Just finished my 2s3p with this setup 1. Capacitor mod 2. 12v 7.2ah x 4(parallel) lead acid battery 3. I only use 5E and it weld perfectly, it surprise me too 4. I attached the notebook fan to keep all components cool I did around 60 weld plus practicing so far. Im quite happy with this little thing. 4 battery in parallel just to be safe. Thanks to you luca for great informative videos 👍
I'm sending mine back. Even with a good, fully charged 5200mah, 80c battery I get zero output on any setting. It makes all the right beeps, but no output. I've checked everything I could think of and can't solve it. I'm going to put that $30 towards something better. It's a shame they can't produce these without problems. It also seems impossible to tell which version you're going to be sent. Thanks for all the info you provide, if nothing else I learned a lot!
I have the same problem with mine, I bought 2, one never did any spot weld, and the second did 1 spot weld and burned out a mosfet. Both do the same now, they do the 3 beeps but no weld (I removed the burned mosfet on the second one). No output. I bought a simple pcb spot welder with no screen, and I have no problems with it, it's welding very well and if the battery is underpowered, you just have a weak weld, you don't burn anything. This spot welder is a shit.
I understand your frustration - unfortunately as we have seen the Quality Control of these units leaves much to be desired which is why I decided to do some investigation and videos on the matter. Not everyone accepts the fact that one has to modify or repair it from the start as it should be sold as a "perfectly working unit". On the other hand, it does come from a low cost manufacturing process and it is cheap so based on these premises I never expect a "perfect" product of this kind. I'm sure that with some patience it is possible to repair and get them all working but I also understand not everyone wants to go through the hassle. In this case it is best to pack it back up and send it back for a refund as the various sellers are perfectly aware of the problems. I was able to get a near full refund on the first one which totally died without sending it back.
@@Luca_Techy I agree with you, but with so many different versions available, and with different combinations of MCU and FET boards even if I understand that I'll need to mod it it's hard to know what to mod. However, I have ordered another one, this time the new, smaller one. I'd keep the older non working one but I've got no idea what's wrong with it. It's not the one that needs the extra cap added and I've never used anything other than fully charged Lipo batteries.
@@3rdpig I could help you diagnose the fault you would need a tester and even better a scope. I suspect the gates aren't being driven because of some short probably. You can start by checking every gate pin (pin 1 of every Fet) and see that there is no contact with the minus (no short). Furthermore between every 2 gates the tester should read 60 ohms. Try to check that first and let me know.
Hello, I would like say thank you for your very informative videos which have helped me so much. I own the earlier version of this spot welder that requires the capacitor mod. That mod was the first thing I did when I bought the welder as I thought it would have been sensible to watch some videos before using it. So, I found that video by Fabio (about the capacitor) and the one you made where you strongly suggested using a car or motorcycle battery instead of a LiPO. I bought a MotoBatt MBTZ14S AGM motorcycle battery with a CCA of 190 and that made all the difference. This battery seems to provide just the right amount of current this welder needs. I use the stock cables, at their original length and they don't get hot at all. What gets hot are the probes and even those, not before forty welds or so. I weld 0.12 strips at 10ms and 0.20 strips at 15ms!!! It takes a single weld at 25ms to join two 0.20 strips (one on top of the other) to a 18650 battery. Incredible, a single weld!!! The welds themselves are perfect, no sign of overheating and they also look nice since I followed your advice to round the tips of the probes! I have more to say but this message got too long, thank you so much!
I've watched many of your videos and they're very interesting. I have 2 of these spot welders and have not used the yet (lost one in the house and bought another!! LOL). I need to take them apart and do the upgrades you mention. At time stamp 12:25 you mentioned not to use the "switch" and just solder it over. Is it the power on - off switch your talking about? If so, why? Thank you for your videos.
Hi Andy, yes it's the power switch and I suggest bridging it as I have seen many flaky ones where just tapping on them would reset the MCU and this isn't good during a weld. As you need it on anyhow when using the welder it's safer to UNPLUG it rather than remove power from the mcu - so the switch is really unnecessary in my opinion. Also a good clean of the pin contacts and strip socket is a good thing as this too is not always making good contact.
That depends on the quality of the BMS board - if you have used them or know it's a reliable product and does properly cutoff at full cell voltage it's possible but I would really suggest getting a proper LiPo charger (there are many in the 60-80$ price range working from car battery or mains) with built in balancer.
Thank you for your review and recomendation.I just buy this spotwelder & i want to make my own diy lithium 3s battery pack to provide enough power to this welder,i will use 21700-40t they are bigger and powerful than 18650.this exact battery have 40amp discharge i think,i will use 15 of them,5x3 for 3s bms i think it will have enough power to weld,My problem and quwstion for you what kind of bms it will be powerfull enough to provide enough peak amps for welding? i see on ebay alot of different 3s bms but neither say max peak power just charging and discharging current. can you tell my what ind of bms is in your battery pack?
