1. This spot welding circuit board is designed for welding 18650/26650/32650 lithium batteries. It's portable, stable, reliable, and durable. 2. Users need to provide their own 12V battery for power. The welding current is approximately 90A~130A, easily welding standard 0.1mm~0.12mm nickel-plated sheets. Ensure your battery can supply over 90A, or welding will not be possible. 3. Battery discharge current directly impacts welding performance. Recommended batteries include: - 20-45Ah lead-acid batteries with good performance and low internal resistance (under 10 milliohms, discharge current over 90A), such as new car batteries. - 35-55Ah model aircraft lithium battery packs around 45C; 30-35Ah capacity packs. 4. Requirements: Spot welding relies on rapid local heating and cooling with high current. Sufficient power supply is crucial. For 0.1-0.15mm nickel-plated sheets, welding current is typically 90-150A, so the circuit board's function must be 150A or greater. 5. Suitable power supply battery packs include: - 12V car jump starters - High-speed model aircraft battery packs - 3-string high-speed lithium battery packs - 40900 3-string battery packs - Lead-acid batteries over 12V 20A with good performance. Calculation formula: Capacity X Discharge Rate = Load Capacity. Example: 4000mAh aeromodel battery with 45C discharge rate (4A x 45C = 180A). User Manual: Function Buttons: 1. Power on the machine. 2. Switch gears. When powered on, it defaults to the first gear. Press and hold the button for 2 seconds to release. Each press increases the gear by one, indicated by the buzzer sounding and the LED flashing the corresponding number of times (e.g., 3 beeps and 3 flashes for 3rd gear). There are 5 gears, with welding intensity gradually increasing from 1 to 5. Press and hold the button again after the 5th gear to power off. In the off state, press and hold to power on, and it will return to the first gear. Color: Black Material: PCB + Plastic + Metal Package Contents: 1 x Circuit Board 4 x Copper Noses 4 x Screws 1 x Buzzer 1 x Nickel Plates 1 x Capacitor 2 x Welding Pencils 2 x Input Cables 2 x Heat Shrinkable Tubes (Other products are not included.) Note: Light and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowed measurement error is +/- 1-3 cm.