Introduction: Mini DIY 18650 Spot Welder

About: I mainly take on projects I have seen here and put my own twist on them. I also like to take garbage or thrown out electronics and make something nice from them. I have no certain area of Expertise, I am new a…

I have noticed on the Facebook groups and watching other videos, DIYers asking if these welders are worth the small price. Then I was surfing amazon the other day and I noticed these were local in the states. So I purchased 5 of them and decided I would do a build video and then a test. If all goes as planned, I plan to give them away on Youtube. You would need to visit the video and like it, share it, subscribe to that channel, and comment. Then after I am done with this series I plan to give them away. This was the most expensive and hardest to put together of the 5, so I started with it.

This build wouldn't have been possible without the partnership of JLCPCB. One of the cheapest Largest Manufacturers in China! Get your 2$ PCB at JLCPCB here-


Mini DIY 18650 Spot Welder Turn Nickel Machine Control Board Lithium Battery Spot Welder(Need to assemble-

Step 1: Inspect the DIY Spot Welder for Defects and Missing Parts

Like most projects, you want to inspect and make sure you have everything, and it of good quality. The only problem I actually had, there was one screw missing (I had spares) and the leads were 2 small solid copper 2mm wires pieces(Spot welding leads was advertised). Luckily I had a spare of spot welding leads to use. I also noticed for a 700amp welder, it only had 40amp lugs. Even the advertised Video he used 50. I decided I wouldn't use these lugs and add an xt90 instead. The overall quality of the board was great, but this must have been an upgraded version or an older version as the tracks on the advertised board was different on the positive side. Not really an issue, but it was a surprise. No instructions came with the unit.

Step 2: Position the Spot Welding Leads and Solder to the Board.

I decided I would do one side at a time, so I started with the negative output of the MOSFET side. The hardest part for me was finding something to hold the leads in place while soldering. But once I did, the soldering went pretty easily. Because this board will carry a large amount of energy, it good to add a fair amount of solder the lead and the track. I need up using alligator clamps to hold in place. I tried to do it as it showed in the video the seller-provided, using my heat gun. But later decided, it was not producing like I wanted and went back to my soldering iron set at 380

Step 3: Beef Up the Negative Switched Side Track

In the video that the seller gave the link to, the DIYer used some of his 8 gauge wire to tin and solder to the board along the track. Doing a little research, I found that solid core would work much better. So I used a 2 x 3mm solid piece of copper twisted. I bent it to match the track. I tined the copper wire and the track before combining the 2. Once I had them ready I again used alligator clamps to hold in place. Here it is really important to add a ton of solder and make sure you get no cold joints and you don't cross into another track. The negative switched side is complete!!!

Step 4: Add the Spot Welding Lead to the Positive Track and Tin Both the Negative and Postive

This time I ended up using a clip to hold the welding lead in place before soldering. Once I got the lead soldered, I went and ahead and added solder to the rest of the track. Use as much as you can, because you will be soldering the Positive wire here later. Then repeat, doing the same to the negative track. Make sure you do not cross any tracks when soldering. Be very liberal with the solder here to beef up the tracks.

Step 5: Mesure, Cut and Tin the Negative Wire, Then Solder to the Negative Track

The title basically says it all. Make after you tin the negative wire, you place it as close as you can to the monsters. You will need to run the positive wire next to this and it needs to have the room. Make sure when you solder the wire to the board, be liberal with the solder with no cold joints. Make sure you do not cross any other tracks.

Step 6: Mesure, Cut and Tin the Positive Wire and Solder to the Track

The title again pretty much says it all. Just make sure when you solder the tinned positive to the board, you do not cross any tracks with the wire. Be very liberal with the solder.

Step 7: Solder the 3 Wire to Both Boards Exactly the Same, Then Screw Top and Btm Together

The kit came with a tiny 3 wire used to give the timer power and to control the Mosfets. You will notice they have letters on both. Just make sure you solder the color to the same letter on both sides. Also, you might solder in a way you can tuck the wires inside the to panels when closed. I also pulled out a multimeter and made sure I didn't cross any tracks. Screw the top and bottom together when done.

Step 8: Add and XT90 to the End of the 8 Gauge Silicone Wire

It came with 2 x 40 amp lugs, but I planned to connect this to a lipo battery with the power of 130c 5000mah 3s. So I added and soldered an xt90 female connector. After I tested it by connecting the lipo battery to make sure everything worked.

Step 9: Test on a Battery Using 8mm X .15 Nickel Strip

After I had everything done, I plugged in and tested using Pure Nickel strip. At first, it was blowing holes in the Nickel strip and I thought the battery was too strong. But I went back and watch the sellers video again and realized, you have to sand the soldering leads at an angle. The reason was because of the way you hold these to make a weld. The angle insure you had proper contact. As soon as I did this, I was getting welds easily. So like with most new welders, you have to get used to it. I know the video I watch, the guy was able to do .2 nickel strip using it on the 3rd setting and 2 x 3000F Capacitors. Also, you will find no paperwork on this, to explain how to use. From what research I have found. The buttons are only timer settings. The first one being the fastest, with the 4th being the longest. Each one allowing full contact with the battery. The longer the welds the stronger the spot weld.

Step 10: Thanks for Watching and Reading the Instructable

Overall I am happy with the way this one turned out. I am sure with more usage, I would figure out how to use this more efficiently. Not really sure how long something like this will last. But it was fairly cheap and fairly easy to put together. Make sure if you want a chance to win this welder or any of the others I will be showing. Head over to the Youtube post and comment, like subscribe and share. I plan on giving all 5 away as long as they work correctly. If they are a bust, I will probably trash. But we will give them all a try first. I hope this helps you decide if you want one of these cheaper versions or not.

Thanks again JLCpcb!!!$2 For 5 PCBs & Cheap SMT(2 Coupons):
njfulwider5(Tons of Awesome DIY Projects)- I really appreciate you guys reading and watching my instructable. Make sure to watch the video also!! Don't forget to Subscribe and Share!! Thank you all!!!!