Due to many requests for the PCBs
I do currently have some PCB Sets and prebuilt kits in stock. Take a look here:
An Arduino Nano based Spot Welder for battery welding This Spot Welder can be used to weld 18650 batteries. It uses a 12V car battery as welding current supply. Typically one 40Ah 440A battery delivers enough current to get good welds with 0.15mm nickel strips and even 0.25mm nickel strips. For thicker nickel strips maybe you will need bigger battery or two in paralell.
The Welder generates a double pulse, where the first one is 12% of the time of the second one by default. Pulse time of the main pulse is adjustable by the rotary encoder and displayed on the screen in ms so you can exactly adjust the time. Its adjustable from 1 … 100 ms by default. (adjustable up to 500ms in the system menu)
Watch the Video to get detailed instructions on how to use it.
Project Files: (BOM, pcb files, aluminum template, arduino code…)
Update 01.2018 (V3.2)
- the Arduino Board was updated so it is now possible to mount a 3.5mm screw terminal to the input pads.
- the voltage measurement now connects directly to the 12V input pad instead of behind the schottky diode. This guarantuees a more precise voltage measurement.
- the 8 small SMAJ13A-13-F TVS diodes have been removed from the mosfet board. There is now one of these diodes on the Arduino board that protects all mosfet gates at once.
Update 12.2017 (V3.1)
- possibility to solder 4 SMD TVS diodes in parallell on the Mosfet PCB
- enough space to solder 4 through hole TVS diodes instead of SMD diodes if no SMD diodes available
- with 4 diodes installed possible to use with car batteries up to 800CCA
Update 09.2017 (V3)
Completely new version 3 of the Spot Welder released. Improvements in V3:
- Mosfet PCB now with 2oz copper layer and wider traces which connect the high current carrying mosfet legs to the u-shaped aluminum part (still compatible to V2 Arduino Board)
- 7 segment display replaced by OLED display
- potentiometer replaced by rotary encoder
- Menu system to easy adjust the low battery alarm, AutoPulse delay and short pulse time
- powered directly by car battery, no more need for extra power supply
- TVS diode integrated on the mosfet pcb, no external diodes necessary
- upgraded Mosfets to IRFB7430 (they can handle up to 1000A welding current with no problem)
Read more: DIY Arduino Battery Spot Welder