Hi Kris, I think you would be best getting a small 3S 5000mAh LiPo pack for this welder. Creating an array of 21700 is a bit of an overkill in size and price (considering you want to slap a BMS on it too). LiPos are more suited for "violent brief discharges" which they can handle easily (similar to 12V AGM car batteries). The 21700 40T yields a constant 35Amps discharge rate, but that's an upper limit scenario and there is no "peak current" spec - they just don't like it and is damaging on the long run. Weld currents easily exceed 250Amp (can reach over 400A). You would need a minimum of 6 up to 8P with a 3S configuration to preserve the cells from those overcurrent peaks and to get the to yield it and then you wouldn't really utilize the capacity in time (24Ah to 32Ah). 18 to 24 cells plus a capable BMS is rather a lot of money invested for a sheap spotwelder, unless you need the pack for other things better stick with a "cheaper" 3S 5000mAH 50C LiPo in my opinion!
@@Luca_Techy thank you for your advice,ivwill try with your recomendation..i got this 21700 cells for fre 100 of them,what if i put supercapacitor i have one laying on the shell 16v 2farrad in prallel with this cellls?
Sure, you can add a supercap (2Farads aren't much but will certainly help with the peak), preferably positioned near the welder to avoid the wire/resistive losses. Keep in mind that the welder setup has been "tuned" for the provided wire lengths and a 3S or 12V AGM battery. Shortening or lengthening wires can have adverse effects - always start from a short weld (5ms) and ramp up from there.
bonjour Luca et merci pour ton travail. Est-ce que le bj07-1k fonctionne sans risque avec une batterie de voiture de 12v 70ah 700a? y'a t'il un risque d'endommager le boitier?
Bonsoir Jeremy, la batterie c'est bon mais (fait le premier tests avec 5ms pour partir) vous devez appliquer le 2 mods, changer la resistance R4 de 1K avec une de 470 Ohm sur le MCU (R4) et la resistance de 20-50Ohm avec le diode M7 (series) avant le cap de 10000uF. Regardez comme fair ici: th-cam.com/video/1ZCbLdymJIs/w-d-xo.html
Hi, thank oyu for perfect reviews, just connecting of 4S battery is possible (or what can be problem?)? Can be this controller used for DIY design with twice more MOSfets (same types) or will be there necessary any modification?? Thank you very much!
Theoretically a 4S is the limit but I don't suggest using such a setup. Adding more FETs to the current design is not really viable and I do not suggest it unless you are willing to completely modify the driver circuit but you would need to modify the PCB for the additional FETs, at that point building one from scratch is the better solution. Please check out my latest video "All Mini Spot Welder versions" for more details.
Nice product, incidentally the weld is known as a "nugget" the strength of the weld is the circumference of the nugget, I used to design 150KVA DC spot welders, the weld splashes when the vapour pressure exceeds the contact pressure,
I really like your videos since i ordered this unit recently, only problem is when will it arrive, i have some stuff that has not arrived in two months and aliexpress refuses dispute requests
That's strange as all my disputes due to either defective or never received material was completely refunded - maybe you need to supply further information to their requests on the reasons and wait for the "order to expire".
could you check the strip you used in a video, as far as i know laptops mostly use 0.1mm nickel. About aliexpress, dont think they want to scam me, but they just couldnt care less about shipping speed, and its somewhat understandable they dont want to return money if item is going to arrive, they should change estimated delivery time tho and not use fake tracking info as evidence. Im getting packages between 40 and 80 days lately and thats honestly unacceptable.
First I want to thank you for your contribution to the community. Before your videos, I didn't realize that there are several versions of these mini spot welders. I ordered one and I am waiting now what will come, I hope it will be first-generation, but if it not just need to resolder the resistor correct? Regarding power supply what do you think about Telwin drive 13000? If this car jump-started can start the truck engine, it should be capable of power this spot welder also ..... Thank you once more for your work and time for the community and I hopes you will have a lot of views just to earn some money you deserve it ;)
When you receive it just open it up and check the version. If it's a BL18/20 or latter and has the same layout as the ones I describe here then all you need is to swap out the R4 resistor with a 470-560Ohms one before using it. Regarding the use of power supplies, don't use them for spot welding. If you are referring to that portable Jump Starter, then it has an internal Lipo battery so yes you can use it though it also has some protection circuit in series with the starter cables which may trip if welding so keep that in mind. You're probably better off using a normal 45Ah car battery or 3S 4000mAh 50C upwards pack which are common and not so expensive (I linked the one I bought in my prior video and is the one I am using for these tests).
