George S.
Well-Known Member
You Tube Creates Clarity and Chaos
Last September, I bought a Chinese spot welder for $25. I went through Amazon thinking there is more protection if something went wrong. The welder took 3 weeks to show up and burned up in the first five minutes. I filed a claim, or whatever, with Amazon. The seller asked for some pictures so I sent what he wanted. He promised to send a new welder and I said I would try it and if it failed, that would be the end of the thing. I said I had bought a lot of Chinese gadgets and they seemed to get better over time. I hoped this might be the case.
I don’t know what went wrong but I started looking at YouTube reviews of this welder. Adam Welch, a reasonable guy, bought one and it failed about as quickly as mine. He’s popular, so people sent him links to a repair. The repair was relatively simple, adding a big capacitor to the circuit. He did the repair and also replaced the Mosfets, a more delicate and expensive repair. But his welder worked.
I held on to the replacement welder and watched the YouTube videos. I finally decided that the instructions had doomed my welder. They said use a certain size battery but my SLA battery was old so the capacity was wrong. The repair videos made it clear that if the voltage drops, the device becomes a semiconductor toaster. The capacitor you insert keeps the voltage up for a tiny fraction of a second. I decided to just use my 130 AH Lifepo4 battery bank, which is 12v as required. There are some ‘gotchas’ with finding a battery. I used a battery with a fuse. The instantaneous current is huge. The fuses blew. I tried a battery pack with a BMS. The BMS went over volt and shut down the current. That pack was unusable for this. I took the fuse off my LFP pack and it worked. I haven’t added the capacitor, on the theory my voltage won’t dip. So I agreed with YT, but speculated that a big LFP pack would not have any real voltage drop, so less need for the caps.
This took 9 months from the order to the first successful weld. I’ve made 5 small packs with this welder. It is very easy to use, if you think about what you need to do. Mostly you need to immobilize the little pieces of zinc that form the circuits. You definitely want to look at videos on how to lay out the strips to make the battery you want.
The problem with You Tube is that now I see hour long videos on how to make a series of repairs to keep this welder going. I suspect my welder will work for a while, and maybe a long while. I hope the repairs that people are working out get incorporated into the welder. But now I notice a newer version of something like my welder. The difference here is that the welder is now a little package like a USB power bank, the kind you use to charge a phone. Inside the small brick is a LiPo battery, the kind used in drones, and a welder like mine. These LiPo packs have huge C rates. They deliver a ton of current, at least for a moment. The addition of this battery solves the voltage-sag-into-oblivion problem. I guess it was a mistake to sell the welder and leave the battery up to the buyer. The instructions were bad. There were a lot of places to go off the track.
At this point, there is a certain sense of the absurd that creeps in. Most spot welders for battery packs use 220 volts and a lot of amps. And yet, somehow, a few select semiconductors do the same thing with a $15 battery. We live in strange times. I want to believe that we are in a spot welder revolution. But I’m not going to mention my welder, and there are several versions. You can find the Adam Welch video and YT will take you to other videos.
The thing is… the world is awash in used cells that work great for ebikes. I’m talking the stuff that is under a buck a cell. You need 52 to make a ‘standard’ 48 volt pack, or go 56 for a 52 volt pack. You see new Chinese cells for a dollar or two. If you buy used you may have to take packs apart. I finally took my four year old Hoverboard packs, tore them apart, and redid them as a 52v/8AH pack. The welder was OK, if not entirely consistent, over a few hundred welds.
A week ago there was a review on Hackaday (this welder). The reviewer burned it up, right out of the box. He got a lot of links in the comments, but basically he said it was junk. I tried going back to the page where I bought my welder, on Amazon. There is a picture of RoRo, one of the dogs of Amazon. Amazon has moved on. I wonder if people have learned the lesson of this welder. I ordered a welder with a Lipo inside over Prime Days. I’ll test it soon.
Last September, I bought a Chinese spot welder for $25. I went through Amazon thinking there is more protection if something went wrong. The welder took 3 weeks to show up and burned up in the first five minutes. I filed a claim, or whatever, with Amazon. The seller asked for some pictures so I sent what he wanted. He promised to send a new welder and I said I would try it and if it failed, that would be the end of the thing. I said I had bought a lot of Chinese gadgets and they seemed to get better over time. I hoped this might be the case.
I don’t know what went wrong but I started looking at YouTube reviews of this welder. Adam Welch, a reasonable guy, bought one and it failed about as quickly as mine. He’s popular, so people sent him links to a repair. The repair was relatively simple, adding a big capacitor to the circuit. He did the repair and also replaced the Mosfets, a more delicate and expensive repair. But his welder worked.
I held on to the replacement welder and watched the YouTube videos. I finally decided that the instructions had doomed my welder. They said use a certain size battery but my SLA battery was old so the capacity was wrong. The repair videos made it clear that if the voltage drops, the device becomes a semiconductor toaster. The capacitor you insert keeps the voltage up for a tiny fraction of a second. I decided to just use my 130 AH Lifepo4 battery bank, which is 12v as required. There are some ‘gotchas’ with finding a battery. I used a battery with a fuse. The instantaneous current is huge. The fuses blew. I tried a battery pack with a BMS. The BMS went over volt and shut down the current. That pack was unusable for this. I took the fuse off my LFP pack and it worked. I haven’t added the capacitor, on the theory my voltage won’t dip. So I agreed with YT, but speculated that a big LFP pack would not have any real voltage drop, so less need for the caps.
This took 9 months from the order to the first successful weld. I’ve made 5 small packs with this welder. It is very easy to use, if you think about what you need to do. Mostly you need to immobilize the little pieces of zinc that form the circuits. You definitely want to look at videos on how to lay out the strips to make the battery you want.
The problem with You Tube is that now I see hour long videos on how to make a series of repairs to keep this welder going. I suspect my welder will work for a while, and maybe a long while. I hope the repairs that people are working out get incorporated into the welder. But now I notice a newer version of something like my welder. The difference here is that the welder is now a little package like a USB power bank, the kind you use to charge a phone. Inside the small brick is a LiPo battery, the kind used in drones, and a welder like mine. These LiPo packs have huge C rates. They deliver a ton of current, at least for a moment. The addition of this battery solves the voltage-sag-into-oblivion problem. I guess it was a mistake to sell the welder and leave the battery up to the buyer. The instructions were bad. There were a lot of places to go off the track.
At this point, there is a certain sense of the absurd that creeps in. Most spot welders for battery packs use 220 volts and a lot of amps. And yet, somehow, a few select semiconductors do the same thing with a $15 battery. We live in strange times. I want to believe that we are in a spot welder revolution. But I’m not going to mention my welder, and there are several versions. You can find the Adam Welch video and YT will take you to other videos.
The thing is… the world is awash in used cells that work great for ebikes. I’m talking the stuff that is under a buck a cell. You need 52 to make a ‘standard’ 48 volt pack, or go 56 for a 52 volt pack. You see new Chinese cells for a dollar or two. If you buy used you may have to take packs apart. I finally took my four year old Hoverboard packs, tore them apart, and redid them as a 52v/8AH pack. The welder was OK, if not entirely consistent, over a few hundred welds.
A week ago there was a review on Hackaday (this welder). The reviewer burned it up, right out of the box. He got a lot of links in the comments, but basically he said it was junk. I tried going back to the page where I bought my welder, on Amazon. There is a picture of RoRo, one of the dogs of Amazon. Amazon has moved on. I wonder if people have learned the lesson of this welder. I ordered a welder with a Lipo inside over Prime Days. I’ll test it soon.
