Make Your Own Crude Battery Spot Welder With a Car Battery!

In this project I will be showing you how to create a crude but functional battery spot welder. Its mains power source is a car battery and all of its components combined cost around 90€ which makes this setup pretty low cost. So sit back and learn how to build your own with an Arduino and a few complementary components. Let's get started!

Step 1: Watch the Video!

The video gives you all the information you need to create your own battery spot welder. During the next steps though I will present you some additional information.

Step 2: Buy Your Components!

Here you can find a parts list with example seller (affiliate links):

Aliexpress:

1x Arduino Pro Mini: https://s.click.aliexpress.com/e/_d6fhP2B

1x TC4420 MOSFET Driver: https://s.click.aliexpress.com/e/_dWHntEP

1x IRLZ34N MOSFET: https://s.click.aliexpress.com/e/_dZCKNc7

1x Power Relay: https://s.click.aliexpress.com/e/_dTCAQQL

1x Foot Switch: https://s.click.aliexpress.com/e/_dZMZIZD

1x OLED: https://s.click.aliexpress.com/e/_dV3a0cn

2x Car Battery Terminal Adapter: https://s.click.aliexpress.com/e/_dTR8v4L

1x Fuse Holder + 200A Fuse: https://s.click.aliexpress.com/e/_dX8c2IF

2x Copper Nail: https://s.click.aliexpress.com/e/_d8aMiXl

Ebay:

1x Arduino Pro Mini: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x TC4420 MOSFET Driver: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x IRLZ34N MOSFET: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x Power Relay: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x Foot Switch: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x OLED: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

2x Car Battery Terminal Adapter: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x Fuse Holder + 200A Fuse: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

2x Copper Nail: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

Amazon.de:

1x Arduino Pro Mini: https://amzn.to/2UOZ6uR

1x TC4420 MOSFET Driver: https://amzn.to/2v1ZcAD

1x IRLZ34N MOSFET: https://amzn.to/2X6zcA3

1x Power Relay: -

1x Foot Switch: https://amzn.to/2X9sysK

1x OLED: https://amzn.to/2USIVN0

2x Car Battery Terminal Adapter: https://amzn.to/2KyNZ5d

1x Fuse Holder + 200A Fuse: https://amzn.to/2Xcuwsx

2x Copper Nail: https://amzn.to/2KyPG2z

Step 3: Build the Circuit and Upload the Code!

Here you can find all information about the circuit and the code for the project. Feel free to use it.

Also make sure to download the Adafruit SSD1306 library before uploading the code to the Arduino: https://github.com/adafruit/Adafruit_SSD1306

Step 4: Do the Power Wiring!

You can get all the components for the power wiring in your next home improvement store. Use my provided pictures as a reference.

Step 5: Success!

You did it! You just made your own crude battery spot welder!

Feel free to check out my YouTube channel for more awesome projects:

http://www.youtube.com/user/greatscottlab

You can also follow me on Facebook, Twitter and Google+ for news about upcoming projects and behind the scenes information:

https://twitter.com/GreatScottLab
https://www.facebook.com/greatscottlab

Comments

[sbsiaf]

Hello Great Scott, that was a very interesting project indeed. I was looking at the overkill of using an arduino (pro or mini) in constructing the welder. Can you suggest an alternate coding to replace the arduino with an ATTiny85 ? It should be possible to interface everything using an ATTiny85, or may be an ATTiny13A, if u can cleverly squeeze in the coding within 1k flash of ATTiny13A or may be 4K flash of ATTiny85 ?.
Waiting eagerly for your answer.
Regards

[startyoutub3]

i need a ful schematic plz

i dont undertand this one

[sarduarte]

Thank you, Scott. With your instructions I made my spotwelder and it is working perfectly. It was a big challenge for me but I got it! Great Scott!!

[megabyte512]

Can i use Arduino UNO for this project without any code changes?

[Pbezza]

I would like to use a rotary encoder instead of the potentiometer. Anyone know how to add support to the code for this?

[slowbearro]

Hello Scott,

Why the MOSFET driver? can't we use a simple BJT tranzistor for driving the MOSFET ?

Best regards!

[neric]

can it work on Arduino Nano...how do I have to change the code

[saadland]

yes, absolutely!!
Codes that works on Arduino Pro Mini, works pretty well on Nano!!

[philipjayfry]

hi! i made it too, it works great and i already used it to fix an e-bike battery, thanks for the awesome project, greatscott!(!) it's just the build i have been waiting for.

the only (minor) issue i have with mine is that it mostly powers on in the closed state. it's not a big deal though, to be on the safe side i just connect the relay after powering on the board and pressing the reset button on the arduino. idk if that's even a design weakness. it may very well be an assembly blunder on my part / caused by the fact that i have left out the small ceramic cap on the back and used one different kind of cap / an issue with my chinese knock-off arduino.

speaking of parts, them from aliexpress allowed me to get the price down to just EUR 34, which makes this build even more amazing. also, get yourself a discarded car battery (ideally from a big diesel) from a place that sells new ones. i got mine there for free (thanks varta!) and according to their fancy test tool, it's still good for 600 amps, at least briefly.

regarding the board layout, there is a bit of room for improvement, i wish i had taken a closer look at it in advance instead of going for an exact copy rightaway. it's not a big deal though (just my personal neatness ocd) and i was still able to improve it a little bit as i went along.

anyway, thanks again to greatscott!, i highly recommend this to anyone who needs to connect some 18650s!

[bobbyboblington]

Hi Scott, thanks for the fantastic project and all your electronics basics videos! I’m about 90% finished on this build, can anyone help? I’ve finished all the solder connections but there is a component I can’t identify from the circuit diagram or the photographs. Does anyone know what it is, where it is in the circuit diagram and what its function is? It looks like a tiny rectangle and I think it has been soldered behind the mosfet driver chip. I took some screenshots of what i think i’m looking for. Thanks in advance!

[bobbyboblington]

Okay, think i’ve figured it out. It looks like capacitor C1 (10uf).

[due204]

Hola y ante todo muy buen proyecto.
Tuve que modificar la la siguiente linea:
timems = map(analogRead(A0), 0, 1023, 0, 100);
por esta:
timems = map(analogRead(A0), 0, 1023, 1, 100);
Ya que al poner en 0ms el disparo ascendía a 1s y eso era mucho tiempo.
Saludos.

[moshes12]

when will may she product