NEW Arduino Battery Spot Welder V2

Arduino Battery Spot Welder info can be found here: DIY-Arduino-Battery-Spot-Welder/

Just wanted to thank KaeptnBalu for this great project and all the hard work that went into it. Again Thanks Marc.

New V2 Arduino Spot Welder

SMT Components added and 1 driver

Most of the Assembly is the same for the new Version 2

You can purchase the boards and other items direct from: Malectrics RC and Electronics Development

This is the Old version assembly that follows

This Arduino Spot Welder is for welding Nickel Solder Tabs or Strips on 18650, button cells, Ni-Cd, Ni-MH or etc. batteries, you can make you own size of battery packs. It requires a 12V power supply, also requires a 12V 400amp min. auto battery for welding current supply.

The Arduino Spot Welder generates a double pulse, the first pulse is 1/8 of the time of the second pulse. Second pulse is adjustable by the potentiometer and displayed on the LED display in msec. you can adjust the time from 1 to 20 msec.

Here is the progress that I have made. I had ordered 10 PC boards, made by PCBWay

DSCF1370 - Copy - Copy - Copy

You can support KaeptnBalu by registering through this link: Ordering your PC Boards from PCBWay

First thing is to cut the Printed Circuit Board into 2 sections along the dotted line or in-between the 2 mounting holes, you now have 1 Control Board and 1 Mosfet Board.


Assembly Process on the Control Board

First is to solder the resistors, diode then the capacitors next the IC sockets then the LED display and the green LED.



Next we will need to mount the Arduino Nano to the header strips then solder the whole Arduino Nano c/w header strip to the circuit board.



Next would be to solder the header strips to the bottom of the control board, to do so by mounting the male and female header strips together and then place the 2 boards together and solder the headers on both Control board and Mosfet board.DSCF1406



The next step would be to mount the JIC male header to the top board for the foot switch and also the potentiometer. Now the top board just needs you to install the IC chips and watch for the proper placement.

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Next Step will be the Assembly of the Mosfet board

First we need the Mosfet’s (cut the center pin from the mosfet’s optional). You may notice that I have use 2 different Mosfets. IRFZ44 for display only. Please use IRF1405 they are 169amp 55volt.


Then bend the pins downward check that the mosfet’s will seat on the board with the screw and nut.


Complete the remaining mosfet’s the same way, once done you can solder the pins to the under side of the board.


The Mosfet board is complete!

The next steps below for Making & Mounting the Buss Bars


Copy the Mosfet board from the Eagle files and layout the center of the drawing by extending the lines and mark the position from the end hole, I use the line that the 50 was marked on for center. then cut out on the lines.


Your template should look like this, then glue it to the 3/4 inch brass bar.


Once glued and cut, drill then file to size, it should look as above.

The next step is to cut 7cm (2.75 inch) from a 5/32″ square brass tube x 2 pcs.

You will also need a 3.5cm (1.378 inch) from a 1/2″ brass bar. You will need to drill a hole in the center.

You can get the Brass tubing and bars from any hobby stores in your area.


Next you will need to mount the buss bar to the Mosfets as shown, use hardware that is available to you. In my case 3 mm hardware was used.


Next step will be to mount the buss bars to the bottom


Solder the 5/32 tubes to the bottom of the Mosfet board


Once done then solder the 1/2″ bar to the 5/32″ tubes as shown


The Mosfet board should look like this when completed.

The next step will be the wiring

The wire that I used is a 10 gauge 8AWG speaker wire it’s flexible and easy to work with, I solder the crimp connectors for a better connection. Cut them to the length of 50cm. The power supply wire is a 22 gauge goes to an external power supply, (Don’t use the same battery).


NEW Update: Ebay’s Arduino Nano’s C/W CH340G chips. some sellers claim they have the boot-loader already installed on them (more likely not) but it’s ok, just follow the link below for programing. They will work fine after this procedure.

Be aware of the fake FTDI FT232RL chips this units will not work without replacing the chip with a new one.

Arduino Nano has now been programed, was missing the Boot-Loader follow this link to program the Ebay products with CH340G chips:

Burning a boot-loader to an Arduino Nano using another Arduino



Back to the project



Negative Input: (bottom of the board) is made from a brass buss bar installed as above with 2pcs 5/32″ Square tubes and a 1/2″ X .062 flat brass buss bar across the top front of the tubes.

Negative Output: is made from a brass buss bar 1/16 thk. was formed from a 3/4″ buss bar and filed down to size from the pattern located from the Eagle files.


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The probes were made from soldering iron tips, they are 3 inch long, also have a new probe (shown below) that I have made with a Tactile push button switch, Momentary Tact SMD 2 Pins 3x6x5mm mounted on the probe so that you have control by hand. The foot switch is still another means of control.

DSCF1361 (2) DSCF1363

Next set of probes I will show you the steps of assembly.

A new instruction will be added soon with 8AWG wire and connector

10AWG stranded wire cut to your desired length, 10ga ring terminals 10ga crimp connector and 1/8″ brass bar cut to 3″ long. you will need to solder all the connectors.

10AWG wire is too light and will not handle the current



The next step is to cover the connectors with heat-shrink Red and Black as shown.