@@Luca_Techy Thank you for replying. We will see what is the version when it comes to me :) will keep you posted, maybe I am going to get some third version who knows. Regarding power supply, it is a little bit tricky to get a battery in my country and since I have this telwin per specification it is more powerful than a lipo battery. 12AH capacity, start power 450A, peek 1500A max duration is 3 sec (www.telwin.com/en/prodotti/index.html?id=829566&lingua=E) If I able to get your battery recommendation from hobby, I will order. I trust your recommendations because I like how you in detail everything check and test.
@@tarikdolovac4354 Try with the Telwin, it will probably do fine. Be *sure* to have a good connection with the spot welder cables, the connection must be securely connected to the power source.
@@Luca_Techy hi, I got mine mini spot wleder it is BL18-2k version. I change R4 on MCU with 470ohm and flip the diode and add in series 15ohm rezistor. I enforced trace for welding and everything that you say in your videos. The sport welder wont work. I looked several time all the videos but could not find this issue. I mean it turn on with all correct bip signals and load into manual weld mode. When i put into automatic and try to weld I can hear sound bip, display get dim for a moment, voltage battery on display drop from 12.5 to 12.4 and back, but there is no a spark. I check resistors for mosfet they are all good and have a connection. Output voltage on tips is allways presented it is 11.55v immediate when i turn on welder, voltage on gate single tranzistor (lower right) is 12V, gate voltage on secound (upper right tranzistor is also 12v). I am not sure what else can I check and why this is not working. I have feeling that everything is working until the mosfets need to be closed to push current and weld it..... Did you have those kind of the issue ? Thank you for your time and reply!!!
@@tarikdolovac4354 It appears your FET gates aren't being driven: can you check that R4 is making proper contact? Check that from pin 19 of the MCU to pin 4 of the connector (trigger output of MCU after R4) you see the resistance value of 470 Ohms. Check that the connector is making proper contact (i used some deoxidizer as my pins weren't making always good contact - apparently there was some sort of residue on the pins). If you have a scope, check the trace on pin 4 of the connector and any Gate pin - something is not right. P.S. it is normal to detect 12V on the contacts as this is the voltage used for the autotrigger circuit - it's a trace voltage just for the contact detection between +Bat and Drain pad going to the detector voltage divider.
@@Luca_Techy First thing i did. it behaves exactly like the BL01 2K, does not memorize settings and appears to work fine (i've reflowed everything). I'd suggest using a pedal for additional security, at least it will not retrigger if the probes are stuck a bit
@@meanxmeanx1763 Yes I also have a pedal which I prefer using more because I can touch the contact points and properly position ans weld when ready not time based. It shouldn't retrigger if u don't remove contacts first.
The BJ07 should be the so called "WISE MAPLE" which just needs the addition of an inrush current limiter resistor to protect the diode in series with the cap. The mod is explained in detail also in my other latter videos (check the playlist).
Great information Luca, did the video finish short? If you were buying your 1st mini spot welder, which one would you buy? PS I have many 3s 3200mah lipos a 5s 1800mah & one 5s 16000mah ! I also have 12 - 24v 1200w DC PSU :)
I'd buy the BL18-2K or later versions; nothing beats the price (approx 20 Euros delivered) and versatility. Granted there are others like the BIFRC and similar single PCB spot welders which work but they have limited settings (4 or 5 "power" aka time settings) which give you in my opinion limited flexibilty in fine tuning your welds (you're either over powered or under powered). I just like the ability to find that sweet spot with my battery and strip setup and get that decent weld "spot on" (pun intended). I don't suggest you use any kind of PSU with the spot welder - you need "pulse" power - you can get away with it if you parallel a large 500F capacitor bank placing it near the spot welder but that is costly. Better use a traditional 12V 45Amp AGM battery or 3S 4000 mAh 50C Lipo - your 3200mAh may work if it is at least 50-60C fully charged. "Remember it's not the voltage but the current that matters here" is my motto. Fully charging a pack lowers the relative internal resistance - that's why you need a fully charged pack - not because of the higher voltage, but because of the lower internal resistance.
If you don't want to touch anything on the board (ex. swap R4) then probably yes, though keep in mind you are limited to 30ms max weld time (though it's more than enough if you use a decent battery and you have the option of shortening the cables to get more "punch").
Hello..will it work if i connect 2 or more standard ups battery in parallel? Will it fried the mosfet with those battery setup? Mine just arrived and i just wanted to make sure before start using it.. your reply really help here..
