Spot Welder 199 Level Adjustable Digital Display Portable Spot Welding Machine with Relay for 18650 DIY Item Type: Spot Welder Applicable Batteries: 1. Batteries: You can use a 12V 14AH-100AH battery. And a 14AH battery needs to be fully charged to be securely soldered). 2. Farad Capacitance: The 2.7V 3000F super Farad capacitor can be soldered by charging three super Farad capacitors in series to 8V, the maximum number of Farad capacitors in series does not exceed 4pcs. 3. Car Starting Battery: The output interface for starting the battery must be EC5, and the peak current must be below 1500A. D. Aircraft Model Battery: Please use XT60 interface, 3S-4S 3000mAh model aircraft battery, discharge rate below 60C.