from there. Be sure you have good contacts with the battery terminals (use screw on connectors, avoid spring clamps). Also be sure you do these (or any) tests *after* the suggested Resistor mods.
Or just use a multimeter maybe?!
Sure, if you are handy with one that's fine - but that wasn't the point here. The method described is an easy, quick and safe way to know if your spot welder is functioning correctly without any multimeter.
I appreciate your video, I don't think this red mini spot welder is good. My advice is not to buy it.I hope you do the same. I have several videos on the red mini spot welder. They just broke for no reason.
I agree. Mine was blown the first time I used it with a 5000 mAh 3S 75C lipo. Replaced the blown fet but it refuses to weld. It is rubbish. I'm gonna buy something else like the BIFRC DH20. It seems pretty trouble free to me and it has an internal battery. However, nice testing method with a regular bulb!