It *all* depends on the batteries: if they are AGM and at *least* 18Ah you may put 2 in parallel with decent 8-10AWG cables. The batteries have to be in good working order and fully charged. *Do not use GEL acid batteries*. Note: before you even start using it check your version and if BL18 or similar swap the R4 1K resistor on the MCU for a 470-560Ohm one. It's explained in m prior videos (version info and resistor location).
@@Luca_Techy Just check mine and no lebel whatsoever. So i couldn't tell which version is mine. For capacitor mod, can i use different capacitor voltage 25v-35v? because i have few laying around. Wonder if it work.
Lipos are a little scary. I'm actually using a 2s 7.4 with mine and it works just fine. I know the welder says 9-12v but these lipos are so strong that 7.4 works and it's not as scary. Plus when you are working towards the bottom end of what works and you have the 0-99 set over 80 you actually have more range of control since it doesn't jump from welding to blowing holes in strips so quickly. Less scary, more control. I like it. I also tried a 3s lipo but I ordered the little 1500mah by mistake and even though I bought the 120c version it just wasn't welding as nice as the 5200mah 2s. Now that I've seen your xt60 connectors in parallel trick I'll give that a shot too, you know...for science and shit.
As I often say, it's the current that matters not the voltage in this case: if you have even just ONE cell but an incredible low internal resistance (lower than 1milliohm) then you will get great welds. Granted that you need thick copper braid cables and good connections and short, but it works. 2 Cells are fine, as long as they have a low internal resistance (the discharge C capacity is inverseley proportional to the internal resistance, the higher 'C' the lower the milliOhms, it's all about this factor). I was curious to see how this mini spot welder performed with a recent, medium rated C (50) 3S LiPo battery (I even shortened the cables) and objectively it's rather overkill for the setup. I also prefer 12V AGMs batteries, basically safer in case of any "disaster" respect to LiPos. Parelleling works as long as you are using identical batteries, otherwise the weakest one will not do much as it "craps out" as soon as it's loaded so the other pack will do all the work.
@@Luca_Techy The batteries came together so I'm guessing they will play nice together. I did use one to do some welds briefly but I wasn't impressed so very briefly. I think I'll go make myself a splitter cable and then see if I burn my house down or not. The things we do for science.
Yes you can use them as long as the power cable connections with the spot welder are solid / screwed on (they are made with 3S 5000mAh+ Lipo packs). Using the spring loaded connectors with just the welder power cable stripped wires is not a good enough connection so keep this in mind.
I cut the jump starter cables about 50mm from the ec5 connector and either solder them onto the welder or fit the u shaped connectors so they can be screwed onto the welder.
First and Foremost. Thank you for all these incredibly in depth and informative videos. Have you considered doing some tests with a super capacitor bank? I have a 200F 13.5v capacitor bank I made of 2 series banks of 5 2.7V 500F super capacitors in parallel. That seems like it would be the ideal solution. Any thoughts?
Though it is possible and others have used Cap banks in parallel with their batteries you may overdrive the device: it works best with a "normal" 40Ah AGM battery or good 50C 5000mAh 3S Lipo and eventually you can shorten the power wires by half to get more current peak once you see how it performs with your setup. If you do add a 500F cap bank be sure to keep those leads as long as they are before shortening them as the drop on the leads is important to limit the peak current. The whole design is goog up to .15mm strips (better .12) not more else you risk. It's not that 5 FETs can't handle the current, it's simply that these FETs are not ideally matched and the driver circuit is not that adeguately designed so pushing it too far will cause it to fail as there is no over current control and the FETs may not be properly matched which means one will be usually taking all the peak current (and will fail first). Keep all this in mind.
Hi Lance, in fact it's not designed to weld .2mm as there is too much drop on the cables (I just did it for testing purposes), it can do .15mm if you have a good enough battery but usually .12mm will be the best thickness on average.
you could try buying copper instead of using the stock wires. oxygen free copper witch is very high quality and expensive used in car audio may work better
Just finished my 2s3p with this setup
1. Capacitor mod
2. 12v 7.2ah x 4(parallel) lead acid battery
3. I only use 5E and it weld perfectly, it surprise me too
4. I attached the notebook fan to keep all components cool
I did around 60 weld plus practicing so far. Im quite happy with this little thing. 4 battery in parallel just to be safe. Thanks to you luca for great informative videos 👍
I'm sending mine back. Even with a good, fully charged 5200mah, 80c battery I get zero output on any setting. It makes all the right beeps, but no output. I've checked everything I could think of and can't solve it. I'm going to put that $30 towards something better. It's a shame they can't produce these without problems. It also seems impossible to tell which version you're going to be sent. Thanks for all the info you provide, if nothing else I learned a lot!
