Easy DIY 12V 220CCA 340CA Car Battery 18650 Tab Spot Welder (#4th Build)

Here is the 4th Battery Tab welder I have created to date. The Pro Tip for this Instructable is how to build a Cheap and Effective Battery Tab Welder for under $30.(minus the fancy Fence)This can be built for under 40$ easily. This one I decided to do with a 12V 220CCA 340CA Battery. This has also ended up to be my 2nd favourite one of the 7. The welds it produces has a slight burn and the tabs are almost perfect when done. Hardly a sound when it fires. It is also one of the simplest to build. Can be done with 2 x 7ah UPS batteries, or Car Battery ranging from 200cca to 400cca. I was inspired by a Youtuber by the name of darkkevind (welder) and Amelia Records (schematics)

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Wasn't really to much to this build, and the parts list is very small. I like to lay out all parts, just to make sure there is no defects. I also like to test for functionality here too. Here is the very small Parts list. Please let me know if you need any links.

Duralast 12V Lawn&Garden 220CCA 340CA Battery(I traded in a few lead bad lead acid batteries for store credit and got next to nothing)

Starter Relay Solenoid Fits TRX500 FOURTRAX FOREMAN RUBICON 2001-2011 M RL34
30V Blue LED Voltmeter Display

TOGGLE SWITCH SPST ON ON MINI TOGGLE 6A/125V 3Pin MTS-102 EC-2510

6 Gauge Solid Bare Copper Wire

2 Gauge Battery Cable from the local hardware store(salvage bin)

Red Cap SPST Momentary Mini Push Button Switch (Normally Open)

Mini DC 3.3-30V 2 wire Voltmeter Blue LED

16 AWG Black and Red Silicone Wire

Kester Solder 24-6040-0027 60/40 Stand 0.031

Kester 951 & 186 Liquid Flux

Mis. Shrink Tubing Sleeves

M5 Bolts and Nuts set Mis from the local Hardware Store

Screw Terminal Barrier Connector Electrical Wire Connection 12Position Barrier Terminal Strip Block 10A—100A

Mis screws salvaged from other projects.

Gorilla Adhesive Glue from the local Hardware Store

This is probably the hardest part of the build and it took the longest. I am sure there are other ways of doing this(more efficient). But I like to use Gorilla Contact Adhesive. I decided after watching other Battery Tab welders, that I wanted to build a wall to protect the lead-acid battery. This is not a requirement to get this working. Just some added protection. In the process of building, I also decided to add a fence and a button holder. Later I decided to add the through bolt and wingnuts with an extra fence to hold the batteries stationary during the welding process. Basically, as I built the frame, I created as I built. I later decide to add the Voltmeter to keep track of the battery voltage. I decided because the frame was clear, I would not cut a hole for the voltmeter(to protect it from any sparks). I added a small monetary button, so I could turn on the voltmeter when needed. Most of the rest of this build was just me glueing the frame. Unfortunately, when you use Gorilla Adhesive, it can take up to 24 hours to build. But, in the rare case you have any squeeze-out, you can easily clean it up with your fingernail.

This again was so simple, I did not write up a schematic. I just tined and solder all wiring I plan on using to get it ready, along with the Selenoid.(also in the picture you will see a Cap timing board, I will leave out because it is a fail. I will explain later). The simple wiring goes like this. The Selenoid needs a Positive and negative signal to get it to engage. You want to place the Monetary button on the Postive side(solenoid) to interrupt the charge. I used a Normally Open Monetary button for this. So when you press the button, it will engage the solenoid. You would connect one side (green wire) to one side of the button. The other side of the button will go to the Positive wire (solenoid"green wire"). The other wire (yellow) will go to the Negative wire(solenoid). There is also 2 bolt terminals on the top of the Selenoid. This is where the Postive power is interrupted to your electrodes. I used a small U-shaped piece of metal I found. One side I connected to the Postive side(battery) and the other, to one side of the solenoid. The opposite side of the solenoid, the terminal would connect to your 2-8 gauge wire going to your electrodes. I used a small terminal clamp to combined the wire to the solenoid. It is Pretty simple and self-explanatory once you understand how the solenoid works. On the Negative side of the battery, I just used another terminal clamp to connect the 2-8 gauge wire going to your electrodes.If you look up the video by" darkkevind" called "DIY Battery Spot Welder - Update & Demonstration". He has a follower that actually made a great Schematic.

