What you get:
- A prebuilt kit of the spot welder V3.3 with all the electronics already soldered to the pcbs.
- 4 M3x25 screws with nuts to screw the two pcbs together sturdy if you like. (They also stay together without the screws installed)
- about 30cm thin wire to connect 12V to the Spot welder PCB
- 2 pin connector with 25cm cable to connect a foot switch
- 2 M6x10 screws with nuts to mount the welding cable or XT90 adapter
- The Arduino Nano is programmed with the latest version of the spot welder software.
- All kits are assembled and tested at our shop in germany
- you need to order accessories like welding cables, battery terminals etc. extra
Please read the Quick Start Guide before using the Spot Welder !
Minimum Setup to start welding:
- Prebuilt Kit
- Welding Cables: 2 about 50cm long, high flexible 10mm² welding wires with solid copper welding tips and crimped cable shoes.
- Car Battery (recommended 12V 400…600 CCA)
- Battery Terminals
Additional parts that can be added:
- Foot Switch: to activate the welding pulse manually if you dont want to use the AutoPulse feature.
- ANL 300A Fuse: to protect the Spot Welder in case of a failure
- Case Kits (Fuse Case, Spot Welder Case)
- Extension Cable: needed for the fuse case
- XT90 adapter: if a Lipo battery is used to power the Spot Welder
The new V3.2 of the prebuilt kit can be finished without soldering required. In case you want to do modifications/improvements to the Spot Welder you can find all pcb files, part list, Arduino code… at my Github page. More detailed information can also be found at the instructables and in the video.
What is it?
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 (max. 800 CCA)
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)
The menu and OLED display features:
In the menu and system menu you can change all imortant settings. See the Quick Start Guide for detailed information.
Improvements in V3.3.2 Software:
- Weld time can be set down to 1ms (before minimum was 3ms)
- Short Pulse (preheat pulse) percentage can be adjusted down to 0% (0% turns the short pulse off)
- on weld times below 3ms the short pulse (preheat pulse) will be automatically disabled
- battery voltage only updates about every 15 seconds now
- low battery message can be canceled by clicking the rotary encoder
Improvements in V3.3 Mosfet Board:
- Much wider traces on the bottom of the pcb for the high current connection to the u-shaped aluminum part
- Mosfet gate resistors directly on the mosfet board, very close to the mosfet gate pins
- All 8 Pins of the female 8 pin header that connects the Arduino and mosfet board are now connected to each other, which eliminates contact problems.
Improvements in the V3.3:
- Arduino software update that improves the AutoPulse feature with a progress bar
Improvements in the V3.2.3:
- Arduino software update, so the weld counter automatically is reset to zero when reaching 9999 welds. This was necessary due to display problems when displaying 10.000 welds.
Improvements in the V3.2.2:
- Arduino software update that removed software reset function. This makes it possible to use the standard Arduino Nano bootloader instead of the optiboot bootloader which makes it much easier for the user to do software updates in the future.
Improvements in the V3.2.1:
- Arduino software update that enables the measurement of pulse voltage and pulse current
Improvements in the V3.2:
- the Arduino Board was updated so it does now come with a terminal block installed to the 12V and GND input pads. This way the prebuilt kits can be finished without soldering.
- 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.
Improvements in the V3.1:
- 4 SMD TVS diodes in parallell on the Mosfet PCB
- with the 4 diodes installed it is possible to use car batteries up to 800CCA
Improvements in the 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
- “AutoPulse” feature, which automatically activates a pulse after a defined delay time when both welding tips touch the nickel strip (thanks to Petr Zverina for the idea)
- 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)
- Standby feature: after 5 minutes of inactivity the Spot Welder will go to standby and the foot switch and AutoPulse will be deactivated while in standby.
- u-shaped aluminum parts is now riveted to the pcb
Customer Batteries built with the “DIY Arduino Battery Spot Welder”
Video on how to use it:
(Assembly starts at 0:48)