I have the same problem with mine, I bought 2, one never did any spot weld, and the second did 1 spot weld and burned out a mosfet. Both do the same now, they do the 3 beeps but no weld (I removed the burned mosfet on the second one). No output. I bought a simple pcb spot welder with no screen, and I have no problems with it, it's welding very well and if the battery is underpowered, you just have a weak weld, you don't burn anything. This spot welder is a shit.
I understand your frustration - unfortunately as we have seen the Quality Control of these units leaves much to be desired which is why I decided to do some investigation and videos on the matter. Not everyone accepts the fact that one has to modify or repair it from the start as it should be sold as a "perfectly working unit". On the other hand, it does come from a low cost manufacturing process and it is cheap so based on these premises I never expect a "perfect" product of this kind. I'm sure that with some patience it is possible to repair and get them all working but I also understand not everyone wants to go through the hassle. In this case it is best to pack it back up and send it back for a refund as the various sellers are perfectly aware of the problems. I was able to get a near full refund on the first one which totally died without sending it back.
@@Luca_Techy I agree with you, but with so many different versions available, and with different combinations of MCU and FET boards even if I understand that I'll need to mod it it's hard to know what to mod. However, I have ordered another one, this time the new, smaller one. I'd keep the older non working one but I've got no idea what's wrong with it. It's not the one that needs the extra cap added and I've never used anything other than fully charged Lipo batteries.
@@3rdpig I could help you diagnose the fault you would need a tester and even better a scope. I suspect the gates aren't being driven because of some short probably. You can start by checking every gate pin (pin 1 of every Fet) and see that there is no contact with the minus (no short). Furthermore between every 2 gates the tester should read 60 ohms. Try to check that first and let me know.
Hello, I would like say thank you for your very informative videos which have helped me so much. I own the earlier version of this spot welder that requires the capacitor mod. That mod was the first thing I did when I bought the welder as I thought it would have been sensible to watch some videos before using it. So, I found that video by Fabio (about the capacitor) and the one you made where you strongly suggested using a car or motorcycle battery instead of a LiPO. I bought a MotoBatt MBTZ14S AGM motorcycle battery with a CCA of 190 and that made all the difference. This battery seems to provide just the right amount of current this welder needs. I use the stock cables, at their original length and they don't get hot at all. What gets hot are the probes and even those, not before forty welds or so. I weld 0.12 strips at 10ms and 0.20 strips at 15ms!!! It takes a single weld at 25ms to join two 0.20 strips (one on top of the other) to a 18650 battery. Incredible, a single weld!!! The welds themselves are perfect, no sign of overheating and they also look nice since I followed your advice to round the tips of the probes! I have more to say but this message got too long, thank you so much!
Glad to hear!
I've watched many of your videos and they're very interesting. I have 2 of these spot welders and have not used the yet (lost one in the house and bought another!! LOL). I need to take them apart and do the upgrades you mention. At time stamp 12:25 you mentioned not to use the "switch" and just solder it over. Is it the power on - off switch your talking about? If so, why? Thank you for your videos.
Hi Andy, yes it's the power switch and I suggest bridging it as I have seen many flaky ones where just tapping on them would reset the MCU and this isn't good during a weld. As you need it on anyhow when using the welder it's safer to UNPLUG it rather than remove power from the mcu - so the switch is really unnecessary in my opinion. Also a good clean of the pin contacts and strip socket is a good thing as this too is not always making good contact.
Luca, Can you recommend a charger for the 3S LIPO battery. Can I use those cheap 3S BMS boards to charge?
That depends on the quality of the BMS board - if you have used them or know it's a reliable product and does properly cutoff at full cell voltage it's possible but I would really suggest getting a proper LiPo charger (there are many in the 60-80$ price range working from car battery or mains) with built in balancer.
Thank you for your review and recomendation.I just buy this spotwelder
& i want to make my own diy lithium 3s battery pack to provide
enough power to this welder,i will use 21700-40t they are bigger and
powerful than 18650.this exact battery have 40amp discharge i think,i
will use 15 of them,5x3 for 3s bms i think it will have enough power to
weld,My problem and quwstion for you what kind of bms it will be
powerfull enough to provide enough peak amps for welding?
i see on ebay alot of different 3s bms but neither say max peak power just charging and discharging current.
can you tell my what ind of bms is in your battery pack?