The power to the solenoid and Monetary button, I used a small wire with block terminal from the batteries Positive and negative side. This also allowed me to run the wiring from the voltmeter to the same block terminals i used with the solenoid. I may write up a quick simple schematic/pictorial if I get any request and add it later.

On the electrodes, I used the biggest Block Terminals I had and placed the other end of my 2 gauge in it. This also helps keep the 2 leads isolated from each other. For Electroid, I just used some 10/12 gauge solid copper I had laying around. I have seen other use Copper Nails with the tops cut off. Later I decided to add a small piece of the plexiglass and a smaller block terminal(casing only) to hold everything stationary. Used zip ties to hold that to the electrodes. This also helped with the electrode spacing.

The voltmeter is 2 wire. I just connected directly to the negative side with the black wire. Then on the positive side, I interrupted the wire with the monetary button. both wires connected to the Block connector.

Major Fail explained-The Circuit you see on the top of the unit works very well. Unforatntly it will not work with this type of setup. The cap welder you will see in this instructable, I used in a video on Youtube( DIY Quick & Simple Capacitor Timer). Because of the way you have to press the monetary button super quick. Any time a DIYer who made one of these and tried to add a timer, had issues with burn through on the weld.I am sure someone out there found a way, I personally tried just about everything. I ended up leaving the circuit there to use as a fail-safe for my momentary button. Most of the batteries energy will flow through the relay instead of my momentary button. For me, this was a fail.

Second Fail-Because of the way you have to press the monetary button super quick. The smaller Monetary button did not work for this design. I later added a much bigger button. I decided to use one that had a blue led ring. The led is not connected, but the switch part of this helps when hitting the button super fast. The switch allows for more pressure when pressing.

After I had everything wired up. I decided it was time to test. Using the bigger Battery in the beginning of the pictures and video. I personally found a little strong. No matter what I did, it would leave burn marks or blow a hole through the nickel strip. I just barely picked up the battery brand new, and I decided I could just return and swap for a smaller one. This time I went with the 220CCA or 340CA Lawn & Garden Battery. Once I added that battery, I could tell a major difference in the power. I no longer had to hit the switch super quick. I still had to be quick with the button, but a little slower. The welds look more professional and I never got any burns or blowouts. I did not create a video of me testing. I plan on making a video a little later, once I catch up, that shows each welder in action and compares the welds based on the type of DIY welder. But I did grab a few quick picks.(the blow out in the picture tab, was because I did not have the nickel strip close to the battery. Compared to my Capacitor Welder, this comes in at #2 in welds and easy use. The fence is super nice to have when holding the batteries straight during welds. I can not complain one bit and I really like the fact I can flip the switch and go(I later added a power switch on the Monetary button wire for safety. Great addition to the 7 I have built so far.

I made this welder more complicated than it should be. I have seen these built with just the solenoid and momentary button. Those welders also used from 8 gauge to 2 gauge wire for the welds. I just added the extra when I found I had extra glass left over from a previous project. Please let me know if you make one of these! I would love to see the welder you make from something so simple.(i still have 2 more to make. One with 2 x 7ah UPS Batteries and one from 350F SuperCaps)

Tip: When welding like any other DIY welder. Pressure on the electrode is everything. To much pressure and you don't get a weld that can hold. Not enough pressure and you get sparks with blowouts. You have to find the happy middle when applying pressure before welds. It is like this on all of my welders.

With this welder, you also have to learn to press the momentary button quickly and release. 220CCA is still pretty strong and done wrong can destroy a battery and may cause damages to property and self. Make sure to protect yourself when welding.

Please let me know if you have any questions. I normally answer back pretty quick. Thanks for reading my instructable and don't forget to vote. If you watch my video, please like subscribe and share. Currently in the middle of a small PowerWall that is taking me forever to build. But I have other Instructables I will release soon!