Hi Kris, I think you would be best getting a small 3S 5000mAh LiPo pack for this welder. Creating an array of 21700 is a bit of an overkill in size and price (considering you want to slap a BMS on it too). LiPos are more suited for "violent brief discharges" which they can handle easily (similar to 12V AGM car batteries). The 21700 40T yields a constant 35Amps discharge rate, but that's an upper limit scenario and there is no "peak current" spec - they just don't like it and is damaging on the long run. Weld currents easily exceed 250Amp (can reach over 400A). You would need a minimum of 6 up to 8P with a 3S configuration to preserve the cells from those overcurrent peaks and to get the to yield it and then you wouldn't really utilize the capacity in time (24Ah to 32Ah). 18 to 24 cells plus a capable BMS is rather a lot of money invested for a sheap spotwelder, unless you need the pack for other things better stick with a "cheaper" 3S 5000mAH 50C LiPo in my opinion!
@@Luca_Techy thank you for your advice,ivwill try with your recomendation..i got this 21700 cells for fre 100 of them,what if i put supercapacitor i have one laying on the shell 16v 2farrad in prallel with this cellls?
Sure, you can add a supercap (2Farads aren't much but will certainly help with the peak), preferably positioned near the welder to avoid the wire/resistive losses. Keep in mind that the welder setup has been "tuned" for the provided wire lengths and a 3S or 12V AGM battery. Shortening or lengthening wires can have adverse effects - always start from a short weld (5ms) and ramp up from there.
bonjour Luca et merci pour ton travail. Est-ce que le bj07-1k fonctionne sans risque avec une batterie de voiture de 12v 70ah 700a? y'a t'il un risque d'endommager le boitier?
Bonsoir Jeremy, la batterie c'est bon mais (fait le premier tests avec 5ms pour partir) vous devez appliquer le 2 mods, changer la resistance R4 de 1K avec une de 470 Ohm sur le MCU (R4) et la resistance de 20-50Ohm avec le diode M7 (series) avant le cap de 10000uF. Regardez comme fair ici: th-cam.com/video/1ZCbLdymJIs/w-d-xo.html
Hi, thank oyu for perfect reviews, just connecting of 4S battery is possible (or what can be problem?)? Can be this controller used for DIY design with twice more MOSfets (same types) or will be there necessary any modification?? Thank you very much!
Theoretically a 4S is the limit but I don't suggest using such a setup. Adding more FETs to the current design is not really viable and I do not suggest it unless you are willing to completely modify the driver circuit but you would need to modify the PCB for the additional FETs, at that point building one from scratch is the better solution. Please check out my latest video "All Mini Spot Welder versions" for more details.
Nice product, incidentally the weld is known as a "nugget" the strength of the weld is the circumference of the nugget, I used to design 150KVA DC spot welders, the weld splashes when the vapour pressure exceeds the contact pressure,
Those must have been big!
I really like your videos since i ordered this unit recently, only problem is when will it arrive, i have some stuff that has not arrived in two months and aliexpress refuses dispute requests
That's strange as all my disputes due to either defective or never received material was completely refunded - maybe you need to supply further information to their requests on the reasons and wait for the "order to expire".
could you check the strip you used in a video, as far as i know laptops mostly use 0.1mm nickel.
About aliexpress, dont think they want to scam me, but they just couldnt care less about shipping speed, and its somewhat understandable they dont want to return money if item is going to arrive, they should change estimated delivery time tho and not use fake tracking info as evidence. Im getting packages between 40 and 80 days lately and thats honestly unacceptable.
Check my latest video - I show the strips used. They are .15mm btw, some packs even use .20 - it really depends on the manufacturer specs.
First I want to thank you for your contribution to the community. Before your videos, I didn't realize that there are several versions of these mini spot welders. I ordered one and I am waiting now what will come, I hope it will be first-generation, but if it not just need to resolder the resistor correct?
Regarding power supply what do you think about Telwin drive 13000? If this car jump-started can start the truck engine, it should be capable of power this spot welder also .....
Thank you once more for your work and time for the community and I hopes you will have a lot of views just to earn some money you deserve it ;)
When you receive it just open it up and check the version. If it's a BL18/20 or latter and has the same layout as the ones I describe here then all you need is to swap out the R4 resistor with a 470-560Ohms one before using it. Regarding the use of power supplies, don't use them for spot welding. If you are referring to that portable Jump Starter, then it has an internal Lipo battery so yes you can use it though it also has some protection circuit in series with the starter cables which may trip if welding so keep that in mind. You're probably better off using a normal 45Ah car battery or 3S 4000mAh 50C upwards pack which are common and not so expensive (I linked the one I bought in my prior video and is the one I am using for these tests).
@@Luca_Techy Thank you for replying. We will see what is the version when it comes to me :) will keep you posted, maybe I am going to get some third version who knows. Regarding power supply, it is a little bit tricky to get a battery in my country and since I have this telwin per specification it is more powerful than a lipo battery. 12AH capacity, start power 450A, peek 1500A max duration is 3 sec (www.telwin.com/en/prodotti/index.html?id=829566&lingua=E) If I able to get your battery recommendation from hobby, I will order. I trust your recommendations because I like how you in detail everything check and test.
@@tarikdolovac4354 Try with the Telwin, it will probably do fine. Be *sure* to have a good connection with the spot welder cables, the connection must be securely connected to the power source.
@@Luca_Techy
hi,
I got mine mini spot wleder it is BL18-2k version. I change R4 on MCU with 470ohm and flip the diode and add in series 15ohm rezistor. I enforced trace for welding and everything that you say in your videos. The sport welder wont work. I looked several time all the videos but could not find this issue. I mean it turn on with all correct bip signals and load into manual weld mode. When i put into automatic and try to weld I can hear sound bip, display get dim for a moment, voltage battery on display drop from 12.5 to 12.4 and back, but there is no a spark. I check resistors for mosfet they are all good and have a connection. Output voltage on tips is allways presented it is 11.55v immediate when i turn on welder, voltage on gate single tranzistor (lower right) is 12V, gate voltage on secound (upper right tranzistor is also 12v).
I am not sure what else can I check and why this is not working. I have feeling that everything is working until the mosfets need to be closed to push current and weld it.....
Did you have those kind of the issue ?
Thank you for your time and reply!!!
@@tarikdolovac4354 It appears your FET gates aren't being driven: can you check that R4 is making proper contact? Check that from pin 19 of the MCU to pin 4 of the connector (trigger output of MCU after R4) you see the resistance value of 470 Ohms. Check that the connector is making proper contact (i used some deoxidizer as my pins weren't making always good contact - apparently there was some sort of residue on the pins). If you have a scope, check the trace on pin 4 of the connector and any Gate pin - something is not right. P.S. it is normal to detect 12V on the contacts as this is the voltage used for the autotrigger circuit - it's a trace voltage just for the contact detection between +Bat and Drain pad going to the detector voltage divider.
I"ve received my replacement unit : revision CA04 2K, seems identical to the BL01 2K i have, without tin reinforced tracks though
Remember to swap R04 for a 470-560Ohm (if the MCU board is of the same layout which I believe it is).
@@Luca_Techy First thing i did. it behaves exactly like the BL01 2K, does not memorize settings and appears to work fine (i've reflowed everything). I'd suggest using a pedal for additional security, at least it will not retrigger if the probes are stuck a bit
@@meanxmeanx1763 Yes I also have a pedal which I prefer using more because I can touch the contact points and properly position ans weld when ready not time based. It shouldn't retrigger if u don't remove contacts first.
Just order a Bj07-1k. I would like to know how to mod it?
The BJ07 should be the so called "WISE MAPLE" which just needs the addition of an inrush current limiter resistor to protect the diode in series with the cap. The mod is explained in detail also in my other latter videos (check the playlist).
@@Luca_Techy thanks
Great information Luca, did the video finish short? If you were buying your 1st mini spot welder, which one would you buy? PS I have many 3s 3200mah lipos a 5s 1800mah & one 5s 16000mah ! I also have 12 - 24v 1200w DC PSU :)
I'd buy the BL18-2K or later versions; nothing beats the price (approx 20 Euros delivered) and versatility. Granted there are others like the BIFRC and similar single PCB spot welders which work but they have limited settings (4 or 5 "power" aka time settings) which give you in my opinion limited flexibilty in fine tuning your welds (you're either over powered or under powered). I just like the ability to find that sweet spot with my battery and strip setup and get that decent weld "spot on" (pun intended). I don't suggest you use any kind of PSU with the spot welder - you need "pulse" power - you can get away with it if you parallel a large 500F capacitor bank placing it near the spot welder but that is costly. Better use a traditional 12V 45Amp AGM battery or 3S 4000 mAh 50C Lipo - your 3200mAh may work if it is at least 50-60C fully charged. "Remember it's not the voltage but the current that matters here" is my motto. Fully charging a pack lowers the relative internal resistance - that's why you need a fully charged pack - not because of the higher voltage, but because of the lower internal resistance.
Thanks Luca, as the bj7-1k is newer and appeared to work without mods as long as it had a decent mah & c rated lipo. Is it the better buy?
If you don't want to touch anything on the board (ex. swap R4) then probably yes, though keep in mind you are limited to 30ms max weld time (though it's more than enough if you use a decent battery and you have the option of shortening the cables to get more "punch").
Hello..will it work if i connect 2 or more standard ups battery in parallel? Will it fried the mosfet with those battery setup? Mine just arrived and i just wanted to make sure before start using it.. your reply really help here..
It *all* depends on the batteries: if they are AGM and at *least* 18Ah you may put 2 in parallel with decent 8-10AWG cables. The batteries have to be in good working order and fully charged. *Do not use GEL acid batteries*. Note: before you even start using it check your version and if BL18 or similar swap the R4 1K resistor on the MCU for a 470-560Ohm one. It's explained in m prior videos (version info and resistor location).
@@Luca_Techy Thank you..i will check out your videos and follow the step. Will update on that 👍
@@Luca_Techy Just check mine and no lebel whatsoever. So i couldn't tell which version is mine. For capacitor mod, can i use different capacitor voltage 25v-35v? because i have few laying around. Wonder if it work.
@@azimzain1211 1000uF 25V will do fine, also a 470uF 25V
@@Luca_Techy thank you so much for your help. Subscribed!!
Lipos are a little scary. I'm actually using a 2s 7.4 with mine and it works just fine. I know the welder says 9-12v but these lipos are so strong that 7.4 works and it's not as scary. Plus when you are working towards the bottom end of what works and you have the 0-99 set over 80 you actually have more range of control since it doesn't jump from welding to blowing holes in strips so quickly. Less scary, more control. I like it.
I also tried a 3s lipo but I ordered the little 1500mah by mistake and even though I bought the 120c version it just wasn't welding as nice as the 5200mah 2s. Now that I've seen your xt60 connectors in parallel trick I'll give that a shot too, you know...for science and shit.
As I often say, it's the current that matters not the voltage in this case: if you have even just ONE cell but an incredible low internal resistance (lower than 1milliohm) then you will get great welds. Granted that you need thick copper braid cables and good connections and short, but it works. 2 Cells are fine, as long as they have a low internal resistance (the discharge C capacity is inverseley proportional to the internal resistance, the higher 'C' the lower the milliOhms, it's all about this factor). I was curious to see how this mini spot welder performed with a recent, medium rated C (50) 3S LiPo battery (I even shortened the cables) and objectively it's rather overkill for the setup. I also prefer 12V AGMs batteries, basically safer in case of any "disaster" respect to LiPos. Parelleling works as long as you are using identical batteries, otherwise the weakest one will not do much as it "craps out" as soon as it's loaded so the other pack will do all the work.
@@Luca_Techy The batteries came together so I'm guessing they will play nice together. I did use one to do some welds briefly but I wasn't impressed so very briefly. I think I'll go make myself a splitter cable and then see if I burn my house down or not. The things we do for science.
@@zentechnician Try to solder the connectors directly on each other without any wires, keeps the losses to a minimum.
Has anyone tried using a Li po jump starter to power these spot welders?
Yes you can use them as long as the power cable connections with the spot welder are solid / screwed on (they are made with 3S 5000mAh+ Lipo packs). Using the spring loaded connectors with just the welder power cable stripped wires is not a good enough connection so keep this in mind.
I cut the jump starter cables about 50mm from the ec5 connector and either solder them onto the welder or fit the u shaped connectors so they can be screwed onto the welder.
First and Foremost. Thank you for all these incredibly in depth and informative videos.
Have you considered doing some tests with a super capacitor bank? I have a 200F 13.5v capacitor bank I made of 2 series banks of 5 2.7V 500F super capacitors in parallel. That seems like it would be the ideal solution. Any thoughts?
Though it is possible and others have used Cap banks in parallel with their batteries you may overdrive the device: it works best with a "normal" 40Ah AGM battery or good 50C 5000mAh 3S Lipo and eventually you can shorten the power wires by half to get more current peak once you see how it performs with your setup. If you do add a 500F cap bank be sure to keep those leads as long as they are before shortening them as the drop on the leads is important to limit the peak current. The whole design is goog up to .15mm strips (better .12) not more else you risk. It's not that 5 FETs can't handle the current, it's simply that these FETs are not ideally matched and the driver circuit is not that adeguately designed so pushing it too far will cause it to fail as there is no over current control and the FETs may not be properly matched which means one will be usually taking all the peak current (and will fail first). Keep all this in mind.
It won't weld 0.2mm nickel stripes. So upgrades to a stronger welder.
Hi Lance, in fact it's not designed to weld .2mm as there is too much drop on the cables (I just did it for testing purposes), it can do .15mm if you have a good enough battery but usually .12mm will be the best thickness on average.
you could try buying copper instead of using the stock wires.
oxygen free copper witch is very high quality and expensive used in car audio may work better
All depends how much money and time are you willing to waste. NOTME. Battery solenoid timer. NO MORE DRAMA
I've come to the conclusion. CARBATTERIES are the answer get a timer $5. These things are all shit